local anesthesia

1. LOCAL ANAESTHESIA
• PRESENTED BY
Tanya Kohli
PG 1st year
GUIDED BY
• Dr. Anurag Jain
• Dr. Sonal Bansal
• Dr. Saurabh Mankeliya

2. CONTENTS
• 1.INTRODUCTION
• 2. HISTORY
• 3.PROPERTIES OF LA
• 4. ELECTROPHSIOLOGY AND
MECHANISM OF ACTION
• 5.CLASSIFICATION
• 6 LIDOCAINE
• 7. THEORIES OF LA
• 8. COMPOSITION
• 9. SYTEMATIC EFFECT
• 10.PHARMACO-KINETICS
• 11.VASOCONSTRICTOR AND ITS
CLASSIFICATION
• 12 TECHNIQUES OF LA
• 13. COMPLICATIONS OF LA
• 14. MANAGEMENT OF
COMPLICATIONS
• 15. RECENT ADVANCES OF LA
• 16. ROLE OF LA IN ENDODONTICS

3. INTRODUCTION
• ANAESTHESIA – GREEK - meaning AN means NOT and AESTHESIA means
SENSATION
• Coined in 1846 by OLIVER WENDELL HOLMES, in a letter to dentist
WILLIAM T. G. MORTON, the first practioner to publicly the use of ether
during surgery
OLIVER WENDELL HOLMES
WILLIAM T. G. MORTON

4. • Local Anaesthesia is defined as a transient reversible 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
STANLEY F. MALAMED

5. • Pain and dentistry are often synonymous in the minds of patients, especially
those with poor dentition due to multiple extractions, periodontal disease
requiring surgery, or symptomatic teeth requiring endodontic therapy.
• The everyday practice of dentistry is therefore based upon achieving adequate
local anesthesia.
• Members of the public perceive a good dentist as a practitioner who causes
little or no discomfort
• the fear of pain associated with dentistry is closely associated with the most
common method for blocking pain during dental procedures- intraoral
administration of local anesthetics

6. HISTORY
The motto behind discussing history is to prove that how important it has always
been to provide a painless treatment.
Different eras had different methods of achieving local anesthesia.
The first attempts at a state of anesthesia were probably herbal remedies
administered in prehistory. Alcohol is the oldest known sedative.
Use of a combination of poppy and hyocyamus by ancient Egyptians.
The main motive was to provide a painless procedure – relief from pain.

7. • Ancient Incas - first to discover the fatigue- chasing and mood
elevating effects of ERYTHROXYLUM COCA ( coca shrub)
 Leaves were chewed by them and spat on wounds and sites to
be operated upon to bring about anesthetic effect in that
region.
• Many attempts were hence, made to isolate the cerebral
stimulating ingredient from the coca bush

8. • COCAINE -first local anesthetic agent isolated by NIEMAN -
1860 from the leaves of the coca tree.
• Its anesthetic action was demonstrated by KARL KOLLER in
1884.
• It was Frued and his colleague Karl Kollar who first noticed
its anesthetic effect. Kollar first introduced it to clinical
ophthalmology as a topical ocular (eye) anesthetic.

9. • First effective and widely used synthetic local anesthetic -
PROCAINE -produced by EINHORN in 1905 from benzoic acid &
diethyl amino ethanol.
• The first synthetic local anesthetic was procaine, better
remembered today by its trade name, "Novocain”
• Novocain was not without its problems. It took a very long time to
set (i.e.. to produce the desired anesthetic result), wore off too
quickly and was not nearly as potent as cocaine. On top of that, it
is classified as an ester. Esters tend to have a very high potential
to cause allergic reactions

10. • LIDOCAINE- LOFGREN in 1948.
• The discovery of its anesthetic properties was followed in
1949 by its clinical use by T. GORDH.
• Thereafter, series of potent anesthetic soon followed with a
wide spectrum of clinical properties.

11. DESIRABLE PROPERTIES OF LOCAL ANESTHESIA
• It should not be irritating to tissue to which it is applied
• It should not cause any permanent alteration of nerve structure .
• Its systemic toxicity should be low .
• Time of onset of anesthesia should be short
• It should be effective regardless of whether it is injected into the tissue or
applied locally to mucous membrane.
• The duration of action should be long enough to permit the completion of
procedure.(yet not so long as to require an extended recovery)

12. •In addition to these qualities,BENNET lists other
desirable properties of ideal L.A
• It should have the potency sufficient to give complete anesthesia without the
use of harmful concentration solutions.
• It should be free from producing allergic reactions
• It should be stable in solution and relatively undergo biotransformation in the
body.
• It should be either sterile or be capable of being sterilized by heat with out
deterioration.

13. ELECTROPHYSIOLOGY OF NERVE CONDUCTION

14. NEUROPHYSIOLOGY AND MECHANISM OF ACTION

15. • STEP 1……a stimulus excites the nerve leading to following sequence of events
1. an initial phase of slow depolarization ,the electrical potential with in the nerve
becomes slightly less negative
2. when the falling electrical potential reaches a critical level an extremely rapid
phase of depolarization results .this is termed threshold potential or firing
potential
3. the phase of rapid depolarization results in a reversal of the electric potential
across the nerve membrane. the anterior of the nerve is now electrically positive
in relation to the exterior

16. • STEP 2……
• After these steps of depolarization,repolarization occurs .the electrical
potential gradually becomes more negative inside nerve cell relative to
outside until the original resting potential of -70mv exists on the interior
of the nerve cell

17. MECHANISM OF ACTION
1. Displacement of calcium ions from the sodium channel receptor
site
2. Binding of the LA molecules to this receptor site
3. Blockade of sodium channel
4. Decrease in sodium conductance
5. Depression of the rate of electrical depolarization
6. Failure to achieve the threshold potential level

18. • 7. Lack of development of propagated action
potentials
• 8.conduction blockade

19. MODE OF ACTION
• Altering the basic RMP of nerve
• Altering the threshold potential
• Decreasing the rate of depolarization
• Prolonging rate of repolarization

20. • Rate
• Non-myelinated 1.2m/s
• Myelinated 14.8 – 120m/s
• Site of action
• Outer bimolecular lipoprotein layer in nerve membrane

21. • Ideal requirements-
• its action must be reversible
• Must be non irritant and not produce any secondary irritation
• Low degree of systemic toxicity
• Must be potent enough
• Have sufficient penetrating properties

22. SYSTEMATIC ACTION
• CNS –
Low levels – no action
Toxic dose – tonic clonic convulsions
Blood- 0.5-4.0 mg/ml-no complication
4.5-7.0 mg/ml-pre seizure sign/
symptom
>7.5mg/ml-tonic clonic seizures.
Anti convulsive property –
As it causes depression of CNS.
Seizure threshold- excitability nerve

23. • CVS-
• Action on Heart
• DECREASE IN
• Electrical excitability of myocardium .
• conduction rate
• Tone of contraction.
clinically effective level-1.8-5mg/ml –anti arrhythmic
used in premature ventricular contractures , arrhythmias.

24. • Action on vasculature-
normal value no change.
over dose- hypo tension.( myocardial
contractility)
Lethal dose- cardio vascular collapse
( myocardial contractility, massive peripheral vaso dilatation )

25. •Action on Respiratory system–
• Normal levels- no over dose- bronchial muscles
relaxation .
• Over dose – Respiratory arrest due to CNS
depression

26. • Least toxic LA- chlorprocaine.
• Most toxic LA- tetracaine- for topical-dicyclomine
• If allergic to LA –diphenhydramine- anti histamine + mild anesthetic
• For children – 2% chlorprocaine
• LA is added with bi carbonate in infections

27. CLASSIFICATION
•Esters –
• Benzoic acid Para Amino benzoic
• Cocaine Procaine
• Benzocaine Propoxycaine
• Hexylcaine Chloroprocaine
• Tetracaine
•Amides –
• Articaine
• Bupivacaine
• Dibucaine
• Lignocaine
• Mepivacaine
• Prilocaine
• procinamide
Based on intermediate group --

28. • Class A
• Class B
• Class C
• Class D
• Agents acting at receptor site –external surface eg Biotoxin -
tetrodotoxin
• .Agents acting at receptor site- internal surface.. Eg Quaternary
amonium-scorpion venom
• Agents acting at receptor independent physico chemical
mechanism. Benzocaine
• Agents acting in combination of receptor and independent
mechanism. Clinically useful agents –Lignocaine etc,most of LA
According to biological site and mode
of action—

31. LIDOCAINE
• Lidocaine, Xylocaine or lignocaine is a common local anesthetic and antiarrhythmic
drug.
• Most widely used LA effective by all routes.
• Faster onset .
• Available as Injections, topical solution, jelly and ointment etc
• Lidocaine is used topically to relieve itching, burning and pain from skin
inflammations, injected as a dental anesthetic or as a local anesthetic for minor
surgery.
• More intense, longer lasting, than procaine.

32. • Sets on quickly and produces a desired anesthetic effect for several hours
• Good alternative for those allergic to ester type
• More potent than procaine but about equal toxicity
• It relieves pain during the dental surgeries
• Quicker CNS effects than others
• Anti arrhythmic
• Cause little allergenic reaction; it is hypoallergenic

33. SS

34. USES
• USE : a) 2% lignocaine with 1: 50000 epi. – hemostasis
• b) 2% lignocaine with 1: 100000 or 1: 200000 – local anesthesia
• COMPARISON OF LIDOCAINE WITH PROCAINE –
• More rapid onset of action
• More profound anesthesia
• Longer duration of action
• Greater potency

35. THEORIES MECHANISM OF ACTION OF LOCAL
ANESTHETICS
• Many theories have been promulgated over the years to explain the
mechanism of action of local anesthetics.
• ACETYLCHOLINE THEORY:
• Stated that acetylcholine was involved in nerve conduction in addition
to its role as a neurotransmitter at nerve synapses.
• There is no evidence that acetylcholine is involved in neural
transmission.

36. CALCIUM DISPLACEMENT THEORY
• States that local anesthetic nerve block was produced by displacement
of calcium from some membrane site that controlled permeability of
sodium.

37. SURFACE CHARGE (REPULSION) THEORY
• Proposed that local anesthetic acted by binding to nerve membrane and
changing the electrical potential at the membrane surface.
• Cationic drug molecule were aligned at the membrane water interface,
and since some of the local anesthetic molecule carried a net positive
charge, they made the electrical potential at the membrane surface more
positive, thus decreasing the excitability of nerve by increasing the
threshold potential.
• Current evidence indicate that resting potential of nerve membrane is
unaltered by local anesthetic.

38. MEMBRANE EXPANSION THEORY
• It states that local anesthetic molecule diffuse to hydrophobic regions of
excitable membranes, producing a general disturbance of bulk membrane
structure, expanding membrane, and thus preventing an increase in
permeability to sodium ions.
• Lipid soluble LA can easily penetrate the lipid portion of cell membrane
changing the configuration of lipoprotein matrix of nerve membrane.
• This results in decreased diameter of sodium channel, which leads to
inhibition of sodium conduction and neural excitation.

39. SPECIFIC RECEPTOR THEORY:
• The most favored today, proposed that local anesthetics act by binding
to specific receptors on sodium channel
• The action of the drug is direct, not mediated by some change in
general properties of cell membrane.
• Biochemical and electrophysiological studies have indicated that
specific receptor sites for local anesthetic agents exists in sodium
channel either on its external surface or on internal axoplasmic surface

41. COMPOSITION
• LOCAL ANESTHETIC AGENT(DRUG) (xylocaine, lignocaine 2%) -Blockade of nerve conduction.
• VASOCONSTRICTOR (adrenaline 1: 80,000) Increase depth and increase duration of
anesthesia; decreases aborption of local anesthetic .
• SODIUM METABISULPHITE - reducing agent (antioxidant)
• METHYL PARABEN,CAPRYL HYDROCUPRIENOTOXIN -Bacteriostatic agent and preservative
• THYMOL -Fungicide
• VEHICLE (DISTILLED WATER and NACL) -Volume and Isotonicity of solution
• Nitrogen bubble- to avoid entrapment of oxygen

42. • The chemical characteristics are so balanced that they have both
lipophilic and hydrophilic properties.
• If hydrophilic group predominates, the ability to diffuse into lipid rich
nerves is diminished.
• If the molecule is too lipophilic it is of little clinical value as an
injectable anesthetic, since it is insoluble in water and unable to diffuse
through interstitial tissue.

44. VASOCONSTRICTORS
• Decrease blood flow to the site of injection bc of vasoconstriction
• Decreases the rate of absorption of LA into CVS
• Lower anesthetic blood levels
• lowers the level of LA in plasma therefore decrease the risk of systemic
toxicity
• Increases duration of action
• Decrease bleeding bc of decreased perfusion. ( for surgical procedure)

45. BASED ON CHEMICAL STC  (CATECHOL NUCLEUS)
CATECHOLAMINES
Epinephrine
Nor epinephrine
Dopamine
NON CATECHOLAMINES FELYPRESSIN
Amphetamine
Meta amphetamine

46. BASED ON MODE OF ACTION
• Direct acting
• Epinephrine
• Nor epinephrine
• Dopamine
• Levonordefrin
• Isoproterenol
• Indirect
acting
• Amphetamine
• Tyramine
Mixed acting
 Ephedrine
• Metaramino

47. • EPINEPHRINE
• Maximum Dose for Dental Appointment
• - Normal healthy patient: 0.2 mg. per appointment
• - Significant cardiovascular impairment: 0.04 mg per appointment
• NOREPINEPHRINE
• Maximum dose : Healthy pt – 0.34 mg per appointment or 10 ml of
1:30000 solution
• pt. with CV disease : 0.14 mg per appointment or 4 ml of 1:30000

48. • FACTORS IN SELECTION OF A LA FOR A PATIENT
• 1. Length of time pain control is necessary.
• 2. Potential need for post treatment pain control
• 3. Possibility of self-mutation in the postoperative period
• 4. Requirement for haemostasis
• 5 . Presence of any contraindication to the LA solution selected for
administration

49. • COMMON QUESTIONS TO ASK THE PATIENT
• Allergic to any medications?
• Have you ever had a reaction to local anesthesia?
• If yes, describe what happened?
• Was treatment given? If so, what?

50. •PREPARATION OF THE PATIENT
•Careful preoperative assessment
• History
• A clear explanation of what to expect

51. • Data should be documented includes:
• *.Baseline vital signs:
• 1.blood pressure
• 2.laboratory values
• 3.Results of ECG monitoring
• 4.any other tests
• *. Weight, height, and age:
• Dosage of some drugs is calculated on the basis of body weight in kilograms
(mg/kg). Some drugs are contraindicated for age extremes (i.e., pediatric or

52. • Current medical problem(s) past history of medical events, including a history of
substance abuse
• Current medications or drug therapy, such as insulin for diabetes or hypertensive
drugs.
• Allergy, or hypersensitivity reactions to previous anesthetics or other drugs
• Mental status, including emotional state and level of consciousness
• Communication ability A patient with hearing impairment or language barrier may
be unable to understand verbal instructions during the procedure or to respond
appropriately.

53. • STRESS REDUCTION PROTOCOL
• Morning appointments are usually best.
• Keep appointments as short as possible.
• Freely discuss any questions, concerns, or fears that the patient has
Establish a honest, supportive relationship with the patient.
• Maintain a calm, quiet, professional environment.
• Provide clear explanations of what the patient should expect and feel

54. • Premedicate with benzodiazepines if needed.
• Ensure good pain control through judicious selection of local anesthetic
agents appropriate for treatment.
• Maintenance of patient comfort throughout the procedure.
• Use nitrous oxide as needed (avoid hypoxia).
• Use gradual position changes to avoid postural hypotension.

56. TECHNIQUES OF
LOCAL
ANAESTHESIA

57. DIFFERENT TECHNIQUES OF
ACHIEVING LA
Local infiltration
Field block
Nerve block
Intraligamentry
Intraseptal
Intrapulpal
Intraosseous injection

58. Computer controlled local anesthetic
delivery system
Electronic dental anesthesia
Topical anesthesia

59. 1. LOCAL INFILTRATION (0.6 – 1.0 ml)small terminal nerve endings are anaesthetized.

60. • NERVE BLOCK (1.8 – 2.0 ml)depositing the LA solution within close proximity to a main nerve
trunk

61. • FIELD BLOCK deposited in proximity to the larger nerve branches

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63. PERIODONTAL LIGAMENT
INJECTION
INDICATIONS
1.Pulpal anesthesia of one or two teeth in a
quadrant
2. Treatment of isolated teeth in mandibular
quadrant
3. Patient for whom residual soft tissue
anesthesia is undesirable
4. Situations in which regional block is
contraindicated
CONTRAINDICATIONS
1..Infection or inflammation at the site of
injection
2. Primary teeth when the permanent tooth
bud is present
3. Patient who requires a “numb” sensation
for psychological discomfort

64. INTRASEPTAL INJECTION
Indications
When both haemostasis & pain control are desired for soft tissue & osseous
periodontal treatment
Contraindications
Infection or severe
inflammation at the
site of injection

65. JET INJECTOR
Principle- based on principle that liquid forced through very small openings,
called jets, at very high pressure can penetrate intact skin or mucous
membrane
The primary use of jet injector is to obtain topical anesthesia before
the insertion of a needle
In addition it may be used to obtain mucosal anesthesia of palate

66. • Jet injector

67. Advantages
1. Does not require use of needle
2. Delivers very small amount of LA
3. Used in lieu of topical anesthesia

68. Disadvantages
1. Is inadequate for pulpal anesthesia or regional anesthesia
2. May damage periodontal tissue
3. Many patients dislike the feeling accompanying use of the jet injector
4. Post-injection soreness of soft tissue may develop

69. INTRAOSSEOUS INJECTION
Indications
Pain control for dental treatment
on single or multiple teeth in a
quadrant
Contraindications
Infection or severe
inflammation at the site of
injection
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70. INTRAPULPAL INJECTION
local anesthesia
Deposition of LA
directly into the pulp
chamber of a pulpally
involved tooth provides
effective anesthesia for
pulpal extirpation &
instrumentation where
other techniques have
failed.

71. COMPUTER-CONTROLLED LOCAL
ANESTHETIC DELIVERY SYSTEM
• The system enables a dentist or hygienist to accurately manipulate needle
placement with fingertip accuracy and deliver the LA with a foot-activated
control

73. • Advantages
• Precise control of flow rate &
pressure, hence a more
comfortable injection
• Increased tactile feel
• Automatic aspiration
• Rotational insertion technique
• minimizes needle deflection
Disadvantages
1. Need for additional
armamentarium
2. Increased cost

74. ELECTRONIC DENTAL
ANESTHESIA
The method of achieving local anesthesia
transcutaneous electrical nerve stimulation {TENS}
which has been used for the relief of pain
• According to the gate control theory of pain, stimulation of large diameter afferents
by TENS inhibits nociceptive fiber evoked responses in the dorsal horn

75. Indications
1. In patients with
needle phobia
2. Ineffective LA
3. Instances where
LA cannot be
administered
Contraindications
1. Neurological disorders
2. Pregnancy
3. Very young pediatric
patients
4. Older patients with
senile dementia
5. Cardiac pacemakers

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77. TOPICAL ANESTHESIA
Anesthesia obtained by the application of a suitable agent to an area of
either the skin or mucous membrane which it penetrates to anesthetize
superficial nerve endings
Spray
Ointments & jelly

78. MAXILLARY ANESTHESIA
• More easily obtained then mandibular
• Most commonly used- infiltration 1.8 ml 2% lidocaine
• Success rate – 90 to 95 %
• Onset – 5 to 7 minute
• Duration = 20 – 30 min. anterior teeth
30- 45 min molars
• Soft tissue anesthesia is not necessarily related to duration of pulpal
anesthesia , pulpal anesthesia dose not last long as soft tissue ones

79. TECHNIQUES OF INJECTION
• Basic points-
• Use a Sterile Sharp Needle
• Check The flow of Solution
• Position the patient
• Dry the tissue/ wipe once.
• Apply topical anesthetic

80. • Topical antiseptic /optional
• Communicate with patient apply firm hand rest
• Inject few drops of soln, communicate with patient,
• Advance to the target slowly ,aspirate , inject
• Withdraw the needle slowly
• Observe the patient & check for anesthetic symptoms

81. TECHNIQUE FOR MAXILLARY BLOCK
• Supra periosteal injection:
• Anaesthetize buccal soft tissue & hard tissue
• Nerves anaesthetized – large terminal branches
• Indication :
• 1 or 2 teeth need to be anaesthetized / small area

83. • Contra-indication :
• Infection
• Dense bone covering
• Target area :
• Behind apices of tooth
• Landmarks :
• Muco-buccal fold
• Crown & root length

85. POSTERIOR SUPERIOR ALVEOLAR NERVE BLOCK
• Area anaesthetized:
• Maxillary 3rd, 2nd & 1st molar (except mesio-buccal root of 1st
molar)
• Bone & periodontium over these
• Indication:
• Treatment of 2 or more molars required
• Supra-periosteal injection – ineffective
• Acute inflammation

86. COMPLICATIONS
• :Hematoma –
• Non visible - pterygoid plexus posteriorly
• Visible – buccal aspect
• Accidental mandibular Anaesthesia
• Orbital contents – anaesthetized accidentally
• Accidental - parotid gland  facial nerve affected

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89. MIDDLE SUPERIOR ALVEOLAR NERVE BLOCK

90. c

92. • ANTERIOR SUPERIOR ALVEOLAR NERVE BLOCK
AKA INFRAORBITAL NERVE BLOCK

97. • GREATER PALATINE NERVE BLOCK
• Technically difficult but high success rate
• 0.45-0.6 ml success rate
• Profound palatal and soft tissue anesthesia
• Potentially traumatic but less than nasoplalantine anesthesia

99. •NASOPALANTINE NERVE BLOCK AKA
INCISIVE NERVE BLOCK

102. Nasopalatine nerve block
Areas anaesthetized
Anterior portion of Hard palate and over
lying structures back to the bicuspid area.
Indications
Anterior palatal procedures
supplementing infraorbital nerve blocks
Anaesthesia of nasal septum
Landmarks
Central incisor & incisive papilla

105. •LOCAL INFILTRATION OF PALATE

115. MAXILLARY NERVE BLOCK
• – Extra Oral
• Areas anaesthetised
• Anterior temporal & zygomatic
region
• Lower eyelid
• Side of nose
• Anterior cheek
• Upper lip
• Maxillary teeth / alveolar bone &
overlying structures – 1side
• Hard & soft palate
• Tonsils – parts of pharynx
• Nasal septum – floor of nose
INDICATIONS
• Extensive surgery – 1
half of maxilla
• Others blocks not
possible
• Therapeutic purposes

117. •Inferior alveolar nerve block
• Areas anaesthetised
• Mandibular teeth upto midline
• Body of mandible
• Inferior portion of ramus
• Buccal periosteum & mucous membrane
• Lingual soft tissue
• Anterior 2/3rd of tongue
• Indications
• Multiple mandibular teeth – procedures
• Buccal / Lingual soft tissue anaesthesia

119. • Contraindications
• Infection / acute inflammation
• Young children / mentally handicapped
• Landmarks
• Coronoid notch
• Pterygomandibular raphe
• Occlusal plane of posterior mandibular teeth
• Complication
• Hematoma
• Trismus
• Transient facial paralysis (parotid gland)

120. • Anatomical structures - final position
• Superiorly –
• Inferior alveolar nerves & vessels
• Insertion of medial pterygoid
• Mylohyoid nerves & vessels
• Anteriorly –
• Deep part of parotid gland
• Laterally –
• Lingual nerve
• Internal pterygoid
• Spehnomandibular ligament
• Medially- ramus of mandible.
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122. • Closed mouth/ Akinosis technique (1977)—
• Nerves anesthetized -
• Area anesthetized
• one half of mandible upto mid line including lingual tissue and inferior portion of the ramus of
the mandible.
• Land mark-
• occluding plane of the teeth.
• Muco gingival junction maxillary teeth.
• Antr border of ramus.
• Orientation of bevel must be oriented away from the bone of mandibulaar ramus (bevel faces
toward mid line).
• More popular now
• Land marks easy
• One prick – mandibular, buccal, lingual n anesthetised.
• Patient more comfortable.
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125. • Advantages
Atraumatic,
pats. with restricted mouth opening.
fewer post op complications.
• Disadvantages
Difficult to visualize the path of needle and depth of insertion.
Complications
hematoma, transient facial n. paralysis.
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126. • Gow gates technique– 1973 (mandibular n. block)
Nerves anaesthetised – inferior alveolar, mental, incisive, lingual, mylohyoid,
auriculotemporal and buccal.
• Area –all mandibular hard and soft tissue Upto mid line.
• Indications- multiple procedures on mandibular teeth, buccal soft tissue anaesthesia from
third molar to midline, conventional inf. alv. n. block is unsuccessful.
• Contraindications – infection or acute inflammation in the area of infection, pats. with
restricted mouth opening.
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127. • Landmarks-
• Extraoral- corner of mouth, lower border of the tragus, intertragic notch
• Intraoral – height of injection established by placement of needle tip just
below the mesiolingual cusp of max. 2nd molar, penetration of soft tissue
distal to 2nd molar at the same height.
• Final position needle is just inferior to condyle and insertion of lateral
pterygoid.
Gained popularity – single needle penetration, relies on soft tissue landmarks
– differ from patient to patient
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129. • Lingual nerve block –
• Area anaesthetised –
• Anterior 2/3rd tongue, floor of mouth, lingual mucoperiosteum
Only used singly to operate on tongue, floor of mouth
• Buccinator / long buccal nerve block
• Area anaesthetised –
• Buccal mucosa & mandibular molar – mucoperiosteum
• Land marks
• External oblique ridge, retromolar triangle
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131. • Mental nerve block
• Areas anaesthetised
• Lower lip, mucous membrane – anterior to mental foramen
• Landmarks
• Mandibular bicuspids
• Indications
• Surgery of lower lip or mucous membrane
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133. EXTRA ORAL TECHNIQUE
• Mandibular nerve
• Area anaesthetised
• Temporal region with auricle of ear & external auditory meatus
• TMJ, salivary glands
• Anterior 2/3rd of tongue
• Mandible – hard & soft tissue – midline
• Landmarks
• mid point of zygomatic arch
• Zygomatic notch
• Cornoid process of mandible
• Lateral pterygoid plate
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134. • Indications
• When need to anaesthetise entire mandibular nerve
• Infection / trauma – makes terminal anaestheisa not possible
• Diagnostic / therapeutic
The needle is pointed posteriorly & to a greater depth of 5 cms
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136. Mental & Incisive nerve block
 Area anaesthetised
Mandibular hard & soft tissue – labial aspect
with lower lip
• Landmarks
Bicuspid teeth, lower ridge of body of
mandible
Supra & infra orbital notch
Pupil of the eye
2 inch 22 gauge needle used & introduced
slightly anteriorly & downwards

137. COMPLICATIONS
• Definition
• An anaesthetic complication may be defined as any deviation
from the normal expected pattern during or after securing
regional anaesthesia
• 2 types
• Local
• Systemic
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138. • SYSTEMIC COMPLICATIONS
• Toxicity
• Idiosyncracy
• Allergy
• Anaphylactoid reaction
• Syncope
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139. • Transient / permanent
• Transient – is one that is severe at occurrence – no residual effects
• Permanent – residual effect; lasts for a life time even though it is mild
• Complications could be a combination of any of the above mentioned
types
• Majority are either Primary Mild & Transient or Secondary Mild &
Transient
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140. • Complications
• Attributed to solutions – toxicity, allergy, idiosyncrasy, anaphylactoid
reaction, local irritation
• Attributed to technique / needle – syncope, muscle trismus, pain,
edema, hematoma
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141. NEEDLE BREAKAGE
• Cause –
• Unexpected movement – patient (if patient movement is opposite to
path of needle insertion)
• Multiple used needle
• Defective manufacture of needles/barbed needles
• smaller gauge – more likely to break
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142. • Prevention
• Correct gauge – 25 gauge
• Long needles – prevent penetration till hub
• Not to redirect when in tissue
• Management
• Patient – not to move – hand in the mouth – mouth open
• Fragment visible – remove it
• Fragment not visible – inform patient – not necessary for intervention
immediately – Radiograph suggested
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143. • Precautions
• Avoid bony contact
• Avoid heavy pressure
• Avoid movement of needle and patient
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144. PAIN ON INJECTION
• Causes –
• Careless injection technique
• Multiple used needle
• Rapid deposition
• Problems –
• Pain – patient anxiety – unexpected movements
• Prevention –
• Proper technique – sharp needles
• Enter topical anaesthetics
• Inject slowly – solution sterilized
• Check temperature of solution
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145. BURNING ON INJECTION
• Causes
• Due to pH of solution  5 (LA) – 3 (LA+VC)
• Rapid injection
• Contamination
• Warm solution
• Problems
• pH  disappears upon LA action – no residual effect
• Contaminated solution  other complications – trismus, edema,
paraesthesia
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146. • Prevention
• Slow injection – 1ml / minute
• Cartridge stored at room temperature – away from
containers with alcohol / other agents
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147. PERSISTENT ANAESTHESIA / PARESTHESIA
• Causes
• Direct trauma to nerve – bevel of needle
• LA solution containing neurotoxic substance – alcohol
• Injection of wrong solution
• Hemorrhage / infection – near to nerve
• Problem
• Persistent anaesthesia – usually rare
• Biting / thermal / chemical insult – without patient awareness
• When lingual nerve is involved – taste impaired
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148. • Prevention
• Proper care & handling of dental cartridge
• Adherence to injection protocol
• Management
• Usually resolve in 8 weeks
• Periodic recall & check up of patients
• Persistence – consult neurosurgeon
• Recall patient every 2 months for check up
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149. TRISMUS
• Definition
• “difficulty in opening the jaws due to muscle spasm”
• Causes
• Trauma – muscle / blood vessel
• Irritating solution
• hemorrhage
• Infection
• Multiple needle punctures
• LA have been known to have slight myotoxicity
• Excessive volume – distension of tissues
• Problems
• Pain / hypomobility
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150. • Prevention
• Use of sharp, sterile, disposable needle
• Aseptic technique
• Practice atraumatic methods
• Avoid repeated injections
• Use minimum volume
• Control infection
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151. • Management
• Heat therapy
• Warm saline rinses, moist hot packs
• Analgesics
• Aspirin, Codeine (30-60mg), muscle relaxants
• Initial physiotherapy
• Thrice a day
• Antibiotic regime
• Possibility of infection
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152. HEMATOMA
• “effusion of blood into extra-vascular spaces”
• Causes
• Arterial & venous puncture – common in PSA & Inf. Alv. nerve blocks
• Patients with bleeding disorders
• Problem
• Bruise – may / may not be visible extra-orally
• Complications – pain & trismus
• Swelling & discoloration
• Prevention
• Knowledge of normal anatomy – proper technique
• Shorter needle – PSA, minimize the number of penetration
• Discard defective needles- barbed needles
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153. • Management
• Immediate – apply firm pressure  5-10minutes
• Inf. Alv. Nr. Block – medial aspect of ramus
• Infra orbital, Mental, Incisive block – directly over
foramen
• PSA – pressure on soft tissue with finger as posteriorly as
tolerated by patient – medial superior direction
• Patient to be reviewed after 24 hours, advice analgesics,
cold application upto 4-6 hours, warm- pack application
next day
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154. INFECTION
• Comparitively rare complication
• Instrument needle solution to be as aseptic as possible
• Area & operative hands – cleaned
• Avoid passing needle through infected area
• Use disposable syringes
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155. EDEMA
• Causes
• Trauma during injection
• Infection, hemorrhage
• Allergy (Angioedema)
• Injection of irritating solution
• Problems
• Pain & dysfunction
• Airway obstruction
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156. • Prevention
• Proper care & handling of armamentarium
• Atraumatic injection technique
• Complete medical evaluation prior to injection
• Management
• Trauma – resolve in few days without therapy
• Hemorrhage – resolve slowly 7-14 days
• Allergy – life threatening, airway impairment – basic life support, call medical help, Epinephrine –
0.3mg, Antihistamine, Corticosteroids
• Total airway obstruction – Tracheostomy / Cricothyroidectomy
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157. SLOUGHING OF TISSUE
• Causes
• Epithelial desquamation – topical anaesthesia – long time, heightened sensitivity to LA
• Sterile abscess – secondary to prolonged ischemia – VC in LA  site – hard palate
• Problems
• Pain & infection
• Prevention
• Topical – for not more than 1-2 minutes
• VC – minimal concentration in solution
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158. • Management
• Symptomatic – pain – analgesia
• Epithelial desquamation – resolve few days
• Sterile abscess resolve  7-10 days
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159. SOFT TISSUE INJURY
• Causes
• Trauma occurs – frequently mentally / physically challenged children
• Primary cause – significantly longer duration of action
• Problem
• Pain & swelling
• Infection of soft tissue
• Prevention
• Cotton roll between lip & teeth
• Patient – guarded against eating / drinking
• Warning sticker
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160. FACIAL NERVE PARALYSIS
• Cause
• LA solution into parotid gland – usually while giving Inf Alv Nr. Block, Akinosis technique
• Problem
• Ipsilateral loss of motor control – Buccinator muscle
• Inability to raise the corner of Mouth, close Eye lid
• Prevention
• Needle tip to contact bone, redirection of needle to be done only after complete withdrawal
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161. • Management
• Reassure the patient
• Resolves after action of LA is over
• Eye patches to the affected – eye drops
• Contact lenses if any – removed
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162. SYSTEMIC COMPLICATIONS
• Toxicity / toxic overdose
• “Signs and symptoms that result from an overly high blood level of a drug in various target
organs and tissues”
• Predisposing factors
• Age – any age
• Weight – greater the body weight greater is the amount of dose
tolerated before overdose reaction
• Gender-during pregnancy – renal function disturbed – females
more affected at this time
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163. • Diseases – hepatic & renal dysfunction reduced
breakdown
• Congestive heart failure – less liver perfusion
• Genetics – pseudocholinesterase deficient

164. • Fearful patients – lower seizure threshold for LA
• Drug factors – Vasoactivity – vasodilation – increase in blood
concentration
• More concentration – greater risk
• Dose smaller dose should always be preferred
• Route of Administration – Intravascular – increased toxicity
• Rate of injection – slower rate preferred
• Vascularity of injection site – more vascular – greater
absorption
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165. • Causes of toxicity –
• Biotransformation usually slow
• Drug – slowly eliminated by kidney
• Too large a total dose
• Absorption from injection site - rapid
• Accidental intra-vascular injection
• Symptoms –
• CNS – cerebral cortical stimulation – talkative,
restless, apprehensiveness, convulsions
• Cerebral cortical depression – lethargy, sleepiness,
unconsciousness
• Medullary stimulation – increased B.P, Pulse rate,
Respiration
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166. • Medullary depression – mild fall in B.P– severe cases drops to 0 , Pulse , Respiration –
similar effect
• Treatment
• Mild overdose reaction – slow onset reaction – > 5 mins administer Oxygen (prevent
acidosis), monitor vital signs, in case of convulsions – anti-convulsants
(diazepam/midazolam)
• Slower onset - >15 mins – same procedure
• Severe overdose reaction – rapid onset – 1 minute – unconsciousness with or without
convulsion, patient in supine position, convulsions – protect hand, leg, tongue, BLS,
administer anti-convulsant
• post seizure – CNS depression usually present
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167. IDIOSYNCRASY
• Common cause – some underlying pathology/psychological /genetic mechanism
• “It is an adverse response that is neither an overdose nor an allergic reaction”
• Pyschotherapy may be helpful
• Treatment – symptomatic ..remember ABC’s!
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168. SYNCOPE
• “transient loss of consciousness that is caused due to cerebral ischemia (neurogenic shock)”
• Anxiety – increased blood supply to muscles, sitting position 2mm Hg, less pressure –
cerebral arteries
• Clinically light headedness, dizziness, tachycardia & palpitation – may further lead to
Unconsciousness
• Treatment – discontinue procedure, supine position, deep breathing, O2 administration if
required, BLS
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169. ALLERGY
• “Hypersensitive state acquired through exposure to a particular allergen reexposure
to which produces a heightened capacity to react”
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170. • 1 % of all reaction in LA is allergy
• Incidence of allergy reduced since introduction of Amides
• Life threatening allergic response rare
• Predisposing factors
• Hyper sensitivity to ester more common-procaine
• Most of patients allergic to methyl paraben
• Recently allergy to sodium meta bisulfide is also increasing
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171. PREVENTIONS
• Ho of allergy to be recorded
- itching,swelling,rashs…..
• Ho any asthmatic attack to be noted.
• Dialogue history.
• Always better to test the patient for allergy before treatment.
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172. • Consultation and allergy testing
• Refer doubtful cases for allergic test –
-Skin test is primary mode of assesing
-Intra cutaneous test most sensitive.
0.1ml of solution- forearm
• Informed consent that includes cardiac arrest and death to
be included.
• I.V infusion to be started and emergency drugs and
equipments must be available
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173. • Signs and symptoms of allergy.
• Dermatological reactions
urticaria –wheal and smooth elevated patches,
angio oedema —localized swelling
• Respiratory reactions–
broncho spasm-
respiratory distress, dysnea, wheezing, flushing, tachycardia etc.
Laryngeal edema – type of angio neurotic oedema to the larynx.
-Edema upper air way – laryngeal edema
- Lower air way affect broncioles- small.
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174. Management
skin reactions-
• Delayed – non life threatening - oral histamine
blockers- 50 mg diphenhidramine or
chlorpheniramine 10 mg -6th hrly 3-4days
• Immediate reaction—with conjunctivitis,
rhinitis,urticaria- vigorous management.
• 0.3 mg epinephrine. IM/ SC
• 50 mg diphenhydramine IM
• medical help summoned.
• Observe for 60 mins
• Oral histamine for 3 days
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175. • Terminate dental treatment
• patient in comfortable position.
• administer - oxygen 5-6 lts/mns
• Admn epinephrine/bronchodilator
• Observe for 60 min , advise anti histamines to prevent relapse.
• Laryngeal edema-
• Patient position ,oxygen, broncho-dilator, epinephrine 0.3mmd im/sc, anti histamines iv,
steroids .
• If condition not improving cricothyrotomy - achieve patent air way if necessary give
artificial ventilation.
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176. • blocker like diphenhydramine as anesthetic.
• General anesthesia
• alternative Patient with confirmed allergy status-
• if patient allergic to any one type of anesthetic ester / amide use the other.
• Use histamine thod of pain control –
• electric anesthesia / hypnosis.
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178. RECENT ADVANCES AND
FUTURE TRENDS IN
PAIN CONTROL

179. • Centbucridine
• Ropivacaine
• EMLA
• TENS ( Transcuteneous Electrical
Nerve
Stimulation)
• Hyaluronidase
• Ultra –long acting local
anesthetics
• Sprays
• Topical gels
• Intraoral lignocaine
patch(dentipatch)
• Iantophoresis
• Jet injection
• Computer controlled system