Local anesthesia

CONTENTS
• DEFINATION
• FUNDAMENTALS OF IMPULSE GENERATION AND
TRANSMISSION
• THEORIES OF MECHANISM OF ACTION OF LOCAL
ANESTHESIA
• Acetyl choline theory
• Calcium Displacement Theory
• Surface charge theory
• membrane Expansion theory
• Specific Receptor theory
• LOCAL ANESTHESIA
• Characteristics
• History
• Composition
• TYPES OF ANESTHETICS USED
• FACTORS EFFECTING LA EQUILIBRIUM
• TOPICAL ANESTHETICS
• PHARMACOKINETICS OF LOCAL ANESTHESIA
• ARMAMENTARIUM
• TECHNIQUES OF LOCAL ANESTHESIA
• Maxillary
• Mandibular
• Supplemental Injection techniques
• COMPLICATIONS OF LOCAL ANESTHESIA
• Local
• Systemic

Anaesthesia
What is local anesthesia?
• Local anesthesia: loss of sensation in a specific area of the
body without the loss of consciousness
DEFINATION
• Local anesthesia is defined as a 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
• Local anesthesia is defined as a reversible temporary cessation
of painful impulses from a particular region of the body. KOCH
FUNDAMENTALS OF IMPULSE GENERATION AND
TRANSMISSION
• The concept behind action of local anaesthetics is simple. They
prevent both generation and conduction of a nerve impulse. They
create a chemical roadblock between source of impulse and the
brain.
• The aborted impulse , prevented from reaching the
brain is not interpreted as pain by the patient
• Neuron or nerve cell- is the structural unit of the nervous
system
• Two types: sensory [afferent] & motor [efferent].
• sensory neurons : conduct impulses from periphery to CNS
• Motor neurons : conduct impulses from CNS to the periphery

• Nerve membrane :is 70-80 Angstrom unit.
• it is a flexible nonstretchable structure consisting of two layers
of lipid molecules
• The lipids are oriented with their hydrophilic ends facing the
outer surface and hydrophobic ends projecting to the middle of the
membrane
• Some nerves are myelinated [vertebrates] while some are not.
• Myelinated nerve fibres are enclosed in spirally wrapped layers
of lipoprotein.
• The outermostlayer of myelin consists of schwann cell
cytoplasm and its nucleus
• There are constictions at regular intervals along the myelinated
nerve fiber [nodes of Ranvier]
• At these nodes the nerve membrane is exposed directly to the
extracellular medium.
Electrophysiology of nerve conduction
• Nerve conduction
Resting stage
Depolarisation
Repolarisation
Resting state / polarized state
• Electric membrane potential is – 90 MV
• Greater no. of anions (-) inside cell membrane and cations (+)
outside cell membrane
• k+
inside and Na+
, Cl-
outside

• Due to relative permeability to k+
and impermeability to Na+
• Maintaiance by Na+
- Ka+
pump
• Depolarization stage
• Repolarization stage
• Resting state:the nerve membrane is
• Slightly permeable to sodium ions [Na+]
migrates inwardly becos of the conc gradient [> ouside] favors
such migration. Resting nerve membrane is relatively impermeable
to sodium
• Freely permeable to potassium ions[K+].- K+ ions remain
within the axoplasm despite its ability to diffuse freely becos the
negative charge of nerve membrane restrains the positively charged
ions by electrostatic attraction.
• Freely permeable to chloride ions [cl-]
remains outside the nerve membrane becos the
opposing , nearly equal electrostatic influence forces outward
migration.
• Membrane channels:
Discrete aqeous pores [sodium channels] are molecular
structures that mediate its its permeability
presence of these channels help membrane permeability or
impermeability to certain ions [ gating the ions ]
Na ions [ hydrated ] are too large to pass thro the channels
at rest
during depolarization they pass easily due to widening of
these channels

Release of the bound calcium ions from the ion channel
receptor site may be the primary factor responsible for inc sodium
permeability
Theories of mechanism of action of Local
Anesthetics
• ACETYL CHOLINE THEORY :
• CALCIUM DISPLACEMENT THEORY
• SURFACE CHARGE THEORY
• MEMBRANE EXPANSION THEORY
• SPECIFIC RECEPTOR THEORY
MEMBRANE EXPANSION THEORY

• LA diffuse to hydrophobic regions of excitable membranes,
expanding critical regions in the membrane and preventing an inc in
the permeability to sodium ions
SPECIFIC RECEPTOR THEORY
• Most favoured theory
• They bind to the sp. Receptor site in the sodium channel
• LA are classified by their ability to react with sp receptor sites in
the sodium channel
LOCAL ANESTHESIA
Desirable characteristics of local anesthesia
• Not be irritating to tissues
• Not cause any permanent alterations of nerve structure
• Low systemic toxicity
• Effective: injected or applied on MM
• Time of onset: short
• Duration of action: long
• Free from allergic reactions
• Rapid biotransformation in body
How local anesthesia work?
• Produce conduction block to decrease permeability of ion
channels to sodium ions
• Sequence of action
• Displacement of calcium ions from sodium channel receptor site
• Binding of local anaesthetic to receptor site

• Blockade of sodium channel
• Decrease in sodium conductance
• Depress rate of depolarisation
History
• Coca leaves from the genus Erythroxylum
• Erythroxylum contains high concentration of alkaloid up to 0.7-
1.8%
• Alkaloid has natural nitrogen bases found in the coca leaves,
also known as cocaine
• Genus Erythroxylum discovered in South America, Venezuela,
Bolivia, and Peru since pre-Columbian periods
• Earliest cultivation and use of the coca leaf went back to about
700 BC in Bolivia and Andes regions
• New discoveries showed humans used coca more than 5,000
years ago in Ecuador
Development of general and local anesthesia
• Took place in Western Europe from 1750 to 1850
• Chemists and physicians collected sample of coca leaves for
experiments
• Isolated active principle of coca leaf, synthesized to a drug for
patients to feel more relief of pain when taking surgeries
• In 1860, German chemist Albert Niemann successfully
isolate the active principle of coca leaf; he named it cocaine
• In 1865, Willhelm Lossen determine the correct molecular
formula of cocaine (C17H21NO4)
• Niemann discovered the effect of numbness of the tongues
caused by alkaloid in 1860
• Based on Niemann’s discovery, Russian physician Basil Von
Anrep did experiments on animals, such as rats, dogs, and cats.
• He injected small quantity of 1% solution to his tongue; tongue
became insensitive
• He concluded cocaine is a good drug for surgical anesthetic
• William Steward Halsted and Richard John Hall
developed the inferior dental nerve block techniques for
dentistry

• Procaine replaced cocaine in later years but it had many draw
backs
• Nitrous oxide gas was more commonly used than procaine
Nitrous oxide
COMPOSITION
• LOCAL ANESTHETIC
• VASOCONSTRICTOR
• ANTIOXIDANT
• PRESERVATIVE
• FUNGICIDE
• SALT
• VEHICLE
• Local anesthetic: may be an amide or ester [lidocaine 2%]
• Vasoconstrictor: Epinephrine
• It causes vasoconstriction and prevents rapid absorption of L.A
into blood stream thereby reducing their toxicity
• Increases duration of action of local anesthetics and also their
potency
• Causes hemostasis in the local area into which it is injected and
helps in creating blood free field
• Epinephrine conc – 1:100,000[normally used]
• Antioxidant : sodium metabisulphite
prevents rapid oxidation of the vc & prolongs shelf life of
the soln
• Preservative : Methyl paraben
• Salt: Bicarbonate is added to make soln isotonic. LA & VS has
a ph of 4-5 which cause burning sensation in pt. so bicarbonate is
added to make soln isotonic
• Ringers lactate/ distilled water – to dissolve all contents and
make it injectable providing addnl vol. for injection without increasing
total dose administered
Local Anesthetic
• A Drug that, when injected into tissue, has little or no
irritating effects and when absorbed into the nerve will
temporarily interrupt its conduction.

Classification of local anesthetic agents
• ESTERS
• Esters of benzoic acid
• Cocaine
• Procaine
• Benzocaine
• Butacaine
• Esters of PABA
• Chlorprocaine
• Propoxycaine
• Tetracaine
• AMIDES
• Atricaine
• Bupivacaine
• Dibucaine
• Etidocaine
• Lidocaine
• Mepivacaine
• Prilocaine
• Ropivacaine
• QUINOLONE
• Centbucridine
CLINICAL CLASSIFICATION
Short duration
• lidocaine HCL 2%
• Mepivacaine HCL 3%
• Prilocaine HCL 4% ( By infiltration )
Intermediate duration
• Articaine HCL 4% + epinephrine 1:100000
• Articaine HCL 4% + epinephrine 1:200000
• lidocaine HCL 2% + epinephrine 1:50000
• lidocaine HCL 2%+ epinephrine 1:100000
• Prilocaine HCL 4% ( By nerve block only )
• Mepivacaine HCL 2% + levonordefrin 1:200000
• Mepivacaine HCL 2% + epinephrine 1:100000
Long duration
• Bupivacaine HCL 0.5% + epinephrine 1: 200000
Classification based on biological site and mode of action

• Class A : External surface of receptor
BIOTOXINS
• Class B : Internal surface of Receptors
SCORPION VENOM
QUARTERNARY AMMONIUM ANALOGUES OF
LIDOCAINE
• Class C : Receptor independent
BENZOCAINE
• Class D : Receptor and receptor independent
MOST CLINICALLY USED AGENTS
Structures of Amides and Esters
• The amine end is hydrophilic (soluble in water), anesthetic
molecule dissolve in water in which it is delivered from the dentist’s
syringe into the patient’s tissue. It’s also responsible for the solution
to remain on either side of the nerve membrane.
• The aromatic end is lipophilic (soluble in lipids). Because nerve
cell is made of lipid bilayer it is possible for anesthetic molecule to
penetrate through the nerve membrane.
• The trick the anesthetic molecule must play is getting from one
side of the membrane to the other
Differences of Esters and Amides
• All local anesthetics are weak bases. Chemical structure of
local anesthetics have an amine group on one end connect to an
aromatic ring on the other and an amine group on the right side. The
amine end is hydrophilic (soluble in water), and the aromatic end is
lipophilic (soluble in lipids)
• Two classes of local anesthetics are amino amides and amino
esters.
Amides: Esters:
--Amide link b/t intermediate --Ester link b/t aromatic ring
intermediate chain

and aromatic ring
--Metabolized in liver and very --Metabolized in stable in the
solution plasma
--Cause allergic reactions
• Ester type local anesthetics are no longer available in cartridge
forms but benzocaine and tetracaine are still used as topical
anesthetic agents
LIDOCAINE
• The most popular contains epinephrine 1:100,000 and provides
good anesthesia for healthy patients.
• Lidocaine with epinephrine 1:50,000 is used for
hemostasis, but because of the rebound effect noted
earlier, it should be used sparingly
• In 1940, the first modern local anesthetic agent was lidocaine,
trade name Xylocaine®
• It developed as a derivative of xylidine
• Lidocaine relieves pain during the dental surgeries
• Belongs to the amide class, cause little allergenic reaction; it’s
hypoallergenic
• Sets on quickly and produces a desired anesthesia
effect for several hours
• Lidocaine Hcl
• Prepared by Nils Lofgren,1943
• 1st
amide to be marketed. Used as standard for
comparison
• Onset of action is 2-3 mins
• Effective dental conc is 2%
• Half life is 1.6 hrs [90 mins ]
• Topical anesthetic action : in 5% conc
• Maxm recommended dose [MRD]
• 2% Lidocaine with epinephrine-3.2mg/lb or 7mg/kg body
wt [not to exceed 500 mg][same for children]
• 2% lidocaine without epinephrine- 2 mg/lb or 4.4 mg/kg
[not to exceed 300mg]
• Vasoconstrictor [adrenaline] – 0.2 mg or 200 ug [healthy pts]
• 0.04mg or 40 ug – cv disease

ARTICAINE
• Articaine is a newer anesthetic typically given in a 4% solution
with 1:100,000 epinephrine.
• Practitioners reported rarely missing a inferior alveolar nerve
block with Articaine.
• However, concern has arisen about its potential for tissue
necrosis and persistent nerve parasthesia.
• High penetrating
MEPIVACAINE
• 3% Mepivacaine without a vasoconstrictor is used as anesthetic
for patients who cannot take a vasoconstrictor or for short
procedures.
• It is appropriate for pedodontics and for use on geriatric
patients.
• 2% Mepivacaine with vasoconstrictor provides pulpal
anesthesia that is similar to lidocaine with epinephrine, but
hemostasis is not as intense
PRILOCAINE
• The action of prilocaine plain varies with the area injected
(longer with a nerve block).
• Prilocaine with vasoconstrictor gives good anesthetic effect and
uses a 1:200,000 concentration of epinephrine
BUPIVACAINE
• Bupivacaine is used when pulpal anesthesia is desired for
longer appointments and when postoperative pain is anticipated.
• Bupivacaine is not recommended for children or handicapped
patients because of the increased risk of postoperative injury
(chewing on a numb lip).
CENTBUCRIDINE
• It does not effect the CNS or CVS adversely except when
administered in very large doses.
• Used in 0.5% concentrations
TAMED BIOTOXINS
• Tetradotoxin and Saxitoxin
• Block axonal depolarization by blocking transmembrane
inward sodium current.

• The diffusion and penetrating abilities are very poor, can not
cross the epineurium.
• Systemic toxicity to brain , heart and muscle is also of concern
HYALURONIDASE
• An enzyme that breaks down intracellular cement.
• Advocated as an additive to local anesthetics as it permits
injected solutions to spread and penetrate tissues
• Available as Wydase in a lyophilized powder and a stabilized
solution.
• Added to the cartridge just before administration by removing
approximately 1/8th of solution.
• Allergic reactions have been demonstrated
PH ALTERATIONS
• When a local anaesthetic is injected into tissue, two particles
are in equilibrium: a lipophilic neutral particle and a positively
charged hydrophilic particle
Three factors can affect this equilibrium:
• The pKa of the local anaesthetic,
• The pH of the local anaesthetic
• The pH of the tissue in which the anaesthetic is being
deposited.
pKa of local anesthetics
• The pKa of a local anaesthetic is defined as the pH at which
half of the local anaesthetic particles in equilibrium are neutral (RN)
and half are charged (RNH+
)
• Most local anaesthetics have pKa > 7.4
RNH+ RN + H+
pH of local anesthetics
• Most local anesthetics have a pH between 5.5 and 7 with out
vasoconstrictor and less than 5.5 with vasoconstrictor
The addition of substances to the anesthetic that alkalinizes the
solution should make the drug’s administration more comfortable.

Higher the pH more rapid is the onset of action and greater potency.
Carbonated local anesthetics
• Nerves internal pH is least affected by external pH fluctuations.
• Gases diffuse readily across the nerve membranes
Co2
CO2 + H2O H2CO3
H +
+ HCO3
RNH+
RN + H+
Block conduction
SODIUM BICARBONATE
Added immediately before injection alkalinizes the solution increasing
the number of uncharged base molecules
NaHCO3 Na+
+ HCO3
RNH+
RN + H+
H2CO3
Disadvantages of alkalinization
• If ph is too high local anesthetic may precipitate out as the drug
base
• Stability of local anesthetic decreases as ph increases hence
shelf life is decreased
TOPICAL ANESTHETICS
• Important component for atraumatic admn of intraoral local
anesthesia
• Do not contain vasoconstrictors
• Effective only on surface tissues
• Benzocaine and Lidocaine are most commonly used
• Effective only on abraded skin

INTRAORAL TOPICAL ANESTHETIC DELIVERY
1. As water soluble salts
2. Dissolved in organic solvents
3. As oil–water emulsions
4. As eutectic mixtures
5. Incorporated into patches and controlled release devices
6. Using iontophoresis and phonophoresis
7. Incorporated into liposome's
EUTECTIC MIXTURE OF LOCAL ANESTHESIA [EMLA
• EUTECTIC…Melts at a temperature lower than either of its
crystalline constituents
• 5% of la +92% of water+ inert stabilizer
• Local anesthetic agent oil is emulsified with water
• 2.5% lidocaine and 2.5% prilocaine
• Agent is made to form a cream with ph of 9 well above the
pka of either local anesthetic agents.
• High ph ensures 90% or more of the local anesthetic
agent is in diffusible uncharged free base for
• Intact skin is barrier to diffusion
• EMLA should be applied 1 hour before the procedure
• Satisfactory numbing occurs 1 hour after application
and reaches maximum at 2 to 3 hours and lasts for 1 to 2
hours after removal
• Supplied in a 5 g or 30 g tube or as an EMLA anesthetic
disc.
• It is white round, cellulose disc preloaded with EMLA
packaged in a protective laminate foil surrounded with adhesive
tape.

LIDOCAINE PATCH
• It is an adhesive containing 46.1 mg of lidocaine.
• The lidocaine is absorbed by the mucosa, and they claim
anesthetic onset within 2.5 minutes of application.
• The patch is left in place up to 15 minutes and the
anesthetic effect can last up to 30 minutes after removal
• levels of lidocaine following application are less than 0.1 µg/mL.
• Unlike conventional anesthetic ointments and gels ,patches
produce a fair amount of periosteal anesthesia when applied to intact
buccal mucosa
Iontophoresis
• Iontophoresis is a means of delivering local anesthetics to
deeper tissue after topical application .
• Positively charged drugs such as lignocaine and adrenaline can
be encouraged to penetrate
the tissue under the influence of electrical charge
PHONOPHORESIS

• Phonophoresis is the use of high frequency radio waves to
drive drugs into tissues and has been suggested as a possible
method of increasing the efficacy of topical applications
• .
LIPOSOMES
• Carrier vehicles composed of naturally occurring lipid and
cholesterol , similar in composition to biological membranes.
• The relatively large size of the liposome's assures that they
remain at the site of administration for a prolonged period of time.
• ELECTRONIC DENTAL ANESTHESIA
WHAT IS THE MECHANISM OF ACTION OF EDA?
• CHRONIC PAIN
• ACUTE PAIN
Chronic pain
• At low frequency setting produces measurable changes in
blood levels of L-tryptophan, Seratonin, and beta endorphins.
• L tryptophan Seratonin
• Seratonin
Analgesic actions

Elevates the pain threshold level
• Beta endorphins and enkephalins
Potent analgesics
ACUTE DENTAL PAIN
• Melzack and walls gate control theory of pain provides
adequate explanation for prevention of acute pain provided by EDA
• At high frequency >120 hzs , Patient experiences sensation
described as vibratory , throbbing , pulsing , twitching
Involves stimulation of large diameter A delta fibers .
• If minimum threshold intensity of large diameter a delta
fibers is maintained pain impulses brought about by smaller
a delta and c fibers will come on a closed gate to be unable
to reach the brain.
• The large fiber input is said to inhibit central transmission of the
overall effects of small fiber input.
• Blood levels of seratonin and endorphins likewise are
also elevated during high frequency stimulation
• Produces elevated blood levels of seratonin and endorphins.
• Increased levels persist for several hours after termination of
TENS.
• Help to block the pain cycle which is responsible for
chronicity of pain
• When EDA is utilized, electrodes initially are placed in the
region of the maxilla/mandible where "anesthesia" is desired.
• After establishing a baseline comfort zone of electrical
impulses, the patient adjusts the electronic stimulation to suit
his or her comfort level.
• Patients who have received both local anesthesia and EDA
report mixed results with regard to the effectiveness of EDA in pain
control and EDA alone does not mitigate the possibility that a
dental local anesthetic may be needed. EDA is used most
appropriately in routine operative procedures and simple pediatric
extractions. Its usefulness may be questioned, however, when cavity
preparations more closely approximate the pulp.
PHARMACOKINETICS

ABSORPTION
DISTRIBUTION
METABOLISM (BIOTRANSFORMATION)
EXCRETION
Absorption:
• VASOACTIVITY : All the LA are vasodilators.
• ESTER LA are potent vasodilators
• COCAINE is the only LA which causes persistent
vasoconstriction. (bcoz it inhibits uptake of catecholamines into tissue
binding sites.)
• PROCAINE is probably the most potent vasodilator
ABSORPTION
• ORAL ROUTE : All LA are poorly absorbed.
• Most LA undergo HEPATIC first pass effect following oral
administration.
• TOPICAL : Absorbed at different rates.
-tracheal –fast as IV
- pharyngeal – slower
-esophageal/bladder- even slower
When no intact layer of skin - it acts.(sunburn
remedies
ABSORPTION
• Injection : The rate of uptake after injection (subcutaneous,
intramuscular, IV ) depends on the vascularity of the injection site and
the vasoactivity of the drug.
• IV- Most rapid intake and is used for the treatment of ventricular
dysrhythmias
DISTRIBUTION
Distribution to body organs :
1. Brain, liver spleen,head,kidney (because they are highly
perfused) –initially high levels of LA.
2.SKELETAL MUSCLE : Greatest percentage because
it makes largest mass of tissue in the body

• LA can readily cross the blood-brain barrier.
• LA can also cross the placenta and can enter the
circulating system of the developing fetus.
METABOLISM
Esters – Hydrolysis in the plasma by the enzyme Pseudo
cholinesterase
Amides – Metabolized in the liver via a Multi step pathway by
Microsomal mixed function Oxidase system (cytochrome
p450).
EXCRETION
The kidneys are the primary excretory organ for both local
anesthetic groups.
ESTERS appear only in very small quantities in the urine as the
parent compound.
Amides bcoz of complex process of biotransformation –
appear in greater percentage than the esters
ARMAMENTARIUM
• Equipment necessary for LA administration
• Syringes
• Needles
• topical anesthetics
• Anesthetics
• Mouth props
Types of syringes
• Nondisposable
breech loading,metallic cartridge type aspirating
breech loading, plastic cartridge type aspirating

breech loading metallic cartridge type self aspirating
Pressure syringe for periodontal ligament injection
• Jet injector
• Disposable syringes
• Safety syringes
• Computer controlled local anesthetic delivery systems
• Breech loading ,metallic,catridge-type aspirating
• Pressure syringes-used for Intra ligamentary injections
JET INJECTOR
• Figge and Scherer 1947 needle less injection
• Margetis et al 1958 in dentistry
• Jet injector-based on principle that liquids forced through very
small openings,called jets, at very high pressure can penetrate intact
skin or mucous membrane
DISADVANTAGES
• Cost
• Potential to frighten patients with the sudden noise

• Pressure sensation that occur on delivery of the anesthetic
• Intrusive appearance of the device
• possibility of small Residual hematomas
• Leakage of anesthetic
• Questionable efficacy for pulpal anesthesia
SAFETY SYRINGES
• Minimizes accidental needle stick injury.
• Syringes posses a sheath that locks over the needle when it is
removed from the patient tissues.
• Safety syringes are designed to be for single use items.
• Reloading the syringe with a second anesthetic catridge and
reinjecting with the same syringe is discouraged because this
obviates the important safety aspect of the device
CCLAD
• Wand/compudent
• Comfort control syringe
• Halstead performed the first anesthetic nerve block a century
ago and identified an appropriate drug delivery system –the syringe
and hollow bore needle.
• Spinello ,later in 1997developed an innovative dental device,
which was commercially available as Wand (Milestone Scientific

What does wand do?
• Provides increased tactile control and ergonomics , precise
needle control during the injection.
• Available flow rates of local anesthetic delivery are computer
controlled and remains consistent from one injection to the next.
• controlled flow of anesthetic is thought to reduce pain and thus
patients fear and anxiety.
FEATURES OF WAND
• With traditional syringe the static position of the needle relative
to the beveled end causes deflection , results in missed block or
delayed onset of result.
• Pen like grasp has the advantage of allowing the operator to
rotate the hand piece during penetration and insertion
• As the needle is inserted anesthetic is delivered in a constant
computer controlled manner regardless of tissue density.
• The device provides a better alternative to traditional recapping
• Aspiration test can be activated at any time by simply releasing
the pressure on foot control rheostat starting a 4.5 second aspiration
cycle.
• Delivers a controlled rate of flow and controls pressure
developing with in the tissue
• Administers local anesthetic agent at 2 specific rates of delivery
COMFORT CONTROL SYRINGE
• CCS has 2 stage delivery system injection begins at an
extremely slow rate to prevent pain associated with quick delivery.
• After 10 seconds CCS automatically increases speed to the
preprogrammed injection rate.
• NEEDLES:
long,medium,short
BIROTATIONAL INSERTION TECHNIQUE
(BRIT
• Minimizing needle deflection
Why needle deflects

• During insertion a force perpendicular to the forward directional
movement acts on the surface of needle.
• This causes the needle to bend or deflect in a direction
opposite to which the bevel faces.
NEEDLE FACTORS INFLUENCING DEFLECTION
• Longer the needle length more is the deflection, because the
needle has to travel greater distance along the deflecting path.
• Smaller the diameter of needle more exaggerated is the
bending or deflection.
• Small gauge is less capable of resisting the deflection.
BRIT AND TRADITIONAL SYRINGE
• Traditional syringe is typically held with a palm and thumb
grasp and does not permit such a technique effectively.
• The wand compudent employs a light weight hand piece that is
held with a pen like or dart grasp that is easily rotated. deflection is
eliminated or neutralized from the constant changing of bevel
orientation as it is rotated
DISADVANTAGES
• Cost
• Potential to frighten patients with the sudden noise
• Pressure sensation that occur on delivery of the anesthetic
• Intrusive appearance of the device
• possibility of small Residual hematomas
• Leakage of anesthetic
• Questionable efficacy for pulpal anesthesia
SAFETY SYRINGES
• Safety syringes are designed to be for single use items.
• Reloading the syringe with a second anesthetic catridge and
reinjecting with the same syringe is discouraged because this
obviates the important safety aspect of the device
ADDITIONAL ARMAMENTARIUM
• Topical antiseptic
• Topical anesthetic
• Applicator sticks
• Cotton gauge

• Hemostat
NERVE BLOCK TECHNIQUES
• For dental anaesthesia, the neuroanatomical focus is the fifth
cranial nerve, also known as the trigeminal nerve.
• This nerve has three divisions - the ophthalmic division (V1),
the maxillary division (V2) and the mandibular division (V3).
• The maxillary dentition receives innervation from V2, and the
mandibular dentition receives innervation from V3.
THE MAXILLARY NERVE
• The maxillary nerve enters the pterygopalatine fossa and
branches into three major sections: the ganglionic branches, the
zygomatic nerve and the posterior superior alveolar nerve.
• The ganglionic branches travel to the pterygopalatine
ganglion, which in turn sends sensory, parasympathetic and
sympathetic fibres back to the maxillary nerve
• The zygomatic nerve enters the orbit and travels along the
lateral wall. It bifurcates into two terminal branches, the
zygomaticofacial nerve, which supplies sensation to the cheek, and

the zygomaticotemporal nerve, which supplies sensation to the
temple area
• There is also a parasympathetic component to the lacrimal
gland
• The posterior superior alveolar nerve travels inferiorly on the
infratemporal surface of the maxilla, entering the maxillary sinus and
eventually terminating in sensory branches for the maxillary molars
and their surrounding buccal gingiva, with the possible exception of
the mesiobuccal root of the first molar
• However,the middle superior alveolar nerve is not present in all
people; if the nerve is absent, these areas are innervated by the
posterior and anterior superior alveolar nerves
• The main areas of sensory innervation for the anterior superior
alveolar nerve are the cuspid, and central and lateral incisors and the
buccal gingiva in that area.
• The infraorbital nerve continues and eventually passes
through the infraorbital foramen onto the face, supplying the
lower eyelid, the side of the nose and the upper lip
• LOCAL INFILTRATION:
• Small terminal nerve endings in the area of dental
treatment are flooded with local anaesthetic
solution.Treatment is done in the same area of in which
solution has been deposited.

• FIELD BLOCK:
Local anaesthetic solution is deposited near the larger
terminal branch, so the anaesthetized area will be circumscribed to
prevent the passage of impulse from the tooth to CNS.Treatment is
done in an area away from the site of injection
NERVE BLOCK:
LA deposited close to the main nerve trunk usually at a
distance from the site of operative intervention.
Eg: posterior superior alveolar nerve block.
Inferior alveolar nerve block
MAXILLARY INJECTION TECHNIQUES
SUPRA PERIOSTEAL INJECTION: ( Local Infiltration )
INDICATIONS:
• Pulpal anaesthesia of maxillary teeth when treatment is limited
to one or two tooth .
• Soft tissue anaesthesia for surgical procedure in a
circumscribed area
CONTRAINDICATION:
• Infection or acute inflammation in the area of injection.
DISADVANTAGES:
• Need for multiple needle insertions.
• Necessary to administer large volume of solution.
TECHNIQUE:

AMOUNT TO BE DEPOSITED- 0.6ml over 20 sec.
POSTERIOR SUPERIOR ALVEOLAR NERVE BLOCK
• One of the frequently used nerve blocks in dentistry.
• The anesthetic solution is deposited behind the
tuberosity , near the posterior superior alveolar nerve before
it enters the maxillary sinus
• The posterior superior alveolar (PSA) nerve block, otherwise
known as the tuberosity block or the zygomatic block, is used to
achieve anesthesia of the maxillary molar teeth up to the 1st molar
with the exception of its mesiobuccal root in some cases.
• One of the potential complications of this technique is the risk
of hematoma formation from injection of anesthetic into the pterygoid
plexus of veins or accidental puncture of the maxillary artery.
Aspiration prior to injection is indicated when the PSA block is given
• The indications for this technique are the need to anesthetize
multiple molar teeth
• In individuals with coagulation disorders, care must be taken to
avoid injection into the pterygoid plexus or puncture of the maxillary
artery. 25- or 27-gauge short needle is preferred for this technique.
Technique
• Identify the height of the mucobuccal fold over the 2nd molar.
This will be the injection site.
• The right handed operator should stand at the nine
o’clock to ten o’clock position whereas the left handed
operator should stand at the two o’clock to three o’clock
position. Retract the lip with a retraction instrumen
• Hold the syringe with the bevel toward the bone.
• Insert the needle at the height of the mucobuccal fold
above the maxillary 2nd molar at a 45 degree angle directed
superiorly, medially, and posteriorly (one continuous

movement). Advance the needle to a depth of three quarters
of its total length
• No resistance should be felt while advancing the needle
through the soft tissue.
• If bone is contacted, the medial angulation is too great. Slowly
retract the needle (without removing it) and bring the syringe barrel
toward the occlusal plane. This will allow the needle to be angulated
slightly more lateral to the posterior aspect of the maxilla.
• Prior to injecting, one should aspirate in two planes to avoid
accidental injection into the pterygoid plexus. After the first aspiration,
the needle should be rotated one quarter turn. The operator should
then reaspirate.
• If positive aspiration occurs, slowly retract the needle one to
two millimeters and reaspirate in two planes.
• Successful injection technique will result in anesthesia of the
maxillary molars (with the exception of the mesiobuccal root of the
first molar in some cases), and associated soft tissue on the buccal
aspect.
Complications
HEMATOMA
• This is commonly produced by inserting the needle too for
posteriorly into the pterygoid plexus of veins .
• In addition maxillary artery may be perforated.
• Use of short needle minimises the risk of pterygoid plexus
puncture
Middle Superior Alveolar Nerve Block
• The middle superior alveolar nerve block is useful for
procedures where the maxillary premolar teeth or the mesiobuccal
root of the 1st molar require anesthesia.
• Although not always present, it is useful if the posterior or
anterior superior alveolar nerve blocks or supraperiosteal infiltration
fails to achieve adequate anesthesia
• Individuals in whom the MSA nerve is absent, the PSA and
ASA nerves provide innervation to the maxillary premolar teeth and
the mesiobuccal root of the 1st molar
• Contraindications include acute inflammation and infection in
the area of injection or a procedure involving one tooth where local

infiltration will be sufficient. A 25- or 27-gauge short needle is
preferred for this technique.
Technique
• Identify the height of the mucobuccal fold above the maxillary
2nd premolar. This will be the injection site.
• The right handed operator should stand at the nine o’clock to
ten o’clock position whereas the left handed operator should stand at
the two o’clock to three o’clock position.
• Retract the lip with a retraction instrument and insert the
needle until the tip is above the apex of the 2nd premolar tooth .
• Aspirate and inject anesthetic solution slowly over the course of
one minute. Successful execution of this technique provides
anesthesia to the pulp, surrounding soft tissue and bone of the 1st
and 2nd premolar teeth and mesiobuccal root of the 1st molar.1
Contraindications
• Infection or inflammation in the area of injection or needle
insertion or drug deposition
Anterior Superior Alveolar Nerve Block/ Infraorbital Nerve Block
• The anterior superior alveolar (ASA) nerve block or infraorbital
nerve block is a useful technique for achieving anesthesia of the
maxillary central and lateral incisors and canine as well as the
surrounding soft tissue on the buccal aspect.
• In patients that do not have an MSA nerve, the ASA nerve may
also innervate the premolar teeth and mesiobuccal root of the 1st
molar. Indications for the use of this technique include procedures

involving multiple teeth and inadequate anesthesia from the
supraperiosteal technique. A 25 gauge long needle is preferred for
this technique
Technique
• Place the patient in the supine position. Identify the height of
the mucobuccal fold above the maxillary 1st premolar.
• This will be the injection site.
• The right handed operator should stand at the ten o’clock
position whereas the left handed operator should stand at the two
o’clock position.
• Identify the infraorbital notch on the inferior orbital rim.
• The infraorbital foramen lies just inferior to the notch usually in
line with the second premolar.
• Slight discomfort is felt by the patient when digital
pressure is placed on the foramen. It is helpful but not
necessary to mark the position of the infraorbital foramen
• Retract the lip with a retraction instrument while noting the
location of the foramen
• Orient the bevel of the needle toward bone and insert the
needle at the height of the mucobuccal fold above the 1st premolar
• The syringe should be angled toward the infraorbital foramen
and kept parallel with the long axis of the 1st premolar to avoid hitting
the maxillary bone prematurely.
• The needle is advanced into the soft tissue until the bone over
the roof of the foramen is contacted. After aspiration, anesthetic
cartridge is deposited slowly over the course of one minute.
• It is recommended that pressure be kept over the site of
injection to facilitate the diffusion of anesthetic solution into the
foramen.
• Successful execution of this technique results in aesthesia of
the lower eyelid, lateral aspect of the nose, and the upper lip.
• Pulpal anesthesia of the maxillary central and lateral
incisors, canine, buccal soft tissue, and bone is also
achieved. In a certain percentage of people, the premolar
teeth and the mesiobuccal root of the 1st molar is also
anesthetized.
• The second direction of insertion bisects the crown of the
central incisor from the mesio incisal angle to the distogingival angle

• The needle is inserted about 5mm from the mucobuccal fold
and guided into position by the thumb marking the location of
infraorbital foramen
Greater Palatine Nerve Block
• The greater palatine nerve block is useful when treatment is
necessary on the palatal aspect of the maxillary premolar and molar
dentition
• Also called as Anterior palatine nerve block.
• This technique targets the area just anterior to the greater
palatine canal. The greater palatine nerve exits the canal and travels
forward between the bone and soft tissue of the palate.
• Contraindications to this technique are acute
inflammation and infection at the injection site. A 25- or 27-
gauge long needle is preferred for this technique
Technique
• The patient should be in the supine position with the chin tilted
upward for visibility of the area to be anesthetized. The right handed
operator should stand at the eight o’clock position whereas the left
handed operator should stand at the four o’clock position.
• Using a cotton swab, locate the greater palatine
foramen by placing it on the palatal tissue approximately one
centimeter medial to the junction of the 2nd and 3rd molar
• While this is the usual position for the foramen, it may be
located slightly anterior or posterior to this location.
• Gently press the swab into the tissue until the depression
created by the foramen is felt. The area approximately one to two
millimeters anterior to the foramen is the target injection site.
• Using the cotton swab, apply pressure to the area of the
foramen until the tissue blanches.

• Aim the syringe perpendicular to the injection site
which is one to two millimeters anterior to the foramen.
• While keeping pressure on the foramen, inject small volumes of
anesthetic solution as the needle is advanced through the tissue until
bone is contacted.
• The tissue will blanch in the area surrounding the injection site.
• Depth of penetration is usually few millimeters.
• Once bone is contacted, aspirate and inject anesthetic
solution.
• Resistance to deposition of anesthetic solution is normally felt
by the operator.
• This technique provides anesthesia to the palatal mucosa and
hard palate from the 1st premolar anteriorly to the posterior aspect of
the hard palate and to the midline medially
Nasopalatine Nerve Block
• The nasopalatine nerve block, otherwise known as the incisive
nerve block and sphenopalatine nerve block, anesthetizes the
nasopalatine nerves bilaterally.
• In this technique anesthetic solution is deposited in the area of
the incisive foramen.
• This technique is indicated when treatment requires anesthesia
of the lingual aspect of multiple anterior teeth. A 25- or 27-gauge
short needle is preferred for this technique.
Technique
• The patient should be in the supine position with the chin tilted
upward for visibility of the area to be anesthetized.
• The right handed operator should be at the nine o’clock
position whereas the left handed operator should be at the three
o’clock position.
• Identify the incisive papillae.

• The area directly lateral to the incisive papilla is the
injection site.
• With a cotton swab, hold pressure over the incisive papilla.
• Insert the needle just lateral to the papilla with the bevel against
the tissue
• Advance the needle slowly toward the incisive foramen while
depositing small volumes of anesthetic and maintaining pressure on
the papilla.
• Once bone is contacted, retract the needle approximately one
millimeter, aspirate, and inject anesthetic solution over the course of
thirty seconds.
• Blanching of surrounding tissues and resistance to the
deposition of anesthetic solution is normal.
• Anesthesia will be provided to the soft and hard tissue of the
lingual aspect of the anterior teeth from the distal of the canine on
one side to the distal of the canine on the opposite side
Anterior Middle Superior alveolar nerve block
• Reported by Friedman and Hochman in 1997 with CCLAD
system
• Provides anesthesia of multiple maxillary teeth incisors,
canines, premolars from single injection site.
WHAT IS AMSA NERVE BLOCK
• It is a field block of the terminal branches subneural dental
plexus of the ASA nerve that innervates the incisors to premolar
teeth.
• Two anatomical structures the nasal aperture and maxillary
sinus cause the convergence of the branches of ASA , MSA nerves
and associated subneural dental plexus in the region of apices of the
premolars

INJECTION SITE
• Hard palate about half way along the imaginary line
connecting the mid palatal suture to the free gingival margin.
• The location of the line is at the contact point between first and
second premolars.
ADVANTAGES
• As local anesthesia is deposited on the palate so muscles of
facial expression and upper lip are not anesthetized.
• Minimum volume of local anesthesia is needed.
AREAS ANESTHETIZED
• Pulpal anesthesia of maxillary incisors, canines and
Premolars.
• Buccal attached gingiva of the same teeth
• Attached palatal tissues from midline to free gingival
margin of the associated teeth.
PALATAL APPROACH ANTERIOR SUPERIOR ALVEOLAR
NERVE BLOCK
• Defined by Friedman and
• Hochman with CCLAD.

• P ASA is similar to nasopalatine nerve block in many aspects
but it differs from it in its final target.
• The position of the needle is within the incisive canal
• Volume of anesthetic administered is 1.4 to 1.8 ml
• Nerves anesthetised
Nasopalatine , Anterior branches of ASA
• Areas anesthetised
• Pulps of maxillary central incisors, lateral incisors, and the
canines(bilaterally)
• Facial periodontal tissue associated with the same teeth
• Palatal periodontal tissue associated with the same teeth
• Area of insertion
Just lateral to the incisive papilla in the papillary groove.
Ensure the needle is in contact with the inner bony wall of the
canal
• A well defined naso-palatine canal may not be present in some
patients
TECHNIQUES OF MANDIBULA ANESTHESIA
TECHNIQUES OF MANDIBULAR REGIONAL ANESTHESIA
• Techniques used in clinical practice for the anesthesia of the
hard and soft tissues of the mandible include the supraperiosteal
technique, PDL injection, intrapulpal anesthesia, intraseptal injection,
inferior alveolar nerve block, long buccal nerve block, Gow -Gates
technique, Vazirani-Akinosi closed mouth mandibular block, mental
nerve block, and incisive nerve block.
• When anesthetizing the mandible the patient should be in the
semisupine or reclined position. The right handed operator should
stand at the nine o’clock to ten o’clock position whereas the left
handed operator should stand at the three o’clock to four o’ clock
position

INFERIOR ALVEOLAR NERVE BLOCK [mandibular block]
• The inferior alveolar nerve block is one of the most commonly
employed techniques in mandibular regional anesthesia.
• It is used when multiple teeth in one quadrant require
treatment.
• While effective, this technique carries a high failure rate even
when strict adherence to protocol is maintained.
• The target for this technique is the mandibular nerve as it
travels on the medial aspect of the ramus, prior to its entry into the
mandibular foramen. The lingual, mental, and incisive nerves are also
anesthetized. A 25 gauge long needle is preferred for this technique.
Technique
• The patient should be in the semisupine position.
• The right handed operator should be in the eight o’clock
position whereas the left handed operator should be in the four
o’clock position.
• With the mouth open maximally, identify the coronoid notch and
the pterygomandibular raphae.
• Three quarters of the anteroposterior distance between these
two landmarks, and approximately six to ten millimeters above the
occlusal plane is the injection site

• Bring the needle to the injection site from the contralateral
premolar region.
• As the needle passes through the soft tissue, deposit one or
two drops of anesthetic solution.
• Advance the needle until bone is contacted.
• Once bone is contacted, withdraw the needle one millimeter
and redirect the needle posteriorly by bringing the barrel of the
syringe towards the occlusal plane
• Advance the needle to three quarters of its depth, aspirate, and
inject three quarters of a cartridge of anesthetic solution slowly over
the course of one minute.
• Successful execution of this technique results in anesthesia of
the mandibular teeth on the ipsilateral side to the midline, associated
buccal and lingual soft tissue, lateral aspect of the tongue on the
ipsilateral side, and lower lip on the ipsilateral side

Buccal Nerve Block
• The buccal nerve block, otherwise known as the long buccal or
buccinator block, is a useful adjunct to the inferior alveolar nerve
block when manipulation of the buccal soft tissue in the mandibular
molar region is indicated.
• The target for this technique is the buccal nerve as it passes
over the anterior aspect of the ramus.
• Contraindications to the procedure include acute inflammation
and infection over the site of injection. A 25 gauge long needle is
preferred for this technique.
Technique
• The patient should be in the semisupine position. The right
handed operator should be in the eight o’clock position whereas the
left handed operator should be in the four o’clock position.
• Identify the most distal molar tooth on the side to be treated.
The tissue just distal and buccal to the last molar tooth is the target
area for injection

• The bevel of the needle should be toward bone and the syringe
should be held parallel to the occlusal plane on the side of the
injection.
• The needle is inserted into the soft tissue and a few drops of
anesthetic solution are administered.
• The needle is advanced approximately one or two millimeters
until bone is contacted.
• Once bone is contacted and aspiration is negative, 0.2cc of
local anesthetic solution is deposited.
the buccal soft tissue of the mandibular molar region
Gow -Gates Technique
• The Gow -Gates technique or third division nerve block is
useful alternative to the inferior alveolar nerve block and is often used
when the latter fails to provide adequate anesthesia.
• Advantages of this technique versus the inferior alveolar
technique are its low failure rate and low incidence of positive
aspiration.
• The Gow-Gates technique anesthetizes the auriculotemporal,
inferior alveolar, buccal, mental, incisive, mylohyoid and lingual
nerves.
• Contraindications to this procedure include acute inflammation
and infection over the site of injection and trismatic patients.
• A 25 gauge long needle is preferred for this technique
Technique
o’clock position.
• The target area for this technique is the neck of the condyle
below the area of insertion of the lateral pterygoid muscle.
• A retraction instrument is used to retract the cheek.

• The patient is asked to open maximally and the mesiolingual
cusp of the maxillary 2nd molar on the side of desired anesthesia is
identified.
• The insertion site of the needle will be just distal to the
maxillary 2nd molar at the level of the mesiolingual cusp.
• Bring the needle to the insertion site in a plane that is parallel to
an imaginary line drawn from the intertragic notch to the corner of the
mouth on the same side as the injection.
• Advance the needle through soft tissue approximately 25mm
until bone is contacted at the neck of the condyle.
• Once bone is contacted, withdraw the needle one millimeter
and aspirate.
• Redirect the needle superiorly and reaspirate.
• If aspiration in two planes is negative, slowly inject one
cartridge of local anesthetic solution over the course of one minute.
• Successful execution of this technique provides anesthesia to
the ipsilateral mandibular teeth up to the midline, and associated
buccal and lingual hard and soft tissue.
• The anterior two thirds of the tongue, floor of the mouth, skin
over the zygoma, posterior aspect of the cheek and temporal region
on the ipsilateral side of injection are also anesthetized
Vazirani -Akinosi Closed Mouth Mandibular Block
• The Vazirani -Akinosi closed mouth mandibular block is a
useful technique for patients with limited opening due trismus or
ankylosis of the temporomandibular joint.
• Limited mandibular opening precludes the administration of the
inferior alveolar nerve block or use of the Gow-Gates technique both
of which require the patient to be open maximally.

• Other advantages to this technique are the minimal risk of
trauma to the inferior alveolar nerve, artery, vein, and pterygoid
muscle, low complication rate and minimal discomfort upon injection.
• Contraindications to this technique are acute inflammation and
infection in the pterygomandibular space, deformity or tumor in the
maxillary tuberosity region or an inability to visualize the medial
aspect of the ramus. A 25 gauge long needle is preferred for this
technique.
TECHNIQUE
o’clock position.
• The gingival margin above the maxillary 2nd and 3rd molars
and the pterygomandibular raphae are the landmarks for this
technique.
• A retraction instrument is used to stretch the cheek laterally.
• The patient should occlude gently on the posterior teeth.
• The needle is held parallel to the occlusal plane at the level of
the gingival margin of the maxillary 2nd and 3rd molars.
• The bevel is directed away from the bone facing the
midline.
• The needle is advanced through the mucous membrane and
buccinator muscle to enter the pterygomandibular space.
• The needle is inserted to approximately one half to three
quarters of its length
• At this point the needle will be in the midsection of the
ptyerygomandibular space.

• Aspirate and if negative, anesthetic solution is deposited over
the course of one minute.
• Diffusion and gravitation of the local anesthetic solution will
anesthetize the lingual and long buccal nerves in addition to the
inferior alveolar nerve.
• Successful execution of this technique provides anesthesia of
the ipsilateral mandibular teeth up to the midline, and associated
buccal and lingual hard and soft tissue. The anterior two thirds of the
tongue and floor of the mouth are also anesthetized
MENTAL NERVE BLOCK
• The mental nerve block is indicated for procedures where
manipulation of buccal soft tissue anterior to the mental foramen is
necessary.
infection over the injection site. A 25 or 27 gauge short needle is
preferred for this technique
Technique
o’clock position.
• The target area is the height of the mucobuccal fold over the
mental foramen
• The foramen can be manually palpated by applying gentle
finger pressure to the body of the mandible in the area of the
premolar apicies.
• The patient will feel slight discomfort upon palpation of
the foramen

• Use a retraction instrument to retract the soft tissue.
• The needle is directed toward the mental foramen with the
bevel facing the bone.
• Penetrate the soft tissue to a depth of five millimeters, aspirate
and inject approximately 0.6cc of anesthetic solution.
the buccal soft tissue anterior to the foramen, lower lip and chin on
the side of the injection.
Incisive Nerve Block
• The incisive nerve block is not as frequently employed in
clinical practice
• However it proves very useful when treatment is limited to
mandibular anterior teeth and full quadrant anesthesia is not
necessary.
• The technique is almost identical to the mental nerve block.
• Both the mental and incisive nerves are anesthetized using this
technique.
infection at the site of injection.
• A 25 or 27 gauge short needle is preferred for this technique.
Technique
o’clock position
• The target area is the height of the mucobuccal fold over the
mental foramen
• Identify the mental foramen as previously described.
• Give the patient a mental nerve block as described above and
apply digital pressure at the site of injection during administration of
anesthetic solution.
• Continue to apply digital pressure at the site of injection two to
three minutes after the injection is complete to aid the anesthetic in
diffusing into the foramen.
• Successful implementation of this technique provides
anesthesia to the premolars, canine, incisor teeth, lower lip, skin of
the chin, and buccal soft tissue anterior to the mental foramen.

SUPPLEMENTAL INJECTION
PERIODONTAL LIGAMENT INJECTION
• Also called intraligamentary injection
• Terminal nerve endings at the site of injection are anaesthetized
• Technique :
• 27 gauge needle is inserted at long axis of tooth to be treated at
depth of gingival sulcus
• Deposit 0.2ml in 20 secs
• Treatment to start after 30 secs and lasts for 5-55mins
PERIODONTAL LIGAMENT INJECTION [pressure syringes]
INTRASEPTAL INJECTION
• Similar to pdl injection
• Anesthetizes terminal nerve endings
• Bone, soft tissue, root structure are anesthetized
• Area of insertion:centre of interdental papilla adj to the tooth to
be treated
• Orient the needle at 450
to the long axis of the tooth
• Deposit 0.2 to 0.4ml of local anesthetic in 20secs
Intraseptal injection
INTRAOSSEOUS INJECTION

• Here a perforation is made into the bone into which the local
anesthetic is injected
• Stabident system is replaced by Intraflow IO system
• A drill makes a perforation thro the bone in a pecking motion
and the guide sleeve is left in place until the LA is injected
• 2mm apical to the gingival margin is the injection site
• Pulpal anesthesia of between 15 and 30 mins can be expected
• Fistula formn is the most common complication
Intra osseous anesthesia
INTRAPULPAL INJECTION
• Deposits LA directly into the pulp chamber
• Very effective for pulp extirpation and instrumentation
procedures
• A small opening in the pulp chamber is sufficient for max
effectiveness
• There is a brief period of sensitivity followed by relief
Local anesthetic dose calculation
• Doses are even more critical in the paediatric patient, and it is
important to note how little one should give to a child..
• High-concentration solutions, namely prilocaine and articaine,
reach toxic levels with fewer cartridges.
• Calculations of Doses Percent solutions represent grams per
100 mL (i.e. lidocaine 2% = 20 mg/mL) Most cartridges = 1.8 mL.
Therefore, one cartridge of 2% lidocaine contains 1.8 mL x 20 mg/mL
= 36 mg

COMPLICATIONS of ANESTHESIA
INTRODUCTION
• An anesthetic complication may be defined as any deviation
from the normally expected pattern during or after the securing of
regional analgesia.
• Complications may be classified as follows:
1.primary or secondary.
2.mild or severe
3.transient or permanent
• They can be classified according to the site
1.Locally in the region of the injection
2. or systemically
Local Complications
• 1)Needle Breakage
• 2)Persistent anaesthesia
• 3)Facial Nerve paralysis
• 4)Trismus
• 5)soft tissue injury
• 6)hematoma
• 7)pain on injection
• 8)burning on injection
• 9)Infection
• 10)Edema
• 11)Sloughing of tissues
• 12)pos anaesthetic intraoral lesions
Systemic complications
• 1)overdose
• 2)allergy
• 3)Idiosyncrasy
Classification of Adverse drug reactions
• 1)toxicity caused by direct extension of the usual
pharmacological effects of the drug:-
-Side Effects
-Overdose
-Local Toxic effects
• 2)Toxicity caused by the alteration in recipient of the drug :-

-disease process – hepatic
dysfunction, heart failure
-Emotional disturbances
-Genetic abberations – atypical plasma
cholinessterse , malignan hyperthermia
- Idiosyncrasy
• 3) Toxicity caused by allergic responses to the drug
• Complications may be further divided into 2 groups:
1.Those attributed to the solutions used
2. Those attributed to the insertion of the needle
Those attributed to the solutions used
1.Toxicity
2.Idiosyncrasy
3.Allergy
4.Anaphylactoid reactions
5.Infections caused by contaminated solutions.
6.Local irritations or tissue reactions caused by solutions
Those attributed to the insertion of the needle
1.Syncope
2.Muscle trismus
3.Pain or hyperalgesia
4.Edema
5.Infections
6.Broken needles
7.Prolonged anesthesia other than from the anesthetic solution.
8.Hematoma
9.Sloughing
10.Bizarre neurological symptoms
COMPLICATIONS CAUSED BY THE ANESTHETIC SOLUTION
• Toxicity
• The term toxicity, or toxic overdose, refers to the
symptoms manifested as the result of over dosage or excessive
administration of a drug
• This complication depends on a sufficient
concentration of the drug in the blood stream to adversely
affect the central nervous system, the respiratory system, or
the circulatory system
• Toxicity

• LA blood level high enough to cause the symptoms of toxic
overdose may come about in one or more of the following four
ways:
1. Too large a dose of local anesthetic drug
2. Unusually rapid absorption of the drug or intravascular
injection
3. Unusually slow biotransformation
4. Slow elimination or redistribution
• The blood level necessary to create a toxic overdose is
variable and depends on a variety of factors, some of which follow:
1. Patient’s general physical condition at the time of the
injection
2. Rapidity of injection
3. Route of administration (for example, inadvertent
intravascular injection)
4. Amount of the drug used
5. Age of patient
• SYMPTOMS.
Usually early central nervous system stimulation followed by a
proportionate degree of depression. (On occasion central nervous
system depression may appear as the first sign of toxicity.)
1. Cerebral cortical stimulation
a. Talkativeness
b. Restlessness
c. Apprehension
d. Excitement
• 2. Cerebral cortical depression
a. Lethargy
b. Sleepiness
c. Unconsciousness
• After mild cortical stimulation the may be little or no cortical
depression. However, convulsions are usually followed by severe
cortical depression and unconsciousness.
• 3. Medullary stimulation
a. increased blood pressure
b. Increased pulse rate
c. Increased respirations

d. Possible nausea and vomiting
• 4. Medullary depression will usually occur in proportion to
the amount of medullary stimulation.
a. Blood pressure may remain normal in mild cases or drop to zero
in severe cases.
b. Pulse may range from normal to weak, thready, or absent.
c. Respiratory changes may be slight, or the patient may become
apneic in severe cases
• Treatment should be directed toward alleviating
symptoms;early recognition and early treatment are imperative.
1. Mildly stimulated patients should require no treatment other
than the discontinuing of further administration of the
anesthetic drug
2. Moderately stimulated patients should be given pentobarbital
sodium or secobarbital intravenously very slowly until they are
calmed, plus inhalations of oxygen
3. Convulsive patients should receive 20 to 40 mg of
succinylcholine chloride intravenous or double the dose
intramuscularly to control the convulsions. Adequate ventilation
must be maintained.
4. Treatment of central nervous system depression should be
directed toward supporting respiration with artificial ventilation
and maintaining adequate cardiovascular system function
through positional changes and vasopressors, if required
PREVENTION Toxicity
1. Aspiration must be performed before injecting.
2. The smallest possible volume of drug should be used.
3. The weakest efficient percentage strength of the drug should be
used.
4. The anesthetic drug should be injected slowly
5 A vasoconstrictor should be employed with the local anesthetic if
not contraindicated
IDIOSYNCRASY

• The term idiosyncrasy is often assigned to a bizarre type of
reaction that cannot be classified as toxic or allergic
ALLERGIC REACTIONS
• CAUSE. The primary cause of allergic reactions is a specific
antigen antibody reaction in a patient who has previously been
sensitized to a particular drug or chemical derivative thereof
• SYMPTOMS. Reaction affects a particular shock organ, most
likely the skin, mucous membrane, or blood vessels.
1. Rashes
2. Urticaria
3.Angioneurotic edema
4.Mucous membrane congestion
a. Rhinitis
b. Asthmatic symptoms
• TREATMENT
1. Antihistaminic agents (Benadryl, 20 to 50 mg)
2. Isoproterenol or epinephrine inhalants
3. Epinephrine (0.5 ml of 1:1,000 intramuscularly)
4. Aminophylline (0.5 gm intravenously)
5. Oxygen
• PREVENTION
1. Adequate preanesthetic evaluation must be done.
2. No drug or drugs should be used if the patient previous allergic
reaction to them.
3. No patient should be tested to attempt to disprove his allergic
history
Complications attributed to the needle insertion or technical
complications
• SYNCOPE

• Syncope or fainting is perhaps the most frequent complication
associated with local anesthesia in the dental office.This is a form of
neurogenic shock and is caused by cerebral ischemia secondary to a
vasodilatation or an increase in the peripheral vascular bed, with a
corresponding drop in blood pressure
• In most instances it is possible to detect a change in the
patient’s appearance, such as pallor. The patient may also
complain of feeling different or strange.
• The operator should discontinue any procedures in progress
and lower the chair back while the patient’s legs are slightly
elevated, thus placing the patient in a semireclining position .This
position aids venous return from the lower portions of the body
while preventing venous congestion in the upper body, as with the
conventional Trendelenburg (head down) position
Muscle Trismus
• Muscle trismus is a fairly common complication of regional
analgesia or anesthesia, particularly after blocks of the inferior
alveolar nerve
• The most common cause of trismus is trauma to a muscle
during the insertion of the needle. Irritating solutions,
hemorrhage, or low-grade infection within the muscle may also
cause varying degrees of trismus
• The treatment should depend on the cause of the trismus. If
the condition arises as the result of trauma, slight exercises and
drug therapy may be necessary to relieve pain, if sufficiently
severe.
• Centrally acting muscle relaxants such as diazepam
(Valium) 2.5 to 5.0 mg four times per day or meprobamate, 1200 to
1600 mg per day in three or four doses coupled with the
application of warm moist compresses for 15 to 20 minutes per
hour will usually relieve the symptoms in several days
• Mild analgesics may also be used for discomfort.
• Physiotherapy consisting of opening and closing the mouth
as well as movement from side to side for 5 to 10 minutes every 3
or 4 hours will also assist recovery

• Trismus may be prevented by the use of sharp, sterile
needles so that the trauma of insertion and any subsequent low-
grade infections are prevented.
• The area of insertion should be cleansed and painted with a
suitable antiseptic solution.
• Care should be exercised also so that the needle is inserted
atraumatically and no muscles are penetrated
Pain or hyperesthesia
• Pain during or after the administration of a regional
anesthetic is very common. It is much more common that it need
be, and in many instances it is the result of carelessness or
indifference.
• Every precaution should be taken to make those maneuvers
associated with securing anesthesia as painless as possible
• Only sharp needles should be used, and the area of
penetration should be anesthetized with a topical anesthetic.
• The insertion of the needle should be slow and as atraumatic
as possible.
• Multiple insertions in the same area should be avoided.
• Solutions should be sterile and compatible with the tissue
• They should also be forced into the tissue very slowly and
with as little pressure as possible. Excessive volumes in
constricted areas should be avoided. Rational concentrations of
vasoconstrictors should be used.
• Infections, low grade or otherwise, are a common cause of
pain after the use of regional anesthesia or analgesia. Extreme
care should be exercised in maintaining aseptic conditions. There
is no excuse for careless contamination or for failure to appreciate
the importance of asepsis
Edema
• Edema, or swelling of the tissues, is usually a symptom and
rarely an entity in itself. Trauma, infection, allergy, hemorrhage,
and other factors can produce edema. Each cause of edema should
be considered under own classification in regard to prevention and
treatment

Infection
• Infection as a factor in producing pain needs little or no
discussion, since it is so obvious. Dentists should constantly apply
all means at their command to prevent infections.
• All areas, instruments, needles, and solutions should be as
aseptic as possible, The operator’s hands should be scrupulous1y
cleansed before working on each patient. All areas should be
cleansed with a suitable antiseptic before needle insertion is
performed. Care should be exercised to avoid passing the needle
through infected areas
BROKEN NEEDLES
• Breakage of needles is one of the most annoying and
depressing,complications of regional anesthesia.
• dentists should not violate fundamental principles when
using them.
• The following principles should be observed to prevent
the possibility of a broken needle
• 1. Do not attempt to force a needle against resistance.
• 2. Do not attempt to change the direction of the needle while
it is embedded in the tissue.
• 3. Do not use a needle of too fine a gauge.
• 4. Do not use resterilizable needles.
• 5. Do not attempt injections if you are uncertain about
the anatomy of the area of the techniques employed
• 6. Do not insert the needle so far as it is out of sight in
tissue.
• 7. Do not surprise the patient with a sudden unexpected
needle insertion. The informed patient is always the best patient
and is much more cooperative
Prolonged anesthesia other than from the anesthetic solution
• Most cases of prolonged anesthesia are caused by solutions
contaminated by alcohol or other sterilizing media.
• The most likely cause associated with the needle insertion is
hemorrhage into the neural sheath caused by the mild trauma of a
needle bumping into the nerve, which creates pressure and
subsequent anesthesia.

Hematoma
• Hematoma is a common complication of intraoral regional
analgesia. is most commonly associated with the posterior
superior alveolar and infraorbital nerve blocks.
• Hematoma is an effusion of blood into the surrounding
tissue as the result of a torn blood vessel. As a rule, the
atraumatic puncture of a vein will not produce a hematoma
• No attempt should be made to aspirate or to interfere with
the normal absorption of the blood in the tissues. The patient
should be told what happened and put at ease by an explanation
of the condition’s lack of severity
Bizarre neurological symptoms
• On rare occasions unexplained neurological symptoms may
occur following the insertion of a needle and the injection of a
solution in a given area.
• Patients may exhibit facial paralysis, crossed eyes,
muscular weakness, temporary blindness, and many other
unexpected complications.
• They are rare and are usually caused by inadvertent
anesthesia to nerves in the area
Facial nerve paralysis

• The best method of preventing these complications is to
follow closely the accepted techniques and to adhere to all the
basic concepts of accepted procedure
References
• Local anasthesia by Stanley Malamed
• Monheims – local anasthesia in dental practice
• Pathways of the pulp – Stephen cohen
• Book of Endodontics- Ingle

Local anesthesia

Recomendados

Recomendados

Mais conteúdo relacionado

Mais procurados

Mais procurados (20)

Destaque

Destaque (20)

Semelhante a Local anesthesia

Semelhante a Local anesthesia (20)

Mais de Indian dental academy

Mais de Indian dental academy (20)

Último

Último (20)

Local anesthesia