oral surgery
lac. innervation
-the posterior superior alveolar nerve.
it decending from the main trunk of maxillary n.in the
pterrgopalatine fossa before the maxillary devision inter
infra orbital fissure. this n. will pass down ward through
the pterigoplatin fossa. they reach the post. surface of
maxilla.gives 2 branchs.
one remains external of bone& supply sensory
innervintion to the buccal gingival in the max. molars&
odjacent facial sursafe.
the other branch the maxilla along with a branch of
internal max. artery to inter maxillary sinus.
branches in the infra orbital canal
within the canal ,the v2 gives the middle sup.& ant. sup.
alveolar nerves. the n in the infra orbital grove& canal is
called infra orbital nerves .
denal plexuse
terminal branches of long nerves forms anerve network
to inn. root of teeth,bone & pdl in both maxilla and
mandible.
?summary of the branches of v3
1-undevided n.(main trunk)
a-nervous spinosus
b-n. to med pterygoid muscle.
2-devided nerve
a-ant. division
• n. to lateral pterygoid muscle.
• n. to the masseter muscle.
• n.to the temporal muscle .
• n. to buccal .or buccal nerve
b-posterior division.
i. articulo temporal nerve.
ii. lingual nerve.
iii. mylohyoid nerve.
iv. inferior alveolar nerve (dental branches)
v. mental nerve.
vi. incisive branch.
long
buccal
nerve
? wholly sensory , branch of ant.division of v3.
? passes between 2 head of the lat. pterygoid muscle
at
the
level
of
occlusal
plane.
ligual
nerve
? the 2end branch of the posterior division of v3
? it passes downwards medial to the lateral pterygoid
muscle.
? it lies between the ramus of mandible& the medial
pterrygoid
muscle.
? reach the side of the base of the tongue.
? slighty below & behind the mand.3rd molar
?
provide
general
sensation
for
?
all
ligual
gingival
?
mucosa
of
the
floor
of
mouth.
? the ant. two third of the tongue(sens& taste)
the
inferior
alveolar
nerve
?
abranch
of
mandibular
division,
? it passes medial to lateral pterygoid muscle.
?
posterior
to
lingual
nerve.
?
it
gives
the
mylohyoid
m.
? with the inferior alveolar artery& vein inter the
mandibular
canal
?
through
the
mandibular
foramen.
the
mental
nerve
?
it exite the man. through mental foramen
? located several mm inf. to the apex of the 2nd premolar
?
or
slightly
anterior
or
posterior.
?
it
devided
into
3
branches
? inn. the skin of the chin+lower lip+mucos membrane of
lower lip.
the
incisive
nerve
it
remains
within
the
man.
canal
form
anerve
plexus
innervat the pulpal tissue of the mand. 1st premolar
,canine& incisor via dental branches.
local
anesthesia
history
the leaves of the coca plant were traditionally used as a
stimulant in peru. it is believed[by whom?] that the local
anesthetic effect of coca was also known and used for
medical purposes. cocaine was isolated in 1860 and first
used as a local anesthetic in 1884. the search for a less
toxic and less addictive substitute led to the development
of the aminoester local anesthetic procaine in 1904. since
then, several synthetic local anesthetic drugs have been
developed and put into clinical use, notably lidocaine in
1943, bupivacaine in 1957 and prilocaine in 1959.
shortly after the first use of cocaine for topical anesthesia,
blocks on peripheral nerves were described. brachial
plexus anesthesia by percutaneous injection through
axillary and supraclavicular approaches was developed in
the early 20th century. the search for the most effective
and least traumatic approach for plexus anesthesia and
peripheral nerve blocks continues to this day. in recent
decades, continuous regional anesthesia using catheters
and automatic pumps has evolved as a method of pain
therapy.
intravenous regional anesthesia was first described by
august bier in 1908. this technique is still in use and is
remarkably safe when drugs of low systemic toxicity such
as
prilocaine
are
used.
spinal anesthesia was first used in 1885 but not
introduced into clinical practice until 1899, when august
bier subjected himself to a clinical experiment in which he
observed the anesthetic effect, but also the typical side
effect of postpunctural headache. within a few years,
spinal anesthesia became widely used for surgical
anesthesia and was accepted as a safe and effective
technique. although atraumatic (non-cutting-tip) cannulas
and modern drugs are used today, the technique has
otherwise changed very little over many decades.
local anesthetics are used in dentistry to anesthetize teeth
and portions of your jaw so as to maximize comfort during
dental
procedures.
dental anesthetics are dispensed in individual, sterile
cartridges into which a sterile needle is inserted.
typical dental anesthetics are "-caine type agents" such as
xylocaine, lidocaine, carbocaine, and marcaine. novocaine
was perhaps the first widely used local anesthetic but it is
no longer available. some anesthetics contain epinephrine
(adrenalin), a vasoconstrictor (reduces blood flow), to
decrease bleeding in the site and increase anesthetic
potency.
dentists inject anesthetic into spaces near nerves that
innervate (supply sensation) the area to be treated. the
goal is to let the anesthetic gently diffuse into the desired
region.
as a patient, you will feel the needle go in and the
pressure of the solution being injected into the
tissues. generally, the slower the injection, the less the
discomfort.
topical anesthetic is a -caine type ointment applied before
the injection to diminish the prick of the needle.
each patient is anatomically unique therefore, it is possible
to inject directly into a nerve. this situation causes
sudden, sharp "shock" followed by immediate anesthesia.
it is also possible to inject into a blood vessel. in those
circumstances, you may feel your heart pound faster. this
is due to the epinephrine (adrenalin) in the
anesthetic. you may also swell and bruise (hematoma).
local anesthetic can block almost every nerve between the
peripheral nerve endings and the central nervous system.
the most peripheral technique is topical anesthesia to the
skin or other body surface. small and large peripheral
nerves can be anesthetized individually (peripheral nerve
block) or in anatomic nerve bundles (plexus anesthesia).
spinal anesthesia and epidural anestem merges into the
central
nervous
system.
injection of local anesthetics is often painful. a number of
methods can be used to decrease this pain including
buffering of the solution with bicarb and warming.[1]
surface anesthesia - application of local anesthetic spray,
solution or cream to the skin or a mucous membrane. the
effect is short lasting and is limited to the area of contact.
infiltration anesthesia - injection of local anesthetic into
the tissue to be anesthetized. surface and infiltration
anesthesia
are
collectively
topical
anesthesia.
field block - subcutaneous injection of a local anesthetic in
an area bordering on the field to be anesthetized.
peripheral nerve block - injection of local anesthetic in the
vicinity of a peripheral nerve to anesthetize that nerve s
area
of
innervation.
plexus anesthesia - injection of local anesthetic in the
vicinity of a nerve plexus, often inside a tissue
compartment that limits the diffusion of the drug away
from the intended site of action. the anesthetic effect
extends to the innervation areas of several or all nerves
stemming from the plexus.
physiology
to achieve conduction anesthesia a local anesthetic is
injected or applied to a body surface. the local anesthetic
then diffuses into nerves where it inhibits the propagation
of signals for pain, muscle contraction, regulation of blood
circulation and other body functions. relatively high drug
doses or concentrations inhibit all qualities of sensation
(pain, touch, temperature etc.) as well as muscle control.
lower doses or concentrations may selectively inhibit pain
sensation with minimal effect on muscle power. some
techniques of pain therapy, such as walking epidurals for
labor pain use this effect, termed differential block.
pathophysiology
reviewing the physiology of nerve conduction is important
before any discussion of local anesthetics. nerves transmit
sensation as a result of the propagation of electrical
impulses this propagation is accomplished by alternating
the ion gradient across the nerve cell wall, or axolemma.
in the normal resting state, the nerve has a negative
membrane potential of -70 mv. this resting potential is
determined by the concentration gradients of 2 major
ions, na+ and k+, and the relative membrane
permeability to these ions (also known as leak currents).
the concentration gradients are maintained by the
sodium/potassium atp pump (in an energy-dependent
process) that transports sodium ions out of the cell and
potassium ions into the cell. this active transport creates a
concentration gradient that favors the extracellular
diffusion of potassium ions. in addition, because the nerve
membrane is permeable to potassium ions and
impermeable to sodium ions, 95% of the ionic leak in
excitable cells is caused by k+ ions in the form of an
outward flux, accounting for the negative resting
potential. the recently identified 2-pore domain potassium
(k2p) channels are believed to be responsible for leak k+
currents.
dentistry (surface anesthesia, infiltration anesthesia or
intraligamentary anesthesia during restorative operations
or extractions, regional nerve blocks during extractions
and
surgeries.)
techniques
of
dental
local
anesthesia
regional dental anesthesia can be divided into component
parts,
depending on the technique employed. there are three
different
techniques used in dental anesthesia: local infiltration
technique,nerve block and periodontal ligament injection
in
local
infiltration
technique,
small
nerve
endings
in
the
area
of
the
dental
treatment
are
flooded
with
local
anesthetic
solution,
preventing
them
from
becoming
stimulated
and
creating
an
impulse.
local
infiltration
technique
is
commonly
used
in
anesthesia
of
the
maxillar
teeth
and
the
mandibular
incisors
\in
nerve
block
anesthesia
(conduction anesthesia), the local anesthetic
solution is deposed within close proximity to a main nerve
trunk, and thus preventing afferent impulses from
traveling
centrally
beyond that point. nerve block is used in anesthesia of the
inferior mandibular nerve, the lingual nerve, the buccal
nerve,
the
greater palatine nerve and the nasopalatine nerve
in
periodontal
ligament
(pdl)
technique
(=
intraligamentary
injection),
the local anesthetic solution is injected into the
desmodontal
space. the pdl technique is useful for anesthesia of
mandibular molars as an alternative to the nerve block
technique.
the injection is painless and the anesthetic effect is limited
to
the
pulp and desmodontal nerve of the tooth anesthesized.
duration
of anesthesia is in the range of 15 to 20 minutes, which
allows
most routine dental treatment. the pdl injection is useful
for
extremely
anxious
patients
and
children,
who
do
not
tolerate
conventional
technique.
the
dose of anesthetic solution, which is required for complete
anesthesia,
is lower than in infiltration technique. for pdl technique,
a high concentration of the local anesthetic is required
due
to
the
limited volume, which can be injected into the narrow
desmodonta
lspace
,
surface anesthesia - application of local anesthetic spray,
solution or cream to the skin or a mucous membrane. the
effect is short lasting and is limited to the area of contact.
infiltration anesthesia - injection of local anesthetic into
the tissue to be anesthetized. surface and infiltration
anesthesia
are
collectively
topical
anesthesia.
field block - subcutaneous injection of a local anesthetic in
an area bordering on the field to be anesthetized.
peripheral nerve block - injection of local anesthetic in the
vicinity of a peripheral nerve to anesthetize that nerve s
area
of
innervation.
plexus anesthesia - injection of local anesthetic in the
vicinity of a nerve plexus, often inside a tissue
compartment that limits the diffusion of the drug away
from the intended site of action. the anesthetic effect
extends to the innervation areas of several or all nerves
stemming
from
the
plexus.
epidural anesthesia - a local anesthetic is injected into the
epidural space where it acts primarily on the spinal nerve
roots. depending on the site of injection and the volume
injected, the anesthetized area varies from limited areas
of the abdomen or chest to large regions of the body.
spinal anesthesia - a local anesthetic is injected into the
cerebrospinal fluid, usually at the lumbar spine (in the
lower back), where it acts on spinal nerve roots and part
of the spinal cord. the resulting anesthesia usually extends
from
the
legs
to
the
abdomen
or
chest.
intravenous regional anesthesia (bier s block) - blood
circulation of a limb is interrupted using a tourniquet (a
device similar to a blood pressure cuff), then a large
volume of local anesthetic is injected into a peripheral
vein. the drug fills the limb s venous system and diffuses
into tissues where peripheral nerves and nerve endings
are anesthetized. the anesthetic effect is limited to the
area that is excluded from blood circulation and resolves
quickly
once
circulation
is
restored.
local anesthesia of body cavities (e.g. intrapleural
anesthesia,
intraarticular
anesthesia)
adverse
effects
adverse effects depend on the local anesthetic agent,
method, and site of administration and is discussed in
depth
in
the
local
anesthetic
sub-article.
overall
the
effects
can
be:
1. localized prolonged anesthesia or paresthesia due to
infection, hematoma, excessive fluid pressure in a
confined cavity, and severing of nerves & support tissue
during
injection,
2. systemic reactions such as depressed cns syndrome,
allergic reaction, vasovagal episode, and cyanosis due to
local
anesthetic
toxicity.
3. lack of anesthetic effect due to infectious pus such as
an
abscess.
uses
acute
pain
acute pain may occur due to trauma, surgery, infection,
disruption of blood circulation or many other conditions in
which there is tissue injury. in a medical setting it is
usually desirable to alleviate pain when its warning
function is no longer needed. besides improving patient
comfort, pain therapy can also reduce harmful
physiological
consequences
of
untreated
pain.
acute pain can often be managed using analgesics.
however, conduction anesthesia may be preferable
because of superior pain control and fewer side effects.
for purposes of pain therapy, local anesthetic drugs are
often given by repeated injection or continuous infusion
through a catheter. low doses of local anesthetic drugs
can be sufficient so that muscle weakness does not occur
and
patients
may
be
mobilized.
some typical uses of conduction anesthesia for acute pain
are:
•
labor
pain
(epidural
anesthesia)
• postoperative pain (peripheral nerve blocks, epidural
anesthesia)
• trauma (peripheral nerve blocks, intravenous regional
anesthesia,
epidural
anesthesia)
chronic
pain
chronic pain of more than minor intensity is a complex
and often serious condition that requires diagnosis and
treatment by an expert in pain medicine. local anesthetics
can be applied repeatedly or continuously for prolonged
periods to relieve chronic pain, usually in combination with
medication such as opioids, nsaids, and anticonvulsants.
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 hydropinghilic
(soluble in water), and the aromatic end is lipophilic
(soluble
in
lipids)
• two classes of local anesthetics are amino amides and
amino
esters.
o
amides:
esters:
o amide link b/t intermediate ester link b/t intermediate
chain and chain and aromatic ring
aromatic ring
o metabolized in liver and very metabolized in plasma
through
soluble
in
the
solution
pseudocholinesterases and not
stable in the solution cause allergic reactions
structures
of
amides
and
esters
the amine end is hydropinghilic (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.
? three special drugs used in dental anesthes bupivicaine
(marcaine®
produce very long acting anesthetic effect to delay the
post operative pain from the surgery for as long as
possible
0.5%
solution
with
vasoconstrictor
toxicity
showed
by
the
pka
is
very
basic
onset time is longer than other drugs b/c most of the
radicals (about 80%) bind to sodium channel proteins
effectively
most
toxic
local
anesthetic
drug
?
prilocaine
(citanest®)
identical pka and same conc. with lidocaine
almost
same
duration
as
lidocaine
less toxic in higher doses than lidocaine b/c small
vasodilatory
activity
?
articaine
(septocaine®)
newest local anesthetic drug approved by fda in 2000
same pka and toxicity as lidocaine, but its half life is less
than
about
¼
of
lidocaine
used
with
vasoconstrictor.
enters
the drug
is
blood
widely
used
barrier
in most
smoothly
nations today
anesthetic pka onset duration (with epinephrine) in
minutes
max
dose
(with
epinephrine)
procaine 9.1 slow 45 - 90 8mg/kg – 10mg/kg
lidocaine 7.9 rapid 120 - 240 4.5mg/kg – 7mg/kg
bupivacaine 8.1 slow 4 hours – 8 hours 2.5mg/kg –
3mg/kg
prilocaine 7.9 medium 90 - 360 5mg/kg – 7.5mg/kg
articaine 7.8 rapid 140 - 270 4.0mg/kg – 7mg/kg
adverse
effects
of
epinephrine
depending on the dose, sympathomimetic amines can
evoke
a
variety
of systemic reactions. the major systemic effects of
injected
sympathicomimetic amines involve the cardiovascular
system.
heart rate and contractile force increase under the
influence
of
epinephrine.
arterioles and veins are constricted or dilatated,
depending on the total dose of epinephrine and the
receptors
activated
(tab.
8).
cardiovascular responses of epinephrine often include
tachycardia,
mild hypertension, and occasionally premature ventricular
contractions. the majority of adverse reactions are mild
and
short
of duration. headache can result in the rare occurrence of
a
severe
hypertensive response. since moderate doses of
epinephrine
lower
total peripheral resistance, the mean arterial pressure may
remain
unchanged or become slightly reduced. in sensitive
patients
or
under certain conditions, epinephrine may cause
•
pronounced
tachycardiaor
•
hypertension
and
may
•
elicit
dangerous
cardiac
•
arrhythmias,
angina pectoris attack or myocardial infarction
serum
levels
of
following
injection
systemic effeccts on cardiovascular system
epinephrine
submucosal
and
designed
mushtag
3rd class
by
mohammed
t.