This document provides an overview of local anesthesia. It begins with the historical background, then defines local anesthesia and discusses relevant anatomy. It explores the physiologic considerations of nerve conduction and impulse propagation. Modes and sites of action for local anesthetics are examined, along with their mechanism of action and pharmacology. Various classifications of local anesthetics are presented based on chemical structure, biological site/mode of action, application method, potency, and duration. Factors influencing local anesthetic action and pharmacokinetics are also summarized.

2. Local anesthesia
Presenter
Dr. DISHA.PATEL

3. CONTENTS
 Introduction
 Historical background
 Definition
 Anatomic consideration
 Neuron
 Nerve fibers
 Schwann cells and myelin sheath
 Nerve membrane.
 Physiologic considerations
 Electrophysiology of nerve
conductive
 Electrochemistry of nerve
conduction
 Impulse propagation
 Impulse spread
 Mode and site of action of local anesthetic
 Mechanism of action
 Theories of L.A.
 Effect of pH
 Pharmacology of LA.
 Classification
 Pharmacokinetics–uptake,
distribution, metabolism excretion
 Individual drugs
 Potentiation of action of local anesthetics-
vasoconstrictors
 Recent advances and future trends in pain
control
 Local anesthesia for special cases
 conclusion
 References

4. INTRODUCTION

5. HISTORY
Koller and Gartner reported
local anesthesia (1884)
1884 Halsted injects cocaine
directly into mandibular
nerve and brachial plexus
1905 Einhorn discovers
procaine (Novocaine)
1943 Lofgren discovers
lidocaine (Xylocaine)
William S. HalstedCarl Koller

6. DEFINITION
• “Loss of sensation in a circumscribed area of
the body caused by a depression of excitation
in nerve endings or an inhibition of the
conduction process in peripheral nerves”
GRUNE &
STRATTON-
1976
• Local anesthesia is defined as a reversible,
temporary cessation of painful impulses from a
particular region of the body.
KOCH
• Local anesthesia has been defined as the direct
administration of an anesthetic agent to tissues
to induce the absence of sensation in a small
area of the body.
MOSBY’S
DICTIONARY

7. 1 April 2018 7
REGIONAL ANALGESIA:
REGIONAL ANESTHESIA:
LOCAL ANESTHETICS:

8. ANATOMIC CONSIDERATIONS

9. 1 April 20189

10. Action potentialELECTROPHYSIOLOGY

11. ELECTROCHEMISTRY

12. Membrane excitation
• Depolarization:
• Increase in permeability to sodium ions accomplished by transient
widening of transmembrane ion channels.
• Rapid influx of sodium inside the cell causes the depolarization from
-50 to-60 mV reaching its firing threshold
• Dramatic incease in permeability to sodium ions
• End of depolarization +40 mV

13. Membrane excitation
• Repolarization:
• Extinction of permeability to sodium ions
• Increase in permeability to potassium ions
• Slight excess of sodium ions
• Pumping of sodium ions outside the cell and potassium inside the cell

14. • Immediately after a stimulus has initiated an action potential ,
nerve is unable to respond to another stimulus regardless of its
strength
• New impulse can initated by stronger than normal stimulus
1. Absolute
2. Relative
Refractory period

15. IMPULSE SPREAD
• Depends on whether nerve is myelinated or not
Unmyelinated nerve:
due to High electrical resistance cell membrane areas immediately
adjacent to depolarization may be adequate to initiate depolarization,
but father it will prove inadequate
Conduction rate:1.2m/sec
Myelinated nerve:
Layer of insulating material separating intra and extracellular charges,
small current required to chrge the membrane, impulse conduction
through node to node called as “saltatory conduction”

16. SUSCEPTIBILITY OF DIFFERENT NERVE FIBERS TO BLOCK BY
LOCAL ANESTHETICS
 Factors Influencing
 The Type Of Fiber
 Degree Of Myelination
 Fiber Length And Diameter
• Small- Diameter Myelinated Fiber
• >Small- Diameter Non Myelinated
Fiber
• > Large-diameter Myelinated Fiber
• > Large- Diameter Nonmyelinated
Fiber

17. ORDER OF SENSORY FUNCTION BLOCK

18. MODE OF ACTION OF LOCAL
ANESTHETIC
Interfere with excitation process in a nerve membrane:
 Altering basic resting potential
 Altering the threshold potential
 Decreasing the rate of depolarization
 Prolonging the rate of repolarization

20. ACETYL CHOLINE THEORY
(DETTBARN-1967)

21. CALCIUM DISPLACEMENT
THEORY
(Goldman-1966)

22. SURFACE CHARGE (REPULSION)
THEORY
(Wei-1969)

23. Membrane expansion theory –LEE 1976

24. SPECIFIC RECEPTOR THEORY

25. Na +Na +
25

26. Dissociation of LA
RNH+ RN + H+
LOW PH RNH+ > RN + H+
When ph( 5.-5.6)
Inadequate anesthesia as it prevents deprotonization
and liberation of free base
HIGH PH RNH+ < RN + H+
PH and pka are same then
Ph=pka- log(RNH+-RN)
RNH+ = RN + H+
Total concentration of la(C ) =RNH+ + RN
At normal ph if la agent has HIGH Pka RNH+ > RN + H+
if la agent has low Pka RNH+ < RN + H+

27. ACTION ON NERVE MEMBRANES
AT NORMAL PH
RNH+(750) RN(250) + H+
RNH+(570) RN(180) + H+
RNH+(990) RN(10) + H+
INADEQUATE ANESTHESIA
LOW PH

28. INDUCTION AND RECOVERY FROM
LOCAL ANAESTHESIA

29. FACTORS AFFECTING LA ACTION
1. Dissociation constant (Pka )
2. Type and size of nerve
3. Lipid solubility
4. Protein binding
5. Perineurium thickness
6. Molar concentration around the nerve
7. Concentration of la agent
8. Non-nervous tissue diffusibility
9. Vasodilator activity
10. too high too low ph
11. excessive dilution with blood or tissue fluids
12.Too rapid absorption of anesthetic in systemic solution
13.Vascularity of site
14.Infection( deprotonization is retarded)
15.Volume of drug
16.vasoconstrictors

30. PATIENT RELATED
Age
Body size:
Renal dysfunction:
Hepatic
dysfunction:
Pregnancy

31. READMINISTRATION OF LOCAL ANAESTHETIC
• At time reinjection core fibres< mantles fibres
• Reinjection mantles fibres core fibres
profound anesthesia
• Tachyphylaxis: It is defined as increasing tolerance to a drug that is
administered repeatedly. Which is more likely to develop if nerve
function is allowed to return before reinjection.

32. MECHANISM OF ACTION
RNH+ displaces calcium ions for the sodium channel receptor site
Binding of the local anesthetic molecules to this receptor site
Blockade of sodium channel
Decrease in sodium conduction
Depression of the rate of electrical depolarization
Failure to achieve the threshold potential level
Lack of development of propagated action potentials
CONDUCTION BLOCKADE

33. IDEAL PROPERTIES OF L.A.
1. Potent
2. Reversible
3. Non irritating to the tissues and produce no secondary local reaction
4. Low degree of systemic toxicity
5. Relatively free from allergic reactions
6. Rapid onset
7. Sufficient duration
8. Sufficient penetrating properties
9. Low cost
10. Stability in solution (long shelf life) and undergoes biotransformation
easily
11. Either sterile or capable of being sterilized

34. CLASSIFICATION
Butacaine
Cocaine
Benzocaine
Hexylcaine
Piperocaine
Articaine
Bupivacaine
Dibucaine
Etidocaine
Lidocaine
Mepivacaine
prilocaine
2-Chlorprocaine
Procaine
Propoxycaine
Tetracaine
Based on chemical structure
ESTER QUINOLINE AMIDES
BENZOIC ACID PABA
Centbucridine
KETONES
Dyclonine

35. Based on biological site
& mode of action
Class BClass A Class C Class D
• Tetrodotoxin
• Saxitoxin
•Quaternary
ammonium
analogues of
lidocaine
• Scorpion
venom
Benzocaine • Lidocaine
• Mepivacane
• Prilocaine

36. Based on mode of application
Topical Injectable
Lidocaine
Mepivacaine
Tetracaine
Bupivacaine
Dibucaine
Soluble Insoluble
Cocaine
Lidocaine
Tetracaine
Benoxinate
Benzocaine
Butylamino-
benzoate

37. Based on duration of action
Ultra short Short Medium Long
Pulpal
5-10 min
Soft tissue
60 – 120 min
• 2%Lidocaine with
1:100000 epinephrine
• 4%Prilocaine
• 2%Mepivacaine
with 1:20000
levonordefrin
• 2% procine .4%
propoxycaine
Pulpal
45 – 90 min
Soft tissue
120 – 240 min
• 4%Prilocaine with
1:200000
epinephrine
• 2%Lidocaine and
2%Mepivacaine
with vasoconstrictor
• Articaine
Pulpal
90 – 180 min
Soft tissue
240 – 540 min
• .5%Bupivacaine
• .5-1.5%Etidocaine
with 1:200000
epinehrine
Pulpal
< 10 min
Soft tissue
30 – 45
• 2-Chlorprocaine
• Procaine without
vasoconstrictor
• Lidocaine
without
vasoconstrictor

38. Based on potency
LOW INTERMEDIATE HIGH
Procaine
chlorprocaine
Lidocaine
mepivacaine
Tetracaine
Bupivacaine
Dibucaine

39. PHARMACOKINETICS
UPTAKE

40. DISTRIBUTION

41. Esters-inactivated by hydrolysis
Water molecule is added to ester linkage which splits it into
two entities
Occurs in plasma and liver
pseudocholinesterase in plasma
Metabolite: PABA
Amides-hepatic microsomal enzymes
Metabolite; 2,6 xylidide and glycinexylidide
Studies have shown 16% of amides are excreted in unchanged
form
EXCRETION: kidneys
BIOTRANSFORMATION & EXCRETION
Relative contraindication
liver and kidney dysfunction

42. Various methods of inducing local anesthesia
 Mechanical trauma
 Low temperature
 Anoxia
 Chemical irritants
 Neurolytic agents - alcohol and phenols
 Chemical agents - local anesthetics.

43. LAs
Differ structurally which alters
• Toxicity
• Potency
• Diffusibility
• Profoundness
• Duration of action
• Irritancy to tissues
Common properties
• All synthetic
• Contain amino group
• Form salts wit strong acid
• Salts are water soluble
• Alkali increases the
concentration of unionized free
base
• unionized free base is soluble in
lipids

44.  White crystalline powder
 Diethylaminoethyl ester of PABA
 Standard for comparing la agents
Available as 4% and
2% procaine with .4% propoxycaine with 1:30000 levarterenol
or 1:20000 levonordefrin
Ph 4.5 and MP 154’C
Pka 9.1
Soluble in water and has alkaline reaction
DURATION: 5MINUTES
WITH VASOCONSTRICTOR: 1 HOUR
Maximum dose: 4% 10ml
2% 20ml
15-20mg/kg not to exceed 1gm
PROCAINE
CNS
CROSSES BBB
STIMULATES AND DEPRESSES
causes
Excitement
Ataxia
tremors
generalized convulsions
CVS :QUINIDINE LIKE ACTION
Depresses excitability
Diminishes contractility
Prolongs conduction time
Respiratory system
Bronchiole dilatation
Toxic overdose: respiratory
arrest before cardiac arrest

45.  White crystalline powder
 10 times more potent and toxic than procaine
 Spinal anesthesia
Available as .15% , 1% and 2%( topical)
.used by moistening cotton pellet
Ph 5.9 and MP 155’C
Pka 8.5
Soluble in water and has alkaline reaction
DURATION: 30 -45 min
With vasoconstrictor (1:100000 epinephrine) : 75-120 min
Maximum dose: 20mg/kg
TETRACAINE
Systemic effects same as
procaine

46.  White powder
 Available as 2% procaine with .4% propoxycaine with
1:30000 levarterenol or 1:20000 levonordefrin
ONSET : EXTREMELY RAPID, PROFOUND
ANESTHESIA, LONG DURATION
Ph 5.5 and MP 148.3’C
Soluble in water and has alkaline reaction
DURATION: PULPAL ANESTHESIA: 1- 11/2 HOUR
SOFT TISSUE ANESTHESIA: 2-3 HOURS
Maximum dose: 6.6mg/kg not to exceed 400mg
PROPOXYCAINE
Systemic effects same as
procaine

47.  white crystalline powder
 more potent and less toxic than procaine
 Occasionally used
Available as 1.2 - 3%
Rapid onset
DURATION: short ( useful in children)
Ph4.8 and MP 173-176’C
Soluble in water and has alkaline reaction
Maximum dose: 11mg/kg not to exceed 800 mg
2 CHLORPROCAINE

48.  Non ester
 white crystalline powder
 2 times more potent and toxic than procaine
ONSET : 2-3 mins
MP 69’C
Pka 7.85
Hydrolysis in liver
Maximum dose: 4.4mg/kg not to exceed 300mg
with vasoconstrictor :7mg/kg not to exceed 500mg
Topical : 5% and 10%
LIDOCAINE
CNS
CROSSES BBB
STIMULATES AND DEPRESSES
causes
Convulsions
lethargic
sleepy
CVS :
Used to correct ventricular
arrhythmias 50-100 mg
Depresses excitability
Decreases contractility
Prolongs conduction time
Respiratory system
Bronchiole dilatation
Toxic overdose: respiratory
arrest

49. Composition of LA Solution
 Lignocaine Hcl (Anesthetic) 24.64 mg (2 %)
 Adrenaline (Vasoconstrictor) 0.0125 mg (1:80,000)
 Sodium metabisulphite (Reducing Agent) 0.5 mg
 Methyl paraben (Preservative) 1 mg
OR
Cupryl hydrocuprinotoxin 1 mg
 Thymol (Fungicide)
 Salts (NaCl) (Isotonicity) 5-6 mg
 Distilled Water (Vehicle) 100 ml
OR
Ringer’s Lactate
49

50. • Total dose 140 mg of lignocaine
• Blood level : 3microgram/ml

51.  Non ester
 white crystalline powder
 2 times more potent and toxic than procaine
Available as 2% ( with vasoconstrictor 1:20000 levonordefrin) and 3%
MP 261’C
Pka 7.6
PULPAL ANESTHESIA: 20-40 mins
Hydrolysis in liver
Maximum dose: 6.6mg/kg not to exceed 400mg
MEPIVACAINE

52.  Non ester
 DERIVATIVE OF TOLUIDINE
 Less toxic than lignocaine
PH 6-7
MP 167-168’C
Pka 7.9
AVAILABLE AS 4%
Partially absorbed in circulation
Metabolite ; orthotoluidine ( produces
methemoglobinemia)
ANESTHESIA ( without vasoconstrictor): 60mins
(with epinephrine 1;200000) 60-90 mins
Hydrolysis in liver
PRILOCAINE
Contraindicated in
congenital or
idiopathic
methemglobinemia

53.  Non ester
 white crystalline powder
PH 4.5-6.5
Pka 8.1
 AVAILABLE AS .25% .5%, .75 % WITH 1:200000
EPINEPHRINE
 4 times more potent and toxic than lignocaine
 35 times more lipid soluble and increase protein binding
 PULPAL ANESTHESIA:: 3 hours
 Soft tissue anesthesia 12 hours
Hydrolysis in liver
Maximum dose:2mg/kg not to exceed 225mg with
vasoconstrictor
175mg without vasoconstrictor
BUPIVACAINE
Systemic effects same as
LIGNOCAINE

54.  Non ester
 white crystalline powder
PH 3-5
Pka 7.7
 AVAILABLE AS .5%, 1 %, 1.5% WITH 1:200000 EPINEPHRINE
 4 times more potent and 2 times(2.16) greater duration,2
times more toxic than lignocaine
 50 times more lipid soluble and 2 times increased protein
binding
Hydrolysis in liver
Maximum dose:4.4mg/kg not to exceed 400mg with
vasoconstrictor
4mg without vasoconstrictor not to exceed 300mg
ETIDOCAINE
Systemic effects same as
LIGNOCAINE

55.  Hybrid molecule
 Thiopene ring
 pka 7.8
 Ph 3.5-4
 Avilable as 4% with 1:100000 and 1:200000
epinephrine
 MRD=7mg/kg
 methemoglobinemia in high doses for regional
block
 Myocardial depressant properties
 Not recommened in younger than 4 years
children
 Toxicity similar as lignocaine
Australian dental journal. 2012 57 : 325-333.
ARTICAINE

56. • Randomized clinical trial
• 95 participants
• 2 ml of 2% articaine with
1:200,000 epinephrine
Or
• 2 ml of 4% articaine with
1:200,000 epinephrine
• Inferior alveolar nerve
anesthesia
• 85% of participants who received 2%
articaine
• 92% of participants who received 4%
articaine
• Result: Patients who received 2%
articaine had soft-tissue anesthesia
lasting for an average of 172 minutes,
whereas patients who received 4%
articaine had anesthesia lasting for an
average of 241 minutes
Conclusion:There were no differences
between the groups in terms of time of
anesthesia onset, number of injections
needed, injection pain, pain during or after
treatment, or complications.

57. • Randomized controlled trials in
patients requiring non-complex
routine dental treatments
• Comparision between 4%
articaine (1:100,000
epinephrine) with 2% lignocaine
(1:100,000 epinephrine) for
maxillary and mandibular
infiltrations and block
anaesthesia; and
• Measures of anaesthetic
success:
 post-injection adverse events
post-injection pain.
• Conclusion
• Articaine is more effective than
lignocaine in providing anaesthetic
success in the first molar region for
routine dental procedures.
• Both drugs appear to have similar
adverse effect profiles.
• The clinical impact of articaine's
higher post-injection pain scores
than lignocaine is negligible.
• Hence, articaine is a superior
anaesthetic to lignocaine for use in
routine dental procedures.

58.  Long- acting amide anesthetic
 Prepared as a isomer
 Greater margin of safety
(shorter t ½=25.9min)
 Decreased cardio-toxicity
 Uses: regional nerve block mainly epidural
 Disadv.-Shorter duration of action
British journal of anesthesia . 1996;76: 300–307
ROPIVACAINE

59. • 1:1 mixture of 0.5%
ropivacaine and 3%
chloroprocaine
• Used for surgical procedures in
cardiac compromised patients
59
WEAVERCAINE

60. Quinoline derivative
Five to eight times the potency of lidocaine
Does not effect CNS & CVS
Uses: subarachnoid, extradural , I.V reg.
Anesthesia , intraocular surgery
International journal of dentistry. 2011;10: 1155-1159
CENTBUCRIDINE

61. Tetrodotoxin -puffer fish
saxitoxin -dinoflagelates.
They specially block the sodium channel
when applied to membrane surface
250000 times more potent than procaine
Disadvantages
Difficult to synthesise
Not stable in aqueous solution
Highly toxic
ULTRA LONG ACTING LA

62. Water insoluble topical anesthetics
• Lacks basic nitrogen group
• Used topically
• Poorly soluble in water
• Rapid onset
• On injecting: irritating
toxic
Used in cough drops, sunburn
lotions
• Lidocaine base
• lidocaine hydrochloride
• Onset 15 secs
• Duration 30 mins
• Poorly absorbed so toxicity
minimal
Ethlyaminobenzoate(Benzocaine) lidocaine

63. Water soluble topical anesthetics
2.Tetracaine:2%
• Duration 45 mins
• Combination with benzocaine
Onset: 30secs
Long lasting
Available in liquid, ointment, spray,
gel form
Cetacaine: benzocaine 14%, butamen
2%, tetracaine 2%, used for
endoscopic procedures
3.Lidocaine hydrochloride: 2% or
4%
• Onset 15 secs
• Duration 30 mins
• absorbed so more toxicity
• Available as syrup for rinses
• max recommended dose 200
mg
1.Benzyl alcohol
Irritating on injection available as 4% and
10%

64.  To counteract vasodilation
 Decrease blood flow
 Lower anesthetic blood levels
 Decrease the risk of toxicity
 Increases duration of action
 Decrease bleeding
vasoconstrictors
All vasoconstrictors are Sympathomimetic amines, unstable in solutions so
preservative should be used to prevent oxidation

65.  Catecholamines(when
it contains 2 hydroxyl
group on carbon 3 and
4 )
 Epinephrine
 Nor-epinephrine
 Dopamine
 Levonordefrin
 Isoproterenol
 Non catecholamines
 Amphetamine
 Methamphetamine
 Hydroxy-
amphetamine
 Ephedrine
 Mephetermine
 Pyrocatechin derivatives
- Epinephrine & Norepinephrine( levophed)
 Benzol derivatives
- Levonordefrin (Neo-cobefrin)
 Phenol derivatives
- Phenylephrine (Neo-synephrine)
Classification
Natural
synthetic

66. Adrenergic receptors

67.  Most potent and widely used
vasoconstrictor in dentistry
 Source: 80% of medullary
secretion, also available as a
synthetic
 Action- both  and , with  being
predominate
 Available 1:50000 to 1:250000
Epinephrine
Synthesis: chromaffin cell of medulla
Sympathetic post ganglionic
nerve
CVS
, Stimulation :
Increase in HR
Increase in stroke volume
Increase in cardiac output
Increase in oxygen consumption
Irritability of myocardium
Premature ventricular contractions
2 causes vasodilatation
 causes vasoconstriction at higher
doses
CNS
Produces “ ALERTING EFFECTS”
Jitteryness
Apprehension
Mild excitation
Others
Increase in blood sugar levels
Increase in glycogenolysis in liver and
muscle
Pupillary dilatation

68.  Therapeutic dose
 .3 to .5 mg
 Maximum Dose for Dental Appointment
 Normal healthy patient
 0.2 mg per appointment
 Significant cardiovascular impairment
 0.04 mg per appointment
 Clinical Applications for Epinephrine
 Acute allergic reaction
 Bronchospasm
 Cardiac arrest
 Hemostasis
 Produce mydriasis
 Vasoconstrictor
Epinephrine

69. Norepinephrine
• 15% amine content of medulla
• White crystalline monohydrate
salt
• Soluble in water
• Ph 3.4
• Predominantly on  receptors
• Available as 1:30000 per ml
Max dose .34mg or 10 ml of
1:30000 concentration
CVS
• Increase in HR
• Increase in stroke volume
• Increase in force of
contraction
• Increase in systolic and
diastolic bp
Respiratory system
• No effect
CNS
• Produces mild“ ALERTING
EFFECTS”

70. levonordephrine
• White crystalline monohydrate
salt
• Soluble in water and alcohol
• Ph 3.4
• Predominantly on  receptors
• Available as 1:10000 per ml
Max dose 1mg or 10 ml of
1:10000 concentration
Cardiac patients .4 mg
CVS
• Reflex decrease in HR
• Increase in cardiac output
Respiratory system
• No effect
CNS
• “NO EFFECT”

71. Phenylephrine
• White crystalline salt
• Soluble in water
• Ph 3.4
• Almost pure  agonist
• Available as 1:2500 per ml
Vasoconstrictor effect less than
epinephrine, norepinephrine,
levonordephrine
Long lasting
Max dose 4mg or 10 ml of 1:2500
concentration
Cardiac patients 1.6 mg
CVS
• Cardiac arrythmias less likely
to occus as it doesnot affect
beta receptors
• Reflex decrease in HR
Respiratory system
• No effect
CNS
• “NO EFFECT”

72.  Analogue of vasopressin(.03 IU/ml with 3%
prilocaine)
 Little direct effect on heart & CNS
 Uses
 Hyperthyroidism
 Hypertension
 Advanced cardiac diseases
 Patients on TCA,MAO inhibitors
 Disadv : poor hemostasis ,
contraindicated in pregnancy
FELYPRESSIN

73. Drug interactions
• Tricyclic antidepressants
Prolongs and enhance the
activity of natural and synthetic
sympathomimetic drugs
Exaggeration of systemic
toxicity
• Monoamine oxidase inhibitors
Prononced prolonged
exaggerated effect
• Alpha adrenergic blockers with
epinephrine
Beta actions predominate
Fall in bp
Epinephrine reversal effect
• Beta adrenergic blockers with
epinephrine
Predominance of alpha effects
• With Cocaine
• With Thyroid Hormone
(Epinephrine and Thyroxine)

74. Selection of vasoconstrictor
• DURATION OF DESIRED EFFECT
• PHYSICAL CONDITION OF PATIENT
• DESIRE TO ACHIEVE HEMOSTASIS
• CONCURRENT MEDICATION

75. CONSIDERATIONS:
• Congenital heart disease: vasoconstrictors to kept minimal or
eliminated
• Rhematic heart disease: vasoconstrictors to kept minimal with
profound analgesia
• coronary artery disease: concentration of 1:100000 or .04mg+
aspiration+advised to eat lightly
• Mailgnant hypertension: moderately sedated + vasoconstrictors to
kept minimal
• Pending congestive heart failure: sedation+good pain control+
vasoconstrictors to kept minimal
• Chronic valvular heart disease : vasoconstrictors to kept minimal
• Diabetes mellitus: vasoconstrictors to kept minimal
• Hypothroidism: amount of vasoconstrictor should be chosen wisely
• Hyperthroidism: reduced amount of vasoconstrictor

76. REVERSAL OF ANAESTHESIA

77. TENS (transcutaneous electrical nerve stimulation)

78. • Approved by US FDA IN 1952
• Short acting
• competitive antagonist at α-adrenergic
receptors
• It antagonizes both α1 and α2
receptors thus it blocks the action of
circulating catecholamines
(epinephrine and norepinephrine)
• Stimulates beta adrenergic receptors in
heart
• Action-vasodilation due to α1 blockade
• reverse the local vasoconstrictor
properties
Clinical effects
• Vasodilation
• Tachycardia
• Increased cardiac output
IV , IM and subcutaneously
Phentolamine Mesylate

79. Candidates for Phentolamine reversal
• Conservative Dentistry
• Non surgical periodontics
• Pediatric dentistry
• Medically compromised patients(type I diabetic patients)
• Geriatric patients
• Special need patients
• Post mandibular implants
Not recommended in
• Children less than 6 years
• Weight less than 15 kgs

80. FAILURE OF ANESTHESIA
•Inaccurate anatomic placement of local anesthetic
solution
•Placing too little solution
• allowing insufficient time for it to diffuse and take
effect
• injecting into inflamed or infected tissues
• using an outdated or improperly stored anesthetic
solution.

81. COMPLICATIONS

82. Local complications
• Pain on injection
• Burning on injection
• Needle breakage
• Paraesthesia
• Facial nerve paralysis
• Trismus
• Soft tissue injury
• Hematoma
• Infection
• Edema
• Sloughing of tissues
• Postanaesthetic intraoral lesions

86. Mepivacaine, lidocaine, Halothane, Succinylcholine
• Autosomal dominant disorder include defect in distribution of
myoplasmic calcium.
Acute episode of rising ca++ concentration
Ca++  increase phosphorylation  Increase ATP production -
Heat formation.
 C/F- Muscular rigidity, Metabolic acidosis , High fever More
than 110 ‘F monitored.
 Tachycardia, Tachypnoea, Dysrythmias, Cyanosis and Death
 Management : Dantrolene sodium I.V 2.5mg/kg , Bicarbonate
1-2 meq/kg
MALIGNANT HYPERTHERMIA

87.  PRILOCAINE,
 BENZOCAINE
 ARTICAINE
 Methemoglobin- 1.5-3g/dl(10-20%)
 Management :
 1% methylene blue 1.5mg/kg (electron
acceptor) ;
 Ascorbic acid 100-200mg/day
Methemoglobinemia

88. Future trends in pain control

89. ADDITION OF SODIUM BICARBONATE
CO2 has direct depressant action on axon
Concentrate LA molecule inside the nerve trunk
through ion trapping
Changes the charge of LA inside the nerve axon
• NaHCO3 added to LA interact with HCl
• Creates water and CO2
• CO2 diffuses out of solution
Speed up of the onset
and potentiate the
action of LA

90. • A Prospective , randomized ,
double- blind, crossover trial
• N=20
• Comparison between STANDARD
LA WITH EPINEPHRINE versus LA
WITH EPINEPHRINE BUFFERED
PHYSIOLOGIC PH USING SODIUM
BICARBONATE
Conclusion:
72% patients: buffered LA more comfortable
17% patients: rated the same
11% patients: unbuffered LA more comfortable
Average time for pulpal anesthesia
7 minutes 29 seconds for standard
LA
1 minute 51 seconds for buffered LA

91. COMPARATIVE EVALUATION OF THE EFFICACY OF
LIGNOCAINE AND BENZOCAINE PATCHES FOR
VARIOUS DENTAL TREATMENTS IN CHILDREN
• Aim: study was done to
evaluate the clinical efficacy of
lidocaine and benzocaine
patches in various dental
treatment in children
• Group A and Group B. Group
A, consisted of 60 children
where lignocaine patches were
placed and Group B consisted
of 60 where Benzocaine
patches were placed
• Procedures performed
Extraction
Pulp therapy
Band adaptation
Result
• The VAS(Visual analogue scale) scores
recorded were statistically significant for
the pulpectomy procedure for Benzocaine
group compared to Lignocaine.
• SEM (Sound eyes motor scale) scores
were suggestive that the children were
more comfortable with the Lignocaine
patches when compared to Benzocaine
patches.
• Conclusion: bioadhesive patches can be
an alternative over infiltration anesthesia
in minimally invasive dental procedures
and also could be used successfully for
reducing the pain of nerve blocks for
children as well as adults which has to be
administered in the case of more invasive
procedures like pulp therapy.
Journal of Health Science . Mar2014

92. HYALURONIDASE
• An enzyme that breaks down intracellular cement.
• Available as Wydase
• Advocated as an additive to local anesthetics as it permit as injected
solutions to spread and penetrate tissues.
• Added to the cartridge just before administration
92

93. Recent advances
1. VIBROTACTILE DEVICES,
2. COMPUTER-CONTROLLED LOCAL ANESTHETIC
DELIVERY (CCLAD) SYSTEMS,
3. JET INJECTORS,
4. SAFETY DENTAL SYRINGES
5. DEVICES FOR INTRA-OSSEOUS (IO) ANESTHESIA.
Natl J Maxillofac Surg. 2013 Jan-Jun; 4(1): 19–24.

94. VibraJect
• It is a small battery-operated
attachment that snaps on to the
standard dental syringe.
• It delivers a high-frequency
vibration to the needle that is
strong enough for the patient to
feel
• Nanitsos et al and Blair have
recommended the use of VibraJect
for painless injection.
• Yoshikawa et al.found no
significant pain reduction when
VibraJect was applied with a
conventional dental syringe.
• Saijo et al. evaluated the
effectiveness of VibraJect in
combination with an electrical
injection device. They also found
no statistically significant decrease
in pain scores at needle insertion
or anesthetic injection
Natl J Maxillofac Surg.2013

95. DentalVibe
• It is a cordless, rechargeable,
hand held device that delivers
soothing, pulsed, percussive
micro-oscillations to the site
where an injection is being
administered.
• Its U-shaped vibrating tip attached
to a microprocessor-controlled
Vibra-Pulse motor gently
stimulates the sensory receptors at
the injection site, effectively
closing the neural pain gate,
blocking the painful sensation of
injections.
• It also lights the injection area and
has an attachment to retract the
lip or cheek
Natl J Maxillofac Surg.2013

96. Accupal
• . The Accupal (Hot Springs, AR,
USA) is a cordless device that
uses both vibration and
pressure to precondition the
oral mucosa
Natl J Maxillofac Surg.2013

97. • Precise control of flow
rates and pressure
• Comfortable even in
tissues of low elasticity
• Increased tactile sensation
• Light weight
• Automatic aspiration
• Minimal needle deflection
• ADVANTAGES
• Requires additional
armamentarium
• High cost
DISADVANTAGES
Natl J Maxillofac Surg.2013

98. Comfort control syringe
• The Comfort Control Syringe differs from the Milestone products in that
there is no foot pedal. It has two main components:
• A base unit and a syringe..
The Comfort Control Syringe has five pre-programmed speeds.
Natl J Maxillofac Surg.2013

99. JET INJECTORS
• FAST
• EASY TO USE
• LESS PAIN
Principle:
anesthesia of surface to a depth over 1cm
without use of needle
MED-JET
Natl J Maxillofac Surg.2013

100. Safety dental syringes
Ultra safety plus XL
syringe
HypoSafety Syringe
SafetyWand™
Natl J Maxillofac Surg.2013

101. STA (SINGLE TOOTH ANAESTHESIA SYSTEM)
Dynamic Pressure Sensing – DPS‟ which
provides continuous feedback to the user
about the pressure at the needle tip to
identify the ideal needle placement for
PDL injections.
Mainly for PDL injections

102. ELECTRONIC DENTAL ANAESTHESIA
RESIDUAL ANALGESIC EFFECT
INDICATIONS
• TMJAdministration and reversal of LA
• Post-operative analgesia
• Non-surgical periodontal procedures
• Fixed prosthodontics
• Restorative procedures
CONTRAINDICATIONS
• Cardiac pacemakers
• Neurological disorders
• Pregnancy
• Very young pediatric patient
• Older patients with senile dementia
• Language communication difficulties
102

103. EMLA
103
5% emulsion preparation, containing 2.5% each
of lidocaine/prilocaine

104. INTRAOSSEOUS
• The devices used for this technique, inject the solution
into the cancellous bone adjacent to the root apex

105.  Lidocaine and epinephrine
molecules are drawn into the tissue
by an electrical current
IONTOPHORESIS

106. LOCAL ANAESTHESIA FOR SPECIAL CASES

107. PEDIATRICS
In pediatric dentistry,
Appropriate patient’s medical history
proper dosage (based on weight)
• to minimize the chance of toxicity
• To avoid prolonged duration of anesthesia, which can lead to
accidental lip or tongue trauma.
• Knowledge of the gross neuroanatomy of the head and neck
allows for proper placement of the anesthetic solution and helps
minimize complications
• Appropriate medical consultation
AMERICAN ACADEMY OF PEDIATRIC DENTISTRY

108. • Aim. To evaluate the pain
experience and behavior during
dental injection, using the Wand
computerized delivery system
versus conventional local
anesthesia in children and
adolescents.
• Methods. An observational
crossover split mouth study was
performed on 67 patients
• Results. . During injection, the
number of patients showing a
relaxed behavior was higher
with the Wand than with the
traditional local anesthesia.
• Conclusions. The Wand
system may provide a less
painful injection when
compared to the conventional
local anesthesia and it seemed
to be better tolerated with
respect to a traditional syringe.

109. In pregnancy
• Highest concentrations in the fetal circulation follow injection of
prilocaine, and the lowest follow bupivacaine, with lidocaine in
between.
• Felypressin, which is a derivative of vasopressin and is related to
oxytocin, has the potential to cause uterine contractions.
• Although this is a highly unlikely effect at the low dose of felypressin
used in local anesthetics, it is best avoided during pregnancy.
• Lidocaine with epinephrine is commonly used for pregnant dental
patients.

110. GERIATRICS
Aging affects
• The pharmacokinetics and pharmacodynamics
• Composition and characteristics of tissues and organs within the
body,
• physiological functions of the body
• Changes in the
• systemic absorption,
• distribution and clearance
• Decreases in neural population, neural conduction velocity and
inter-Schwann cell distance can lead to an increased sensitivity
to local anaesthetics in the elderly.
• .

111. Medically compromised patients
SIMPLE SAFETY GUIDELINES
universal for administration of local anesthetics to all patients:
* Aspirate carefully before injecting
* Inject slowly
* Select the anesthetic agent and whether to use it with or without a
vasoconstrictor based upon the duration of anesthesia appropriate for
the planned procedure; and
• * Use the minimum amount of anesthetic solution that is needed to
achieve an adequate level of anesthesia to keep the patient
comfortable throughout the dental procedure.
2000 CDA Journal

112. conclusion

113. REFERENCES
 Handbook of local anesthesia- Stanley F. Malamed.
 Neural blockade in clinical anesthesia & management of pain – Michael j. Cousins
, philip o. Bridenbaugh
 Textbook of pharmacology & pharmacotherpautics- Goodman & Gilman- 10th
edition
 Regional anesthesia of the oral cavity- J . Theodore Jastak, John a. Yagiela
 Monehim”s local anesthesia and pain control, Benett
 Principles of anesthesiology- Vincent j. Collins
 Local anesthesia- Rudolph Dejong
 Newer local anaesthetic drugs and delivery systems in dentistry – an update. Iosr journal of
dental and medical sciences (JDMS)
 Iontophoresis: A Needle-Free, Electrical System of Local Anesthesia Delivery for Pediatric
Surgical Ofice Procedures. Journal of Pediatric Surgery, Vol34, No 6 (June), 1999: pp 946-949
 CARDIOVASCULAR COMPROMISED PATIENTSMED SCI MONIT. 2014; 20: 393–398