Pain Control in Operative Dentistry-dharam
Transcript of Pain Control in Operative Dentistry-dharam
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PAIN CONTROL IN OPERATIVE DENTISTRY
A quickened pulse rate, a hastened heart beat, clammy, sweaty skin,
thirsty dry mouth, a tightness in the gut and a feeling in the mind Do we
really have to do this.
Hold on, control your imagination, all Im describing is an attack of
dental anxiety, phobia and pain.
Good morning and welcome to todays seminar on pain control in
operative dentistry.
Lets confabulate on this under the following topics:
Introduction
Definition and etiology of pain
Methods of pain control
Latest advances
Conclusion
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INTRODUCTION
Since ancient times, the profession of dentistry has been associated
with excruciating trauma and unbearable discomfort. Vivid imagery and
exaggerated cartoonery depicted dentists as the epitome of satanic devils
ready to inflict merciless agony. So much so, that pain become
synonymous with dentistry and dentistry with pain. However, the era of
modern dentistry decided to shun this image and made rapid strides in
changing the perception of dentistry from a heartless monster to a caring
angel. Various advances in anesthetics, operating techniques and clinical
ambience and approach have shown the way towards truly painless
dentistry.
Definition What is painPain is defined as an unpleasant sensory and emotional experience
resulting from a stimulus causing, or likely to cause, tissue damage or
expressed in terms of that damage. This is affected by emotional factors.
Various assessments are used to evaluate pain like the linear and
visual analog scale, Minnesotta Multiphasic Personality Index (MMPS)
and other subjective and objective criteria.
Now, lets have a look at the various possible causative factors for
pain in operative dentistry.
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1) Firstly the patient Pain being a highly subjective and
individualistic response, the patient plays a major role in how much
pain is felt. Stoic, controlled patients may bear even the most
unpleasant procedures quietly while highly hysteric patients might
jump even if you dont touch them. Hence, patient conditioning is
such an integral and vital part of pain management.
2) Second are the instruments, materials and armamentarium used in
dentistry rotary instrumentation, caustic chemicals, improperly
handled hand instruments and ironically the anesthetic needle itself
are associated with pain responses. Heat and pressure play an
important role in these mechanisms.
3) The Pulp- Dentin Organ Enamel is sensationless. Any procedure
performed purely on enamel is incapable of causing pain. However,
procedures that involve the dentin and pulp elicit only pain as a
response; if any. The various theories of pain transmission of pain in
dentin and pulp are still exploring the exact cause but sensitivity is
an integral part of the dentinal response.
4) Improper handling of tissues Careless and insensitive handling of
the oral tissues may result in operative or post operative discomfort
and pain. Hence, delicate management of oral tissues is a must.
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Now we come to the methods or techniques of pain control:
These can be broadly described under
1) Gaining the confidence of the patient.
2) Ideal instrumentation and proper implementation.
3) Use of cooling devices.
4) Use of palliative drugs and obtundants.
5) Dessication of dentin.
6) Pressure anesthesia with cocaine.
7) Local anesthesia.
8) Use of inhalation sedation or nitrous oxide sedation
9) Hypnosis and psychotherapy.
10)General anesthetics.
1) Gaining the confidence of the patient: The first axiom is Treat the
individual, not just the tooth. A patient is an individual just like us
with his / her own complexes, beliefs and fears. The correct
psychological approach will help us not only to understand their
needs but also alleviate any apprehension skillfully.
Individual personality of the dentist and the right demeanour can
have a profound influence on patient confidence and reduction of
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anxiety with subsequently reduced perception of pain. The art and
science of skillful conversation should be mastered to create a warm
and lasting relationship.
Succinct yet thorough explanation of the involved procedures with
required modalities to accommodate age related understanding goes
a long way in achieving patient cooperation.
Also important is the look and feel of the workplace. The ambience
of the operatory, the care manifested in minor detailing and the
entire interior the sights,smells and sounds should convey a warm,
caring message to soothe the patient.
Every procedure and action should be performed confidently to give
the impression of efficiency and instill a sense of security in the
patient.
All these measures can indeed make the experience highly
rewarding for the individual and the clinician.
2) Correct instrumentation: Instrumentation can be either
Hand cutting
Rotary instrumentation Slow speed or High speed.
Hand cutting instruments:
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The main principle of cutting with hand instruments is to concentrate force
in a very thin cross section of the instrument at the cutting edge. Therefore,
the thinner the cross section, the more sharper the instrument and hence the
more efficient it is.
Dull or blunt instruments require more pressure to cut the tooth structure
which also causes more frictional heat thus eliciting pain.
It has been shown that when a force of 10 lbs is applied on a sharp edged
instrument, the cutting efficiency is equal to 200lbs whereas in a dull edged
instrument it falls down to 20lbs.
Thus sharpening stones should be used to always maintain sharp
instruments resulting in efficient work and lesser trauma.
Rotary instruments: Rotary instrumentation can govern the presence or
absence of pain through
1) Speed 2) Pressure 3) Heat production and 4) Vibration all of which
are inter related.
a) Low speed instruments such as micromotor and other devices
results in
(Ultra low 300-3000rpm, low 3000-6000 rpm, medium
20,000-45,000, high 45,000-1,00,000, ultrahigh 1,00,000 and
more).
1. Application of more pressure on the cutting surface.
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2. Increase in the vibration which is 2 fold in origin
i.e., amplitude and undesirable modulating
frequency.
At low speed, amplitude is increased and frequency
is decreased.
3. Because of the friction, there is more heat
production which is also directly proportional to
pressure, revolutions per minute and area of tooth in
contact because if any of these factors are increased,
heat production increases which can cause damage
to the pulp if temperatures reach 130F though even
110-113F can produce inflammatory responses.
To overcome the disadvantages of low speed, high and ultrahigh speed
instrumentation was introduced into dentistry. These rotate at speeds above
45,000 to 1,50,000 rpm and more and their advantages include:
1) Efficient rapid cutting.
2) Convenient to operator and patient.
3) Minimal vibration.
4) Low frictional heat with coolants.
5) Longevity of cutting instruments.
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6) Less pressure and sensitivity low speed (25lb), high speed (1lb),
ultrahigh (1-4 ounces).
Disadvantages:
1. Overcutting.
2. Visibility is hampered.
3. Lesser tactile sensation.
A major advancement with high speed cutting was the introduction of
coolants to lower the frictional heat and enhance efficiency and comfort.
3) Use of cooling devices: Coolants minimize pain and maximize
efficiency with high speed. The commonly used coolants are:
a) Air.
b) Water.
c) Combination of both which is the most popular and highly
effective.
Also, the use of chilled burs is said to diminish pain. CO2 and ethyl
chloride have also been experimented with.
4) Use of Obtundants: Here, soothing and palliative type of cements or
medicaments are used on dentin.
Desensitizing agents like ZnCl2, Ag(NO3)2, Ferric oxalates can minimize
dentinal sensitivity.
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Commonly used obtundant is ZOE which can be placed over cut dentin as
an intermediate dressing in patients having severe sensitivity.
Also in cases like cracked tooth syndrome a band is cemented around the
tooth with ZOE where it acts as an obtundant as well as a cementing
medium.
5) Dessication of dentin:
Previously, a school of thought advocated that dessication or drying of
dentin by a blast of warm air gives relief from sensitivity and
subsequent pain.
However, recent school of thought states that over dessication should
be avoided so as to prevent the fluid movement inside the dentinal
tubules, which causes pain, as hypothetized by the hydrodynamic
theory.
Even during cavity cleansing, a 3-way syringe should be used taking
advantage of both air and water.
6) Pressure anesthesia with cocaine:
This method is particularly effective in anesthetizing the pulp of
deciduous and young permanent teeth but not effective in areas of
secondary dentin and carious areas. It is quite effective for a short
duration procedure.
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The solution used has the following ingredients as elucidated by
Stanley W. Clark.
a) Cocaine 25%
b) Ether 10%
c) Chlorophenol 15%
d) Alcohol 50%.
Technique:
Access should be gained to the dentin cutting through enamel with a 1mm
inverted cone bur.
The opening is enlarged, changing it to the form of a section of a conewith
the larger end at the surface.
A very small bit of cotton pledget (1mm) should be moistened with the
solution and placed at the bottom of the opening.
A slightly larger piece of unvulcanized rubber should then be placed over
the cotton and pressure, at first light and gradually increased to heavy is
applied in a series of thrusts using a round, flat faced condenser about 1 to
2mm in diameter.
This forces the solution through the dentinal tubules to anesthetize the
pulp.
This must be done in a dry field.
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7) Local Anesthesia: It is the most widely used and popular technique
of effective pain control
8) . It is defined as a transient regional loss of sensation to a painful or
potentially painful stimulus resulting from a reversible interruption
of peripheral conduction along a specific neural pathway to its
central integration and perception in the brain.
Cavity preparation and Endodontic procedures may be painlessly
carried out after securing anesthesia by infiltrating the apical tissues or
by nerve blocking with one of the LA solutions.
It reduces pain as well as permits the dentists to work faster and save
time.
One should operate just as carefully when preparing cavities in teeth
with anesthetized pulps as though they are not anesthetized.
Local anesthesia administration should be monitored by performing a
preanesthetic evaluation.
Any history of allergies, cardiac anomalies, anemia or other blood
dyscrasias, kidney, liver or thyroid problems, infectious diseases,
epilepsy, bleeding disorders, diabetic complications or psychiatric
disturbances should be noted and adequate provisions or preparations
made for their handling.
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The various local anesthetics used are basically of ester and amine type.
Though choice mainly depends on situation and dentist, lignocaine with
a vasoconstrictor, specifically adrenaline is the most popular anesthetic
of choice. The vasoconstrictor aids in prolonging the action of the
anesthetic. The average duration of pulpal anesthesia obtained with
vasoconstrictor is approximately 1 hour while it is just 5-10 minutes
without vasoconstrictor.
Another important consideration is preparedness for any medical
emergencies. Anesthetic toxicity, allergic reactions, syncope,
hyperventilation etc are all contingencies for which an average
practitioner should be equipped and emergency drugs should be
available at hand. Proper preparation and precautions will make local
anesthesia a safe and predictable pain control procedure.
LA techniques:
1. Local infiltration (supraperiosteal infiltration)
Supraperiosteal anesthesia is described as a technique in
which anesthetic is deposited into the area of treatment (0.6-
0.9ml).
Small terminal nerve fibres in the area are blocked and thus
rendered incapable of transmitting impulses.
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This is commonly employed in maxillary teeth because of the
ability of anesthetic solutions to diffuse through periosteum and
relatively thin cancellous bone.
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2. Regional nerve block:
Nerve block is defined as a method of achieving regional
anesthesia by depositing a suitable local anesthetic solution close
to a main nerve trunk, preventing afferent impulses from
traveling centrally beyond that point.
i) Maxillary anesthesia Maxillary nerves that can
be anesthetized include the PSA, the anterior
superior alveolar, greater palatine, the
nasopalatine and the second division of the
trigeminal.
PSA block, also called as the zygomatic or tuberosity
block, is indicated when pulpal anesthesia is required
for the maxillary third, second and first molars (except
mesiobuccal root of 1st molar) with the underlying
buccal alveolar process, periosteum, connective tissue
and mucous membrane also being anesthetized.
Infraorbital nerve block produces anesthesia of anterior
superior alveolar and middle superior alveolar providing
anesthesia for central and lateral incisors, canines and
premolar.
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Greater (anterior) palatine nerve block provides
anesthesia to both the hard and soft tissues ranging from
the 3rd molar as far anterior to as the first premolar. In
the region of first premolar, partial anesthesia may be
encountered as branches of the nasopalatine nerve
overlap.
Nasopalatine nerves enter the palate through the incisive
foramina, located in the midline just palatal to the
central incisors and directly beneath the incisive papilla,
which anesthetize the premaxilla as far distal as the first
premolar.
Palatal anesthesias are often traumatic because of the
density of the palatal soft tissues and their firm
attachment to bone. So, it is advisable to use topical
anesthesia before palatal injections.
Maxillary or second division nerve block-
Though rarely necessary, it should be considered when other techniques
prove inadequate because of infection accompanied by inflammation.
This block provides anesthesia of the entire maxillary nerve peripheral to
the site of injection, pulp of all maxillary teeth on the side of injection,
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buccal soft tissues and bone; hard palate on the injected side, upper lip,
cheek, side of the nose and lower eyelid.
2) Mandibular anesthesia Mandibular pulpal anesthesia is normally
achieved through the inferior alveolar nerve block. Additionally,
anesthesia of the buccal soft tissues and bone anterior to the
mandibular molars is provided.
The lingual nerve is usually anesthetized along with the inferior
alveolar nerve. It provides anesthesia in the anterior 2/3 rd of the tongue,
the floor of the oral cavity and the mucous membrane and
mucoperiosteum on the lingual side of the mandible.
A successful inferior alveolar and lingual nerve block provides
anesthesia to all mandibular tissues except the buccal mucous
membrane and mucoperiosteum over the molars. To achieve anesthesia
of this region, the buccal nerve block must be administered.
Incisive or mental nerve block: The incisive and mental nerves are
terminal branches of the inferior alveolar nerve, arising at the mental
foramen.
This provides sensory innervation to the skin of the lower lip and chin
and the mucous membrane lining the lower lip, also, the incisive nerve
remaining within the mandibular canal provides sensory innervation to
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the pulps of premolars, canine and incisors and the bone anterior to the
mental foramen.
Mandibular nerve block: A true mandibular block injection provides
adequate anesthesia of all sensory portions of the mandibular nerve
(buccal, inferior alveolar, lingual and mylohyoid). This can be achieved
through the Gow Gates techniques involving the lateral side of the neck
of the mandibular condyle below the insertion of the lateral pterygoid
muscle.
Akinosi or closed mouth technique: This is indicated when opening of
the mandible is limited owing to infection, trauma or trismus.
Additional local anesthetic techniques:
1) Periodontal ligament injection:
The PDL injection is frequently used when isolated areas of inadequate
anesthesia are present. It is also indicated to achieve anesthesia in a
single mandibular and / or maxillary tooth.
Advantages include adequate pulpal anesthesia with a minimal volume
of solution (0.2-0.4ml) and absence of lingual and lower lip anesthesia.
2) Intraseptal infiltration (variation of intraosseous) Here the 27-
gauge 1-inch needle is inserted into the interseptal tissue in the area
to be anesthetized. Its success rate is not so high. It is relatively
more successful in young patients due to decreased bone density.
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3) Intrapulpal injections Though rarely indicated in operative
procedures, intrapulpal technique may be used to achieve pain
control when pulp chamber of a tooth is exposed.
The needle is firmly wedged into the canal to a snug fit and the solution
administered under pressure.
4) Intraosseous injection Though rarely employed since the
acceptance of the PDL injection, the intraosseous injection can be
effective in producing anesthesia adequate to permit certain
operative procedures.
To administer an intraosseous injection, the dentist must anesthetize the
soft tissues and bone overlying the apical region of the tooth through
local infiltration.
Effect of Local Anesthetics on the pulp:
A special consideration here must be given to the action of local anesthetic
with a vasoconstrictor on the health of the pulp organ.
The purpose of adding a vasoconstrictor to LA is to potentiate and prolong
the anesthetic effect by reducing the blood flow in the area to which it is
administered.
However, at the same time it causes a significant decrease in pulpal blood
flow although the flow reduction lasts a relatively short time.
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There is a direct relationship between the length of flow cessation and the
concentration of the vasoconstrictor used. Increased concentration of
epinephrine causes a longer cessation of pulpal blood flow.
Researchers have reported that pulpal blood flow returned to normal levels
after 3 hours of total cessation of blood flow.
Presumably, irreversible pulp damage resulting from tooth preparation is
caused by the release of substantial amounts of vasoactive agents
(substance P) into the extracellular compartment of the underlying pulp.
Under normal circumstances, these vasoactive substances are quickly
removed from pulp by the blood stream but when blood flow is decreased
these substances are accumulated along with other metabolic waste
products thus damaging the pulp.
Therefore wherever possible, it is advisable to use vasoconstrictor free LA
for restorative procedures on vital teeth.
9) Inhalation or Conscious Sedation:
Conscious sedation and inhalational analgesia are now accepted
modalities of pain control. Various pharmacotherapeutic agents have
been advocated. Myriad chemicals that have been proposed are
barbiturates, psychosedative drugs like phenothiazine derivatives,
propyl alcohol derivatives, benzodiazepine derivatives, and narcotics
like morphine but the most popular and widely used is nitrous oxide
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and oxygen inhalational analgesia. This technique basically relies on
elevation of pain threshold.
Nitrous oxide and oxygen in a controlled combination produce highly
effective sedation. Concentrations of 35-40% produce enhanced
sedative effects and are the recommended concentrations and produce
its peak effect in 3-5 minutes. Being inert, it does not combine with any
body tissue and is eliminated unchanged through the lungs is less than 5
minutes. However, the use of this technique requires elaborate
equipment and care during administration.
10)Hypnosis and psychotherapy Hypnosis is a sleep-like state with
persistence of certain behavioral responses. The subject is
susceptible to and may respond to the hypnotic suggestions
concerning aspects of behavior, environment, memory etc. It has
been used in various modalities in medicine and dentistry to alter
responses to pain. It is currently used to define an area of research
and treatment that employs suggestion. The long history of hypnosis
with various contributions is testimony to its effectiveness.
Combined with other techniques, it is a powerful tool.
The dentist and the patient may derive certain benefits:
The dentist has the opportunity to work on a more relaxed and
cooperative patient while the patient is less fatigued with no specific
recollection of having experienced discomfort. The operation must have
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a through knowledge of the mechanics of hypnosis and the associated
psychological, emotional and mental factors as well as the principles
associated with hypnosis. Posthypnotic suggestion has also been
proposed as a way of alleviating certain noxious dental habits.
Other psychological techniques include psychotherapy, operant
conditioning, biofeedback, systematic deconditioning and relaxation
techniques.
Biofeedback deserves mention as an interesting adjunct to pain control.
Its principal aim is the control and regulation of disordered nervous
system behavior. The therapeutic applications usually translate to the
direct control and elimination of the symptom. Hirschman and
coworkers reported success in lowering dental phobia and pain
perception and anxiety levels with a procedure that used forearm
extensor EMG biofeedback during dental treatment. Its mastery and
effectiveness await further research and trials.
11) General anesthesia: This technique involves complete transient
reversible of consciousness. Various agents like ether, halothane,
Fentanyl with Domperidone etc are utilized. It is employed as the
last report and this finds rare application in dental pain control. The
various stages of anesthesia as described by Guedal is 1957 are:
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Stage I Analgesia.
Stage II Excitement.
Stage III Surgical anesthesia
Plane I
Plane II
Plane III
Plane IV
Stage IV Overdose
General anesthesia is a highly specialized field and requires the
assistance of medical specialists and preparatory equipment.
Preanesthetic evaluation and medication have to be charted into the
treatment plan. Its use is reserved for highly demanding cases.
Role of medication in pre and postoperative pain control:
Most of the patients suffering from pulpitis are likely to have been
taking oral analgesics. NSAIDS can be used to control patient
discomfort postoperatively or preoperatively as well as for possible
placebo effect. Their myriad range from acetylsalicylates to ibuprofen,
and the latest COX-2 inhibitors afford a huge array of medicaments to
choose from.
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Advances and Newer concepts in pain control:
1) Newer, better acting local anesthetics with fewer side effects and
better safety profile like confbuinidine and repivacaine may change
the pharmaceutical range of anesthetics used in future. Also
alterations to local anesthetic profile like EMLA (Eutectic mixture
of local anesthetics) which allows profound topical anesthesia and
pH alteration to make administration more comfortable as well as
hyaluronidase to permit better penetration are but a few of the
research modalities.
2) Electronic dental anesthesia The use of electricity as a therapeutic
modality is not really new dating back to 40 A.D. but momentum in
this field gathered since the 1960s when TENS was introduced into
medicine and EDA was proposed for dentistry.
The mechanics differs for chronic and acute pain. Basically low
frequency setting of 2Hz and higher frequency of 120Hz for chronic
and acute pain is used which produces changes in blood serotonins, L-
tryptophan, endorphins, and enkephalins. Also the gate control theory is
employed upon for acute pain control.
In dentistry, it has found applications in Myofacial pain dysfunction
syndrome, acute dental pain for restorative and prosthetic procedures,
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adjunct to local anesthesia and as an aid in its administration and
reversal of LA.
It is basically administered with use of electrodes. Low frequency of
2.5Hz for 40-60 minutes is used for chronic pain while high frequency
of 120Hz is employed for restorative procedures adjusting the
controller and maintaining the electronic pad positions for various teeth
and procedures.
At present, it is basically indicated as an adjunct to local anesthesia and
future prediction for use in all spheres of dentistry exists. It is
contraindicated in cardiac pacemaker patients, neurological disorders,
pregnancy, maturity etc.
While advantages of no needle or infection exist the cost, training and
experimental nature of the modality are the drawbacks. Presently
available systems include Cedata, H-wave and 3M patient comfort
system. Only future research will show which way this technique
progresses.
3) Alternative tooth preparation These include the modality of air
abrasion, lasers, ultrasonics and chemomechanical means. Air
abrasion utilizes micron sized particles to remove tooth structure. It
is relatively more comfortable but has the disadvantage of lack of
control and has not caught the popular imagination. Lasers are now
available for hard tissue lasing and are reported as painless,
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noiseless and highly patient friendly. However, it is still under
research and the cost too is highly prohibitive.
4) A new treatment modality that promises to revolutionize the way we
look at operative dentistry also promises to eliminate pain
completely. This involves the use of ozone as a means to sanitize
carious lesions and employ remineralization techniques to
regenerate tooth structure with minimal, if any, restorative
procedures. Kavos Healozone is a novel, experimental device under
trial. Only time will tell, if it will deliver on it promises.
Newer techniques and ideas are being constantly researched upon to
achieve the ideal.
CONCLUSION:
No pain, no gain, goes the old axiom; however, it can be modified in
modern dentistry to state no pain, all gain. The application of ideal
techniques and procedures with expertise and an attitude of empathy and
understanding will help the clinician control and eliminate this highly
unwelcome stimulus to achieve greater efficiency and highly contented
individuals. Remember, to the whole world you might just be one man,
but to one man you just might be the whole world. That one man is the
individual who comes to us for relief-OUR PATIENT.
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BIBLIOGRAPHY
1) Local anesthesia and pain control in Dental practice Monheim.
2) Anesthesia A to Z Yentis, Hirsch, Smith.
3) Handbook of local anesthesia Stanley Malamed.
4) Sturdevants art and science of operative dentistry.
5) Operative Dentistry Marzouk.
6) DCNA Anesthesia in dentistry April 1999.
7) DCNA Dental Phobia and Anxiety October 1988.
8) Operative dentistry by G.V. Black.
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