FLUID CONTROL AND GINGIVAL

DISPLACEMENT

PRESENTED BY- NAZAM TAFADARFINAL YEAR BDS

GUIDED BY:Dr MANJULA DAS HEAD OF DEPARTMENT, PROSTHODONTICS

CONTENTSIntroductionFluid control

Objectives of fluid control and tissue management Mechanical methods chemical methods

 Soft tissue management

Mechanical technique Chemico-mechanical technique Surgical techniques

Recent advancesNew gingival retraction agentsDiscussionConclusion Bibliography

INTRODUCTION To obtain a accurate impression control

of fluids and appropriate displacement of gingiva are essential. Impression making is technique sensitive because accurate reproduction of finish line is essential for the fabrication of fixed partial denture. Fluid control and gingival displacement enhance the operator visibility , increased patient comfort, and aid in exacting optimum benefits from the impression and cementation procedure.

When the preparation margins extend subgingivally, the adjacent tissues must be retract or displaced laterally to allow acess and to provide adequate thickness of the impression material. This may require enlarging the gingival sulcus through mechanical , chemical , or surgical means and must be done without jeopardizing periodontal health.

FLUID CONTROL Objectives 1) to obtain a dry clean operating field . 2) to enhance operating visibility and

patient comfort. 3) improve the properties of restorative

material. 4) to improve the operating efficiency. 5) protect from swallowing and aspirating

foreign bodies.

Sources of moisture in clinical environment

Saliva

Salivary glands-parotid, submandibular, sublingual

The mean flow rate (+/- SD) of unstimulated saliva was 0.26 +/- 0.16 ml/min and that of saliva while chewing six different foods was 3.6 +/- 0.8 ml/min.

BloodInflamed gingival tissues/Iatrogenic damage

Water/dental materialsRotary instruments, triplex syringe, etchants, irrigant solutions

On a average has high speed rotatory cutting instrument is 30 mL per minute

Gingival crevicular fluid0.05 to 0.20 µL per minute

METHOD OF FLUID CONTROL Mechanical Chemical other

Mechanical methods

• Rubber dam • Suction devices• High volume vacuum• Saliva ejector• Svedopter• Cotton rolls

Rubber damIntroduced by S C Barnum, 1864

Uses For core build up, pattern fabrication Impression making of inlays and onlays Removal of old restoration and caries For cementation

Contraindication

Should not be used with poly-vinylsiloxane as interferes with polymerization

Patients allergic to latex

Advantages

Isolate one/more teeth

Eliminates saliva from operating site

Retracts soft tissue

Disadvantages Time consuming and patients objection

Unusual tooth shapes or positions that cause inadequate clamp placement

Partially erupted teeth Broken down teeth

Patients suffering from asthma

High volume vacuum

Powerful suction device, use of 10mm diameter HVE tips, and a properly functioning suction pump set to evacuate one liter per minute of fluid

Uses Apparatus also removes small operatory debris Excellent lip retractor

Disadvantages Cannot be used for impression & cementation procedure

HIGH VOLUME VACUUM SUCTION

Saliva ejector• Low volume suction devices• 300 ml/ min is the suction rate• Adjunct to high volume vacuum/ rubber dam/cotton

rolls Uses Removes saliva from the floor of mouth Removes water slowly

Suction tips/ saliva ejectors

Disposable saliva ejectors - Transparent [ plastic] - Multi coloured [ plastic] - Hygoformic saliva ejector - Mirror vac - Lingua fix

SVEDOPTER It is used for isolating mandibular teeth It is a metal saliva ejector attached with a

tongue deflector

DISADVANTAGES -

Access to the lingual surface of mandibular teeth is limited

Cannot be used when mandibular tori prevents its use.

It may injure the soft tissues.

Commonest and cheap

Preparation in maxillary arch & mandibular arch

Cotton rolls

Controls small amounts of moisture and retracts cheek and tongue

Keeps its shape and does not fall apart when full of saliva

Provides acceptable dryness for procedures Cementation Impression making

Uses

Absorbents Useful for short period of isolation

Alternatives when rubber dam application is impractical

Retracts cheek & provide absorbency

CHEMICAL METHODS OF FLUID CONTROL

ANTI-SIALOGOUGES

LOCAL ANASTHETICS

CLONIDINE (ANTI-HYPERTENSIVE DRUG)

ANTI-SIALOGOGUES Controls salivary flow

They are gastrointestinal anti-cholinergics that inhibit the action of myoepithelial cells in salivary glands, producing dry mouth.

These drugs inhibit parasympathetic inervation and thereby reduce secretions, including saliva.

This group of drugs includes –atropine, dicyclomine, and methantheline.

CONTRAINDICATIONS –

-Patient with heart disease Asthma, obstructive conditions of

congestive heart failure.etc -Glaucoma,

because they can cause permanent blindness.

COMMONLY USED ANTI-SIALOGOGUES

Methantheline bromide (banthine) : 50 mg 1 hour before procedure

Propantheline bromide (pro-banthine) : 15 mg 1 hour before procedure

Clonidine hydrochloride (antihypertensive) :

0.2 mg 1 hour befor procedure

LOCAL ANESTHETICS

In addition to pain control normally needed during tissue displacement, local anesthesia may help considerably with saliva control during impression making.

Nerve impulse from periodontal ligament form part of the mechanism that regulates salivary flow, when these are blocked by anesthetics , saliva production is considerably reduced.

Local anesthetics drugs are Lignocaine, lidocaine, bupivacaine etc.

CLONIDINE (ANTI-HYPERTENSIVE)

It is considered safer than anticholinergics and has no specified contraindications.

However it should be used cautiously in patients who take hypertention medication.

In clinical trial, 0.2 mg of clonidine reduced salivary flow as effectively as 50mg of methantheline.

GINGIVAL RETRACTION

Definition

Gingival Retraction is the deflection of the marginal gingiva away from a tooth.

Gingival retraction is a process of exposing margins when making impression of prepared teeth.

Need of gingival displacement

• For accurate impressions in case of finish line at or below the gingival sulcus.

• For restoration of cervical lesions

FINISH LINE EXPOSURE

Finish line

The peripheral extension of a tooth preparation / or

The planned junction of two materials / or

The terminal portion of prepared tooth

It is a line of demarcation / or

IMPORTANCE OF FINISH LINE EXPOSURE

The gingival tissue must be healthy & free of inflammation before cast restorations are fabricated

The finish line must be reproduced in the impression.The marginal fit is very important in preventing recurrent caries and gingival inflammation (marginal intergrity)

Hence the finish line should be temporarily exposed to reproduce entire preparation.

Classification of gingival tissue displacement

Non-surgical Surgical

Mechanical Mechano-chemical

MECHANICAL METHODS

Commonly used mechanical methods of gingival retraction are :Copper bandRetraction cordRubber dam

COPPER BAND Copper band is a welded tube corresponding to

the size of the prepared tooth.

It is used to carry the impression as well as to displace the gingiva to expose the finish line.

Impression compound or elastometric impression materials can be used along with this band.

Disadvantage -Causes injury to the gingival tissues

TECHNIQUE

Gingival retraction cords

Gingival retraction cord is a tapered diameter cord that can be wrapped several times about a tooth that causes flared gingival crevice.

Plain cord provides mechanical retraction

Gingival retraction using chemically impregnated retraction cord is a mechanico-chemical method of displacement

Classification of retraction cords

Depending on the configuration TwistedKnittedBraided

Depending on surface finishWax Unwaxed

Depending on the chemical treatmentPlain Impregnated

Depending on number strandsSingle Double-string

They are available in a variety of configurations to provide for different diameters.

Fig : Braided type retraction cord Fig : Non-braided type or knitted type retraction cord

DESIRABLE QUALITIES OF CORD- Dark color to maximize contrast with

tissues, tooth & cord. Absorbent to allow for uptake of wet

medicament. Available in different diameters to

accommodate varying morphologies of gingival sulcus.

CHEMICALS USED FOR GINGIVAL RERACTION

They are generally local vasoconstrictors which produce gingival shrinkage.

8 % racemic epinephrineAluminium chloride (AlCl3)Alum (aluminium potassium sulphate)Alumminium sulphate Ferric sulphate (Fe2(SO4)3)

(Alluminium Chloride and Ferric sulphate are most commonly used because of its minimal tissue damage.)

CONTRAINDICATIONS OF EPINEPHRINE

It is contraindicated in patient with-

CVS Disease Hypertension Diabetes Hyperthyroidism Known hypersensitivity to Epinephrine.

IDEAL REQUIREMENTS OF CHEMICAL USED WITH GINGIVAL RETRACTION CORDS :-

It should produce effective gingival displacement and haemostasis.

It should not produce any irreversible damage to the gingival.

It should not have any systemic side effects.

Single cord technique.

Double cord technique.

Infusion technique of gingival displacement.

Every other tooth technique.

Techniques of gingival retraction

STEP-BY-STEP PROCEDURE. (DOUBLE CORD TECHNIQUE )

1. Isolate the prepared teeth with cotton rolls, place saliva evacuators as required, and dry the field with air. Loop the cord.

2. Cut a length of cord sufficient to encircle the tooth. Do not over-

desiccate the tooth, because this may lead to postoperative sensitivity.(Cord is left in the sulcus during impression making. – single cord technique)

0

7. Preparation is dried and impression is made with primary cord in place.

8. After impression making, small diameter cord is soaked in water and removed from the sulcus.

RETRACTION CORD PACKERS

CLINICAL TIP : If bleeding is persistent when the first cord is

removed, continue with the impression making certain to syringe the impression material within the sulcus. Even with the expectation that the impression will be unsuccessful. This impression will maintain the retraction while allowing for hemostasis. Remove the first impression and DO NOT look at it. Immediately make a second impression. The sulcus will still be open and will not be bleeding.

-(According to Dr Howard Strassler, Professor, University of Maryland Dental School )

# It is best to start in the interproximal area , because the cord can be more easily placed here than facially or lingually.

# The instrument should be angled toward the tooth so the cord is pushed directly into the area.

# It should also be angled slightly toward any cord already packed; otherwise, that portion might be displaced.

NOTE: Overpacking should be avoided because it could cause tearing of the gingival attachment, leading to irreversible recession. Repeated use of displacement cord in the sulcus also should be avoided, since this can cause gingival recession.

Infusion technique

Indication Controls hemorrhage

Procedure

Retraction cord packed into the sulcus for 1-3 minutes.

Infuser used with a burnishing motion in the sulcus circumferentially 360° around the sulcus

Every other tooth technique

Anterior tooth preparation when the roots are in proximity

Prevents collapse of gingival papilla.

SURGICAL METHOD

ROTARY CURETTAGE (GINGETTAGE)

It is a troughing technique , wherein a portion of the epithelium within the sulcus is removed to expose the finish line.

It should be done only on the healthy gingival tissue

Criteria for rotary curettage

Done on healthy and inflammation free tissue to prevent tissue shrinkage

Absence of bleeding on probing

Sulcus depth less than 3.0 mm

Presence of adequate keratinized gingiva

TechniqueShoulder finish line preparation prepared at

gingival crest using flat end tapered diamond

Finish line extended apically1/2-2/3 the depth of the sulcus by torpedo diamond

Aluminum chloride impregnated retraction cord placed in sulcus

Cord removed after 4-8 minutes

Shoulder prepared at the gingival level

Torpedo diamond bur to form chamfer finish line and removal

of epithelial sulcus

Cord placed in the troughed sulcus

DISADVANTAGES OF GINGETTAGE

Instrument has poor tactile sense so this technique is very sensitive.

It can potentially damage the periodontium .

ELECTROSURGERY The procedure is called surgical diathermy or

Electrosurgical retraction

It is the surgical retraction of the sulcular epithelium using an electrode to produce gingival retraction

The inner epithelial lining of gingival sulcus is removed, thus improving access for a subgingival crown margin and effectively controlling post surgical hemorrhage (provided the tissue are not inflamed).

An electrosurgery unit works by passage of a high frequency current (1 to 4 million Hz) through the tissue from the large electrode to a small one. At the small electrode , the current induces rapid localized polarity changes that cause cell breakdown.

For restorative procedure, an unmodulated alternating current (AC) is recommended, because it will minimize damage to deeper tissue.

INDICATIONS -

Areas of inflammation in gingival tissue where the retraction cord cannot be used

Gingival proliferation around the prepared finish line

CONTRAINDICATIONS -1. Patients with cardiac pacemakers or patients

with any electronic medical devices.2. Use of topical anesthesia such as ethylchloride

and other inflammable aerosols should be avoided when electrosurgery is to be used.

3. Not suitable on thin attached gingivae (e.g labial tissue of maxillary canines)

ADVANTAGES –

1) Sophisticated technique.2) Can be done in cases with gingival

inflammation.3) Produces little to no bleeding.4) Quick procedure.

DISADVANTAGES –1. Very technique sensitive2. Application of excessive pressure may produce

severe tissue damage.3. Difficult to control lateral dissipation of heat.4. It cannot be done in a dry field. The operatory

area should be very moist during the procedure. This leads to compromised access and visibility.

ELECTROSURGICAL UNIT (ESU)

Specially designed electrosurgical units are available for gingival reduction.

The major uses of these electrodes include :

Gingival sulcus enlargement. Crown lengthening. Removal of edentulous cuff.

The unit has knobs to alter the frequency and the flow of current.

Two electrodes can be attached to each unit. One is surgical electrode and the other is the ground electrode or ground plate.

GROUND ELECTRODE : The ground plate should be placed under the thigh or the back of the patient. It is used to complete electrical circuit.

SURGICAL ELECTRODE or CUTTING ELECTRODE : It is similar to a probe, and is designed to produce intense heat during surgical procedures. This heat helps to vaporize the target tissue. It may be either straight or J-shaped.

MOST COMMON EDGE DESIGNS ARE – COAGULATING PROBE, DIAMOND LOOP, ROUND LOOP,

SMALL STRAIGHT PROBE, SMALL LOOP ,ETC.

MECHANISM OF ELECTROSURGERY

TECHNIQUE Basic principles to be followed during

Electrosurgical procedures: Local anaesthesia should be given. Proper power setting – Grounding should be

done before usage of electrode. Swift passage of electrode – During its use,

electrode should be applied with no pressure and swift strokes.

Rest interval between strokes – It should never be placed stagnant at one point

rather it should move very smooth ,

the probe should move at minimal speed of 7mm per second.

A rest period of 8-10 seconds should be allowed to elapse if second stroke is needed.

The electrode can be cleaned by wiping it with an alcohol-soaked sponge.

TECHNIQUE FOR GINGIVAL SULCUS ENLARGEMENT

A small (straight or J-shaped ) electrode is used.

The electrode should be positioned such that it is parallel to the long axis of the tooth.

The procedure is done in four motions namely – facial, mesial , lingual and distal.

Debris in the sulcus should be removed using a cotton pellet dipped in Hydrogen peroxide (H2O2).

TECHNIQUE FOR SURGICAL CROWN LENGTHENING

Removal of hyperplastic gingiva (gingivectomy) inorder to expose anatomical crown to increase accessibility.

It is done using a diamond electrode.

The diamond electrode is run over the tissues such that one of its surfaces follows the incline of the tooth where the procedure is carried out.

The bevel should be done on attached gingival to prevent re-growth.

If there is an extensive wound, a periodontal dressing should be given and should be changed weekly.

TECHNIQUE FOR REMOVAL OF EDENTULOUS CUFF

Edentulous cuff is a remnant of inter dental papilla.

Which is seen in the proximal sides of the adjacent edentulous space.

It is removed by using an electrosurgically by using loop electrode.

RECENT ADVANCES IN SOFT TISSUE MANAGEMENT

MAGIC FOAM CORD MEROCEL LASER EXPASYL RETRAC

MAGIC FOAM CORD

First expanding VPS material designed for easy and fast retraction of sulcus without potentially traumatic packing or Pressure.

Fig : Foam cord

TECHNIQUE -

a)Initial situation

b) Pre-fit the comprecap. C) Apply magic foam cord

D) Aplly magic foam e) Comprecap after remaval.

ADVANTAGES1. Not technique sensitive, flows directly into the

sulcus. 2. Easy to use.3. Atraumatic.4. Rinsing not required.5. More efficient in multiple preparations.

Disadvantage –-No hemostatic action

Merocel strips

Marco Ferrari et al in 1996 found Merocel Synthetic material that is biocompatible polymer

(hydroxylate polyvinyl acetate)

Mechanism of action

Expands by absorption of oral fluids and exerts pressure on surrounding tissue

Method

About 2 mm of merocel retraction strip

Provisional crown inserted

Maintain pressure on crown for 10-15 min

Advantages

Easily shaped and adapted around tooth

Highly effective in absorption of oral fluids

Chemically pure- no post surgical complications

Non abrasive

LasersIndication Controlled tissue removal before impression

making Tissue contouring

Properties of laser depends on Wavelength Waveform

Types of lasers

Neodymium: yttrium-aluminium-garnet

Erbium: yttrium- aluminum-garnet

Advantage

Minimum pain and discomfort Less fear ,anxiety and stress Minimum or no anesthesia No drill sounds Less chair time Reduced post operative complications Minimum or no bleeding

Disadvantage

Overuse causes shrinkage of tissue and also results in exposure of crown margin

Introduced by Satalec Pierre Rolland Cordless gingival retraction (SDS/Kerr Company)

Composition Aluminum chloride-15% astringent & hemostatic

agent Kaolin Excipients

Expasyl

Mechanism of action

It has both mechanical and chemical action

Aluminum chloride provides- hemostasis Viscosity of Kaolin- retracts the tissue

Recommended time of application-1-2 min

AdvantagesEffectively achieves hemostasis.

Effectively retracts gingival tissues

Less traumatic to tissues than cord packing.

Faster than traditional cord.

Easy removal from sulcus by rinsing.

Dispenser tips can bent- improves intraoral access.

DisadvantagesExpensive

Effective under limited conditions.

Disposable metal dispenser tips are too large causes difficulty to express

Thickness makes it difficult to express

NEW GINGIVAL RETRACTION AGENTS-(W.H.BOWLES, S.J.TARDY & A.VAHADI)

 

 A sympathomimetic amine containing eye drops and nasal decongestant have been shown to be effective in gingival retraction.

Tetrahydrazoline hCl 0.05% - (Visine)

Oxymetazoline hcl 0.05% - (Afrin)

Phenylephrine hcl 0.25% -(Neosynephrine)

Visine & afrin-produced -greater displacement than any other agents.(alum , racemic epinephrine & phenylephrine etc)

Visine produced :-50% greater tissue displacement-better control of crevicula seepage-no detectable side-effects

Neosynephrine–-is as effective as, epinephrine & alumin widening the gingival sulcus.

DISCUSSION

The choice of gingival retraction cord has proven itself to be one of personal preference by the clinician. Keep in mind that different cord types offer a variety of properties that to some make them more desirable

A 20-25% alluminium chloride and 15.5 – 20 % ferric sulfate are most popularly used chemical reagents. When used for durations within the gingival sulcus of less than 10mins, they cause minimal tissue damage.

Unfortunately , gingival bleeding is difficult to control when packing a cord into the sulcus, the tissue starts to bleed making impression difficult or impossible. For this reason a new class of gingival retraction material have been introduced. These cordless retraction materials eg. Expasyl ( Kerr), Racegel ( Septodont ) , Traxodent ( Premier ) etc provide for excellent hemostasis and some gingival retraction.

High viscosity hemostatic gel can be placed in the sulcus to both help with hemostasis and act as lubricant for atraumatic placement of gingival retraction cord and can be placed on the cord itself. For this case 25% alluminium sulfate hemostatic gel is used to impregnate and lubricate a knitted cord.

(According to Dr Howard Strassler,Professor, University of Maryland Dental School,)

CONCLUSION

Gingival displacement is an important procedure for fabricating indirect restoration especially when subgingival finish line is used. Proper management of tissues and fuilds around the prepared teeth is essential for making an excellent impression in a field free from capillary seepage. But before any procedure is attempted, the dentist should analyse for the best suited technique which would minimally harm the adjacent tissues.

BIBLIOGRAPHY Fundamentals of FIXED PROSTHODONTICS,

Herbert T. Shillinburg, David A. Sather, Edwin L. Wilson, Joseph R. Cain, Donald L. Mitchell, Luis J. Blanco, James C. Kessler

Text book of Prosthodontics by V Rangarajan & TV Padmanabhan

THANKS