INTRODUCTIONThe requirements for producing a satisfactory replica model or die for indirect

crowns, fixed partial dentures, or inlay procedures must include reproduction of sub-gingivally

prepared margins. The methods and techniques for attaining this goal have varied greatly. Each

technique has advantages and disadvantages and should be judged on its own merits. After trial and

error with a number of methods, materials, and instruments and after slight modification of existing

materials and techniques, the author has arrived at a simple adaptation of procedure which satisfies

the requirements.

Impression materials may be classified in two categories: (1) materials which displace the

free gingival and register subgingivally prepared margins and (2) those which do not displace the

gingiva.

A great number of materials, instruments, and chemicals are available to displace the

gingival tissue. Among these are a heavy rubber dam, cotton threads and fibers, electrosurgical

instruments, and cords saturated with various chemicals such as epinephrine, alum solution,

aluminum chloride solution, Monsel’s solution (ferric subsulfate), tannic acid, zinc chloride,

levoepinephrine, potassium alum, and others. The criteria which should be used in evaluating these

various modes follow:

1. A trough or space must be crated which makes the subgingivally prepared margins both accessible

and visible.

2. The through or space must be wide enough to accommodate elastic impression material of

sufficient thickness and strength so that it cannot be torn during the removal of the finished

impression. The material must have bulk such that it is rigid enough to resist distortion when poured

with a gypsum die material.

3. The trough or space must be free of blood and tissue fluids and must remaindry for a time

sufficient for placement and set (or gel) of the elastic impression materials.

4. There must be minimum tissue damage resulting from the gingival displacement procedure, as well

as minimum tissue damage resulting from the preparation of the subgingival margins.

5. The tissues must recover within a reasonable period of time.

6. The resulting tissue contours must be predictable.

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7. The general systemic effect must be minimal and certainly must be tolerable to the individual

patient.

The trough or space is created by converting the gingival sulcus from a potential space to a

real space. Cords saturated with vasoconstrictive drugs provide the greatest possible benefits. It is

also important that the thickness of the cord be the maximum allowable by the anatomic situation and

that the cord be soft and loosely twisted.

Vasoconstrictors can be supplemented by astringent drugs to reduce the fluid content of the

displaced tissue, thus giving an even wider trough. Once displaced and affected by vasoconstrictive

and astringent drugs, the tissue is quite flaccid and must be supported in an open position by a small-

diameter cord placed at the depth of the sulcus. There is no purpose in using a drug-saturated cord

here. This cord simply “props” the tissue away from the tooth structure. Our greatest success has

been achieved by using cotton button thread.

There can be several reasons for occurrence of bleeding and tissue fluid in the sulcus. The

first, of course, is existence of periodontal inflammation. This is managed by: (1) treating

periodontal disease before attempting restorative procedures (2) arranging the appointment schedule

so that the patient has a thorough prophylaxis about 1 week prior to the tooth preparation

appointment and (3) teaching all patients, particularly those who will undergo restorative procedures,

basic plaque-control techniques.

Another common cause of bleeding in the sulcus is rough placement of retraction materials.

These cords must be gently rolled into the sulcus with a fine tapered instrument which can be

controlled and which will control the cord. The blunt or flat instruments designed for this purpose

are inadequate. The Hollenbach NO.3 carver is far more suitable. Its tapered design affords optimal

visibility, it can be manipulated with ease on all surfaces of the tooth, and its point will control and

roll the cord exactly as the dentistchoose.

Abrasion of the sulcular epithelium accounts for the greatest amount of tissue bleeding.

Under ordinary circumstances, the epithelial lining of the gingival is in contact with the tooth

structure which must be removed to establish a subgingival margin. It is too much to expect the

dentist to remove this tooth structure without lacerating, nicking, abrading, or irritating the sulcular

epithelium, regardless of whether a high-speed, low speed, diamond stone, carbide bur, or hand

instrument is employed.

Exposing the gingival margin of a preparation prior to making an impression may be one of

the most difficult procedures for the dentist to perform. The difficult of the procedure is further

complicated by variations in sulcular depth, distendability of the gingival tissues, degree of gingival

inflammation, level of margin placement, and tissue laceration. To obtain consistent predictable

results, the dentist must alter the armamentarium and technique to meet the specific clinical demand.

Acceptable criteria for gingival deflection procedures have been described. Basically and technique

used should (1) create sufficient lateral and vertical space between the gingival finish line and the

gingival tissue to allow the margin of the prepared tooth to be recorded in an impression medium; (2)

provide absolute control of gingival fluid seepage and hemorrhage, especially when elastomeric

2

impression materials are used; (3) not cause significant irreversible soft or hard tissue damage; and

(4) not produce any potentially dangerous systemic effects.

One of the prime requisites to successful tissue management is to begin the restorative procedure only

after the gingival tissues are deemed healthy. This is not always possible in the clinical setting, but

nonetheless it should be a constant goal. Gingival deflection and impression making in the presence

of inflamed tissues is an unpredictable produre even through it is technically possible with the system

described. The gingival finish line of the tooth preparation can be recorded in the impression;

however, it is impossible to predict the ultimate level of the gingival tissues. The implications in

terms of esthetics and periodontal health are obvious.

The entire impression process for fixed prosthodontics requires careful managers of the soft

tissue. The inability of impression materials to adequately displace soft tissue, fluids, or debris

mandates adequate isolation. Various methods and techniques have been described in the literature to

achieve exposure of the finish line and create an acceptable environment for the impression materials:

(1) mechanical methods (2) mechanico-chemical methods, (3) rotary gingival curettage (gingitage)

and (4) electrosurgical methods. Each of these methods and individual techniques are described and

their relative advantages and disadvantages summarized in this article.

Procedures for fixed partial dentures require adequate duplication of the prepared tooth and

the finish line. Finish lines are frequently placed below the crest of the gingival margin and

necessitate gingival retraction when impressions are made. The margins of the prepared teeth must

be exposed at this time without irreversible damage to the gingival tissues.

DISCUSSION:

MECHANICAL METHODS:

Mechanical methods of gingival displacement were among the first developed. These

methods involve physical displacement of the gingival tissue by placement of materials within the

gingival sulcus. The materials can be used alone or in conjuction with the other methods. Several

types of materials may be used.

Use of the rubber dam is not only an asset in the preparation of the tooth, but also when the

impression is made. With this technique, wax must be used to block out the clamp and prevent its

displacement. Excellent impressions are obtained when the prepared teeth are in a clean and dry

environment. However, it is not feasible to make complete arch impressions and the rubber dam

should only be used on relatively simple preparations with minimal subgingival extension.

String or fibers of different types have been advocated for placement, wet or dry, in the

gingival sulcus. Included are plain cotton thread, unwaxed floss, cotton cord, and 2/0 untreated

surgical silk. Cords are available in varying thicknesses and may be plain, braided, or in other

3

configurations. With this technique, a blunt-ended instrument is used to gently pack the string or

cord into the crevice. The displacement should not cause hemorrhage or laceration of the gingival

attachment. The development of elastic retraction rings is intended to facilitate placement and

retention in the crevice.

Another mechanical method is that of the impression material-filled band. A band is

festooned, contoured, and fitted to the prepared tooth. The impression material is mechanically

carried to the finish line of the preparation and displaces the gingiva to produce and adequate

impression. This technique can use rubber base and other elastomeric impression materials with or

instead of the modeling compound, gutta–percha, or autopolymeriszed acrylic resin.

A technique has been described in which a temporary acrylic resin coping is constructed.

The inside is relieved by approximately 1mm, and adhesive is applied. The temporary restoration is

then filled with an elastomeric impression material and reseated. The tissue is displaced when the

impression material is mechanically forced into the sulcus. A complete arch impression is

subsequently made over the coping, and the coping becomes an integral part of the complete arch

impression. A variation involves the use of wax rather than an acrylic resin coping to force the

material apically.

Another mechanical technique involves using adapted temporary metal crown filled with

thermoplastic stopping material. A temporary metal crown adapated to the finish line of the tooth

and lined with excess of temporary stopping material. The crown is placed on the prepared tooth, and

the excess stopping is rounded and smoothed with a hot instrument where it protrudes into the

crevice. The temporary crown thus fabricated is left in place until the next appointment, at which

time the final impression is made.

The last mechanical technique to be described here in uses fine sterile twills of cotton with a

slow-setting zinc oxide-eugenol cement. It works be gently pressure and is most conservative with

respect to tissue tolerance. Cotton twills the size of floss are rolled in a creamy mixture of the zinc

oxide-eugenol cement. Several twills are placed in the sulcus and covered with a faster setting

cement. A minimum of 48 hours is recommended for placement, but the material should not be left

in place more than 5 to 7 days according to Schultz et al.

The use of a rubber dam for soft tissue displacement is recommended in operative dentistry

textbooks. The limited application to more than simple fixed prosthetic procedures is the

disadvantage. Complete Arch impressions are not compatible with this technique.

The use of cotton fibers, cord, string, or unwaxed floss are the products most commonly

used to displace gingival tissue. Plain cotton cord is poor in its ability to adequately displace gingival

when compared with chemically impregnated cords. Tissue recovery, on the other hand, is excellent.

Over packing can traumatize the tissue; the cord must be placed firmly but gently. Wetting the cord

with water before removal from the sulcus to prevent injury to delicate epithelial lining has been

recommended. The plain cord also provides pressure hemostasis.

4

Zinc oxide-eugenol cement placed on cotton twill is a technique recommended for deep

cervically involved teeth. The advantages are acceptable tissue tolerance and extended working time

to finish the preparation and make the impression. The disadvantage is the time necessary to make

this technique work adequately.

A temporary crown filled with thermoplastic stopping material or gutta-percha can cause

prolonged or lasting recession if left in place for more than 12 hours. The resulting uncovered neck

of the tooth may be sensitive and susceptible to caries. Impressions cannot be made at the same

appointment as the tooth preparation.

On the basis of wound healing and gingival recession the metal band with medeling

compound was better than either surgery or retraction cords (with or without chemicals). The

disadvantages of this technique include the amount of time necessary to fit and adapt the band, the

difficulty in removing the modeling compound-filled band from undercuts, and the trauma to the

tissue caused by the band itself. The variety of techniques incorporating modeling compound,

elastomeric impression materials, and autopolymerizing acrylic resin to the metal band do not appear

to alter the tissue response. They do save time.

MECHANICOCHEMICAL METHODS:

Most of the chemical solutions recommended for use in tissue management are used in

conjunction with retraction cords as described in mechanical methods. The cords or strings used to

keep the chemicals in contact with tissue and confine them to the application site. The cord may be

saturated with solution prior to insertion or placed dry and the solution applied. Some cords are

previously impregnated by the manufacturer and do not require additional application of chemicals.

Combinations of chemicals are advocated by some.

Various drugs are used for gingival displacement. They include (1) 0.1%and 8% racemic

epinephrine, (2) 100% alum solution (potassium aluminum sulfate), (3) 5% and 25% aluminum

chloride solutions, (4) ferric subsulfate (Monsel’s solution) , (5) 13.3% ferric sulfate solution, (6) 8%

and 40% zinc chloride solution, (7) 20% and 100% tannic acid solution, (8) 45% negatol solution,

and (9) various combinations of drugs.

Epinephrine used in concentrations of 0.1% and 8% to saturate the retraction cord creates

local vasoconstriction of the gingival tissues and seems to have fairly minimal systemic effects if

used in an intact sulcus. Controversy has developed over the used of epinephrine, because it has been

shown that 1 inch of cord saturated with 8% solution contains 2 to 15 times the safe dose of

epinephrine recommended for outpatients. Contraindications include a positive history of

cardiovascular disease, hyperthyroidism, and known hypersensitivity to epinephrine. Caution should

also be observed in patients using rauwolfia compounds, ganglionic blockers, or epinephrine-

potentiating drugs. There is evidence of increased heart rate and elevated blood pressure when

epinephrine is applied to lacerated gingiva and the capillary bed is exposed. This may occur in

patients who do not fall into the constraindicated categories. When a 0.1% solution was placed in the

sulcus, it did not produce appreciable injury to the epithelium at 5-and 10-minute intervals. Slight

injury was noted at 30 minutes, but it healed within 10 days. The 8% solution caused greater injury

5

than did the lesser concentration. The injurious effects of the 5- and 10-minutes exposures healed

within 10 days, and the effects of the 30- minute exposure took 14 days to dissipate. A permanent

crestal gingival loss of 0.1 mm is reported with this chemical.

Epinephrine appears to act primarily on the walls of small arterioles and to a lesser degree

on the walls of capillaries, venules, and large arterioles. This is why epinephrine is sometimes not

effective in controlling gingival bleeding.

Epinephrine syndrome has also been reported in patients with none of the contraindications

noted previously. The syndrome includes tachycardia, increased respirations, increased blood

pressure, nervousness, fright on occasion, and postoperative depression. The symptoms appear either

after the cord has been in for a few minutes or shortly after removal. It has been recommended that

0.1% epinephrine should be used rather than the 8% solution.

Alum (potassium aluminum sulfate) in a 100% concentration has been shown to be only

slightly less effective in shrinking the gingival tissues than epinephrine, and its shows good tissue

recovery. Only slight tissue injury was noted in a 10 minute application, and that completely healed

in 10 days. A 0.1 mm permanent loss of crestal gingival usually occurs. Fischer indicates that

although alum is kind to the tissue, the tissue retraction and hemostatic ability is limited. Alum has

been recommended for use in place of epinephrine because it is safer and has fewer systemic effects.

The cord should be wet when placed to avoid tearing the tissue on removal. Cord saturated with

100% alum can be safely left in the sulcus for as long as 20 minutes without adverse effect.

Aluminum chloride is one of the most commonly used chemicals in concentrations of 5%

and 25%. Studies have shown that solutions stronger than 105 can produce local tissue destruction.

A 10-minute application in the sulcus is usually sufficient. Aluminum chloride has not been shown

to demonstrate a significantly different inflammatory reaction than alum or 8% racemic epinephrine.

A permanent crestal gingival loss of 0.1mm can be expected. There are no known contraindications

and minimal systemic effects. The 25% solution has been advocated for use with other chemical

agents because it approximately doubled the hemostatic success of each of the other chemicals

studied. Some feel that aluminum chloride-impregnated cord is the most effective chemical to

control bleeding and displace tissue with no resultant tissue damage.

Ferric subsulfate, also known as Monsel’s solution, has been advocated for use in gingival

displacement. It is slightly more effective than epinephrine in gingival displacement. Tissue

recovery is good, but the solution is messy to use. The recommended time of use is 3 minutes. The

literature infers that ferric or ferrous salts should not be used because they are corrosive and injurious

to the soft tissues and enamel and because they stain the teeth. These properties are attributed to the

high acidity(72%) of the solution.

Ferric sulfate (13.3%) used for tissue displacement has recently been reported. It soes not

traumatize the tissue as noticabley, and healing is more rapid than with aluminum chloride. Ferric

sulfate is compatible with aluminum chloride but not with epinephrine. When used with epinephrine,

a massive blue precipitate develops. Ferric sulfate coagulates blood so quickly that it must be placed

directly against the cut tissue. If it is not, the ferric sulfate becomes tied up with the extravasted

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blood and floats away, leaving a bleeding surface. The recommended use time is 1 to 3 minutes, but

can be used for 10 to 20 minutes. The resulting tissue displacement is maintained for at least 30

minutes. So that repacking is seldom necessary for multiple impressions. The tissue is temporarily

discolored to a black or bluish color but will appear pink again after 1 or 2 days. In vitro tests failed

to show the corrosive or staining effects on the enamel that had previously been reported with ferric

compounds.

Zinc chloride (bitartrate) has been used in 8% and 40% solutions. Gingival displacement

effectiveness of the 8% solution is about equal to that of epinephrine, while the 40% solution is a

little more effective. The 8% solution caused severe necrosis of the tissue that didd not heal for 60

days. The 40% solution is so caustic that it has been classified as a chemical cautery agent. Because

both of these concentrations are escharotic and cause permanent injury to the soft tissue and

sometimes to the bone, their use is not recommended.

Tannic acid (20% and 100%) is less effective than epinephrine but shows very good tissue

recovery. The recommended use is for 10 minutes. The hemostatic effectiveness of tannic acid is

minimal.

Negatol solution is a 45% condensation product of meta cresol sulfonic acid and

formaldehyde. It provides better retraction than epinephrine. Tissue recovery is poor. It is highly

acidic and decalcifies teeth in both 10% and 100% solutions. It is classified as a chemical cautery

agent and is not recommended for gingival displacement.

Various combinations of chemicals have also been described as tissue displacement agents.

Cocaine (10% with 0.1% epinephrine) showed poor gingival retraction effectiveness but good tissue

recovery. This was the only solution that did not shrink the gingival tissue when applied. Zinc

chloride with 8% epinephrine gave better retraction than epinephrine alone but only fair tissue

recovery. If applied for an excessive time, the tissue may be cauterized. Alum and aluminum

chloride is reported as an acceptable combination that attempts to gain the advantages of both

chemicals. Rather than mixing the two chemicals together, it is recommended that the cord be

saturated with one solution before insertion and the other applied after the cord has been placed in the

sulcus. Other combinations noted in the literature are 4% levoepinephrine with 9% potassium alum

and epinephrine with alum. The epinephrine with alum combination showed a slightly better gingival

retraction effectiveness than epinephrine alone and fair tissue recovery.

The advantages and disavatages of the mechanicochemical methods are summarized in

Table I.

Drug Advantages

Disadvantages

Epinephrine 0.1% and 8% Good displacement Minimal Systemic reactions

Tissue loss Good respons

7

Epinephrin

e

Good hemostatis syndrome

Alum 100% (potassium aluminum Minimal tissue loss Less displacement

Sulfate) Extended working time and hemostais than

Epinephrin

e.

Aluminum chloride 5%and 25% Minimal tissue loss Local tissue

Good hemostasis distruction

in

concentrati

on>10%

Ferric sulsulfate(Monsel’s Good displacement Messy to use

Solution) High

acidity

Corrosive

to tooth

structure

and soft

tissue

Ferric sulfate 13.3% Good tissue response Not

compatible with Compatible with aluminum

epinephrine.

Chloride Transient tissue

Extended working time discoloration

Good displacement Unpleasant

taste.

Zinc chloride 8% and 40% Good displacement Tissue necrosis

Permanent

tissue

injury

Tannic acid 20% and 100% Good tissue response less

displacement than

with epinephrine.

Minimal

hemostasis.

Negatol 10% and 100% Good displacement Poor tissue response

8

Corrosive

to teeth

High

acidity

CRITERIA FOR GINGIVAL RETRACTION MEDICAMENTS

A variety of medicaments are available for use with gingival retraction procedures;

therefore, the dentist must choose which material to use based on well define criteria. The

contemporary techniques used to accomplish gingival deflection can be classified as mechanical,

chemical, surgical, or combinations of the here. This analysis is limited to the mechanical – chemical

system (impregnated retraction cord), because the survey demonstrated that it is the most commonly

used. The mechanical effects of the cord itself will be considered equal for all materials, so that

differences discussed will be solely a result of the medicaments used.

Materials used for gingival retraction should satisfy the following criteria.

1. It must be effective. Use of medicament in a cord must result in sufficient lateral and

vertical displacement of the gingival tissues concomitant with tissue shrinkage and control of

hemorrhage and fluid seepage to allow the dentist to make an adequate impression of the gingival

finish line of the prepared tooth. This requires that the entire gingival margin of the preparation and a

small surface beyond the finish line be recorded in the impression. Sufficient room must be provided

in a lateral direction to provide adequate bulk of impression material to resist tearing.

2. Use of the material should not cause significant irreversible tissue damage. It must be

understood that even the most meticulous retraction procedure results in tissue injury. However, the

damage should be reversible, and complete clinical and histologic healing should occur within 2

weeks. A slight apical positioning of the marginal gingival can be expected, but it should only be in

the order of 0.1 mm, which would be unlikely to be clinically significant in most instances.

3. Use of the material should not produce potentially harmful systemic effects. The impregnated

retraction cord is placed in the gingival sulcus where the medicament has the potential to be absorbed

into the systemic circulation. The amount of absorption depends on the medicament used, the

amount of laceration of the gingival tissue, and the number of teeth prepared. Consideration should

be given to potential reaction from local anesthetics, medications taken for medical purposes,

endogenous secretions, and the patient’s cardiovascular status.

EPINEPHRINE AND ITS SYSTEMIC EFFECTS:

The synthesis, metabolism, and functions of epinephrine have been extensively studied and

are widely known. The systemic effects of epinephrine involve many organ systems; the one with

which we are most concerned is the cardiovascular system. Epinephrine acts as a potent myocardial

stimulant that increases the strength of ventricular contraction and increases heart rate. It causes

vasoconstriction in many vascular beds. These actions result in a rise in blood pressure that is

proportional to the dose.

Symptoms of an epinephrine overdose include fear, anxiety, restlessness, headache, tremor,

weakness, dizziness, pallor, respiratory difficult, palpitations, and perspiration with the patient

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complaining of nervousness and pounding hear. Blood pressure (primarily systolic) is raised and

pulse rate is increased.

In general, the effects of an epinephrine overdose subside within minutes because of rapid

inactivation by the body. However, in some patients, particularly those in whom there is an

impairment of cardiac function, there may be a predisposition toward ventricular arrhythmias die to

the rapid increase in pulse rate. This can lead to ventricular tachycardia and potentially to ventricular

fibrillation, which may be fatal if not managed properly. Patients with cardiovascular disease may

develop acute exacerbations of preexisiting disorders such as anginal pains, acute myocardial

infarction, heart failure, or cerebral vascular accidents. Epinephrine overdose can cause dangerous

rises in blood pressure in hypertensive individuals.

Administration of epinephrine is also contraindicated in patients with hyperthyroidism, and

those receiving monoamine oxidase inhibitors for treatment of depression. In these patients, severe

hypertensive episodes may occur because of slowed inactivation of epinephrine. Epinephrine is

contraindicated in diabetic patients because it increases blood glucose by inhibiting glucose uptake in

peripheral tissues and by promoting glycogen slysis. Diabetic patients who use oral contraceptives

may have increased insulin requirements, which complicate the situation further.

The maximal dose for epinephrine in a healthy adult is 0.2 mg, which is equivalent to the

amount contained in 10 Carpules of local anaesthetic of a 1/100,000 dilution of epinephrine. The

maximum recommended dose for the cardiac patient is 0.04mg of epinephrine, the amount contained

in approximately two Carpules of local anesthetic of a 1/100,000 dilution.

Epinephrine – impregnated retraction cord contains 0.2 to 1 mg of racemic epinephrine per

inch of cord, depending on diameter and brand. In the brand most commonly used in our study

(52.12%, Gingi-pak, Gingi-Pak-Belport, Co., Camarillo, Calif.), 0.5mg/inch is standard in all

diameters. One inch of this cord contains moret han the maximum recommended dose for healthy

patients and six times the maximum recomddended dose for cardiac patients. One inch of cord with

1 mg of racemic epinephrine contains 2 ½ times the maximal dose for healthy patients and more than

12 times the recommended dose for cardiac patients. Therefore, the epinephrine in gingival

retraction cord is potential source of overdose.

Possible cumulative effects of epinephrine from cord combined with epinephrine from other

sources must also be considered. The anxious dental patient often has an increased secretion of

epinephrine as a response to stress.

Manipulation of gingival tissues during retraction procedures can cause an increase in blood

pressure that would suggest the influence of endogenous epinephrine.

Local anesthetics that contain epinephrine to prolong the anesthetic effect are also a

consideration. In one study plasma epinephrine concentrations were doubled 3 and 5 minutes after

injection with one Carpule of 2% lidocaine with 1/100,000 epinephrine . The hemodynamic

responses in the healthy young subjects used in the study were negligible, but the authors advised

careful use in high-risk patients. Many restorative procedures require several Carpules of anesthetic,

which would increase the administered dose of epinephrine.

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The literature on the absorption of epinephrine from retraction cords is somewhat

contradictory. There are two general approaches to the study of epinephrine absorption. One is to

measure the level of circulating catecholamines over time and the other is to observe various

hemodynamic responses that would indicate increased levels of circulating epinephrine. The main

problem with the latter approach is that it is impossible to attribute a hyperdynamic response solely to

absorbed epinephrine as opposed to endogenous epinephrine or that resulting from the local

anesthetic injection. In any event, it is the cumulative effect of the three sources of epinephrine that

is really the critical factor.

Gogerty et al. studied the vasopressor effects of the use of various concentrations of topical

epinephrine in several dental procedures in dogs. They found that epinephrine was absorbed with a

corresponding rise in blood pressure. Absorption and vasopressor effects were greater with increased

vascular exposure and increased concentration of epinephrine. Woychesin found similar results with

dogs. Phatak and Lang, and Houston et at. Found no significant increase in hemodynamic variables

in dental patients with epinephrine-impregnated cords. Poque and Harrison used dogs and carbon –

14 – labeled racemic epinephrine and could measure no significant rise in radioactivity in the blood

stream after gingival retraction procedures. They concluded that little or no epinephrine is absorbed

into the circulatory system with retraction procedures.

Forsyth et al. used monkeys to measure both hemodynamic response and levels of carbon-

14-labeled epinephrine. Blood pressure and pulse rate rose during gingival retraction procedures, and

generally higher increases were recorded when epinephrine was used. They also measured an

increase of 24% to 92% radioactivity in the blood stream, which demonstrated definite absorption of

the labeled epinephrine, Pelzner et al. reported a human study involving gingival retraction on one

tooth with 4% and 8% epinephrine versus plain cord . They found that the blood pressure was

elevated with use of epinephrine and was highest when the 8% concentration was used.

In correlating the data from these studies, it can be concluded that under certain conditions,

epinephrine from gingival retraction cords is absorbed systemically. Conditions that limit systemic

absorption are not clear, but increased absorption seems to occur with increased exposure of the

vascular bed and an increase in the total amount of epinephrine used. Epinephrine in local anesthetic

solutions can be absorbed in amounts that may be significant for some patients. This could be a

problem for patients with cardiovascular disease, particularly when multiple injections are given to

allow the dentist to prepare several teeth simultaneously. In addition, some patients secrete a certain

amount of endogenous epinephrine during dental procedures. Any dangerous hyperdynamic

response that could occur in patients will be a result of the cumulative amount of circulating

epinephrine.

Data from a survey of 495 dentist indicate that most dentist used the mechanical-chemical

method of gingival-felfection. 79.39% of those used cord containing epinephrine.

It can be concluded that potentially significant amount of epinephrine can be absorbed

systemically from the local anesthetic solution, that secretion of endogenous epinephrine in response

to stress occurs, often at levels sufficient to cause measurable changes in hemodynamic variables, and

11

that absorption of epinephrine from impregnated strings occurs. The amount of absorption will vary

with the exposure of the vascular bed, the length and concentration of the impregnated cord, and the

length of time of application. It is possible that the actual tottal amount of circulating catecholamine

would be cumulative, and the corresponding cardiovascular response would be related to the total

amount of epinephrine in the bloodstream, regardless of the source.

When the fact that we usually have inadequate data on the cardiovascular status of our

patients is considered, as well as the tendency to make impressions of multiple prepared teeth, the

continued use of epinephrine cord in dentistry must be viewed with alarm.

Equally effective astringent gingival deflection agents such alum, aluminum sulfate, and

aluminum chloride exert no systemic effects. Therefore, there is little indication for use of

epinephrine containing retraction cords. Adequate medical evaluation, careful use of anesthetics that

contain epinephrine, and sedative techniques when indicated will assure the safety of our patients.

RETRACTION CORD ARMAMENTARIUM:

1. Evacuator (saliva ejector, svedopter)

2. Scissors

3. Cotton pliers

4. Mouth mirror

5. Explorer

6. Fisher Ultrapak Packer (small)

7. DE plastic filling instrument IPPA

8. Cotton rolls

9. Retraction cord

10. Hemodent liquid

11. Dappen dish

12. Cotton pellets

13. 2*2 gauze sponges

The operating area must be dry. An evacuating device is placed in the mouth, and the quadrant

containing the prepared tooth is isolated with cotton rolls. The retraction cord is drawn from the

dispenser bottle with sterile cotton pliers, and a piece approximately 5.0 cm (2.0 inches) long is cut

of. If a twisted or wound cord is used, grasp the ends between the thumb and forefinger of each hand.

Hold the cord taut and twist the ends to produce a tightly wound cord small diameter. If a braided or

woven cord is used, twisting is not necessary.

Be careful not to touch any of the cord other than the ends, which will be cut off later, with your

gloved fingers. It has been postulated that handling the cord with latex gloves may indirectly inhibit

polymerization of a polyvinyl siloxane impression. If that happens, it will occur in that segment of

the impression replicating the gingival crevice and the gingival finish line of the preparation.

The retraction cord should be moistened by dipping it in buffered 25% aluminum chloride

solution ( Hemodent, Premier Dental Products Co. Norristown, PA) in a dappendish. Cords

impregnated with either epinephrine or aluminum sulfates are twice as effective when saturated with

12

aluminum chloride solution prior to insertion into the gingival crevice. If there is slight hemorrhage

in the gingival crevice, it can be controlled by the use of hemostatic agent, such a Hemodent liquid

(aluminum chloride). In any event, the cord must be slightly moist before it is removed from the

sulcus. Removing dry cord from the gingival crevice can cause injury to delicate epithelial lining that

is not unlike the “cotton roll burn” produced by prying an adhering cotton roll of the desiccated

mucous membrane of the mouth.

From the cord into a “U” and loop it around the prepared tooth. Hold the cord between the

thumb and forefinger, and apply slight tension in an apical direction. Gently slip the cord between

the tooth and the gingival in the mesial interproximal area with a fischer packing instrument or a DE

plastic instrument IPPA. Cord placement is a finesse move, not a power play. Once the cord has

been tucked in on the mesial, use the instrument to lightly secure it in the distal interproximal area.

Proceed to the lingual surface and begin working from the mesiolingual corner around to the

distolingual corner. The tip of the instrument should be inclined slightly toward the area where the

cord has already been placed; ie, the mesial. If the tip of the instrument is inclined away from the

area in which the cord has been placed, the cord may be displaced and pulled out.

In some instances where there is a shallow sulcus or a finish line with drastically changing

contours, it may be necessary to hold the cord already placed in position with Gregg 4-5 instrument

held in the left hand. Placement of the cord can then proceed with the packing instrument held in the

right hand. Gently press apically on the cord with the instrument, directing the tip slightly toward the

tooth. Slide the cord gingivally along the preparation until the finish line is felt. Then push the cord

into the crevice.

If the instrument is directed totally in an apical direction, the cord will rebound off the gingival

and roll out of the sulcus. If cord persists in rebounding from a particularly tight area of the sulcus,

do not apply greater force. Instead, maintain gentle force for a longer time. If it still rebounds,

change to a smaller or more pliable cord (ie, twisted rather than braided).

Continue on around to the mesial, firmly securing the cord where it was lightly tacked

before. Cut off the length of cord protruding from the mesial sulcus as closely as possible to the

interdental papilla. Continue packing the cord around the facial surface, overlapping the cord in the

mesial interproximal area. The overlap must always occur in the proximal area, where the bulk of

tissue will tolerate the extra bulk of cord. If the overlap ccurs on the facial or lingual surface where

the gingival is tight, there will be a gap apical to the crossover, and the finish line in that area may not

be replicated in the impression.

Pack all but the last 2.0 or 3.0 mm of cord. This tag is left protruding so that it can be

grasped for easy removal. Tissue retraction should be done firmly but gently, so that the cord will

rest at the finish line. Heavy-handed operators can traumatize the tissue, create gingival problems,

and jeopardize the longevity of the restorations that they place. Do not over pack!

Place a large bulk of gauze in the patient’s mouth. This will make the patient more

comfortable by having something to close on and, at the same time, it will keep the area dry. After

10 minutes, remove the cord slowly to avoid bleeding. Inject impression material onlyif the sulcus

13

remains clean and dry. It may be necessary to gently rinse away any coagulum, then lightly blow air

on it. If active bleeding persists, abort the impression attempt. Electrocoagulation and ferric sulfate

are sometimes effective in stopping persistent bleeding.

If ferric sulfate (Astingendent, Ultradent products, salt lake city, UT) is used as the

chemical, soak a plain knitted cord in it and place the cord in the gingival sulcus as just described.

After 3 minutes, remove the cord. Load the 1.00cc special syringe (Dento-Infusor) with the

astringent chemical, and place a tip on the syringe. Use the fibrous syringe tip to rub or burnish cut

sulcular tissue until all bleeding stops. Using the tip in this manner will wipe of excess coagulum.

Keep the sulcus moist so that the coagulum will be easy to remove. Keep circling the

preparation until bleeding has stopped completely. The solution usually will puddle in the sulcus

when hemostasis is complete. Verify this by thoroughly rinsing the preparation with a water/aor

spray. The coagulum is black, and traces may linger in the sulcus for a few days.

ROTARY CURETTAGE:

Rotary curettage is a “troughing” technique, the purpose of which is to produce limited

removal of epithelial tissue in the sulcus while a chamfer finish line is being created in tooth

structure. The technique, which also has been called “gingettage”, is used with the subgingival

placement of restoration margins. It has been compared with periodontal curettage, but the rationale

for its use is decidedly different. Periodontal curettage is used to debride diseased tissue from the

sulcus to allow re epithlialization and healing.

The removal of epithelium from the sulcus by rotary curettage is accomplished with little

detectable trauma to soft tissue, although there is lessened tactile sense for the dentist. Rotary

curettage, however, must be done only one healthy, inflammation free tissue to avoid the tissue

shrinkage that occurs when diseased tissue heals.

The concept of using rotary curettage was described by Amsterdam in 1954. The technique

described here was developed by Hansing and subsequently enlarged upon by Ingraham. Suitability

of gingival for the use of this method is determined by three factors: absence of bleeding upon

probing, sulcus depth less than 3.0 mm, and presence of adequate keratinized gingival. The latter is

determined by inserting a periodontal probe into the sulcus. If the segment of the probe in the sulcus

cannot be seen, there is sufficient keratinized tissue to employ rotary curettage. Kamansky et al

found that thick palatal tissues responded better to the technique than did the thinner tissues on the

facial aspect of maxillary anterior teeth.

In conjunction with axial reduction, a shoulder finish line is prepared at the level of the

gingival crest with a flat-end tapered diamond. Then a torpedonosed diamond of 150 to 180 grit is

used to extend the finish line apically, one half to two thirds the depth of the sulcus, converting the

finish line to a chamfer. A generous water spray is used while preparing the finish line and curetting

the adjacent gingival. Cord impregnated with aluminum chloride or alum is gently placed to control

hemorrhage. The cord is removed after 4 to 8 minutes, and the sulcus is thoroughly irrigated with

water. This technique is well suited for use with reversible hydrocolloid.

14

Several studies have been done to compare both the efficacy and the wound healing of

rotary curettage with those of conventional techniques. Kamansky and his associates reported less

change in gingival height with rotary curettage than with lateral gingival displacement using

retraction cord. With curettage there was an apparent disruption of the apical sulcular and attachment

epithelium, resulting in apical repositioning and an increase in sulcus depth. The changes were quite

small, however, and they were not regarded as clinically significant.

Tupac and Neacy found no significant histologic differences between retraction cord and

rotary curettage. Ingraham et al reported slight differences in healing among rotary curettage,

pressure packing, and electro surgery at different time intervals after the tooth preparation and

impression. However, complete healing has occurred by 3 weeks with all techniques.

There is poor tactile sensation when using diamonds on sulcular walls, which can produce

deepening of the sulcus. The technique also has the potential for destruction of periodontium if used

incorrectly, making this a method that is probably best used only by experienced dentists.

Eighteen adolescents, 13 boys and five girls, who needed premolar extractions prior to

orthodontic treatment, were selected as experimental subjects. None of the subjects showed clinical

evidence of marginal gingivitis. Paired maxillary premolars that were to be extracted later were

identified and divided into four receptor sites – right buccal,right lingual, left buccal, and left lingual.

AT random, a different retraction cord was placed into each of the four . These four different

cords were either untreated or contained potassium aluminum sulfate ( Alum cord), aluminum

chloride (Hemodent, Premier Dental Products Co., Norristown, Pa), or 8% racemic epinephrine

(Gingipak, Lactona Corp., Hatfield, Pa). Each cord remained in place for 15 minutes and was

removed while wet.

Half of the subjects retured in 24 hours, and the other half returned in 7 days. The free

gingival tissue and part of the attached gingival tissue were excised surgically from each of the four

receptor sites.

Potassium aluminum sulfate tended to present the most favorable findings after both time

intervals, even though differences in the number of inflammatory cells were not always statiscally

significant and may have been due to chance variation. In all other comparisons, there was as much

variation in degree of inflammation present between patients treated with the same type of gingival

retraction material as there was in each patient treated with different gingival retraction materials.

This suggests that other factors such as physiologic differences among patients may have a grater

effect on the number of inflammatory cells present than does the substance with which the gingival

retraction cords are treated.

By way of comparison, Harrison used three dogs to determine the effect on the sulcus of (1)

o.1% epinephrine, (2) *% epinephrine, (3) 100% alum, (4) 8% zinc chloride, and (5) 40% zinc

chloride. Using block sections taken up to 21 days later, the indicated essentially no injury resulting

from either untreated cord or cord soaked in 0.1% epinephrine. Eight percent epinephrine cord

showed slight injury that lasted upto 10 days, whereas the areas treated with alum cord healed within

7 days. It is interesting to note that both concentrations of zinc chloride caused severe damage that

15

lasted past the 21 day course of the experiment. Harrison concluded that zinc chloride should not be

used.

Loe and silness also used dogs. They essentially repeated Harrison’s experiment using two

dogs as subjects and longer time period of up to 42 days. Eight percent zinc chloride and 8%

epinephrine were studied and found to have similar characteristics. Both chemicals caused

immediate surface necrosis and superficial connective tissue cellular degeneration. Healing was

complete with in 6 to 9 days.

The authors cannot explain why the control did not produce the least inflammation. One

possible explanation is that the lack of hemostasis enabled acute inflammatory cells to react to the

mechanical trauma of tissue retraction t a greater degree than with agents that inhibit blood flow.

This hypothesis might be tested by using an additional control site that does not undergo retraction.

In this way, baseline of inflammation for the individual patient could be established.

OBJECTIVES:

The objectives of this study were to:

1. Evaluate the possible cardiovascular effects of 4% racemic epinephrine-impregnated

retraction cord.

2. Evaluate the clinical reliability of 4% racemic epinephrine-impregnated retraction cord

in obtaining accurate impressions.

3. Assess the placebo effect of nonimpregnated retraction cord on cardiovascular

functions.

4. Compare any hemodynamic effects of the 4% racemic epinephrine cord, to those

induced by the commonly used 8% racemic epinephrine retraction cord.

The test population consisted of 63 men and women patients, ranging between 22 and 56

years of age. All patients were treated by dental students. Two patients reported a history of

controlled diabetes. One tooth of each patient, prepared for a complete crown, served to test

the cords. Champfer or shoulder cervical margins were prepared imm apical to the crest of

the gingival.

The three types of cords were: (1) cord impregnated with an 8% solution of racemic

epinerphrine HCK, * (2) cord impregnated with a 4% solution of racemic epinephrine

HCL,* and (3) non impregnated placebo cord. Cords used in all tests were of identical

physical type and size. A reversible hydrocolloid was used to make the impressions.

Blood pressure and pulse rate were evaluated using three different audible aneroid

sphygmomanometers. This was done to minimize these possible error in reading which may

occu with the use of manual standard sphygmomanometers.

Pulse rate fluctuations:

Rises in pulse rate were observed following use of all the retraction cords. With the

placebo cord there were also high increases during the clinical session. The degree of

increase in pulse rate was similar for all three cords.

16

It can be concluded that the anxiety and stress that the patient experiences are

important factors which may cause fluctuations in heart rate during clinical procedures.

Similar observations were reported by Munoz and Fritts and associates, who correlated rise

in pulse rate with the anxiety of the patient, especially prior to the local anesthetic injection

and the impression making.

It is important to note that anxiety and stress persisted even though all of the

patients were informed as to what treatment was to be performed.

Blood pressure fluctuations:

Under stress and anxiety, the body elicits “alarm reactions” that consist of

hypothalamic –oriented vasoconstriction and dilation, a release of epinephrine and

norepinephrine, increased hart rate, and increased cardiac output. The arterial blood

pressure is thus elevated. Similar reactions occur when exogenous epinephrine is present in

the body.

The results show that blood pressure is influenced by racemic epinephrine absorbed

from retraction cords, and that the amount of racemic epinephrine in the cord is also an

important factor. This was demonstrated by the higher elevation in blood pressure when

using 8% compared to 4% racemic epinephrine-impregnated cords. The role of endogenous

epinephrine released within the body at time of stress is also important, as demonstrated by

the fact that even with placebo cord there was an elevation in blood pressure. Others have

reported similar observations.

The laceration of the tissue and the placement of the cord itself have been shown to

cause rises in blood pressure, as reported by Forsyth and associates. The fact that the

highest degree of blood pressure was recorded after the use of 8% racemic epinephrine

clearly demonstrates the effect of the amount of exogenous epinephrine upon the blood

pressure values. This effect has also been widely reported.

The persistence of high blood pressure values 15 minutes after removal of the

retraction cords is related to endogenous epinephrine and anxiety, rather than to the

epinephrine absorbed from the cord. Parallel observations have been made in comparing

pulse rates after impression making, which can be a high-stress time for the patient.

The amount of racemic epinephrine in the 8% racemic epinephrine cord, equated to

USP epinephrine, is 0.14mg/cm. The lengths of cord used in this study were between 5 and

7 cm. Thus, the application of these lengths of cord brought between 0.7 and 98mg of

racemic epinephrine in contact with the exposed vascular bed. With the use of 4% racemic

epinephrine 0.35 and 0.49 mg. Although the elevations in blood pressure were in a narrow

range, they might have proved hazardous to patients with cardiac complications. Therefore,

the use of 4% racemic epinephrine-impregnated cords should be recommended in all

instances, and especially with cardiac patients.

The adequate retraction of tissue afforded by the 4% racemic epinephrine cord may

show it to be a valid substitute for 8% cord, providing a wider safety margin with regard to

17

the known effects of epinephrine. The degree of retraction produced by the placebo cord,

although sometimes adequate, depended entirely on mechanical deflection of the tissue.

Non medicated dry cord has no vasoconstrictive properties, causes sloughing of the tissue,

and tears tissue upon removal. There fore, placebo cord should not be used. As reported in

the results, 75% of the impressions made after use of placebo cord showed blood on the

surface, and 60% of the impressions had to be repeated. Based on this study, the placebo

cord is contraindicated for retraction purposes.

Polyvinyl siloxane impressions have become popular in recent years because of

their accuracy, ease of manipulation excellent elastic recovery, and dimensional stability.

Inhibition of polymerization of these materials by chemical agents in latex rubber has been

well documented. This can occur when putty materials are mixed with latex gloves, when

the impression material is in contact with a rubber dam, and even by indirect intraoral

contact of teeth and soft tissue structures with latex gloves before impression making. The

mechanism of inhibition of polymerization is thought to be contamination of the

chloraplatinic acid catalyst by sulfur compounds in the latex products.

Many different medicaments are used on gingival retraction cords to attempt to

minimize hemorrhage grom the gingival sulcus during impression making. This is

especially critical in using hydrophobic impression materials such as polyvinyl siloxanes.

Manufacturer’s claims to the contrary, these materials are not truly hydrophilic and they

require an absolutely dry sulcus if impressions are to be predictabley successful. It has been

suggested that certain of these medicaments may inhibit the polymerization of polyvinyl

siloxanes in a manner similar to that of latex rubber. Clinicians have reported such

occurrences anecdotally in the clinical setting to one of the authors on numerous occasions.

Concern with some of the medicaments, especially those containing aluminum

sulfate or ferric sulfate, seems valid. It is also possible that the inhibition reported

anecdotally was caused by contact of the intraoral soft and hard tissues with latex gloves,

and had nothing to do with the medicament used. This study was done to determine whether

any of the commonly used gingival retraction medicaments could inhibit the polymerization

of polyvinyl siloxane impression materials when they are in direct contact with the setting

material.

Inhibited polymerization of polyvinyl siloxanes is manifested by the appearance of

a rippled surface on the set impression material. The material on the surface of the

impression areas that were contaminated will be slippery to the touch. This inhibition is

limited and superficial, not unlike the oxegen-inhibited layer encountered with resin

composites. This rippling is duplicated in the gypsum cast, and the cast may appear wet,

wrinkled, or poorly defined. Often, unpolymerized impression material will be adherent to

the prepared teeth or to the cast when the impression is separated. Regardless, the surface

detail of the cast will be compromised and unsuitable for use in the fabrication of cast

restorations.

18

The concern that certain medicaments used with gingival retraction procedures may

interfere with polymerization of polyvinyl siloxane is understandable. This inhibitory effect

has been clearly demonstrated in the case of latex rubber products, likely because of

unreacted sulfur that remained from the manufacturing process. However, on the basis of

data from this study, does not appear that any of the materials commonly used in gingival

retraction procedures have and inhibitory effect.

A likely explanation for the clinical situations in which inhibited polymerization

was reported is that the teeth and /or the surrounding soft tissues were contaminated by latex

gloves before the impression making. This contamination, which is difficult to remove, was

likely the cause of the inhibited set. In this regard, it is interesting to note that all of the

reports of inhibition have surfaced in recent years since improved infection control and

barrier technique have become widespread. Before this, polyvinyl siloxame had been used

successfully for many years in conjunctions with all of the medicaments tested. The

evidenced points to the latex gloves and not the medicaments.

In light of the finding that the polymerization of polyvinyl siloxane impression

materials can be inhibited by sulfur in latex rubber products, and because many gingival

retraction medicaments contain chemically active agents a study was conducted to determine

whether any of the commonly used gingival retraction medicaments inhibited the set of

these materials. The following conclusions appear to be valid:

1. Latex rubber can inhibit the set of polyvinyl siloxane impression materials.

2. The inhibition of set seen with latex rubber is limited to the most superficial layer of the

impression material.

3. None of the medicaments tested had any inhibition effect whatsoever on

polymerization.

4. The inhibited polymerization mentioned in anecdoted reports is more likely caused by

inadvertent contaminated by latex rubber gloves than by the gingival retraction

medicaments.

Various types of hemostatic agents are available for tissue displacement prior to dental

impression procedures. Chemically, hemostatic solutions can be listed in five groups1)

aluminum chloride,(2) aluminum sulfate, (3) ferric sulfate,(4) epinephrine and (5)

tetrahydrozoline.

Clinically, some hemostatic agents appear to cause varying degrees of tissue

damage and others have been suspected of initiating pulpal irritation. Because a low pH

may explain some of the side effects, knowledge of pH of tsese agents would be helpful to

the dentist.

Ten different agents were recorded on Corming pH meter (Model7, Corning Glass

Works, Medfield, and Mass). The pH of many hemostatic agents was extremely low or

acidic, and most solutions were within the 1 through 3 range. This pH range is equivalent to

dilute HCI or concentrated lemon juice. Aluminum chloride and ferric sulfate also

19

hydrolyze in water to form hydrochloric acid and sulfuric acid respectively. * These

solutions can damage oral tissues and may have a more profound effect that the etchants

used for bonded composite resin restorations. Phosphoric acid dissolves the mineral content

of the tooth and develops phosphate buffer that diminishes the chemical reaction. However,

hydrochloric and sulfuric acid are not self-limiting and their action is continuous until

diluted. The addition of a displacement cord did not significantly limit the effect on the pH

compared to the solution.

Newer hemostatic agents such as the tetrahydrozoline and oxymetazolines have a

more acceptable pH and should be kinder to tooth structure and soft tissue than the

conventional solutions. Although additional study is needed it would seem prudent to be

cautious in using low pH he mostatic agents and avoid the exposure to sensitive intraoral

tissues – particularly delicate tissues – or tooth preparation close to the dental pulp.

A NEW GINGIVAL RETRACTION IMPRESSION SYSTEM FOR A ONE-STAGE ROOT-FORM

IMPLANT

Gingival displacement during impression making has not been a problem with a screw-

retained implant crown because most dental implant systems use either machined components or

plastic pattern that can be accurately adapted directly to a dental implant. Machined components

allow placement of an accurately fitting transmucosal abutment to the implant with a center screw.

Under certain situations , a machined gold coping may also be used for a screw-retained crown. The

cement-retained restoration is more popular because of better contour and esthetics, so an accurate

impression, produced efficiently is critical.

PROCEDURE:

Three parts are used for this impression method (Fig.1); a nylon, gingival retractor

impression cap, a shoulder analog, and a reinforcement pin for the die(ITI) Dental Implant System,

Straumann USA, Boston, Mass)

1. Screw on the solid abutment with the ITI ratchet (Straumann USA) to the desired torque.

(The abutment can be modified if necessary to correct the path of insertion or its length)

2. Snap the white nylon gingival retractor impression cap over the abutments and on the

exposed portion of the dental implant. Rotate the cap to verify that it is seated in position.

The cap should snap to place and not impinge on adjacent teeth (Fig.2)

3. Make a conventional impression using a stiff impression material such as polyvinyl siloxane

or polyether. Select a stock tray because it allows space for the impression cap. Inject the

light bodies material into the impression cap and place heavy-body material, in the tray, over

the impression caps.

4. Remove impression from the patient and inspect for accuracy. Secure the impression cap so

that it has not been dislodged or so that its position has not been distorted.

20

5. Snap the shoulder analog on the white nylon gingival retractor impression cap in the final

impression(Fig.3). Ensure that no change of portion or distortion has occuured when

snapping shoulder analog in the cap.

6. Pour the impression in type IV die stone. Place the reinforcement pin in the assembly as the

impression cap/shoulder analog is filled with stone (Fig 4)

7. Section the cast to make a removable die after the stone has set. Trim the die so the

shoulder analog is accessible (Fig.5)

8. Construct conventional restorations with physiologic emergence profiles (Fig.6)

9. Cement the restorations with use of conventional techniques after fitting (Fig.7)

There are a number of advantages of the cement retained implant restoration. The procedure is

convenient because the materials and techniques are similar to conventional fixed

prosthodontics. Most restorative dentists are familiar with these procedures and are comfortable

with this approach. Additional expertise is not required. The procedure ensures passive fit.

Cemented multiunit restorations can be more passive than screw-retained multiunit prostheses.

Esthetics are enhanced with this procedure. In certain situations, it may be difficult to achieve

optimal esthetics with screw retained restorations because of compromised contours necessary to

accommodate the screw. This procedure is also less time consuming regarding the purchasing

and coordinating of specific parts, and cost is reduced, unlike a screw retained prosthesis,

because refined components are an additional expense of the restoration.

A technique has been described that eliminates the need for conventional gingival retraction

cord for a I stage dental implant system. This technique results in consistently accurate and

stronger dies for a cement retained implant crown.

TISSUE RETRACTION FOR ESTHETIC CERAMOMETAL CROWNS:

Healthy gingival tissue is held tightly against the tooth by the elastic fibers of the free

gingival. During crown preparation only one third of the rotary instrument is actually used for

tooth reduction; the remaining two thirds can damage the sulcular epithelium of the gingival

cuff. It is possible to displace the gingival, turning the potential space of the sulcus into a real

space where the unused portion of the rotating instrument can turn without lacerating the

gingival tissues.

TECHNIQUE

Immediately after the proximal contacts are separated, retraction cord (wound to 0.5 mm

thickness) is placed to the depth of the gingival sulcus (Fig 1). Bulk reduction of the tooth is

accomplished to establish the buccal ledge at the new position of the gingival crest. A flat

bladed instrument (interpoximal carver, American Dental No, KC1155, American Dental

Mfg.Co., Missoula, Mont.) is placed on top of the cord to assure that the cord remains at the

attachment and away from the rotating instrument. The shape of the instrument allows the

gingival to be deflected buccally, while the blade of the interproximal carver physically comes

between the gingival and the rotary instrument (Fig.2). A high-speed finishing carbide bur

( Teledyne Emesco RCB No.15, Englewood, N.J.) is then used to place the bevel finish line

21

sufficiently subgingival to hide the 0.5 mm metal collar of the ceramometal restoration. The

interproximal carver is moved parallel with the movement of the rotating instrument as the bevel

is established to prevent the cord from wrapping around the bur (Fig.3)

Preservation of the integrity of the periodontium and esthetic results are important

consideration in a ceramometal restoration. There is a biologic width of epithelial and

connective tissue attachment around the teeth measuring approximately 2 mm. Maintenance of

the gingival integrity depends on the establishment of the crown tooth margin 1 mm or more

away from the epithelial attachment. If the attachment is encroached upon or cut, its loss and

apical migration to reform the 2 mm biologic width occurs, and the metal crown collar will be

exposed. Curettage of the internal surface of the gingival cuff can also alter the height and width

of the free gingival, exposing the metal collar of the ceramometal restoration. Gingival recession

is not a problem when retraction cord is used wet.

I

TECHNIQUES:

Specific techniques vary with the clinical situation. The following outline relates the

gingival deflection system to certain clinical demands and provides guidelines for use of the

different modalities.

In most patients, placement of a small cord in the sulcus prior to definitive margin

placement allows better visibility and access. Atraumatic margin placement should be a routine

procedure in most preparations.

I. Deflection where minimum tissue laceration has occurred and where the tissue is easily

distended is accomplished as follows.

1. Place the appropriate – size moist lubricated astringent cord between the tooth and the

gingival tissue.

2. Wait approximately 10 minutes, wash with copious amounts of water, remove the cord, and

wash and dry the gingival crevice.

3. Make a careful assessment of the sulcular space. If there is any bleeding or oozing of fluids,

the hemostyptic with syringe applicator is used with a rubbing motion while the hemostypic

22

is expressed simultaneously through the syringe tip. Copious water spray and high velocity

evacuation are essential during this procedure to control the precipitate that forms.

4. Wash and dry the sulcus, and when deemed satisfactory make the impression.

II. Deflection in preparations with minimal tissue laceration, but with tissue that is difficult to

distend, should be handled in a different manner as follows.

1. Place a small astringent cord below the margin of the tooth preparation. Untreated surgical

silk (Deknatel 2/0, J.Deknatel Co., Queens Village, N.Y.) works well for this function,

because it is 0.3 mm in diameter in the dry state and slightly larger after absorbing moisture

from the crevice.

2. Allow the cord to remain in place while the impression is made. The ends of the cord

should meet exactly at right angles with no overlapping, to avoid its removal with the

impression. It is advantageous to have the cut ends meet in an interproximal space. Curved,

tungsten-carbide tipped surgical scissors (MX60-216TC Gum Scissors, Miltex Instrument

Co., Lake Success, N.Y.) greatly aid in cutting the cord to an exact length.

3. Now follow the procedures described under “I” above.

III.Deflection in preparations where a considerable amount of tissue laceration has occurred,

either intentionally (rotary gingival curettage) or unintentionally is accomplished as follows.

1. Use the hemostypic syringe applicator to stop bleeding and control koozing crevicular fluid.

2. Wash and dry the region; assess the crevicular space and tooth preparation.

3. When hemostasis is sufficient, follow the procedures outlined in step NO. 3 above.

IV. Deflection in preparations where excess gingival tissue bulges over the cord and abscures

visibility of the margin should be approached in the following manner.

1. Judiciously remove the overhanging gingival tissue by electrosurgery.

2. Control minor hemorrhage with the hemostypic syringe.

Careful attention to technique will result in predictable tissue management with resultant

esthetic and periodontal health.

II;

Although the absorbed amounts reported by Kellam et al are lower than estimates by some

authors, the patient nonetheless is receiving a large dose from the cord around one tooth. If cord is

placed around more than one tooth. If more than one impression is made of a single tooth ( not an

uncommon occurrence in a teaching institution), and /or if a epinephrine containing anesthetic is

used, a patient could easily exceed the recommended maximum dosage of epinephrine.

Donovan and associates report that only 3% of the dentists they surveyed recorded the

patient’s pulse, and fewer than 10% recorded blood pressures routinely. Given this, it is likely that

few patients would receive even a rudimentary cardiovascular evaluation. The routine use of

epinephrine in dentistry, even on healthy patients, has been questioned.

23

Because epinephrine has been used successfully for nearly half a century, there is reluctance

to abandon its use. However, the fact that many dentist manage without it proves that it is not

indispensable. Its proper niche probably lies in utilization as an adjunct method in difficult situations

where other agents have been ineffective. Even then it must be used only one healthy patients with

no history of cardiovascular problems.

Aluminum chloride (AICI3) alum (aluminum potassium sulfate) [AIK (SO4)2], aluminum

sulfate [AL2 (SO4)3]. And ferric sulfate [Fe2(SO4)3] are also used for gingival retraction. Investigators

have compared several of these agents with epinephrine for displacement effectiveness, hemostasis

and tissue irritation.

No significant difference was found in sulcular width around teeth treated with alum- and

epinephrine-impregnated cord before impression (0.49mm vs 0.51 mm respectively). In an in vivo

study of 120 human teeth, Weir and Williams found no significant difference between the

hemorrhage control offered by cords impregnated with aluminum sulfate and those impregnated with

epinephrine.

In a study conducted on dogs, shaw et al found no additional inflammation in gingival

crevices in which dilute aluminum chloride (0.033%) was placed, but those receiving concentrated

solutions (60%) demonstrated severe inflammation and necrosis. Another study on human subjects

found no significant difference in gingival inflammation produced by alum –aluminum chloride, or

epinephrine-impregnated cords.

Over the counter drugs commonly used as nasal and ophthalmic decongestants show

promise as gingival retraction agents. Phenylephrine hydrochloride 0.25% (Neosynephrine,

Winthrop Consumer Products Div, Sterling Drug, New York, NY) was found to be as effective as

epinephrine and alum in widening the gingival sulcus, while oxymetazoline hydrochloride 0.05%

(Afrin, schering-plough Health Care Products, Memphis, TN) and tetrahydrozoline hydrochloride

o.5% (Visine, Consumer Health Care Div, Pfizer, New York, NY) were 56% more effective.

There is evidence to suggest that tissue hemorrhage can also be controlled indirectly by the

adjunctive use of antimicrobial rinses. Sorensen et al report lowered plaque, bleeding, and gingivitis

indices with the administration of 0.12% chlorhexidine gluconate (Peridex, Proctor & Gamble,

Cincinnati, OH) 2 weeks before tooth preparation, 3 weeks during provisional restorations, and 2

weeks after final restoration cementation.

III:

The soaking time required for liquid uptake by retraction cords is crucial factor in the

successful gingival retraction procedure. It is evident that the amount of medicament solution

absorbed by cords during soaking is of importance to achieve a proper hemostatic action. In addition

to the length, thickness, structure, and moistening properties of the cord, the amount of medicament

absorbed also depends on the length of soaking time. With a given cord size, the strengths of the

responses in gingival microcirculation are expected to depend on the amount of medicament crossing

the sulcus epithelium; therefore standardization of the conditions during the soaking procedure is

24

critical. Little attention has been paid in the literature to the kinetics of fluid absorption of retraction

cords.

The gingival retraction technique applied before dental impression procedures should be

chosen such that the gingival sulcus is properly retracted and that hemostatic action and elimination

of tissue fluid (crevicular fluid) are ensured. The agent used and the proper pore size for the

appropriately moistened retraction cord ensure the required actions during the mechanical-chemical

retraction procedures. This study was designed to simulate clinical practice as closely as possible.

Soaking the cords in the medicament solutions ensured fluid uptake. The conditions for this step

were standardized for reproduction in everyday practice. The proposed protocol allows reproducible

estimation of the saturation times of cords with a given thickness immersed in medicament solutions.

The results obtained in the fluid absorbency kinetic study support that, in an aqueous

environment, the fluid absorption of medicament test solutions be cords depends on soaking time ,

but the properties of the medicament solutions also have an influence. Long term storage of cords in

the medicament solutions may cause some problems; thus, on the basis of these data, it is

recommended that cords cut to the proper size be incubated in the medicament solution for 20

minutes before use. A shorter incubation time generally does not ensure even impregnation of the

cords, whereas long-term storage yield only an insignificant increase in the amount of fluid absorbed.

The results of this study also suggest that an inverse relationship between fluid absorption

rate and cord thickness exists. Thus cords with smaller diameters exhibit faster absorption rates than

thicker cords. Nevertheless, these values do not lead to conclusions regarding saturation time, as this

parameter also depends on the maximum of fluid cord thickness. This can possibly be explained by

the differences among cords in pore structure, moistening of inner surfaces, and swelling of threads.

The soaking time ensured for the liquid uptake of retraction cords was a crucial factor in the

successful gingival retraction procedure. The results of this study indicated that prior to clinical use,

20 minutes of soaking in the medicament solution was necessary when air bubles were removed from

the cords before soaking.

The rate of liquid uptake depended on the thickness of the cords as well. Thethinner cords.

The saturation time, however, did not correlate with the thickness of cords, as the time also depended

on the maximum of the fluid absorption capacity.

IV;

Studies of chemical-mechanical and purely mechanical cord-retraction techniques have

shown various degrees of necrosis and/or stripping of the gingival sulcus with complete healing

within 7 to 10 days. No histologic studies have been reported on using copper bands on the sulcular

tissue, though disruption of the sulcular epithelium could be expected. Taylor and Campbell found

that pressure from a thin steel blade not exceeding0.8 gm caused complete separation of the epithelial

attachment and complete reattachment within 5 days. In a 6-month study, Coelho and Brisman found

an average gingival recession of 0.33 mm after complete crown preparation, modeling plastic-copper-

band impressions, ;and insertions of temporary acrylic resin crowns. The copper-band impression

was implicated as the major factor producing this recession.

25

Sulcus damage with electrosurgery was reported to vary depending on the type of unit used.

Electro-section (undamped, fully rectified, high –frequency alternating current with biterminal

application) causes cell dehydration and volatilization only along the line of incision.

Electrocoagulation (highly or moderately damped, uncertified alternating current with biterminal

application) causes tissue necrosis over a moderately localized area. Electrodessication (highly-

damped alternating current with monoterminal application), or electrocautery; produces coagulation

necrosis over a wide area, extending into underlying tissues.

Pope et al found that wound healing following electrosurgical retraction in dogs lagged

about 4 days behind healing of similar wounds produced by a scalpel. A histologic study indicated

that vasodilation and influx of fibrinogen and polymorphonuclear leukocytes occurred immediately

after retraction using a scalpel but was delayed 4 days with electrosurgery. Others have reported

delays in wound healing with an electrosurgical technique versus blade incision.

On the other hand, Eisenmann et al, in an electron microscopic study of the incision line

comparing electrosection and use of scapel, found comparable tissue trauma after surgery with

equivalent healing at the cellular level.

IV:

This study is the first direct comparison of sulcus retraction by cord, copper-band, and

electrosurgery. Although similar complete wound haling was found in 24 days with the three

procedures, the nature and extend of the wound, the degree of permanent recession, and the duration

of the haling process differed considerably. Retraction by cord involved damage to the sulcular and

junctional epithelia and underlying connective tissue. Healing was characterized by the rapid influx

of polymorphonuclear leukocytes. Retraction using copper bands was most often atraumatic but

often involved an incisional wound in the junctional epithelium and underlying connective tissue.

The wound from copper bands healed most rapidly (4days) and produced the least permanent

recession (O.1 MM). Electrosurgery resulted in annihilation of the sulcular epithelium but left the

junctional epithelium largely untouched. The haling was relatively slow (16 to 24 days) and involved

the greatest permanent recession (0.6mm0. In all cases, no damage to the bony attachment apparatus

was observed in the wound haling.

On the basis of wound haling and gingival recession caused by the three procedures, the

copper band retraction method was the most satisfactory.

V:

Chemical retraction agents used in fixed prosthodontics for temporary displacement of free

gingival tissue before impression making can cause injury to the gingival tissue cells.

This study evaluated changes in cultured rat keratinocytes treated with 2 chemical agents

used for gingival retraction. Treated cultures were compared with untreated cultures.

Keratinocytes of rat gingival were grown in a specific medium for 10 days. After treating 1

group of specimens with 0.05% tetrahydrozoline and another group with 25 % aluminum chloride,

both for 10 minutes, the cultured cells were examined with scanning and transmission electron

microscopy and compared with control specimens.

26

Twenty-five percent aluminum chloride produced a significantly greater extent of cellular

damage than 0.05% tetrahydrozoline, which caused only mild changes in the cultured cells.

On the basis of the morphologic and ultrastructural changes in primary cell cultures of rat

keratinocytes observed in this study, it was concluded that 25% aluminum chloride was significantly

more aggressive than 0.05% tetrahydrozoline. (J Prosthet Dent 2002;87:51-6)

VI:

Another method of tissue removal, which is comparable to electrosurgery, is use of a 12-

fluted flame-shaped carbide bur. This method can provide adequate retraction for reversible

hydrocolloid impression techniques with less damage to gingival tissues. The bur method resulted in

less tissue loss at each time interval tested.

The bur method obviously is a less traumatic and more conservative method of gingival

retraction. Tupac and Neacy compared the rotary method, using a diamond instead of a carbide, with

conventional cord retraction and found no significant differences. This research supports the bur

technique as a more conservative method of gingival retraction than the electrosurgical method. It

also produced evidence that there is a direct relationship between initial tissue damage and resultant

tissue loss.

ELECTRO SURGERY

There are situations in which it may not be feasible or desirable to manage the gingiva with

retraction cord alone. Even if the general condition of the gingiva in a mouth is healthy, areas of

inflammation and granulation tissue may be encouered around a given tooth. This can be caused by

overhangs on previous restorations or by the caries itself. It may have been necessary to place the

finish line of the preparation so near the epithelial attachment that it is impossible to retract the

gingiva sufficiently to get an adequate impression. In these cases, it may be necessary to use some

means other than cord impregnated with chemicals to gain access and stop minor bleeding.

27

The use of electrosurgery has been recommended for enlargement of the gingival sulcus and

control of hemorrhage to facilitate impression making. Strictly speaking, electrosurgery cannot stop

bleeding once it starts. If hemorrhage occurs, it first must be controlled with pressure and/or

chemicals, and then the vessels can be sealed with a coagulating ball electrode.

Electrosurgery has been described for the removal of irritated tissue that has proliferated

over preparation finish lines, and it is commonly used for that purpose. There has been concern

expressed about the use of electrosurgery on inflamed tissue, be used on exaggerated response to an

electrosurgical procedure. Proximity to bone and lateral heat production may have been responsible

for the response. Bone is very sensitive to heat.

Electrosurgery is unquestionably capable of tissue damage, Most surgical instruments are

dangerous if used improperly. Tremendous iatrogenic damage has been done over the years by the

rotary handpiece, but no one has suggested that it not be used. Kalkwarf et al reported that wounds

created by a fully rectified, filtered current in the healthy gingiva of adult males demonstrated

epithelial bridging at 48 hours and complete clinical healing at 72 hpurs. In a double-blind study on

27 patients. Aremband and Wade detected no difference in healing in gingivectomies done by

scalpel or electrosurgery. When variables are properly controlled in electrosurgery. Untoward events

in wound healing are rare.

An electrosurgery unit is a high-frequency oscillator or radio transmitter that uses either a

vaccum tube or a transistor to delver a high-frequency electrical current of at least 1.0 MHZ (one

million cycles per second). It generated heat in a way that is similar to a producing heat in muscle

tissue for physical therapy. Electrosuregy has been called surgical diathermy.

Credit for being the direct progenitor of electrosurgery is generally given to d’Arsonval.

His experiments in 1891 demonstrated that electricity at ;high frequency will pass through a body

without producing a shock (pain or muscle spasm_, producing instead an increase in the internal

temperature of the tissue. This discovery was used as the basis for the eventual development of

electrosurgery.

Electrosurgery produces controlled tissue destruction to achieve a surgical result. Current

flows from a small cutting electrode that produces a high current density and rapid temperature rise at

its point of contact with the tissue. The cells directly adjacent to the electrode are destroyed by this

28

temperature increase. The concentrates at points and sharp bends. Cutting electrodes are designed to

take advantage of this property so they will have maximum effectiveness. The circuit is completed

by contact between the patient and a ground electrode that will not generate heat in the tissue because

its large surface area produces a low current density, even though the same amount of current passes

through it. The cutting electrode remains cold, this differs from electrocautery, in which a hot

electrode is applied to the tissue.

Types of Current:

There are different forms of current that can be generated for electrosurgical use, depending

on the type of machine (and circuitry) used or the setting on any given machine. These current

exhibit different wave forms when viewed on an oscilloscope. They are significant because each

produces a different tissue response

The unrectified, damped current is characterized by recurring peaks of power that rapidly

diminish. It is the current produced by the old hyfurcator or spark gap generator, an it given rise to

intense dehydration and necrosis. It causes considerable coagulation, and healing is slow and painful.

Sometimes referred to as the Oudin or Telsa current. It is not used routinely in dental electrosurgery

today.

A partially rectified, damped (half-wave modulated) current produces a wave form with a

damping in the second half of each cycle. there is lateral penetration of heat, with slow healing

occurring in deep tissues. The damping effect produces good coagulation and hemostatis but tissue

destruction is considerable and healing is slow.

A better current for enlargement of the gingival sulcus is found in the fully rectified (full-

wave modulated) current that produces a continuous flow of energy. Cutting characteristics are good

and there is some hemostasis.

The fully rectified, filtered is a continuous wave that produces excellent cutting. Healing of

tissues cut be a continuous wave current will be better initially than tissues cut by a modulated wave.

The continuous wave produces less injury to the tissue than does a modulated wave. However, a

controlled histologic study found that after 2 weeks, haling of wounds produced by filtered current

29

was nor remarkably better than healing of wounds produced by nonfiltered full-wave modulated

current.

Filtered current probably produces better healing in situations requiring an incision and

healing by primary intention, because there is less coagulation of the tissues in the walls of the

wound. This is not critical in those procedures done in conjuction with restorative dentistry, when

either the inner wall of the gingival sulcus is removed, or modified gingivosplasty is accomplished by

planning the surface of the tissue. In thsese cases, hemostatis is required, and moderate tissue

coagulation is not only tolerated but desired.

Grounding:

For the patients safety, it is important that the circuit be completed by the use of the ground

electrode, which is also known as a g round plate, indifferent plate, indifferent electrode, neutral

electrode, dispersive electrode, passive electrode, or patient return. Some dentists, prompted by the

unfortunate advertising of a few electrosurgical manufactures, have chosen to dispense with the used

of this vital piece of equipment. An electrosurgery unit will work without one, but it is neither as

efficient nor as safe.

Grounding the chair is not an acceptable alternative. Current will be dissipated through the

path of least resistance, and patient contact with a piece of equipment, including metal parts of the

chair, could cause a burn. It is acceptable, however, to permanently attach a metallic mesh grounding

antenna to the chain under the upholstery and insultated from all metal chain parts. This can do much

to reduce patient anxiety.

The safe use of electrosurgery dictates that current flow be facilitated along the proper

circuit from the generator to the active electrode, the patient, and back to the generator. Because

patient burns have been attributed to faulty grounding in many cases, the proper grounding of a

patient is considered to be the single most important safety factor when electrosurgery is used.

Oringer recommends that the ground be placed under the thigh rather than behind the back,

as is often done. Contact with a small, bony protuberance, such a vertebra or shoulder blade, could

produce a high enough current density to cause a burn. The only precaution to be observed in placing

the ground under the legs is that the patient doesn not have keys in a pants pocket or is not wearing

metal garters ( the latter is unlikely in this day).

30

Contraindications:

For reasons of safety, electrosurgery should not be used in some circumstances. It should

not be employed on patients with cardiac pacemakers. The demand (synchronous) type of

pacemaker, which is the most common, is designed to sense cardiac impulses ( the R wave). When

bradycardia occurs because the heart does not emit an impulse, the pacemaker fires at an appropriate

rate to keep the heart beating. External electromagnetic interference hinders the pacemaker’s sensing

function. Incorrectly sensing the interference as an intrinsic myocardial impulse, the generator shuts

down until the interference ceases, with consequences that could be quite serious for the patient.

Electrosurgery will alter the normal function of a pacemaker, an it presents a hazard to the patient

who wars one. Shielding in recent pacemaker models diminishes the risks from extraneous

electromagnetic interferences, but the use of electrosurgery is still contraindicated for those patients

who wear pacemakers.

Because it can produce sparks in use, electrosurgery should not be used in the presence of

flammable agents. This does not present the risk in dentistry that it does in medicine, because

flammable gases are not routinely employed as dental anesthetics such as ethylchloride and other

flammable aerosols should be avoided when electrosurgery is to be used.

Many fires in hospital operating rooms do not involve flammable anesthetics. Instead they

occur when ordinary combustible materials are ignited in an oxygenated atmosphere that will support

a fire. There is a slight danger attached to the use of nitrous oxide with electrosurgery because of the

enriched oxygen atmosphere that will be present in the oral cavity and nasopharynx. The number of

reported cases involving flash fires caused by dental electrosurgery in the presence of nitrous oxide-

oxygen analgesia is minimal. Oringer describes two such occurances. Given the right circumstances

with an extremely dry mouth and an accumulation of oxygen, a small spark caused by the electrode

touching a metallic restoration could conceivably set off a dry cotton packing. Therefore, whenever

electrosurgery is used in the presence of nitrous oxide-oxygen analgesia, be sure that any cotton

packing in the mouth is kept slightly moist, if in fact it is not already that way from absorption of oral

fluids.

Electrosurgery Armamentarium

31

1. Electrosurgery unit

2. Set of cutting electrodes

3. Cotton pliers

4. Mouth mirror

5. Fischer Ultrapak Packer

6. DE plastic filling instrument

7. High-volume vaccum with plastic tip

8. Wooden tongue depressor

9. Cotton rolls

10. Cotton-tipped applicator

11. Aromatic oil

12. Hydrogen peroxide

13. Dappen dish

14. Alcohol sponges

15. Retraction cord

Electrosurgery technique:

Before an electro surgical procedure is done, verify that anesthesia is profound and reinforce

it if necessary. With a cotton-tipped applicator, place a drop of a pleasant smelling aromatic oil, such

as peppermint, at the vermillion border of the upper lip. The odor from it will help to mask some of

the unpleasant odor emanating from the mouth during electrodurgery.

Check the equipment to make sure all the connections are solid. Be especially certain that

the cutting electrode is seated completely in the handpiece. If any uninsulated portion of it other than

the cutting tip is an accidental burn on the patient’s lip.

Proper use of electrosurgery requires that the cutting electrode be applied with very light

pressure and quick, deft strokes. The pressure required has been described as the same needed to

draw a line with an ink-dipped brush without bending the bristles. It is obvious that the electrode is

being guided, and not pushed, through the tissue.

To prevent lateral penetration of heat into the tissues with subsequent injury, the electrode

should move at a speed of no lessthan 7 mm per second. If it is necessary to retrace the path of a

32

previous cut, 8 to 10 seconds should be allowed to elapse before repeating the stroke. This will

minimize the buildup of lateral heat that could disrupt normal healing.

Initially set the power selector dial at the level recommended by the manufacturer and make

adjustments as necessary. As the electrode passes through the tissue, it should do so smoothly

without dragging or charring the tissue. If the tip drags and collects shreds of clinging tissue, the unit

has been placed on a setting that is too low. On the other hand, if the tissue chars or discolors, or it

there is parking, the setting is too high. If an error must be made initially, it is better to have a setting

that is slightly too high. Moist tissue will cut best. If it dries out, spray it lightly. Avoid collections

of water, however, because that will increase resistance and decrease efficiency.

A high –volume vaccum tip should be kept immediately adjacent to the cutting electrode at

all times to draw off the unpleasant odors that are generated. The lip must be plastic to prevent any

burns that might be caused by accidental contact with the electrode. For the same reason, a wooden

tongue depressor or plastic-handled mirror should be used rather than the metal-backed mouth mirror

that would customarily be employed.

Stop frequently to clean any fragments of tissue from the electrode by wiping it with an

alcohol-soaked 4x4 sponge. The electrode is completely safe as soon as the foot switch has been

released. Proper technique with the cutting electrode can be summed up in three points.

1. Proper power setting

2. Quick passes with the electrode

3. Adequate time intervals between strokes

Gingival Sulcus Enlargement

Before any tissue is removed, it is important to assess the width of the band of attached

gingiva. The electrosurgery tip is a surgical instrument; it cannot restore lost gingiva. If there is

unattached alveolar mucosa too near the gingival crest, peridodontal surgery, probably in the form of

a gingival graft, must be employed to reinstate an adequate bend of healthy, attached tissue.

To enlarge the gingival sulcus for impression making, a small, straight or J-shaped electrode

is selected. It is used with the wire parallel with the long axis of the tooth so that tissue is removed

from the inner wall of the sulcus. If the electrode is maintained in this direction, the loss of gingival

33

height will be about 0.1 mm. Holding the electrode at an angle to the tooth, however, is likely to

result in a loss of gingival height.

Around those teeth where the attached gingival tissue is thin and stretched tightly over the

bone on the labial surface, there is a greater chance for a loss of gingival height. This is frequently

true of maxillary anterior teeth, and particularly the canines, and is worth bearing in mind if the

esthetic requirements are great and any gingival recession will be unacceptable.

With the electrosurgery unit off, the electrode is held over the tooth to be operated and the

cutting strokes are traced over the tissue. Depress the foot switch before contacting the tissue, and

then move the electrode through the first pass. A whole tooth should be encompassed in four

separate motions: facial, mesial, lingual and distal at a speed of no less than 7 mm per second one

area. Wait 8 to 10 seconds before repeating that stroke. This will minimize the production of lateral

heat. Clean tissue debris off the electrode tip after each stroke. Use a cotton pellet dipped in

hydrogen peroxide to clean debris from the sulcus. Better results are usually obtained if retraction

cord is loosely packed in the enlarged sulcus before the impression is made.

Dental electrosurgery can provide a safe and efficient modality for crating a space in the

gingival sulcus by the removal of a small wedge of tissue with an electrode tip. This tissue dilation

34

method is commonly referred to as creating a sub gingival tissue through or subgingival impression

funnel. The procedure creates a wedge or soft –tissue funnel that extends from the tissue crest to

approximately 0.3 to 0.5 mm below the finish margin. This provides space for an adequate bulk of

the elastic impression material beneath the margin and results in more accurate duplication of the

preparation for fabricating master casts and dies. The tooth margin is prepared to the gingival crest,

the soft tissue funnel is established, and then the margin is refined to the desired sulcular depth.

Caution must be exercised in preparing the margin to the base of the tissue funnel since the

impression material will not duplicate tooth structure beneath the finishing line.

When electrosurgery is satisfactorily utilized the tissue response is excellent. Research has

established the need for biterminal electrode application and has shown that thehear produced

because of tissue resistance disperses in a lateral direction. A fully rectified surgical current produces

the least amount of tissue heat and allows for healing by primary intention. A thin layer of coagulum

also provides a clot for haling. Bleeding is either non-existent or minimal in the majority of patients.

In the authors opinion, dental electrosurgery provides the following advantages when compared

with the other two methods: (1) excellent vision of the margins; (2) refinement of margins to the

desired depth in the sulcus after tissue dilation; (3) access to root caries by rapid tissue removal; (4)

hemostasis; (5) predictable healing of the tissues; (6) improved accuracy for impression materials by

providing increased bulk; (7) reduction in chair time and stress for the patient and the dentist; (8)

better access to margins for construction of treatment restorations; (9) ability to remove irregular or

excess tissue around the teeth and recontour the pontic space just prior to making impressions; and

(10) minimal postoperative discomfort for the patient.

INSTRUMENTATION

The electronic current of choice for tissue displacement is the surgical current. The

coagulation current should only be used for bleeding control. Small single or thin double wire loop

electrodes are suggested to expose the margins. Electrode is commonly used for anterior teeth and

the single or double wire loop for posterior teeth (Fig.2, A and B). For the neophyte, the J loop or

A.P. 11/2 electrode (Fig.2c) can provide guidance in establishing the depth of the subgingival tissue

trough. The short end of the J loop electrode is 1.5 subgingival tissue trough. The short end of the J

loop electrode is 1.5 mm and the exposed portion of the A.P. 1 ½ electrode is the same length. The

depth can then be controlled by the amount of the electrode visible above the tissue crest. As an

example, for a 0.75 mm trough depth, 0.75 mm of the J loop or A.P. 1 ½ electrode would be above

the gingival crest as trough is established. The short side of the J loop is furthest from the tooth. A

disadvantage of the J loop is cleaning the shortside of the electrode between application. The

cleaning the shortside of the electrode between applications. The short end catches in the 2”X2”

gauze pads used to clean the electrode.

Additionally, small loop electrodes are used in removing redundant tissue approximating the

teeth or in the pontic area (Fig.3). Whether the dentist is restoring several single teeth or placing a

fixed partial denture, the tissue should be recontoured to provide the treatment indicated for the

individual patient.

35

ANTERIOR RESTRORATIONS

Exposure of the preparation margin for single or multiple individual restorations on the

anterior teeth is most exacting. The tissue is thinner at the gingival crest than at the posterior teeth,

with the possible exception of the mandibular first premolars. Regardless of the tissue dilation

method used, great care must be exercised during the procedure. Figure 1 illustrates the type of

gingival tissue that yields predictable results when using tissue dilation procedures. For the maxillary

and mandibular central and lateral incisors a single wire tip electrode is suggested. The tooth

preparation margin is usually placed beneath the crest of the tissue on the facial surface because of

esthetic considerations. The margin is prepared to the crest of the facial tissue, the through

established around the tooth, and the margin refined beneath the gingival crest to the desired depth in

the sulcus (Fig.4). The dial setting of the surgical current is selected and the electrode is passed

around the tooth with a programmed, rapid, non-pressure stroke using three or four separate

applications. A biterminal electronic current is concentrated in the electrode tip to remove the tissue.

The current is activated before tissue contact. If the electrode is placed in contact with the tissue

before the unit is activated, excess tissue coagulation and shrinkage will occur. The electrode tip is

kept parallel or at a slightly acute angle (15 to 200) with the tooth, and the through is created on the

lingual surface moving the electrode mesial-to-distal or vice-versa. The facial trough is formed in a

similar manner and is completed by passing through the proximals. If the three-stroke application is

utilized, the electrode can be moved from midlingual to distoproximal, facioproximal to midlingual,

and mesiofacial to distoproximal. Frequently, the tooth margins on the lingual surfaces are finished

supragingivally so it is not necessary to remove tissue in this area. The trough is required only on the

facial.

If any refinement is needed, a minimum time lapse of five seconds is required before

passing through the same tissue. This allows for lateral dispersement of the heat generated in the

tissue. The postoperative treatment consists of applying 4 to 5 air-dried layers of tincture of benzoin

and myrrh just prior to placing the treatment restoration.

Figure 5 illustrates electrosurgical tissue dilation for a young patient on fractured maxillary

central incisors with exposed pulps resulting from a bicycle accident. After successful endodontic

therapy, cast cores were cemented and electrosurgery performed to expose gingival margins. As a

result of the accident, the fracture on the left incisor resulted in a root defect which extended into the

gingival sulcus (Fig.5A). Slight hemorrhage along the lingual gingival of the left cuspid and lateral

incisor resulted from the palatal injection.

Marginal tissue was excised and the root defect exposed using the adjustable vari-tip

electrode and fully rectified current. Further hemorrhage would obscure the defect, so a slightly

higher current setting was used on the distolingual aspect of the left central. A heavier border of

white coagulum can be seen on the remaining gingival crest in the area. Note the absence of

coagulum around the other surgical areas. The placement of the porcelain to metal crowns at the time

of cementation is shown in Figure 5C. Absence of tissue blanching and general gingival health can

be observed.

36

In figures 6, a combination of electrosurgical uses during tooth preparation is shown. Figure

6A illustrates the need for clinical crown lengthening, smoothing the pontic space, and tissue dilation

before the impression is made. The fully rectified current and the vari-tip electrode were used to

remove a wedge of tissue from the lingual aspect of the anterior teeth (Fig. 6B). The edentulous

areas were then planed with a loop electrode to remove the excess tissue which approximate the

abutments. This facilitates the use of desirable pontic to tissue form.

The final tooth and soft tissue preparation is shown prior to impression making in Figure 6C.

While a large surface area has undergone surgery, note the lack of bleeding, the thin layer of

coagulum, and the overall form of edentulous a res. Figure 6D illustrates the hydrocolloid impression

with detailed sharpness and lack of marginal color change which could b e indicates of hemorrhage.

Figure 6E is a lingual view with the pin-ledge retainers in place. The lingual and pontic areas have

healed uneventfully. Figure 6F presents the facial view of the bridges. Tissue response to disciplined

electrosurgical application is excellent and predictable.

Another valuable electrosurgical tissue dilation procedure is immediately prior to

cementation. When treatment restoration have been in place several weeks, the epithelial tissue

around the treatment restoration margins grows into any voids. If the tissue is not removed, it will be

trapped over the margins during cementation. The pressure of cementation and the cement will cause

this small amount of tissue of degenerate, leaving a microscopic void. Leakage can occur in these

spaces, and the potential for recurrent caries is enhanced. A fully rectified surgical current with a

single wire tip electrode is passed around the margins prior to cementation (Fig 7A) to remove any

epithelial tabs over the margins. The area is flushed with a 3 per cent solution of hydrogen peroxide

before restoration is before cementation (Fig 7B).

A patient with multiple anterior fixed restorations is shown in Figure 8A just prior to

cementation. Electrosurgical tissue dilation was previously used to expose the margins in order to

make the impression. Several weeks postoperatively, healthy tissue and margin coverage were noted

(Fig 8B). The slight irritation between the right and left lateral incisors was due to retained cement.

After removal of the cement, the tissue in this area also returned to normal.

ANTERIOR TISSUE DILATION FOR CANINES

Tissue displacement around canines is usually approached with a modified troughing

technique. Since canine tissue is knife edged (more than other anterior teeth), a straight wire tip of a

medium loop electrode is used at right angles to the tissue. The margin edge is blunted on the facial

surface, then the trough is established. This technique results in a thicker gingival margin and

removes the thin tissue margin that shrinks regardless of the tissue displacement method (Fig .9)

POSTERIOR RESTORATIONS

The electrosurgical tissue dilation technique for posterior teeth is similar to that for anterior

teeth. For the neophyte it is recommended that the subgingival troughing procedure on posterior

teeth be perfected. The gingival tissue is usually thicker and a slight exposure of a crown or retainer

margin is not as critical. Use of single or double wire electrodes follows the same principles as for

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anterior teeth. Initially the J loop electrode can be used as discussed earlier to gauge the trough depth

in the sulcus.

Figure 10A demonstrates the use of a thin double wire loop electrode and Figure 10B the

use of the J loop provide a trough 1.5 mm in the gingival sulcus. The double wire loop or J loop can

be squeezed together to remove less sulcus tissue. All electrodes can be bent for easier access to the

area concerned. A schematic diagram of the subgingival tissue trough with the margin refined to the

desired depth in the sulcus is shown in Figure 10C.

The electrosurgical technique for full coverage preparations for a fixed partial denture is

demonstrated on a mandibular right premolar abutment preparation. The tooth was prepared slightly

below the tissue crest without tissue laceration. A thin double wire loop electrode w3as then used to

remove a small wedge of tissue beneath the crest. Immediately postoperatively a slight amount of

bleeding was noted in the distofacial area (Fig 11B). The area was sprayed lightly with a 3 percent

hydrogen peroxide solution to rinse away the small amount of blood and tissue debris (Fig. 11C).

The margin was refined to the desired depth in the sulcus on the facial and proximals. Lingually

(starting just lingual to the contact area) a chamfer finish line was used and finished supraginginvally;

electro surgical margin exposure was therefore unnecessary. Figure 11D shows the rubber base

impression; note the margin detail and the recording of the tooth surface 0.3 to 0.5 mm beneath the

margin. The second molar was finished supragingivally both because esthetic appearance was not

critical in this area and, more importantly the tissue health is easier to maintain. Normal tissue color,

lack of bleeding, and absence of excessive tissue coagulation can be noted around the premolar

abutment after making the impression (Fig.11E)

Many restorative procedures cannot be accomplished without tissue recontouring in addition

to tissue dilation. Figure 12 demonstrates the recontouring of the pontic tissue on the mesial of the

molar abutment. The initial preparation of a full veneer crown with the margin at the gingival crest is

shown in Figure 12A. Using an angled single wire electrode and a fully rectified current, a gingival

wedge of tissue was removed to gain direct vision below the alloy margin (Fig.12B). The soft tissue

was excised and a medium – sized loop electrode was used to plane the gingival adjacent to the molar

to improve soft tissue form for pontic adaptation (Fig.12C).

Dr. J.R. Schmidt of Edwardsville, Illinois re-fabricated an anterior bridge which necessitated

soft and hard tissue preparation (Fig.13A). The soft tissue condition around the abutment teeth and

pontic area was unacceptable for the placement of a restoration. The fixed retainers and connector;

have been removed, and the diseased marginal tissue can be easily observed (Fig. 13B)

The excess tissue was removed and the pontic tissue recontoured, the preparation refined,

and the troughing completed. A fully rectified surgical current was used with a medium loop

electrode for planning and a single wire electrode for a troughing procedure (Fig. 13 C). The tissues

were rinsed with 3 percent hydrogen peroxide, and the impression was made. The completion of the

porcelain/metal bridge is shown in Figure

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13, D-F. A small gingival colored resin insert (not shown) was made for the lingual area to enhance

speech.

Figure 14A shows a clinical view of tissue overgrowth into a fractured distal amalgam

restoration. The metal mirror is being used to restrain the tongue in the figure. Plastic mirror are

desirable, but they are not always necessary. If a metal mirror or evacuator is adjacent to the surgery

site and either is momentarily contacted by the electrode, some sparking from the active electrode

may occur, but the tissue contacted will not be damaged. However, sparking may startle the patient;

therefore, the use of plastic mirrors and evacuation tips are recommended. The position of the

suction tip to remove odor and keep the tissues dry but not dessicated can be noted after tissue

removal (Fig.14B). The removed tissue is a normal color and shows virtually no coagulation along

the incision site (Fig 14C). The alloy build-up is shown prior to tooth preparation, and the tissue at

the excision site exhibits normal tissue color (Fig 14D). As in other procedures, postoperative

treatment consists of applying 4 to 5 air dried layers of tincture of benzoin and myrrh.

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