LOCAL ANAESTHESIABLOCKS IN PEDIATRIC DENTISTRY

BYKOMAL TEWARIUPASANA MAHESHWARI(GROUP 3)

CONTENTS• Definition of LA• Classification• Composition• General structure of LA• Mode of action• Metabolism• Maxium recommended doses• Types of injection procedeure• Anaesthesia for maxilary and mandibular tissues• Mandibular blocks• Maxillary blocks• Complications• Recent advances• Conclusion

DEFINITION Reversible loss of sensation in a

circumscribed area of the body caused by a depression of a excitation in nerve ending or an inhibition of the conduction process in peripheral nerves.

MALAMED(1980)

CLASSIFICATION

BASED ON COMPOSITION

• ESTER GROUP• AMIDE GROUP• QUINOLONE

ESTER GROUP

1.Esters of benzoic acid

Cocain

Butacaine

Tetracaine

Benzocaine

2.Esters of para-amino benzoic acid

Procaine

Chloroprocaine

Propoxycaine

AMIDE GROUP• Bupivacaine• Lidocaine• Prilocaine• Articaine• Mepivacaine

QUIONOLONE• CENTBUCRIDINE

Classification based on mode of administration

• Topical –it can be supplied in solution or ointment or spray form .

Benzocaine Lignocaine

• Injectable – Lignocaine Procaine

CLASSIFICATION BASED ON DURATION

• SHORT ACTING- Procaine

• INTERMEDIATE ACTING- Lidocaine

• LONG ACTING- Bupivacaine

CLASSIFICATION BASED ON ITS SOURCE

• Natural• Synthetic

EXCEPT COCAINE ALL OTHER ARE SYNTHETIC

CLASSIFICATION BASED ON POTENCY

• VERY POTENT-Etidocaine

• MODERATELY POTENT- Lidocaine

COMPOSITION

1.Local anesthetic agent• Lignocaine hydrochloride 2% is most

commony used local anesthetic agent.• 2% lignocaine mean…….• 2 mg in 100 ml

or• 20mg in 1 ml• USES- CONDUCTION BLOCKADE

2. vasoconstrictorAdrenaline in the concentration of 1:50000 to

1:200000 is commonly used.

1:200000 means….

1 gm in------------- 200000 ml

Or

1mg in-----------------200 ml (0.02 mg/ml)

USES

1. Delays absorption of LA from the site

2. Provides blood less field

3. Prolongs the action

4. Reduces the systemic toxicity

3.Reducing agent• Sodium metabisulphite is used to

prevent the oxidation of the vasoconstrictor.

4.Preservative

• Methylparaben• It increases the self life of the anesthetic

solution• Acts as a bacterostatic agent

5.Fungicide• Thymol is used as fungicide

6.Isotonic agent• Sodium chloride is used to make

the solution isotonic with the tissues.it makes the solution alkaline.

7.vehicle• Modified ringer’s solution or distilled

water is used as vehicle.• It produces the volume of the

solution and act as dilutent.

GENERAL STRUCTURE• A lipophilic group…usually a

benzene ring• A Hydrophilic group…usually a

tertiary amine• These are connected by an

intermediate chain that includes an ester or amide linkage

• LAs are weak bases.

HOW LOCAL ANAESTHEICS WORK (mode of action)

THEORIES• Different theories have been given to explain mode of

action of local anesthetic agent:-

1. ACETYLCHOLINE THEORY by Dett Barn in 1967.

2. CALCIUM DISPLACEMENT THEORY by Goldman in 1966.

3. SURFACE CHARGE THEORY by Wei in 1969.

4. MEMBRANE EXPANSION by Lee in 1976

5. SPECIFIC RECEPTOR

SPECIFIC RECEPTOR THEORY

• It says that the blocking of local anesthetic is due to the binding of the drug to a specific site inside the nerve cell. This decreases the permeability of nerve membrane to sodium ions thus preventing the influx of the sodium ions into nerve. Thus the threshold potential of the nerve is increased which causes the decreased conduction of the impulse.

Calcium ions are present in bound form within the nerve cell membrane (sodium ion channel receptor site)

• LA molecules displaces these calcium ions from the sodium channel receptor site

Binding of the LA molecule to this receptor site.

Blockade of the sodium channel..

in sodium conductance

Depression of the rate of depolarization

Failure to achieve the threshold potential level

Lack of development of propagated action potential

CONDUCTION BLOCKADE

METABOLISM

ESTER GROUP• They are hydrolyzed in the plasma by the

enzymes pseudocholinesterase . Allergic reactions that occur in response to ester drugs are usually related to the metabolic product of ester local anesthetic i.e paraaminobenzoic acid.

AMIDE GROUP • There metabolism is more complex than

that of esters.

• Primary site of biotransformation is in liver.

• Hence the liver function & hepatic perfusion significantly affect it.

EXCRETION

• The local anaesthetic agent is excreated from kidney.

Factors affecting the onset 1. pH & pKa of tissue

2. Protien binding of the local anesthetic

3. Use of vasoconstrictor

4. Site of deposition of LA

5. Nerve morphology

6. Concentration of anesthetic agent used

ANAESTHETIC AGENT SUITABLE FOR CHILDREN

• 1.Lidocaine hydrochloride 2% with epinephrine 1:100,000

• 2.mepivacaine hydrochloride 2% with levonordefin 1:20,000

• 3.prilocaine hydrochloride 4% with epinephrine 1:200,000

POTENCY OF LA AGENTS

• It depends on--• 1.lipid solubility• 2.tissue diffusion characteristics• 3.intrinsic vasodilator activity

MAXIMUM RECOMMENDED DOSES• 4.4 mg/kg body weight with

adrenalin• 7.5 mg/kg body weight without

adrenalin

• DOSE CALCULATION• %CONCENTRATION(mg/ml) x ml/cartage

= total mg/cartage

example

• In a 10 kg child• If 1 kg-------------=4.4mg• Then 10kg-----------=44mg• 20 mg------------------=1ml (2% lignocaine)• Then 44mg------------2.2 ml• So in a child of 10 kg maximum

recommended dose of LA is 2.2 ml.

POINTS TO BE KEPT IN MIND REGARDING THE DIFFERENCE B/W THE CHILD AND ADULT PATIENT

• 1.Density and calcification of maxillary and mandibular bone

• 2.Anatomic structures• 3.Penetration of the needle• 4.Depth of needle penetration• 5.Emotional aspect

TYPES OF INJECTION PROCEDURES

1.Nerve block-depositing the LA solution within close proximity to a main nerve trunk

2.Field block-depositing a in proximity to the larger nerve branches

3.Local infiltration-small terminal nerve endings are anaesthetised.

ANAESTHESIA FOR THE MANDI BULAR TISSUE

• 1.infiltration• 2.inferior alveolar nerve block• 3.mental nerve block

INFERIOR ALVEOLAR NERVE BLOCK

• Nerve anaesthetized-• Inferior alveolar nerve and its sub

division• Mental nerve• Incisive nerve• Lingual nerve(occasionally)

• Areas anaesthetized-• Body of mandible and an inferior portion of

the ramus• Mandibular teeth• Mucous membrane and underlying tissue

anterior to molar

Anatomical landmarks

• Position of the patient-body of the mandible is parallel to the floor.

• The operator stands to the right side of the patient with left index finger palpates the mucobuccal fold.

• Aspirate slowely• Needle depth---8-10 mm• Amount deposited-----0.9-1.0 ml• LINGUAL NERVE is anterior and medial to

ingerior alveolar nerve• So withdraw the needlea bout 1mm and

deposite the 0.5 ml of LA• LONG BUCCAL NERVE can be

anaesthtized by infilteration in the buccal sulcus distal to permanent teeth

• Amount deposited---0.2 ml

MENTAL NERVE BLOCK

MAXILLARY NERVEBLOCK

TYPES OF NEEDLE

• The types of needle employed are:-• Long• Short • Extra short – for maxilla

ANAESTHESIA FOR MAXILLARY TISSUES

• 1.Infiltration• 2.Posterior superior alveolar nerve block• 3.Middle superior alveolar nerve block• 4.Maxillary anterior region block• 5.Nasopalatine nerve block• 6.Greater palatine nerve block

INFILTRATION

The infiltration can be of :-

1. Labial infiltration

2. Buccal infiltration

3. Palatal infiltration

• In local infiltration the nerve endings in the area of the surgery are flooded with local anesthesic solution. The incision is made through the same area in which solution has been deposited.

• Landmark- Mucobuccal fold.• Needle used- 1inch, 25 gauge

needle• Amount- 0.45 to 0.6 ml

ANTERIOR SUPERIOR NERVE

BLOCK

Anterior Superior Alveolar Nerve Block (ASA)

MIDDLE SUPERIOR ALVEOLAR NERVE

Middle Superior Alveolar Nerve Block (MSA)

POSTERIOR SUPERIOR ALVEOLAR NERVE

BLOCK

Posterior Superior Alveolar Nerve Block (PSA)

Posterior Superior Alveolar Nerve Block (PSA)

PALATAL ANESTHESIA

GREATER PALATINE NERVE BLOCK

Greater Palatine Nerve Block

NASOPALATINE

Nasopalatine Nerve Block

COMPLICATION

DUE TO SOLUTION

Toxicity Idiosyncrasy Anaphylactic reaction Infection Local irritation

DUE TO NEEDLE • Edema • Broken needle in soft tissue• Hematoma • Sloughing • Trismus• Infection • Syncope

SELF INFLICTED INJURY• Lip biting • Tongue biting • Cheek biting

RECENT ADVANCES

1.IONTOPHORESIS

• Iontophoresis (a.k.a. Electromotive Drug Administration (EMDA)) is a technique using a small electric charge to deliver a medicine or other chemical through the skin.

INTRAORAL LIGNOCAINE

PATCH

JET INJECTION• This is a technique in which a small

amount of local anesthetic solution is propelled as a jet into submucosa without the use of hypodermic needle.

COMPUTER CONTROLLED

SYSTEM• The wand local anesthesia system is a

computer controlled injection device. The wnd/compuDent system administers local anesthetic at two specific rates of delivery.

• The slow rate is 0.5ml/min and• fast rate is 1.8ml/min .

COMFORT CONTROL SYRINGE

• The CCS system is an electronic , preprogrammed delivery device that provides the operator with the control needed to make the patient’s local anesthetic injection experience as pleasant as possible.

ELECTRONIC DENTAL ANESTHESIA

• This method of achieving local anesthesia involves the use of the principle of TRANSCUTANEOUS ELECTRICAL NERVE STIMULATION which causes relief of pain.

CONCLUSION• Local anesthetics are useful for a range of

applications in infants and children. Recent research has elucidated developmental pharmacology of local anesthetics and has suggested approaches to safer and more effective use of these drugs. In the future,

• there may be ways to produce new local anesthetics that expand their utility for treatment of both acute

• and chronic pain.

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