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INTRODUCTION: It is said that teeth with progressive caries and vital pulps are

sensitive

to

any

form

of

mechanical

interference.

This

sensitiveness varies greatly in different persons and in different carious

cavities

of

the

teeth

of

the

same

person.

The

great

variation in sensitiveness of normal dentin is remarkable. The

dentist

procedures

causes

in

pathological

the

pain

in

treatment

conditions

of

the

carrying

of

out

dental

teeth.

If

the

caries this

technical and

pain

other

could

be

completely or even largely eliminated, the conservation of teeth of a

tremendously

larger

number

of

persons

could

be

effectively

done. Many persons who are really anxious to preserve their teeth do not come to dentist due to this fear. The

pain

produced

by

in

cavity

the

preparation

friction

of

may

rotary

be

caused

by

instruments/

heat

cutting

instruments applied to sensitive dentin. Pressure applied by instruments to the dentin. Heat probably causes the most severe and prolonged pain, if not controlled is likely to be responsible for hyperemia of pulp. Methods of control of pain: 1.

Gaining confidence of the patient.

2.

Proper instruments employed with skill and confidence.

3.

The use of cooling devices.

4.

Use of obtundents.

5.

Desiccation of the dentin.

6.

Pressure anesthesia with cocaine.

7.

Local anesthesia.

8.

General anesthesia or analgesia with N 2O gas or other.

1.

Gaining the confidence of the patient: Pain during operative procedure is a manifestation of fear. So

control

the

fear

and

the

problem

of

pain

control

is

greatly

simplified. The

right

psychological

approach

is

very

important.

With

some dentists the effect of individual personality amounts almost 1


to hypnosis. This is a gift derived to many and yet the average person should be able to cultivate a manner of approach that will avoid fear completely. One must always let the patient know about the procedures by explaining it properly to them. Dentists who operate with confidence and with efficient use of all instruments and appliances soon gain the confidence, so that

the

judicious

sufficient

to

use

make

of

sharp

cavity

burs

and

preparation

hand

instruments

without

is

anesthesia

acceptable to many. 2. Use of instruments: It can be divided as: Hand cutting Rotary instruments

Bur

Slow speed High speed Hand cutting: The

main

principle

of

cutting

with

hand

instruments

is

to

concentrate forces in a very thin cross section of the instrument at the cutting edge. Therefore the thinner this cross section the more sharper the instrument and the more efficient it is. Dull or blunt instruments require more pressure to cut the tooth structure, which also causes more frictional heat in turn causing pain. It has been proven that when a force of 10 lbs is applied on a sharp edged instrument the cutting efficiency is equal to 200 lbs whereas in a dull edged instrument is falls down to 20 lbs. 10 lbs

10 lbs

2


200 lbs

20 lbs

Rotary instruments: The factors that governs the presence or absence of pain can be briefly listed as: Speed,

pressure,

heat

production

and

vibration,

which

are

interrelated. Low

speed

instruments

(micro

motor

and

other

foot

driven

devices) results in a)

Application of more pressure on the cutting surface.

b)

Increase in the vibration which is two fold in origin i.e. amplitude and undesirable modulating frequency. At

low

speed

amplitude

is

increased

and

frequency

is

decreased. c)

Because

of

the

friction

there

is

more

heat

production

which is also directly proportional to pressure, rpm 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 the temperature reaches around 130째F) even at 113째F it can produce inflammatory response. To

overcome

these

disadvantages

of

low

speed,

high

speed

and ultra high-speed instruments were introduced. The

only

addition

in

high-speed

devices

was

the

usage

of

cooling devices to overcome the increased heat production due to increased rpm. 3. Use of cooling devices: Water

as

coolant

minimizes

the

pain

during

high-speed

cutting (as in airotor). Advantages of high speed with coolants: -

Rapid cutting.

-

Less pressure Low speed

(2-5 pounds).

High speed (1 pound) 3


Ultra high (1-4 ounces). -

Less sensitivity.

Disadvantages: -

Over cutting (this can reduced using low speed for e.g. lateral pressure with small sharp inverted cone burs using slow speed under DEJ gives good results).

-

Block the vision.

-

The use of chilled burs is said to diminish or eliminate pain.

-

Compressed

air,

carbon

dioxide

gas

and

ethyl

chloride

are

also used. 4. Use of obtundents: Sensitivity of dentin can be minimized with ferric solutions, chlorides etc. Commonly used obtundent is ZOE, it can be placed over cut dentin,

as

an

intermediate

dressing

in

patients

having

severe

sensitivity. Also in cases like cracked tooth syndrome where a band is cemented around the tooth in ZOE where it acts as an obtundent as well as a cementing medium. 5. Desiccation of dentin: Previously some school of thought believed that desiccation of dentin

by

blast

of

warm

air

gives

school

of

thought

relief

from

sensitivity

subsequent pain. But

recent

says

that

over

desiccation

should be avoided so as to prevent the fluid movement inside the dentinal

tubules,

which

causes

pain,

which

is

explained

by

hydrodynamic theory.

4


Even

during

cavity

cleansing,

three-way

syringe

should

be

pulp

of

used taking advantage of water and air. 6. Pressure anesthesia with cocaine: It

is

particularly

useful

in

anesthetizing

the

deciduous teeth and of young permanent teeth but not effective in areas of secondary dentin. The solution used suggested the following ingredients.

5


W. Clark contains: Cocaine – 25% Ether – 10% Chlorophenol – 15% 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 cone with the larger end at the surface. A very small bit of cotton pledget (1mm) should be moistened with the solution and is placed in 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 heavy pressure is applied in a series of thrusts using a round, flat faced condenser 1.2mm in diameter. This

forces

the

solution

through

the

dentinal

tubules

to

anesthetize the pulp. This must be done in a dry field. 7. Local anesthesia: May be 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 LA solutions. It reduces pain as well as permit the dentist 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.

6


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 to 0.9ml) (3-4 min). Small terminal nerve fibres in the area are blocked and thus rendered incapable of transmitting impulses. This is commonly employed in maxillary teeth because of the ability of anesthetic solutions to diffuse through periosteum and relatively thin cancellous bone. 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 maxillary. Posterior

superior

alveolar

nerve

block,

also

called

as

the

zygomatic or tuberosity block, is indicated when pulpal anesthesia is required for the maxillary third, second and first molars with the

underlying

buccal

alveolar

process,

periosteum,

CT,

and

mucous membrane are anesthetized (0.6ml to buccal fold). Infraorbital nerve

block is an

easy injection to administer,

producing anesthesia of three nerves – the Infraorbital, anterior superior

alveolar

and

middle

superior

alveolar

providing

anesthesia for central lateral, canine, premolar. Greater palatine (anterior) nerve block provides anesthesia to both the hard and soft tissues ranging from the third 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. 7


Nasopalatine

nerves

enter

the

palate

through

the

incisive

foramen, 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 density of bone.

So

anesthesias

the it

is

palatal

are

soft

advised

to

often

tissues use

traumatic

and

topical

their

because

firm

of

attachment

anesthesia

before

the to

palatal

infections.

Maxillary or second division nerve block: Though rarely necessary should be considerable 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 infection, pulp of all maxillary teeth on the side of injection; buccal soft tissues and bone; hard palate on the injected side; upper lip, cheek, side of the nose and lower eye lid. Mandibular anesthesia (1.5ml): Mandibular the

inferior

pulpal

alveolar

anesthesia

nerve

is

block.

normally

Additionally

achieved

through

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. Anesthesia is achieved in the anterior 2/3 of

the

tongue,

membrane

and

the

floor

of

the

mucoperiosteum

oral on

cavity, the

and

lingual

the side

mucous of

the

mandible. Inferior alveolar nerve block (branch of posterior division of mandibular nerve): Successful inferior alveolar and lingual nerve block

provides

anesthesia

to

all

mandibular

tissues

except

the

buccal mucous membrane and mucoperiosteum over the molars. If the anesthesia of this region is required, the buccal nerve must be blocked (branch of anterior division). 8


Incisive nerve block: The incisive and mental nerves are terminal branches of the inferior alveolar nerve, arising at the mental foramen. This provides sensory innervations to the skin of the lower lip and chin regions and the mucous membrane lining the lower lip; the incisive nerve, remaining within the mandibular canal provides sensory

innervations

to

the

pulps

of

premolars,

canine

and

incisors and the bone anterior to the mental foramen. Mandibular block: A

true

mandibular

block

injection

provides

adequate

anesthesia of all sensory portions of the mandibular nerve (buccal, inferior alveolar, lingual, mylohyoid) can be obtained through Gow Gates

mandibular

mandibular

block

condyle

below

(the the

lateral

side

insertion

of

of

the

the

neck

lateral

of

the

pterygoid

muscle). Akinosi technique: (closed mouth technique) Indicated especially when opening of the mandible is limited opening to infection, trauma or trismus. Additional local anesthetic procedures: i.

Periodontal ligament injection: The PDL injection is frequently used in restorative dentistry

when isolated areas of inadequate anesthesia are present. It may also be used alone to achieve anesthesia in a single mandibular teeth. Advantage

includes

adequate

pulpal

anesthesia

with

a

minimal volume of solution (0.2-0.4ml) and absence of lingual and lower lip anesthesia. Intraseptal infiltration: (variation of intraosseous): Here

the

27-gauge

1-inch

needle

is

inserted

into

the

intraseptal tissue in the area to be anesthetized. Its success rate is not so high. Because

of

younger patients.

decrease

bone

density

it

is

more

successful

in 9


Intrapulpal injections: When the pulp chamber of a tooth has been exposed, either surgically or pathologically, the intrapulpal injections may be used to achieve adequate pain control. The needle will be firmly wedged into the canal to a snug fit and the solution must be inserted under pressure. Intraosseous injection: Though rarely employed since the reintroduction of the PDL injection, the intraosseous injection can be effective in producing anesthesia adequate permit opening of the pulp chamber, at which time intrapulpal anesthesia can be administered. To

administer

an

intraosseous

infection

the

dentist

must

anesthetize the soft tissues and bone overlying the apical region of the tooth through local infiltration.

Pain control Additional Considerations: Electronic dental anesthesia (EDA): EDA methods,

devices

provide

including

gate

clinical

pain

control

control

theory

of

via

one

pain,

or

more

release

of

endorphine or release of serotonin. EDA

is

always

more

effective

in

combinations

with

local

anesthetics. Advantages: Significant decrease of edema and pain in the post surgical period

when

patients

receive

low-frequency

electronic

nerve

stimulation immediately following apical surgery. Requirement

of

postoperative

analgesics

was

decreased

in

patients who received EDA. Preoperative and postoperative pain control: Most of the patients suffering from pulpitis are likely to have been taking oral analgesics for sometime before their visit to the clinic. 10


The

patient

should

continue

to

take

the

NSAID

following

treatment for a period of time determined by the treating doctor (23 days depending on probable post treatment discomfort). Oral premedication

8. GA or Analgesia with N 2O gas: (Inhalation Sedation): Oral

Intravenous

premedicatiaon -

sedation

Hypnotherapy

Benzodiazepam

The oxygen.

technique To

deliver

used the

in

N2O

correct

inhalation

mixture

of

administered

these

gases,

with

specific

equipment is required with skilled person. Classification (Guedel) of anesthesia describes 3 stages: Stage I : Analgesia Stage II : Excitement Stage III: Surgical anesthesia Stage I is divided into 3 planes: -

15-30% N2O plane 1 – inhalation sedations

-

25-35% N2O plane 2 – relative analgesia

-

>55% N2O plane 3 – total analgesia unconsciousness.

Effect of local anesthetics on the pulp: The purpose of adding a vasoconstrictor to LA is to potentate and prolong the anesthetic effect by reducing the blood flow in the area which it is administered. At the same time it causes a significant decrease in pulpal blood flow, although the flow reduction lasts a

relatively short

time.

11


There

is

a

direct

relationship

between

the

length

of

flow

cessation and the concentration of the vasoconstrictor used with increased concentration of epinephrine the cessation of pulp flow lasts longer. Researchers blood

activity

reported

returned

to

that

pulpal

normal

blood

levels

flow

after

3

and

hours

sensory of

total

cessation of blood flow. Presumably

irreversible

preparation

is

caused

vasoactive

agents

by

pulp

the

damage

release

(substance

P)

of

resulting substantial

into

the

from

tooth

amount

extra

of

cellular

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 as well as with other metabolic waste products thus damaging the pulp. Therefore

whenever

possible,

it

is

advisable

to

use

vasoconstrictor – free LA for restorative procedures on vital tooth. REFERENCES:  The

art

and

science

of

Operative

dentistry

by

Sturdevant(3 rd

Edn.)  Operative Dentistry by G.V.Black  Monheim’s

Local

Anesthesia

and

pain

control

in

dental

practice(7th edn.)C.Richard Bennet

12


Pain control in operative procedure/ dental implant courses by Indian dental academy