DENTAL
ANESTHESIA
- Dental anesthesia is a branch of anesthesiology
which deals with the dental surgeries, to limit the
amount of patient’s discomfort experienced during
procedures
(general anest., local anest.)
- Painless medical treatment in dentists is in
present days expected and required
- Local anesthetics (LA) cause:
reversible block of sensory nerve conduction
of noxious stimuli from periphery to the CNS
▪ Operative (surgical) procedures require cutting through
sensitive structures, producing extreme discomfort and pain
▪ Pain is a result of stimulation of nociceptors
that are receptors preferentially sensitive to a
noxious stimulus (Aδ, C fiber aferent axons)
▪ Local anesthetics (LA) cause:
reversible block sensory nerve conduction of
noxious stimuli from periphery to the CNS
(LA cause reversible block of sodium canals of the nerve cells
– they block formation and conduction of cell excitation)
▪ increase - duration of action
- depth of anesthesia !!!
▪ decrease - systemic toxic reactions
- local bleeding !!!
LA infulence also autonomic nerve system and
cause VAZODILATATION.
The effectiveness of local anesthetics is improved
by the addition of a vasoconstrictor:
▪ To minimize anesthetic failure,
the dentist must have a good knowledge of the
anatomy of the head region, particularly the
neuroanatomy of the maxillary and mandibular
regions of the face !
Onset of action of anesthesia!!!
not to start the dental treatment before the
local anesthetic can take effect !
Carefully observe the patient
Slow aplication
Use of proper amount of LA
(possible failure or systemic toxic reaction)
General Potential Complications
1. Nerve injury
2. Injuries to blood vessels
3. Intraglandular injections
4. Trauma to muscles
5. Systematic reactions
6. Infection spread
1) Paresthesia (loss of sensation)
- commonly involve the tongue and lower
lip
2) Hyperesthesia (increased sensitivity to
painful stimuli)
3) Dysesthesia (pain following nonnoxious
stimuli)
4) Dysgeusia (impaired sense of taste)
1. Nerve Injury
5) Xerostomia (reduced salivation)
- the chorda tympani is traumatized
6) Ocular and extraocular symptoms
The passive process of diffusion of anesthetic
through the orbit leads to ocular and
extraocular symptoms:
- paralysis of extraocular muscle
- diplopia
- amaurosis (temporary blindness)
- Horner´s syndrome (enophthalmos, miosis,
palpebral ptosis)
▪ Intravascular injection → vascular damage →
hemorrhage with hematoma formation
▪ If the vein is engaged, the bleeding is small and
is usually evidenced a few days later
▪ Artery damage means significant hematoma
formation and extensive intra or extraoral
swelling, which are fast
2. Bleeding
Transient paralysis of the ipsilateral facial
muscles - caused by anesthesia of the facial
nerve in parotid gland
3. Intraglandular injection
Muscle trismus = spasm of jaw muscles,
which restricts mouth opening (temporal and
medial pterygoid muscle)
4. Trauma of muscle
Usually when LA is aplicated intravasculary (i.a.,
i.v.). Failure of the cardiorespiratory system,
anaphylaxis, irritation of CNS.
Prevention of intravascular aplication is repeated
ASPIRATION.
5. Systematic complication
6. Infection spread
➢ Infection may be spread to deeper tissues by
needle- tract contamination
➢ The clinicianmust never inject through an area
with an abscess, cellulitis or osteomyelitis so as
to prevent the spread of dental infection
➢ The effectiveness of LA is greatly reduced, when
administered in area of infection
➢ The fifth cranial nerve (trigeminal) and
its branches provide sensory
information from the teeth and
associated tissues.
➢ Thus branches of n.V. are those
anesthetized before most dental
procedures.
I. Local anesthesia – infiltration, superficial
Types of local anesthesia
II. Nerve block – regional anest.
III. Field blocks
x GENERAL anaesthesia
Types of local anesthesia
I. Local infiltration anesthetizes a small area (one or two teeth
and associated structures) by injection near their apices.
LA is deposited near terminal nerve endings, just small amount of local
anesthetic solution is needed.
II. Nerve block affects a larger area - more teeth.
The local anesthetic solution is deposited near a main
peripheral nerve branch and its entrances or exits from the
bones.
III. Field blocks
Local anesthetic is deposited near a large nerve trunks
(V2 – in fossa pterygopalatina near for. rotundum, V3 – near
for. ovale) during large orofacial surgery or trismus
x GENERAL anaesthesia
Aplication of LA through soft tissues near the bone,
diffusion of LA across compact bone and spreading
through spongy bone to plexus dentalis (and its
terminal branches) in the apical area of alveoli
I. Local Infiltration
Needle penetrates:
➢ To sumucosal tissue
➢ Near to dental apex
➢ supraperiostally
➢ Aspiration needed !
M.J.Fehrenbach, S.W. Herring,
Anatomy Head and Neck
Correct Incorrect
the anesthetic agent is deposited supraperiostally !
Rr. labiales sup.
N. buccalis
Rr. alveolares sup. ant.
et medii
Rr. alveolares sup. post.
N. nasopalatinus
Nn. palatini
MAXILLA – sensitive inervation areas ( areae nervinae)
partially overlap
N. mentalis
N. alveolaris inf.
N. buccalis
N. lingualis
N. glossopharyngeus
N. vagus
MANDIBLE
Alternative delivery methods of local
anesthesia - supplementary techniques
1. Topical anesthetic patches
2. Intraligamentary injection
3. Intrapulpal injection
4. Intraosseous injection
1. Topical anesthetic patches
▪ A topical anesthetic is a local anesthetic that is used to
numb the surface of a body part. They can be used to
numb any area of the skin as well as mucosa.
▪ is indicated to minimize the sensation of needle
insertion or for very brief relief from painful mucosal
lesions
▪Typically, is used to anesthetize only the outer 1-3 mm of
mucosa, not deeper structures
Spray
Gel
▪Topical anesthetics are available in
creams, aerosols, sprays, lotions, and
jellies.
2. Intraligamentary Injection
▪ Is occasionally used as the sole technique for
anesthesing a single tooth
▪ The needle is inserted, directly along the long
axis and as apically as possible, through the
gingival sulcus and into the periodontal space
between the tooth and the alveolar bone
▪ Slowly injected approximately 0,2ml of anesthetic solution
under pressure to control the pain of the associated tooth
Contraindication:
- deciduous teeth
- periodontal infection
3. Intrapulpal Injection
▪ When pulp chamber has been exposed and
treatment can´t proceed
Technique - a small needle is insetred into the
pulp chamber until resistance is encountered →
LA injected under the pressure
▪ As the injection is started there will be a brief
moment of intense discomfort
4. Intraosseous Injection
▪ Involves the placement of anesthetic solution
directly into the cancellous bone adjacent to the
tooth to be anesthetized, and allows for rapid
onset of profound pulpal anesthesia
▪ The site of injection involves the attached
gingiva 2mm apical to the gingival margin and
interproximal relative to the teeth
▪ Provide anesthesia of a single tooth or multiple
teeth in a quadrant
The first step - to drill a
small hole through the soft
tissue and cortical bone to
a depth of 5 – 8mm
The second step inserting
a needle to the
same depth and manually
injected the desired
volume of anesthetic
solution into the
cancellous bone
II. Nerve Block – LA is deposited near peripheral
branches of n. V
Substances deposited nearby peripheral nerves must diffuse
across enveloping connective tissue sheaths before reaching
neuronal axons, namely: epineurium, perineurium and
endoneurium.
We can aply LA after negative aspiration, supraperiostally
MAXILLA - tuber maxillae
- for. infraorbitale
- for. incisivum
- for. palatinum majus
MANDIBLE - for. mandibulae
- for. mentale
1. Posterior superior alveolar - PSA
2. Middle superior alveolar - MSA
3. Anterior superior alveolar - ASA
4. Infraorbital
5. Greater palatine
6. Nasopalatine
7. Alveolar inferior (Halstead, Gow-Gates, Akinosi)
8. Mental
9. Lingual
10. Buccal
MANDIBULAR
NERVE AND ITS
BRANCHES
MAXILLARY
NERVE AND ITS
BRANCHES
Infraorbital nerve
ASA
MSA
PSA
1. PSA Block
▪ Anesthetize the pulps and periodontal
ligaments of the maxillary molars,
corresponding buccal alveolar bone and
gingival tissue and posterior portion of the
maxillary sinus.
▪ Mesiobuccal root of 6 (M1) can be
innervated by middle superior alveolar nerve !
Technique - between 1st and 2nd molar at a height of
insertion of mucobuccal fold, angle at 45° superiorly
and medially
2. MSA Block
▪ Anesthetize the maxillary premolars,
corresponding buccal alveolar bone and gingival
tissue, partially M1
▪ It is used, if the infraorbital block fails to
anesthetize premolars
In the Czech republic MSA is a rarely used
technique, more often are used local
infiltration
Technique - between 1st and 2nd premolar at a
height of insertion of mucobuccal fold
3. ASA Block
▪ Anesthetize the canine, incisors, corresponding
buccal alveolar bone and gingival tissue
In the Czech republic MSA is a rarely used
technique, more often are used local
infiltration
Technique the
area of
lateral incisor
at a height of
insertion of
mucobuccal
fold
4. Infraorbital Nerve Block
▪ Combination of ASA and MSA blocks
▪ Anesthetize the maxillary premolars, canine,
incisors, corresponding buccal alveolar bone and
gingiva, also the terminal branches of infraorbital
nerve (lower eyelid, external nose tissue, upper
lip, the anterior aspect of the maxillary sinus)
Technique palpate
infraorbital
foramen
→ retract the
upper lip →
inject to area of
3/4
→ contact bone in
infraorbital region
→ inject 0,9 -1,2ml
5. Greater Palatine Nerve Block
▪ Anesthetize all palatal mucosa of the side
injected and lingual gingivae posterior to the
maxillary canines and corresponding bone
Technique - on the hard palate between the 2nd and 3rd
molars approximately 1cm medially, inject cca 0,3 - 0,5ml
6. Nasopalatine Nerve Block
▪ Anesthetize the soft and hard tissue of the
maxillary anterior six teeth - from canine one side
to canine other side
Technique - approximately 1,5 cm posterior to the alveolar crest between the
central incisors - posterior to the incisive papilla; depth less than 10mm and
inject 0,3 - 0,5 ml
Maxilla – local anesthetic blocks
and the tissues anesthetized
Infraorbital
nerve block
Nasopalatine
block
Greater
palatine
block
Posterior
superior
alveolar
block
Middle
superior
alveolar
block
Anterior
superior
alveolar
block
a) Halstead method
b) Gow-Gates method
c) Akinosi method
7. Inferior Alveolar Nerve Block
▪ Consider individual variations in the locations
of the mandibular foramen !
▪ Be aware of the proximal extremity of the
maxillary artery. Aspiration !
▪ The finger in the retromolar fossa with the
fingernail poiting backward
▪ A line is sighted from occlusal surfaces of the
premolars of the opposite side to the midpoint of
the fingernail
▪ Inject 0,5 - 1ml solution
▪ Continue to inject 0,5ml on removal from
injection site to anesthetize the lingual branch
a) Halstead Open-Mouth method
▪ Inject remaining anesthetic into coronoid notch region in
the mucous membrane distal and buccal to most distal molar
to perform a long buccal nerve block
▪ Field block anesthesia
▪ The injection site is higher than Halstead
▪ Below the insertion of the lateral pterygoid
muscle at the anterior side of the condyle at
maximal opening in relatively avascular area
▪ The injection line is parralel with the external
line from the intertragal notch to the angle of the
mouth
b) Gow-Gates method
▪ The diffusion of the anesthetic solution
reach all three oral sensory portion of
mandibular branch V.n. and other sensory
nerves in this region
▪ High success rate, fewer complication x slower
rate of onset
▪ Field block anesthesia
▪ For patient with limited opening due trismus,
ankylosis, fracture
The gingival margin above the maxillary 2nd
and 3rd molars and the pterygomandibular
raphae serve as landmarks for this technique
c) Vazirani-Akinosi
closed mouth method
▪ The needle is advanced through the mucous
membrane and buccinator muscle to enter the
pterygomandibular space
▪ Penetrate to a depht 25mm
▪ Remaining
anesthetic in long
buccal nerve area
8. Mental Nerve Block
▪ Terminal branch of the inferior alveolar
nerve, exits the mandible via the mental
foramen
▪ The position of this foramen is most
frequently near the apex of the mandibular
2nd premolar
▪ The foramen opens upward and slightly
posteriorly!
▪ Anesthetize lower lip, chin, labial gingiva,
alveolar mucosa, pulpal/periodontal tissue for the
canine, incisors and premolars on side blocked
Technique
The tip of needle be directed or anterior to
approximate the position of the foramen, but
not enter the foramen !
Penetrate to a depth 5 mm, inject 0,5 - 1,0 ml
To provide incisive nerve anesthesia via the
application of finger pressure over the foramen
after local anesthetic solution is deposited there
Mental nerve
9. Lingual Nerve Block
▪ Nerve passes from the infratemporal fossa into
the floor of the mouth, in the vicinity of the 2nd
and 3rd molars, it is quite vulnerable
▪ Is anesthetizes during the inferior alveolar
nerve block or with a bolus of anesthetic solution
injected after an inferior alveolar nerve block
▪ Anesthetize anterior ⅔ of the tongue, lingual
gingiva and adjacent mucosa
Lingual nerve
10. Buccal Nerve Block
▪ Arises in the infratemporal fossa and crosses
the anterior border of the ramus to give multiple
branches
▪ Supplies buccal gingiva and mucosa of the
mandible for a variable length, from the vicinity
of the 3th molar to the canine
Technique - anterior ramus of the mandible at the level of
the mandibular molar occlusal plane in the vicinity of the
retromolar fossa
Buccal
nerve
Buccal
nerve
Lingual
nerve
Inferior
alveolar
nerve
Mental
nerve
Mandible - local anesthetic blocks and the tissues anesthetized
Buccal
block
Inferior
alveolar
block
Incisive
block
Thanks for your attention