The document provides information on local anesthetics used in dentistry. It begins with definitions of local anesthesia and local anesthetic agents. It then discusses the history of local anesthesia, ideal properties, mechanism of action, pharmacokinetics, commonly used local anesthetic drugs (lidocaine, bupivacaine, articaine), dosages, and complications. It also covers topics like vasoconstrictors, topical anesthetics, and recent advances in local anesthesia.

1. 1

2. CAN U IMAGINE A DENTAL
EXTRACTION WITHOUT ANY
ANESTHESIA?????
2

3. INTRODUCTION
3
5500 B.C -Isn’t it comforting to know that the dental drill dates back 9,000
years ago and the first local anesthetic only appeared in 1846…………
Does it mean that anesthetics wouldn’t emerge until 1846?

4. “IT NUMBS THE
TONGUE AND TAKES
AWAY BOTH FEELING
AND TASTE”
The History of Local Anesthesia, Malvin e.
RING 4

5. SEMINAR ON
LOCAL ANAESTHETICS
PRESENTED BY
KHUSHBOO BARJATYA
DEPT OF PEDODONTICS
5

6. CONTENTS
 Definition
 Ideal Properties Of LA
 History
 Structure and activity
 Mechanism Of Action
 Pharmacokinetics-
Uptake,distribution,
Metabolism,excretion
 Factors Affecting LA
 Role of vasoconstrictors
 Common used drugs (local
anesthetics)
 Topical anesthesia
 Complications, adverse
effects
 Clinical considerations
 Recent advances.
 Anesthesia and law
 Conclusion
 References
6

7. DEFINITION
 Local anesthesia has been defined as a loss
of sensation in a circumscribed area of the
body caused by depression of excitation in
nerve endings and inhibition of the
conduction process in peripheral nerves.
 LA produces loss of sensation without
inducing a loss of consciousness. LA differs
from GA. Malamed.
Malamed SF. Handbook of local anesthesia. 4th ed. St. Louis: Mosby; 1997.
7

8.  A local anesthetic is an agent that
interrupts pain impulses in a specific
region of the body without a loss of
patient consciousness. Normally, the
process is completely reversible--the
agent does not produce any residual effect
on the nerve fiber.
8
Robert L. Copeland

9. TERMS USED INTERCHANGINLY
9
LOCAL
ANESTHESI
A

10. 10
IDEAL PROPERTIES OF
LA

11. 11
 Nonirritating to the tissues.
 Not cause any permanent alteration of
nerve .
Low systemic toxicity.
It must be effective.
 Time of onset should be short.
The duration of action must be enough.

12. Desirable properties by Bennett
12
.
Sufficient potency to give complete anesthesia
without the conc. solutions.
 No allergic reactions.
 Stable in solution & undergo
biotransformation in the body.
 Sterile or capable of being sterilized by heat
without deterioration.

13. HISTORY
13

14. • COCAINE was the first local anesthetic
isolated from coca leaves by Albert Niemann
in 1860s.
• Newer agents Lidocaine in 1943,
Bupivicaine in 1957 and Prilocaine in 1959.
14

15. 15
STRUCTURE-ACTIVITY RELATIONSHIPS

16. 16

17. CLASSIFICATION
17
ESTER
• Hydrolyzed in
plasma by pseudo-
cholinesterase.
• By-product of
metabolism is
PABA
• cause of allergic
reactions
• include cocaine,
procaine,
tetracaine, and
chloroprocaine
AMIDE
• Metabolized in
the liver to
inactive agents.
• True allergic
reactions are rare.
• lidocaine,
mepivicaine,
prilocaine,
bupivacaine, and
etidocaine

18. MECHANISM OF ACTION
18

19. Essentials of Local Anesthetic Pharmacology. Daniel E. 19

20. Essentials of Local Anesthetic Pharmacology. Daniel E. Becker 20
Change in Membrane Permeability to Na+ and K+ During the Action
Potential

21. PHARMACOKINETICS
Malamed SF. Handbook of local anesthesia 21
Uptake
Distribution
Biotransformation
Excretion

22. UPTAKE-
22
Relationship Between Local Anesthetic Plasma Level and Route of
Administration

23.  METABOLISM
1. Ester-type Local Anesthetics
a. Hydrolyzed in plasma by pseudocholinesterases.
b. Metabolites as PABA imp as may produce allergic
reactions.
2. Amide-type Local Anesthetics: In the liver by CYP P450
 EXCRETION:
 Kidney is the major excretory route for excretion of
unchanged drug and metabolites
23

24. HENDERSON HASSELBALCH EQUATION
 Determines how much of a local anesthetic will be in a
non-ionized vs ionized form Based on tissue pH and
anesthetic Pka.
 Injectable local anesthetics are acidic salts of weak bases
(pka=7.5-9.5).
 The non-ionized base is what diffuses into the nerve.
 Hence If the tissue is infected, the pH more acidic,- less of
the non-ionized drug to cross into the nerve (rendering the
LA less effective)
24

25. FACTORS AFFECTING LA
1. Effect of pH :-
PH ~ ONSET OF ACTION
Acidic pH – slow onset of action
25
2 EFFECT OF LIPOPHILICITY ON ANESTHETIC POTENCY
 lipophilic agents are more potent as local
anesthetics
 MORE LIPOPHILIC~MORE PENETRATION INTO
THE NERVE

26.  Effect of protein binding –
Increased binding increases duration of action
 Effect of diffusibility –
Increased diffusibility - decreased time of
onset
 Effect of vasodilator activity –
Greater vasodilator activity - decreased
potency and duration of action.
26

27. FACTORS AFFECTING SENSITIVITY OF
NERVE FIBERS
 FIBER SIZE
27
TYPE FUNCTION DIAMETER(μ
m)
Conduction
velocity (m/sec)
α Proprioception, somatic
motor
12-20 70-120
β Touch, pressure 5-12 30-70
γ Motor to muscle spindles 3-6 15-30
δ Pain, temperature 2-5 12-30
B Preganglionic autonomic <3 3-15
C-DORSAL
ROOT
Pain 0.4-1.2 0.5-2
SYPMATHETIC Postganglionic
sympathetics
0.3-1.3 0.7-2

28. SUSCEPTIBILITY TO BLOCK - TYPES OF
NERVE FIBERS
 In general, small nerve fibers are more
susceptible than large fibers; however,
the type of fiber
 degree of myelination
 fiber length and
frequency- dependence are also important.
28

29. ORDER OF SENSORY FUNCTION BLOCK
1. PAIN
2. COLD
3. WARMTH
4. TOUCH
5. DEEP PRESSURE
6. MOTOR
 Recovery in reverse order
29

30. VASOCONSTRICTORS
30

31. IMPROTANCE OF VASOCONSTRICTORS
Malamed SF. Handbook of local anesthesia. 4th ed. St. Louis: Mosby; 1997. 31
It slows absorption of
LA into blood stream
and thus reduces
toxicity
Increases duration of
action
Provides clean
bloodless field

32. SYMPATHOMIMETIC AMINES ACT BY
 Attaching directly to stimulating adrenergic
receptors.
 Acting indirectly by provoking release of
endogenous catecholamine from their
intraneuronal storage sites;
 A combination of direct and indirect actions.
32

33. DRUG INTERACTIONS WITH EPINEPHRINE AND
LEVONORDEFRIN
 Nonselective ß-blockers-
 Tricyclic antidepressants-
General anesthetic (halothane ,
Fluothane] serious cardiac
dysrhythmia
Cocaine
 So, FELYPRESSIN SAFER. 33

34. Examples of calculations of doses of vasoconstrictors
• Ratio concentrations represent grams per millilitre
• 1:100,000 = 0.01 mg/mL or 10 μg/mL
• 1:200,000 = 0.005 mg/mL or 5 μg/mL
• 1:50,000 = 0.02 mg/mL or 20 μg/mL
• 1 cartridge of epinephrine 1:200,000 = 9 μg
• 1 cartridge of epinephrine 1:100,000 = 18 μg
• 1 cartridge of epinephrine 1:50,000 = 36 μg
• 1 cartridge of levonordefrin 1:20,000 = 90 μg
34
The most common agent is epinephrine, which is available in
formulations of 1:50,000, 1:100,000 in USA and 1:200,000 in
other countries.

35. 35
COMMONLY USED AGENTS

36. AAPD Recommendations:
1. Selection of local anesthetic agents should be
based upon:
a. The patient’s medical history and
mental/developmental status;
b. The anticipated duration of the dental procedure;
c. the need for hemorrhage control;
d. The planned administration of other agents (eg,
nitrous oxide, sedative agents, general anesthesia)
e. The practitioner’s knowledge agent.
36

37. 2. Use of vasoconstrictors in local anesthetics is
recommended to decrease the risk of toxicity of
the anesthetic agent.
3. In cases of bisulfate allergy, use of a local
anesthetic without a vasoconstrictor is indicated.
4. The established maximum dosage for any
anesthetic should not be exceeded.
AAPD GUIDELINES 37

38. procaine
• Ester type local anesthetic
• Slower onset of action than lidocaine
• Duration of action is approx one hr.
• Metabolized in the plasma.
• Infiltration: 0.25%, 0.5%
• Nerve block: 1.0%, 2.0%
• Maximum dose 11 mg/kg or 13 mg/kg
with Epinephrine
• Toxic IV dose: 450 mg
38

39. Chloroprocaine
• It is a benzoic acid ester and short-acting local
anesthetic.
• Onset of action is rapid (6-12 min.)
• Duration of anesthesia is up to 60 min.
• Ineffective for topical anesthesia.
39

40. DOSES AND ROUTE
• Local infiltration: 2.0%, 3.0% for motor
block
• Peripheral nerve block: 1.0%, 2.0%
• Maximum dose 11 mg/kg or 13 mg/kg with
Epinephrine
• Toxic IV dose: 450 mg
40

41. LIGNOCAINE
 In 1943, the first modern LA agent trade
name Xylocaine® By Lofgren.
 Derivative of xylidine
 Belongs to the amide class, it’s
hypoallergenic
 Sets on quickly and produces a desired
anesthesia effect for several hours 41

42.  Onset for infiltration is 0.5 to 1 minute.
 Duration- 30 minutes to 1 hour.
42
This drug is also a class1B antidysrhythmic
agent that suppresses automaticity and
shortens the effective refractory period and
action potential duration of the His/Purkinje
system

43. DOSE AND ROUTES LIDOCAINE
 Regional infiltration: 0.5%
 Peripheral nerve: 1.0%, 1.5%,
2.0%
 Max dose 4 mg/kg or 7 mg/kg with
epinephrine
 Toxic IV dose: 250 mg
Repeated doses cause significant increases in blood
level because of slow accumulation
43

44. ADVERSE REACTIONS, PRECAUTIONS, AND
INTERACTIONS
 Contraindicated in patients with a known
sensitivity to amide anesthetics
 All LA can produce CNS stimulation,
depression, or both
 Use with caution in patients with hypovolemia,
severe congestive heart failure, shock, and all
forms of heart block.
44

45. BUPIVICAINE
 Amide-type local anesthetic
 Onset of action is slower than lidocaine and
anesthesia is long acting
 Metabolized in the liver and excreted by the
kidneys.
 Normally provides 2-4 hours of anesthesia
 Can be extended in some cases by using
solution with epinephrine to 7 hours
45

46. DOSES :-
 Local infiltration: 0.25%
 Peripheral nerve block: 0.25%, 0.5%
 Maximum dose 3 mg/kg or 4 mg/kg with
Epinephrine
 Toxic IV dose 80 mg
 Not recommended for the child or the
physically or mentally disabled.
46

47. ARTICAINE
Amide type
Synthesized in 1969 in Germany,
In April 2000, the U.S. FDA approved
4 percent articaine with 1:100,000
epinephrine, as septocaine
(septodont
47

48.  The primary metabolite, articainic acid, is
inactive. Eliminated via the kidneys.
 The use of 2% articaine in pediatric dentistry
is particularly advantageous because of the
lower C max and the shorter half-life.
 Serum Levels of Articaine 2% and 4% in
Children.
W. Jakobs,, B. Ladwig, P. Cichon, R. Ortel, Kirch, Anesth Prog 42:113-115 1995. 48

49. Expected duration of action of local
anesthetics Duration of action (min
49
Maxillary infiltration Inferior alveolar block
Formulation Pulp Soft tissue Pulp Soft
Articaine 4% with epinephrine 1:100,000 or 1:200,000 60 190 90 230
Bupivacaine 0.5% with epinephrine 1:200,000 40 340 240 440
Lidocaine 2% with epinephrine 1:50,000 or 1:100,000 60 170 85 190
Mepivacaine 2% with levonordefrin 1:20,000 50 130 75 185
Mepivacaine 3% plain 25 90 40 165
Prilocaine 4% with epinephrine 1:200,000 40 140 60 220
Prilocaine 4% plain 20 105 55 190

50. RECOMMENDED MAXIMUM DOSES OF
LOCAL ANESTHETICS WITH VASOCONSTRICTOR
3% solution without vasoconstrictor
50
DRUG MAXIMUM DOSE MAX NO. OF
CARTRGES
Articaine 7 mg/kg (up to 500 mg)
5 mg/kg in children
7
Bupivacaine 2 mg/kg (up to 200 mg 10
Lidocaine 7 mg/kg (up to 500 mg 13
Mepivacaine 6.6 mg/kg (up to 400 mg) 11 , 7 if plain
Prilocaine 8 mg/kg (up to 500 mg 8
An Update on Local Anesthetics in Dentistry, Daniel A. Haas, J Can Dent Assoc 2002; 68(9):546-51

51. TOPICAL ANESTHETICS
51

52. • Topical anesthetic is effective on
surface tissues (2-3 mm in depth) to
reduce painful needle penetration of
the oral mucosa.
• A variety of agents are available in
 Gel,
 Liquid,
 Ointment,
 Patch,
 Aerosol forms.
52

53. Benzocaine conc. up to 20%;
Benzocaine has a rapid onset. Not toxic.
• lidocaine is available as a solution or
ointment up to 5% and as a spray up to
a 10% conc.
• Topical lidocaine has low incidence of
allergic reactions, but increase the risk
of overdose
53

54. • Compounded topical anesthetics have
been used in:-
• Orthodontic procedures for placement of
mini-screw implants to aid tooth
movement,
• In pediatric dentistry to anesthetize
palatal tissues prior to injection and for
extraction of loose primary teeth without
the need for an injection.
54

55. • Recommendations:
• 1. Topical anesthetic to reduce discomfort associated
with needle penetration.
• 2. The pharmacological properties of the topical
agent should be understood.
• 3. A metered spray is suggested if an aerosol
preparation is selected.
• 4. Systemic absorption of the drugs in topical
anesthetics must be considered when calculating the
total amount of anesthetic administered.
• The AAPD recommends further investigation
regarding the safety and efficacy of compounded
topical anesthetics and their applications for pediatric
dental patients
55

56. ADVERSE REACTIONS OF LOCAL ANESTHETICS
 Psychogenic
 Syncope
 Hyperventilation
 Nausea, vomiting
 Alterations in heart rate or blood pressure
 Mimicking of an allergic reaction
 ALLERGIC (POTENTIAL ALLERGENS)
 Esters (true amide allergy is very rare)
 Metabisulfite (present with epinephrine and with
levonordefrin)
 Methylparaben (no longer added to dental
cartridges)
56

57. TOXIC EFFECTS
57
PRIMARI
LY
• Sedation, lightheadedness, slurred
speech, mood alteration, diplopia,
• Sensory disturbances, disorientation,
muscle twitching.
High levels
• Tremors, respiratory
depression, tonic– clonic
seizures
severe
• coma, respiratory
arrest, cardiovascular
collapse TOXICITY TO LIGNOCA

58. METHEMOGLOBINEMIA
 Prilocaine, articaine, benzocaine. It is
induced by an excess of the metabolites of
these drugs and manifests as a cyanotic
appearance that does not respond to the
administration of 100% oxygen.
 Prilocaine C/I in methemoglobinemia, sickle
cell anemia, hypoxia or
 Acetaminophen or Phenacetin, both elevate
methemoglobin levels.
58

59. PARESTHESIA
 Common with 4% articaine and
prilocaine.
 Most cases resolve in 8 weeks
59

60.  SOFT TISSUE INJURY
 Most lip- and cheek-biting lesions are self-
limiting and heal easily,
 bleeding and infection may result.
 To avoid use:-
 use pheytolamine mesylate injections to
reduce the duration of action.
 Placing a cotton roll - mucobuccal fold may
help prevent injury, lubricating the lips with
petroleum jelly helps prevent drying.
60

61. SPECIAL PRECAUTIONS
61

62. Pregnant and Lactating Women
• Lidocaine and prilocaine have
the best FDA ranking.
• Although high-dose
vasoconstrictors used to manage
hypotension may be a concern
for pregnant patients,
• the doses of epinephrine used in
formulations are so low that they
are unlikely to affect uterine
blood flow.
62

63. Children
• Determine the child’s
weight and age , to avoid
overdosage.
• Thus, 2% lidocaine with
epinephrine 1:100,000
may be the ideal local
anesthetic for a child.
63

64. ELDERLY
 There are no significant differences in the
response to local anesthetics between
younger and older adults.
64

65. CARDIOVASCULAR DISEASES
 For such patients dental treatment may
be routine fashion,but amount of
vasoconstrictor- containing anesthetics
need to be limited
 Patient carefully monitored.
 Dose- .04 mg per appointment.
 2ml of 1:50,000 (1 cartridge)
65

66. HYPERTENSION
 If a patient has uncontrolled hypertension,
dental treatment -delayed until BP under
control.
 But if emergency treatment is needed, the
clinician may elect to sedate the patient
with valium and use one to two cartridges
of local anesthetics with a
vasoconstrictors.
66

67. ANGINA PECTORIS AND POST-MYOCARDIAL
INFARCTION
 The use vasoconstrictor should be
limited.
 Only emergency treatment is done stress-
reduction protocols with antianxiety
agents.
67

68. CEREBROVASCULAR ACCIDENT
 No dental treatment performed Six months
after stroke .
 After six months, dental procedures may be
provide with the use of vasoconstrictors-
containing local anesthetics where required
for adequate pain control.
68

69. DIABETES
 No special precaution required if control of
their disease is well-managed.
69

70. LOCAL ANESTHESIA WITH SEDATION, GENERAL ANESTHESIA,
AND/OR NITROUS OXIDE/OXYGEN ANALGESIA/ANXIOLYSIS
 Particular attention on LA doses used in
children.
 The dosage of local anesthetic should not be
altered if nitrous oxide/oxygen
analgesia/anxiolysis is administered.
 When general anesthesia is employed, LA may
be used to reduce the maintenance dosage of
the anesthetic drugs. The anesthesiologist
should be informed of the type and dosage of
the local anesthetic used.
 Recovery room personnel also should be
informed
70

71. Recent Advances in LA
71

72. ELMA
 EUTECTIC MIXTURE OF LA.
 Clark in 1986.
 Cream with mixture of lignocaine and
prilocaine.
 Used as anesthesia on intact skin before
venipuncture.
 c/I in children below 6yrs
 Rashes and erythema seen.
72

73. CENTBURIDINE- Quinoline derivative
no side effects
 ROPIVACAINE – Long acting amide, has
greater safety margin , less toxicity than
bupivicaine.
 pH ALTERATION- sodium bicarbonate is
being added immediate to injection , which
makes solution alkaline and thus increases
its absorption into nerve.
73

74. CARBONDIOXIDE – Enhances diffusion
of LA, so more rapid onset of action
 INTRAORAL LIGNOCAINE PATCH
 10-20% Lignocaine can be used on buccal
mucosa for 15 mins.
 ELECTRONIC DENTAL ANESTHESIA –
Use principle of transcutaneous electric nerve
stimulation which relives pain. Pain control
in case of needle phobia.
74

75. JET INJECTIONS
75
Solution is propelled out into mucosa as a jet
without any needle.
Effective for palatal anesthesia.

76. "when it comes to the actual fear of needles..well
one thing i have found that helps the most with that
is a numbing machine called 'THE WAND'
76

77. THE MAGIC WAND COMPUDENT OR
STA SYSTEM
 The Wand is essentially a computer-controlled
dental injection.
 ADVANTAGES
 non-threatening . Researchers have found
that the Wand induces less anxiety (Kudo et
al, 2001)
 DISAVANTAGES
 Costly, takes more time and space in clinic.
77

78. ANESTHESIA AND LAW
78

79. INFORMED CONSENT – THE VERDICT IS IN
 Anesthesia specific consent form should
be implemented, all risk factors should
be highlighted….as a defense for various
medical issues.
79

80. DOCUMENTATION OF LOCAL ANESTHESIA
 AAPD Recommendations:
 1. Documentation must include the type and
dosage of LA. Dosage of vasoconstrictors
must be noted.
 2. Documentation may include the type of
injection(s) given (eg, infiltration, block,
intraosseous), needle selection and patient’s
reaction to the injection.
80

81.  If the LA was administered in conjunction
with sedative drugs, the doses of all agents
must be noted on a time-based record.
 4. For whom maximum dosage of LA may
be a concern, the weight should be
documented pre-op.
 5. Documentation should include that post-
injection instructions were reviewed with the
patient and parent.
81

82. CONCLUSION
“PAIN FREE CARE ”
82

83. REFERENCES
 Malamed SF. Handbook of local anesthesia. 4th
ed. St. Louis: Mosby; 1997.
 Monheims local anesthesia and pain control in
dental practice.
 Textbook of Pedodontics- Shobha Tondon
 An Update on Local Anesthetics in Dentistry,
Daniel A. Haas, J Can Dent Assoc 2002;
68(9):546-51
 Guide lines for local anesthesia in pediatric
patients.(AAPD) pediatric dentistry 2009.
 Local Anesthetics in Dentistry, Bach Van Pham
,Southern Methodist University; November 30, 83

84.  Local Anesthetics; Robert L. Copeland
 Lidocaine Toxicity - Pushkar Mehra, Alfons Caiazzo,
and Philip Maloney.
 Essentials of Local Anesthetic Pharmacology.
Daniel E. Becker, DDS, and Kenneth L. Reed,
Anesth Prog 53:98–109 2006
 The History of Local Anesthesia, Malvin e. RING.
 www.wikipedia.com
 Effectiveness of 20% Benzocaine as a Topical
anesthetic for Intraoral Injections. John M. Nusstein,
and Mike Beck, Anesth Prog 50:159-163 2003.
84

85. 85
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