Local anesthesia in dentistry /certified fixed orthodontic courses by Indian dental academy

LOCAL ANESTHESIA IN
DENTISTRY

www.indiandentalacademy.com

INDIAN DENTAL ACADEMY
Leader in continuing dental education


HISTORY


500’s: Coca leaves were first used by Peruvians for
psychotropic properties.



1850’s: German chemist Albert Niemann
successfully isolated the active principle of
coca leaf; he named it cocaine. Hypodermic
needle developed



1884: Sigmund Freud studied the effects of
cocaine.



1884: Carl Koller introduced cocaine into medical
practice.


….History


1884 : Local anesthesia used in dentistry by Halsted
and Hall



1905 : Procaine synthesized by Einhorn



1921: Cartridge syringe marketed by Cook



1947: Aspirating syringe developed



1948: Lidocaine marketed



1959: Disposable needle introduced

DEFINITON.
“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 & Straton-1976)




REGIONAL ANALGESIA: loss of pain sensation over
a portion of the anatomy without loss of
consciousness



REGIONAL ANESTHESIA: it applies not only to loss
of pain sensation over a specific area of anatomy
without loss of consciousness but also to the
interruption of all other sensations, including
temperature, pressure and motor function.


CLASSIFICATION


BASED ON CHEMICAL STRUCTURE



ESTERS:



Benzoic acid esters:

AMIDES:


Articaine





Bupivacaine





Benzocaine
Cocaine



Etidocaine

Para-amino benzoic



Lidocaine

esters:



Mepivacaine



Prilocaine



Tetracaine



Chlorprocaine



Procaine



Propoxycaine



QUINOLINE:


Centbucridine


STRUCTURES OF AMIDES
AND ESTERS
R3
Ester:

R1 —COO—R —N
2
R4
R3

Amide:

R 1 —NHCO—R —N
2
R4

R1 — Lipophilic aromatic residue.
R2 — Aliphatic intermediate connector.
R3 , R4 — Alkyl groups

Based on biological site and mode of action
Class A
Class BClass CClass D


Based on the source
Natural

Synthetic


Others

Based on duration of action
Short



eg: Lidocaine HCl 2%, Mepivacaine HCl 3%

Intermediate duration –




Long

Short duration –




Intermediate

eg: Lidocaine HCl 2% + epinephrine 1:1,00,000

Long duration–


eg: Bupivacaine HCl 0.5% + epinephrine 1:2,00,000, Etidocaine

Based on mode of application
Topical

Injectable


NEROPHYSIOLOGY


MODE OF ACTION OF LOCAL
ANESTHETIC…
Local anesthetic agents interfere with excitation
process in a nerve membrane in one or more of the
following ways:





Altering basic resting potential



Altering the threshold potential



Decreasing the rate of depolarization



Prolonging the rate of repolarization

THEORIES OF MECHANISM
OF ACTION OF L.A…


Ca2+ DISPLACEMENT THEORY



SURFACE CHARGE THEORY

(Wei-1969)



ACETYLCHOLINE THEORY

(Dett barn-1967)



MEMBRANE EXPANSION THEORY



SPECIFIC RECEPTOR THEORY

(Goldman-1966)

(Lee-1976)

(Strichartz-1987)

ACETYL CHOLINE THEORY


MEMBRANE EXPANSION
THEORY


SPECIFIC RECEPTOR THEORY


CHEMICAL REACTON OF LA
RNHOH + HCl  RNHCl + H2O
Weak strong
acid
water
Base
acid
salt
RNHCl  RNH+ + CI-


EFFECT OF PH
Basic environment (higher pH)
RNH+ > RN + H+
Acidic environment (low pH)
RNH+ < RN + H+


RNH+ displaces calcium ions for the sodium channel receptor site.
↓ which causes
Binding of the local anesthetic molecules to this receptor site
↓ which produce
Blockade of sodium channel
↓ and
Decrease in sodium conduction
↓ which leads to
Depression of the rate of electrical depolarization
↓ and
Failure to achieve the threshold potential level
↓
Lack of development of propagated action potentials
↓ called

Conduction blockade

HENDERSON – HASSELBALCH EQUATION



Log Base

=

pH – pKa

Acid


INDIVIDUAL LOCAL ANESTHETIC
AGENTS…
Drug

pka

ph

Conc

Onset

½ life

2-4%

6-10 min

½ hr

used
Procaine

9.1

5-6.5
3.5-5.5

Propoxycaine

-

-

0.4%

2-3 min

-

Lidocaine

7.9

6.5

2%

2-3 min

1.6 hr

4.5

3%

1.5-2

1.9 hr

3-3.5

2%

min

4.5

4%

2-4 min

1.6 hr

4%

2-3 min

1.25

5-5.5
Mepivacaine
Prilocaine

7.6
7.9

3-4
Articaine

7.8

4.4-5.2

hrs
Bupivacaine

8.1

4.5-6 :3-4.5

0.5%

6-10 min

Etidocaine

7.7
4.5
1.5%
1.5 3www.indiandentalacademy.com
min
3-3.5

2.7 hr
2.6 hr

PHARMACOKINETICS


UPTAKE


Oral route :
 “Hepatic



first pass effect”. 72% Lignocaine.

Topical route:
 Tracheal

mucosa. (lignocaine. Adrenaline, fumazenil).
 Pharyngeal mucosa.
 Esophageal or bladder mucosa.
 Skin or oral mucosal.


Injection:
 Activity



depends on:

Vascularity of the tissue.
Vasoactivity of the drug.

 IV

caution. ( used in treatment of ventricular
dyrhythmias).

DISTRIBUTION.


High conc seen in well purfused organs such as brain,
kidney, lungs, heart.



Level of drug in blood depend on:


Rate at which drug is absorbed into CVS.



Rate at which drug is distribute from vasculature to tissue.



Elimination of drug through excretion.
“Elimination half life.”

BITRANSFORMATION.


Esters:







Amides:









Pseudocholinesterase.
Succinylcholine.
Atypical pseudo cholinesterase.
PABA (cause allergic reactions).
More complicated.
Hepatic microsomal enzymes.
Liver function and perfusion play an important role.

Intermediate products cause complications.
Prilocaine metabolite: orthotoluidine
- methhemoglobinemia.
Lilocaine metabolites: monoethyl glycine xylidide & xylidide
- sedation

EXCRETION.


Kidneys are the primary
excretory organs.



Less % of parent molecules
of ester anesthetics.



Large% of unchanged amide
parent molecules.



Renal impairment causes
accumulation of drug and its
metabolites causing toxity.

SYSTEMIC ACTIONS.


CNS.



CVS.



LOCAL TISSUE TOXICITY.



RESPIRATORY SYSTEM.



MISCELLANEOUS.


Neuromuscular blockade.



Drug interactions.



Malignant hyperthermia.

CNS-Pathophysiology
Local anesthetics cross blood-brain barrier, producing
CNS depression as level rises
eg. LIDOCAINE
Blood Level

Action Produced

< .5 ug/ml

- no adverse CNS effects

0.5-4 ug/ml

- anticonvulsant

4.5-7.5 ug/ml

- agitation,irritability (pre - convulsant)

> 7.5 ug/ml

- tonic-clonic seizures

Analgesia.
Mood elevation.

CVS-Pathophysiology
Local anesthetics exert a lesser effect on the
cardiovascular system
eg. LIDOCAINE
Blood Level

Action Produced

1.8-5 ug/ml

- treat PVCs, tachycardia

5-10 ug/ml

- cardiac depression

>10 ug/ml

- severe depression,

bradycardia, vasodilatation, arrest


MINIMAL TO MODERATE
OVERDOSE.
SIGNS
Talkativeness
Excitability
Apprehension
Slurred speech
Stutter( Muscular twitching /
tremors )
Euphoria
Dysarthria
Nystagmus
Sweating
Nausea/vomiting
Failure to follow commands / reason
Elevated BP
Elevated heart rate
Elevated resp rate

SYMPTOMS:
Light-headed and dizzy
Restless
Nervous
Numbness
Nervousness
Sensation of twitching (before
actual
twitching is observed)
Metallic taste
Visual disturbances
Auditory disturbances
Drowsy and disoriented
Losing consciousness


MODERATE TO HIGH OVER
DOSE.
Generalized tonic-clonic seizure activity
followed by
Generalized CNS depression
Depressed BP, heart rate
Depressed respiratory rate


LOCAL TISSUE TOXICITY.
 RESPIRATORY SYSTEM.
 MISCELLANEOUS.


Neuromuscular blockade.
 Drug interactions.


 Potentiates

the action the action of CNS depressants.
 Prolongs the action of succinlycholine.


Malignant hyperthermia.
 Thachycardia,

tachypnea, cynosis, unstable BP,
 Respiratory and metabolic acidosis, fever.
 Muscle rigidity and death

FACTORS AFFECT THE REACTION OF
LOCAL ANESTHETICS
pKa:
 Local anesthetics have two forms, ionized and nonionized. The
nonionized form can cross the nerve membranes and block the
sodium channels.
So, the more nonionized presented, the faster the onset action.
pH influence:
 Usually at range 7.6 – 8.9
 Decrease in pH shifts equilibrium toward the ionized form,
delaying the onset action.


Lipid solubility:


All local anesthetics have weak bases. Increasing the lipid
solubility leads to faster nerve penetration, block sodium channels,
and speed up the onset of action.

Protein binding:


The more tightly local anesthetics bind to the protein, the longer
the duration of onset action.

Vasodilation:






Vasodilator activity of a local anesthetic leads to a faster
absorption and slower duration of action
Vasoconstrictor is a substance used to keep the anesthetic
solution in place at a longer period and prolongs the action of the
drug
vasoconstrictor delays the absorption which slows down the
absorption into the bloodstream
Vasoconstrictor used the naturally hormone called epinephrine
(adrenaline). Epinephrine decreases vasodilator.

VASOCONSTRICTORS


Decrease blood flow



Lower anesthetic blood levels



Decrease the risk of toxicity



Increases duration of action



Decrease bleeding

ADRENERGIC RECEPTORS


Ahlquist in 1948



Two types


Alpha (α) – vasoconstriction





α1  excitatory – post synaptic
α2  inhibitory – post synaptic.

Beta (β) - vasodilation and bronchodilation + cardiac
stimulation


β1 Found in heart & small intestines & responsible for cardiac
stimulation & lipolysis



β2  found in bronchi, vascular beds, & uterus & produces
bronchodilation and vasodilation

EPINEPHRINE


Most potent and widely used vasoconstrictor in dentistry



Source: 80% of medullary secretion, also available as a synthetic



MOA- both α and β, with β being predominate



Systemic Effects of Epinephrine


Myocardium - ↑ heart rate & cardiac output



Pacemaker - ↑ risk of dysrhythmias



Coronary Artery-Dilation of coronary artery



B P- ↑ systolic pressure, effect on diastolic pressure is dose
related



Cardiovascular -Decrease cardiac efficiency




Vasculature
 Vasoconstriction

in skin, mucous membrane &

kidneys
 Vasodilation

in skeletal muscle in small doses



Respiratory - Bronchodilator



CNS - Not a potent CNS stimulant



Metabolism
 Increase

oxygen consumption

 Glycogenolysis-

↑ blood sugar




Termination of Epinephrine



COMT and MAO





Reuptake

Excreted unchanged in urine (1%)

Clinical Manifestations of Epinephrine Overdose


CNS stimulation - fear, anxiety, tremor, pallor, dizziness



Cardiac dysrhythmia



Ventricular fibrillation



Drastic increase in BP - can cause cerebral hemorrhage



Angina in patientswww.indiandentalacademy.com
with coronary insufficiency



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



Norepinephrine


ARMAMENTARIUM


SYRINGE


NEEDLE


ANESTHETIC SOLUTION


TOPICAL ANESTHETIC


Minimize sensation of needle penetrating the
soft tissue.



Used in greater concentration than LA in
order to penetrate the mucous membrane.


TOPICAL ANESTHETIC AGENTS
Lidocaine

Benzocaine



14-20% liquid, gel
Onset 30 seconds





5% ointment, gel, liquid






Longer duration than the
others



Lower toxicity potential than
the others



Best one for Pedo although
some children say it feels
“hot”

10% metered spray
Onset 3-5 minutes


RECOMMENDATIONS


For the administration of local dental anesthesia,
dentists should select aspirating syringes that meet
the standards of the ADA.
1.
2.
3.

4.
5.

Short needles may be used for any injection in which the
thickness of soft tissue is less than 20 mm
Long needle for a deeper injection into soft tissue.
Any 23- through 30-gauge needle may be used for intraoral
injections since blood can be aspirated through all of them;
however, aspiration can be more difficult when smaller gauge
needles are used.
An extra-short, 30-gauge is appropriate for infiltration
injections.
Needles should not be bent or inserted to their hub for
injections to avoid needle breakage.

BASIC INJECTION
TECHNIQUE



Use sterile sharp needle.



Check the temperature of the local
anesthetic solution



Check the flow of local anesthetic solution.



Operator position.



Position the patient.


Dry the tissue.
Apply topical antiseptic.
Apply topical anesthetic.
















Establish a firm hand rest.
Make the tissue taut.
Keep the syringe out of the patients line of sight.
Orientation of the bevel.
Insert the needle into the mucosa.
Watch and communicate with the patient.
Inject several drops of solution
Slowly advance the needle to the target site.
Aspirate.
Slowly deposit the solution.
Communicate with the patient.
Slowly withdraw the syringe.
Observe the patient after injection.



Indications :






Contraindications :








Comparatively simple, safe technique
Minimized volume of solution
Minimized number of needle punctures

Disadvantages:




Discrete treatment areas (1-2 teeth only) Hemostasis
Bleeding problems (eg. hemophelia, etc..)

Advantages :




Anesthesia of more than two teeth
Supraperiosteal injections ineffective
Inflammation/infection contraindicating local infiltration

Vary according to the type of block.

Failure:


TECHNIQUES
OF
LOCAL ANESTHESIA


TECHNIQUES
OF
MAXILLARY ANESTHESIA


LOCAL INFILTRATION
FIELD BLOCK
NERVE BLOCK


MAXILLARY INJECTION
TECHNIQUES


Supraperiosteal



Periodontal ligament



Intraseptal injection



Posterior superior alveolar nerve block



Middle superior alveolar nerve block



Anterior superior alveolar nerve block



Maxillary (second division) nerve block



Greater (anterior) palatine nerve block



Nasopalatine nerve block

LOCAL INFILTRATION


LOCAL INFILTRATION


Areas anesthetized:







Indications:






Entire area innervated by the large terminal nerve branches
Tooth pulp and root area
Buccal periosteum
Mucous membrane and connective tissue

Pulpal anesthesia of one or two maxillary teeth
Soft tissue anesthesia when indicated
Hemostasis

Contraindications:



Infection or acute inflammation in the area
Dense bone covering apices of teeth



Advantages:






Disadvantages:






Not suitable for large areas
Multiple needle insertions
Large volumes of anesthetic solution

Percent Positive Aspiration:




High success rate (>95%)
Technically easy injection
Usually entirely atraumatic

Negligible, but possible (<1%)

Alternatives:



Periodontal ligament injection
Regional nerve block

Technique


Apply topical



Landmarks:


Mucobuccal fold.



Long axis of tooth.



Insert needle: At height of mucobuccal fold



Target area: Apex of tooth



Aspirate, deposit approx. 0.6-1 ml solution




Signs and Symptoms:





Safety Feature:





Numbness
Absence of pain during dental therapy

Minimum opportunity for intravascular
Administration

Failures of Anesthesia:



Needle tip below the apex of the tooth.
Needle too far from bone.

POSTERIOR SUPERIOR
ALVEOLAR NERVE BLOCK
Nerve Anesthetized:
Posterior Superior Alveolar Nerve (PSA)
- for maxillary molars and buccal tissue




Indications for PSA Block:





Contraindication:








Atraumatic
High success rate
Less number of injections
Minimize amount of local used

Disadvantages:






Risk of hemorrhage is too great
(eg. hemophilia, coumadin)

Advantages:




First or second maxillary molar
Supraperiosteal injection is contraindicated

Risk of hematoma
Does not anesthetize first molar completel
No bony landmarks

Positive Aspiration :Approximately 3.1%


Technique


25 gauge, long needle



Landmarks:



Maxillary tuberosity





Mucobuccal fold
Zygomatic process of maxilla

Area of Insertion :





Mucobuccal fold above maxillary second molar

Advance needle upward, inward and backward
Aspirate, inject 1.8 ml of solution







Needle not deep enough





Needle too lateral
Needle too far superior

Complications :


Hematoma



Mandibular anesthesia


MIDDLE SUPERIOR ALVEOLAR
NERVE BLOCK


Nerve Anesthetized:




Middle Superior Alveolar Nerve

Areas Anesthetized:


Maxillary premolars and buccal tissues




Indications :





Contraindications :






Minimized number of injections

Disadvantage :




Infection /inflammation in area of injection

Advantage :




Anesthesia of maxillary premolars only
Infraorbital nerve block failure

MSA nerve is only present 28% of the time

Alternatives :




Local infiltration (supraperiosteal)
Periodontal ligament injection (PDL)
Infraorbital nerve block

Technique - MSA


Landmarks / Area of Insertion :










Apply topical
Position patient and identify landmarks
Insert needle 5-10 mm
Aspirate
Inject 0.9 ml of solution, slowly
Signs and Symptoms:





Mucobuccal fold above second premolar
Apex of second premolar

Numb upper lip
Pain free dental therapy

Safety Features :





Anatomically safe (no signifcant structures)
Relatively avascular area
Positive aspirations - negligible (< 3%)
Complications are rare





Needle inserted too high, or not high enough



Deposition of solution too far laterally


INFRAORBITAL NERVE BLOCK


Nerves Anesthetized:








Anterior Superior Alveolar Nerve
Middle Superior Alveolar Nerve
Superior Labial Nerve
Inferior Palpebral Nerve
Lateral Nasal Nerve

Areas Anesthetized:






Pulpal anesthesia of maxillary anterior teeth
Pulpal anesthesia of premolars and mesiobuccal root of first
molar
Buccal soft tissue and bone of same teeth
Lower eyelid, lateral nose, and upper lip

NERVES ANESTHETIZED


AREAS ANESTHETIZED




Indications :



Supraperiosteal injections ineffective





Anesthesia of more than two maxillary teeth
Inflammation/infection contraindicating local
infiltration

Contraindications :


Discrete treatment areas (1-2 teeth only)
Hemostasis



Bleeding problems (eg. hemophelia, etc..)



Advantages :






Disadvantages:







Comparatively simple, safe technique
Minimized number of needle punctures

Psychological
Administrator- fear of eye involvement
Patient- apprehension of extraoral approach
Anatomical-Difficulty defining landmarks

Alternatives:



Supraperiosteal injection for each tooth
Maxillary nerve block

Technique




Apply topical
Position patient and identify landmarks
Landmarks :






Mucobuccal fold above first premolar
Infraorbital notch
Infraorbital foramen

Area of Insertion :



Mucobuccal fold above first premolar
Target area







Infraorbital foramen
Neurovascular bundle

Insert needle to upper rim of infraorbital foramen
Aspirate



Signs and Symptoms :




Numbness in teeth and soft tissues





Tingling and numbness of lower eyelid, side of
nose, and upper lip
No pain during dental therapy

Safety Features :


Needle contacting bone



Finger over infraorbital foramen


Failures of Anesthesia
Bone contact below infraorbital foramen
Needle deviates laterally or medially
Complications :
Hematoma (rare)
Positive aspirations - 0.7 %


ANTERIOR MIDDLE SUPERIOR
ALVEOLAR NERVE BLOCK.


PALATAL ANESTHESIA


NERVES ANESTHETIZED.


GREATER PALATINE NERVE
BLOCK



Anterior Palatine Nerve
Areas anesthetized:






Indications




Pain control in posterior palatal hard and/or soft tissues

Contraindications





Posterior portion of hard palate and overlying soft tissues
Anteriorly to 1st premolar
Medially to midline

Inflammation / infection at injection site
Only small area necessary (eg. 1-2 teeth)

Advantages



Minimizes penetrations and discomfort
Minimizes volume of solution (0.5 ml)

Greater Palatine Nerve Block


Disadvantages





Alternatives:





Local infiltration in each area
Maxillary Nerve Block

Aspiration:




Limited hemostasis
Potentially traumatic

< 1% positive

Landmarks



Greater palatine foramen
Junction of alveolus and palatine bone

Greater Palatine Nerve Block


Area of Insertion




Precautions








Position - open wide, extend & turn head
Cotton swab - identify landmarks, topical
Approach - bevel to tissue, advance to bone
Aspirate; inject 0.5 ml slowly

Failure:





Bone contacted; aspiration

Technique




Numb posterior palate; painfree treatment

Safety features




Do not enter canal

Signs & symptoms




Soft tissue anterior to foramen, from opposite side

Overlap of fibers from Nasopalatine nerve
Injection too anterior

Complications:



Soft tissue ischemia / necrosis
Post injection pain, hematoma

NASOPALATINE NERVE
BLOCK


Nasopalatine Nerve Block


Indications:




Pain control in anterior hard and/or soft tissues

Contraindications:





Inflammation / infection at injection site
Only small area necessary (eg. 1-2 teeth)

Advantages:





Minimizes needle penetrations
Minimizes volume of solution (0.4 ml)

Disadvantages:


Limited hemostasis



Potentially traumatic



Alternatives





Local infiltration
Maxillary Nerve Block

Aspiration




< 1% positive

Precautions





Do not inject directly into papilla/canal
Inject slowly, with small volume

Signs / symptoms


Numb anterior palate; painfree treatment



Safety features



Bone contacted; aspiration



Technique



Landmarks - incisive papilla, central incisors



Approach - lateral to incisive papilla, starting with cotton swab, topical





Position - open wide, extend head

Deposit approx. 0.4 ml / 30 sec

Failure





May be only unilateral
May have overlap with Greater Palatine

Complications


Ischemia, tissue necrosis



Others rare

TECHNIQUES
OF
MANDIBULAR ANESTHESIA


MANDIBULAR ANESTHESIA


Lower success rate than Maxillary anesthesia



Related to bone density



Less access to nerve trunks.


Success depends on depositing solution within 1 mm
of nerve trunk


MANDIBULAR NERVE BLOCKS


INFERIOR ALVEOLAR



BUCCAL



LINGUAL



MENTAL - INCISIVE



GOW-GATES



AKINOSI


INFERIOR ALVEOLAR NERVE
BLOCK


Not a complete mandibular nerve block.



Requires supplemental buccal nerve block



May require infiltration of incisors or mesial root of first molar



Nerves anesthetized



Mental



Incisive





Inferior Alveolar

Lingual

Areas Anesthetized


Mandibular teeth to midline



Body of mandible, inferior ramus



Buccal mucosa anterior to mental foramen



Anterior 2/3 tongue & floor of mouth



Lingual soft tissue and periosteum

Inferior Alveolar Nerve Block


Indications



Buccal anterior soft tissue





Multiple mandibular teeth
Lingual anesthesia.

Contraindications


Infection/inflammation at injection site



Patients at risk for self injury (eg. children)

10%-15% positive aspiration




Alternatives


Mental nerve block



Incisive nerve block



Anterior infiltration



Periodontal ligament injection (PDL)



Gow-Gates



Akinosi



Intraseptal

Technique
Apply topical
Area of insertion:
medial ramus, mid-coronoid notch,
level with occlusal plane (1 cm above),
3/4 posterior from coronoid notch to pterygomandibular raphe
advance to bone (20-25 mm)
Target Area
Inferior alveolar nerve, near mandibular foramen
Landmarks
Coronoid notch
Pterygomandibular raphe
Occlusal plane of mandibular posteriors

Precautions
Do not inject if bone not contacted
Avoid forceful bone contact
Failure of Anesthesia
Injection too low
Injection too anterior
Accessory innervation
-Mylohyoid nerve
-contralateral Incisive nerve innervation
Complications
Hematoma
Trismus
Facial paralysis

Long Buccal Nerve Block





Anterior branch of Mandibular nerve (V3)
Provides buccal soft tissue anesthesia adjacent to
mandibular molars
Not required for most restorative procedures.
Indications




Contraindications





Advantages





Anesthesia required - mucoperiosteum buccal to mandibular
molars

Technically easy
High success rate

Disadvantages


Buccal Nerve Block
Alternatives
Buccal infiltration
Gow-Gates
PDL
Intraseptal


Buccal Nerve Block


Technique






Apply topical
Insertion distil and buccal to last molar
Target - Long Buccal nerve as it passes anterior border of ramus
Insert approx. 2 mm, aspirate





Landmarks

- 25-27 gauge needle
Area of insertion:
 - Mucosa adjacent to most distal

Mandibular molars
 Mucobuccal fold
Complications
Hematoma (unusual)
Positive aspiration
0.7 %








Mental Nerve Block




Terminal branch of IAN as it exits mental foramen
Provides sensory innervation to buccal soft tissue
anterior to mental foramen, lip and chin
Indication




Contraindication





Advantages





Need for anesthesia in innervated area

Easy, high success rate
Usually atraumatic

Disadvantage


Hematoma


INFILTRATION


Incisive Nerve Block
Terminal branch of IAN
Originates in mental foramen and proceeds
anteriorly
Good for bilateral anterior anesthesia



Not effective for anterior lingual anesthesia


Incisive Nerve Block


Nerves anesthetized





Areas Anesthetized








Lack of lingual or midline anesthesia

Complications




High success rate
Pulpal anesthesia w/o lingual anesthesia

Disadvantages





Advantages




Anesthesia of pulp or tissue required anterior to mental foramen

Contraindication




Mandibular labial mucous membranes
Lower lip / skin of chin
Incisor, cuspid and bicuspid teeth

Indication




Incisive
Mental

Hematoma

Positive aspiration


5.7 %


ALTERNATIVE INJECTION
TECHNIQUES.


INTRAPULPAL


INTRASEPTAL


INRA OSSEOUS


COMPLICATIONS
IN
ANESTHESIA
ADMINISTRATION

LOCAL COMPLICATIONS
IN
ANESTHESIA
ADMINISTRATION

Local Complications


Needle breakage



Trismus



Pain on injection



Hematoma



Burning on injection



Infection



Persistent anesthesia
or paresthesia



Edema



Sloughing of tissues



Lip chewing



Facial nerve paralysis



Post-anesthetic
intraoral lesions

NEEDLE BREAKAGE


Causes







Prevention







Unexpected movement
Small needle size
Bent needles
Defective needles
Use large needles
Use long needles for deep injection,>18mm
Never insert to hub
Redirect only when adequately withdrawn

Management






Remain calm
Don't explore
Have the patient keep opening wide
If the needle is out remove it
Refer to an Oral Surgeon

PAIN ON INJECTION


Causes



Dull needles



Rapid deposit of solution





Careless technique

Needles with barbs

Prevention


Careful technique



Sharp needles



Topical anesthetic



Slow injections



Room temperature solutions

BURNING ON INJECTION


Causes


pH of solution



Rapid injection



Contamination



Warmed solutions


PERSISTENT ANESTHESIA
OR PARESTHESIA


Causes







Prevention




Trauma to nerve
Hematoma
Neurolytic agents (alcohol, phenol)
Intraneural injection
Careful injection technique

Management





Patient counseling and reassurance
Documentation
Follow-up
Appropriate referral

TRISMUS


Causes








Prevention








Trauma to muscles or blood vessels
Contaminated anesthetic solutions
Hemorrhage
Infection
Excessive anesthetic volume
Sharp needles
Proper care and handling of cartridges
Aseptic technique and clean injection site
Atraumatic insertion
Minimal injections and volume

Management



Examination
Conservative therapy






passive ROM therapy
analgesics
heat
muscle relaxants

HEMATOMA



The effusion of blood into extravascular spaces
Prevention









Care with needle placement
Minimize injections
Don't probe with needle
Modify technique
short needles
penetration depth

Management with






IAN block
Infraorbital block
Mental Nerve block
Buccal block
PSA block

INFECTION


Causes







Prevention






Needle contamination
Improper handling of armamentarium
Infection at injection site
Improper handling of tissue
Disposable needles
Proper care of equipment
Aseptic technique

Management




Usual sign is trismus
Trismus persists (1-3 day resolution )
Antibiotics, if suspicious

EDEMA


Causes



Infection



Allergy



Hemorrhage





Trauma during injection

Irritating solutions

Management


Address cause and treat accordingly

SLOUGHING OF TISSUE


Causes





Topical anesthetic
Prolonged ischemia

Management


Observation



Documentation


LIP CHEWING


Management


Analgesics



Antibiotics



Saline rinses



Lip lubricants


FACIAL NERVE PARALYSIS


Cause: Anesthesia of peripheral Facial nerve branches



Prevention



Avoid over penetration





Bone contact when injecting
Avoid arbitrary injection

Management


Reassure patient



Documentation



Consider deferring dental care


POST ANESTHETIC
INTRAORAL LESIONS
Recurrent apthous
Herpes Simplex


SYSTEMIC
COMPLICATIONS


ADVERSE DRUG REACTIONS


Direct extensions of usual effects






Altered recipient







Side effects
Overdose
Local toxic effects

Disease process
Emotional disturbances
Genetic aberrations
Idiosyncracy

Allergic reaction



Immediate - anaphylaxis
Delayed - contact dermatitis

OVERDOSE


Dose related



Systemic distribution



Extension of pharmacologic effects



Selective CNS or CVS depression


ALLERGIC REACTIONS


Not dose related



May be systemic or localized



Unrelated to pharmacological effects



Exaggerated immune system response


IDIOSYNCRACY REACTION


Unexplained by any known mechanism of the
drug’s action



Neither overdose nor allergic reaction



Unpredictable; treat symptoms


CAUSE OF OVERDOSE LEVELS


Total dose is too large



Absorption is too rapid



Intravascular injection



Biotransformed too slowly



Eliminated too slowly


INTRAVASCULAR INJECTION
Occurrence varies with type of injection:
Nerve Block

% positive aspirate

Inf. alveolar

11.7

Mental/Incisive

5.7

Post. sup. alv.

3.1

Ant. sup. alv./ Buccal

<1


CLINICAL
MANIFESTATIONS
of
OVERDOSE


Minimal to Moderate
SIGNS
Talkativeness
Excitability
Apprehension
Slurred speech
Stutter( Muscular twitching /
tremors )
Euphoria
Dysarthria
Nystagmus
Sweating
Nausea/vomiting
Failure to follow commands / reason
Elevated BP
Elevated heart rate
Elevated resp rate

SYMPTOMS:
Light-headed and dizzy
Restless
Nervous
Numbness
Nervousness
Sensation of twitching (before
actual
twitching is observed)
Metallic taste
Visual disturbances
Auditory disturbances
Drowsy and disoriented
Losing consciousness


Moderate to High
Generalized tonic-clonic seizure activity
followed by
Generalized CNS depression
Depressed BP, heart rate
Depressed respiratory rate


Pathophysiology
Local anesthetics cross blood-brain barrier, producing
CNS depression as level rises
eg. LIDOCAINE
Blood Level
< .5 ug/ml

Action Produced
- no adverse CNS effects

0.5-4 ug/ml

- anticonvulsant

4.5-7.5 ug/ml

- agitation, irritability

> 7.5 ug/ml

- tonic-clonic seizures


Pathophysiology
Local anesthetics exert a lesser effect on the
cardiovascular system
eg. LIDOCAINE
Blood Level

Action Produced

1.8-5 ug/ml

- treat PVCs, tachycardia

5-10 ug/ml

- cardiac depression

>10 ug/ml

- severe depression,

bradycardia, vasodilatation, arrest


VASOCONSTRICTOR OVERDOSE
Clinical manifestations:
Fear, anxiety
Tenseness
Restlessness
Tremor
Weakness
Throbbing headache
Perspiration
Dizziness
Pallor
Respiratory difficulty
Palpitations

ALLERGIC REACTIONS
Type Mechanism

Time Clinical Example

I Antigen induc. sec/min Angioedema,
Anaphylaxis
IV Cell mediated

48 hrs

Contact
dermatitis


ALLERGENS IN LOCAL


Esters - usually to the Para-amino-benzoicacid product



Na bisulfite or metabisulfite - found in
anesthetics as perservative for
vasoconstrictors



Methylparaben - no longer used as
perservative in dental cartridges


PREVENTION
of
SYSTEMIC
COMPLICATIONS


PRIOR TO TREATMENT


Complete review of medical status
(including vital signs)



Anxiety / Fear should be assessed and
managed before administering anesthetic


ADMINISTRATION OF ANESTHETIC













Place pt. supine or semi-supine position
Dry site, apply topical X 1 min
Select appropriate drug for treatment (time)
Vasoconstrictor unless contraindicated
Weakest anesthetic in the minimum volume
(compatible with successful anesthesia)
Inject slowly (minimum of 60 sec / 1.8 ml)
Continually observe Never leave patient alone after injection
Use only aspirating syringe
Aspirate in two planes, before injecting
Use sharp, disposable needles of adequate diameter and length

LOCAL ANESTHESIA FOR
CHILDREN


Use with Sedative Drugs
With conscious sedation, especially narcotics,
decrease dosage of both local anesthetic and
the sedative drug to avoid toxicity (additive
depressant effect).


Recommended Dosage Levels


2% lidocaine - 2 mg/lb



2% lidocaine 1/100,000 epi - 2 mg/lb



2% carbocaine 1/20,00 neocobefrin - 2 mg/lb

In general, 2 mg/lb WITH or WITHOUT
vasoconstrictor


Delivery Methods
Aspirating Syringe


ALWAYS ASPIRATE!!!



Loading the syringe


Place carpule in syringe. Engage harpoon. Place
needle on syringe and puncture carpule.


Delivery Methods
Air Jet Syringe


LA injected at pressure of ~2000 psi


Use of Topical


Benzocaine is best.
Allow at least one minute for application
(onset in 30 seconds).


GENERAL TECHNIQUES
Use of Assistant


Assistant should be ready at all times to
restrain hands.



Assistant can help block view and keep patient
distracted.


General Techniques
Body Control


Operator should be in
control of patient's
head - it may move
suddenly!!



Hands - at side, in
pockets, sit on them,
hold belly button.


General Techniques
Syringe Management and Etiquette


HIDE IT!!!



Pass behind or over patient.



Block patient's view with your retracting
hand.



BE CONFIDENT.


SYRINGE MANAGEMENT
AND ETIQUETTE


EUPHEMISMS


Tooth jelly



Sleepy juice/medicine



Bubble blower



Mosquito bite, pinch



Tooth will take a nap and feel fat & fuzzy.


DISTRACTION









Verbal - chitter-chatter
(talk about anything)
Overwhelm patient with
stimulus
Pull on cheek, touch
face
Keep things moving
Pulling the tissue taut as
the needle enters makes
the procedure less
painful

DESENSITIZATION


ANATOMIC DIFFERENCES


ANATOMIC DIFFERENCES
Mandible


Ramus is shorter vertically and
narrower anteroposteriorly.



Mandibular foramen is lower than in adult
(may be below occlusal plane
in < 4yo).


SPECIFIC INJECTION SITES
FOR CHILDREN MANDIBLE


Inferior alveolar block - Injection site is
lower and more posterior.



Do not need to penetrate tissue as far as in
adult.


Anesthesia Technique

Occasionally the mylohyoid will
have accessory innervation to the
mandibular molar. Infiltrate on
the lingual.

SPECIFIC INJECTION SITES FOR CHILDREN
MANDIBLE


BILATERAL INFERIOR ALVEOLAR BLOCKS
SHOULD NOT BE ADMINISTERED TO
CHILDREN.
Bilateral blocks greatly increase the chance
of post anesthesia trauma


Extractions


Infiltration works in mandibular anterior
although block may be best for posterior
extractions (look at root length and
difficulty level).


Infiltration


Used effectively for incisor and canine
restorations.




BUCCAL NERVE BLOCK:





SUBMUCOSAL INFILTRATION
FIELD BLOCK

MENTAL NERVE BLOCK :


TARGET:







Mesio buccal fold apical to prim 1 and 2 molar
Inter-radicular area of 1 and 2 premolar

NEEDLE PENETRATION: just anterior to mental foramen

RULE OF 20: AGE OF CHILD X NO. OF TOOTH
4 X 4 = 16

FOR CHILDREN MAXILLA


Apices of primary anterior teeth are at depth
of mucobuccal fold.



Inject at depth of mucobuccal fold.



Short or extra-short needle.


FOR CHILDREN MAXILLA


Primary teeth and premolars - infiltrate



Permanent molars - PSA, MSA




FOR PRIMARY ANTERIOR TEETH:





Inj made close to gingival margin
Needle penetration: muco-buccal fold

FOR PERMANENT INCISORS:


Inj made close to muco-buccal fold



Small amount of sol deposited at apex

of opposite side of incisor


FOR FIRST PRIMARY MOLAR:


Bone is thin – sol deposited at apices of root




FOR SECOND PRIMARY MOLAR:


Dense overlying bone – suprapeiosteal inj ineffective




FOR ASA:




LANDMARK: loose alv tissue superior to max canine

FOR MSA:





LANDMARK: loose alv tissue apical to first prim molar or first premolar
For perm first molar and second prim molar – additional PSA block reqd

FOR PSA:


LANDMARK: red, loose alv tissue, apical to most post erupted molar tooth distal to zygomatic process


NASOPALATINE NERVE BLOCK:


Penetration site: MM lateral to incisive papilla



TWO WAYS:


INTERDENTAL PAPILLARY APPROACH



USE OF PRESSURE-TOPICAL ANESTHETIC


GREATER PALATINE NERVE
BLOCK


IN A CHILD WITH PRIMARY DENTITION: inj 10mm
post to distal surface of second primary molar



ALTERNATIVES:





BLANCHING TARGET AREA
INTRAPAPILLARY INJECTION

0.2-0.3 ml of sol is deposited


Specific Injection Sites for
Children Maxilla


Primary molars (same as premolars) - Inject
over primary first molar.



Primary second molar may have innervation
from posterior superior alveolar nerve.
Inject behind tuberosity.


Specific Injection Sites for
Children Maxilla


Permanent molars - PSA injection - Inject
behind tuberosity.



Also inject over MB root of permanent first
molar to anesthetize MSA.


Specific Injection Sites for Children
Maxilla


Interdental papilla - To achieve palatal
anesthesia. Inject as go through
papilla from facial to lingual. Should see
blanching as inject.


DO


BE CONFIDENT



Use good syringe etiquette



Keep talking



Maintain hand and head control



Have assistant stay alert



Shield and distract vision of the recipient and
neighbors.


DON’T:


Openly display syringe



“S(hot)”, “N(eedle)”, or “H(urt)” word



Inject too fast


POST-ANESTHESIA
TRAUMA


The number one postoperative complication of local
anesthesia in children.


POST-ANESTHESIA
TRAUMA

Minor to major. Always painful.

POST-ANESTHESIA
TRAUMA
Prevention:
 Remind

both parent and child that area will remain
numb after the appointment.

 Caution

that child should not to chew, bite or pick
at area. Extremely important for young children
and "first timers".

 Sometimes

placing a cotton roll between the teeth
will help remind patient not to chew.


CALCULATION OF MG. OF LOCAL
ANESTHETIC PER CARTRIDGE


2% solution = 20 mg/ml



Volume of cartridge = 1.8 ml



So for a 2% solution:
20mg/ml x 1.8 ml/ cartridge = 36.0 mg/ cartridge


CALCULATION OF MG. OF LOCAL
ANESTHETIC PER CARTRIDGE


CALCULATION OF MG. OF
VASOCONSTRICTOR PER CARTRIDGE


1:20,000 concentration = 0.05 mg/ml



Volume of cartridge = 1.8 ml



So for a 1:20,000 concentration:
0.05mg/ml x 1.8 ml/ cartridge = 0.09 mg/ cartridge


Mg/Ml VALUES OF
CALCULATION OF MG. of
VASOCONSTRICTORS VASOCONSTRICTOR
PER CARTRIDGE
CONCENTRATION

Mg/Ml

VOLUME OF
CARTRIDGE

Mg PER
CARTRIDGE

1:1,000

1.0

1.8

1.8

1:2,500

0.4

1.8

.72

1:10,000

0.1

1.8

.18

1:20,000

0.05

1.8

.09

1:30,000

0.033

1.8

.06

1:50,000

0.02

1.8

.036

1:100,000

0.01

1.8

.018

1:200,000

0.005

1.8

.009


Other Post-Anesthesia
Conditions

Blanching due
to
vasoconstrictor


Other Post-Anesthesia
Conditions

Hematoma due to local anesthesia

RECENT ADVANCES
FUTURE TRENDS IN
CONTROL…


AND
PAIN

CENTBUCRIDINE


Quinalone derivative



Five to eight times the potency of lidocaine



It does not effect CNS & CVS significantly



Vacharajini et al


pH ALTERATIONS


Alkalinization - ↑ RN:
 Sodium

bicarbonate.
 Rapid onset of action.



Carbonation :
 Helps

in the rapid diffusion of local anesthetic through
the nerve membranes.
 Decreases intracellular pH traps RNH+ in the cell.
 Anesthetic drug must be administered immediately after
preparing the syringe.


HYALURONIDASE


Breaks down intercellular cement.



Added to the anesthetic cartridge just before administering
the LA.



Causes rapid onset of anesthesia.



Allergic reactions have been reported.


ULTRA –LONG ACTING LOCAL
ANESTHETICS


Biotoxins:


Tetradotoxin -puffer fish



saxitoxin -dinoflagelates.



Block Na channels of nerve membrane.



250,000 as potent as procaine.


TENS




Contraindications





Cardiac pacemakers
Neurological disorders
Pregnancy
Immaturity (in ability to understand) the concept of patient control of pain)







Very young pediatric patient
Older patients with senile dementia

Language communication difficulties

Advantages



No injection of drug



Patient is in control of the anesthesia



No residual anesthetic effect at the end of procedure





No needle

Residual analgesic effect remain for several hours

Disadvantages


Cost of the unit



Training



Intra oral electrodes – weak link in the entire system.

Computer Controlled Local Anesthetic
Delivery System (CCLADS)


JET INJECTORS


Eutectic Mixture of Local Anesthetic
(EMLA)


………………………conclusion

REFERENCES.


Hand book of local anesthesia ………………………….5th ed Stanley F. Malamed.



Monheim’s Local anesthesia and pain control in dental practice….. 7 th ed.



Clinical Guideline on Appropriate Use of Local Anesthesia for Pediatric
Dental Patients ……………………………..……………. AAPD Reference manual 2005



Pediatric dentistry infancy through adolescence………….…. 4 th ed Pinkham.



Dentistry for child and adolescent……………………………….… 8 th ed McDonald.



Pediatric dentistry total patient care …………….……………Stephen H. Y. Wei.


THANK YOU


Local anesthesia in dentistry /certified fixed orthodontic courses by Indian dental academy

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