Mandibular anesthesia techniques

Mandibular
anaesthesia
19 October 2017
I.Kassem,BDS,MSc,MFDS RCS Ed,MOMS RCPS Glasg,
FDSRCS
Consultant Oral & Maxillofacial surgeon

Mandibular Anesthesia
Lower success rate than Maxillary
anesthesia - approx. 80-85 %
Related to bone density
Less access to nerve trunks

Mandibular Nerve Blocks
Inferior alveolar
Mental - Incisive
Buccal
Lingual
Gow-Gates
Akinosi

Mandibular Anesthesia
Most commonly performed technique
Has highest failure rate (15-20%)
Success depends on depositing solution within 1 mm of
nerve trunk

Inferior Alveolar Nerve Block
Not a complete mandibular nerve block.
Requires supplemental buccal nerve block
May require infiltration of incisors or
mesial root of first molar

Nerves anesthetized
Inferior Alveolar
Mental
Incisive
Lingual

Areas Anesthetized
Mandibular teeth to midline
Body of mandible, inferior ramus
Buccal mucosa anterior to mental foramen
Anterior 2/3 tongue & floor of mouth
Lingual soft tissue and periosteum

Indications
Multiple mandibular teeth
Buccal anterior soft tissue
Lingual anesthesia

Contraindications
Infection/inflammation at injection site
Patients at risk for self injury (eg.
children)

10%-15% positive aspiration

Alternatives
Mental nerve block
Incisive nerve block
Anterior infiltration

Alternatives (cont.)
Periodontal ligament injection (PDL)
Gow-Gates
Akinosi
Intraseptal

Technique
Apply topical
Area of insertion:
medial ramus, mid-coronoid notch,
level with occlusal plane (1 cm above),
3/4 posterior from coronoid notch to
pterygomandibular raphe
advance to bone (20-25 mm)

Target Area
Inferior alveolar nerve, near mandibular foramen
Landmarks
Coronoid notch
Pterygomandibular raphe
Occlusal plane of mandibular posteriors

Precautions
Do not inject if bone not contacted
Avoid forceful bone contact

Complications
Hematoma
Trismus
Facial paralysis

a) Halstead method
b) Gow-Gates method
c) Akinosi method
1. Inferior Alveolar Nerve Block
a) Individual variations in the locations of the
mandibular foramen
b) Be aware of the proximal extremity of the
maxillary artery. Aspiration !

a) The finger in the retromolar fossa with the
fingernail poiting backward
a) A line is sighted from occlusal surfaces of the
premolars of the opposite side to the midpoint of
the fingernail
b) Inject 0,5 - 1ml solution
c) Continue to inject 0,5ml on removal from
injection site to anesthetize the lingual branch
a) Halstead Open-Mouth method

a) 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

a) Field block anesthesia
b) The injection site is higher than Halstead
c) Below the insertion of the lateral pterygoid
muscle at the anterior side of the condyle at
maximal opening in relatively avascular area
d) The injection line is parralel with the external
line from the intertragal notch to the angle of the
mouth
b) Gow-Gates method

a) The diffusion of the anesthetic solution reach all
three oral sensory portion of mandibular branch
V.n. and other sensory nerves in this region
b) High success rate, fewer complication x slower
rate of onset

a) Field block anesthesia
b) 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

a) The needle is advanced through the mucous
membrane and buccinator muscle to enter the
pterygomandibular space
b) Penetrate to a depht 25mm
a) Remaining
anesthetic in long
buccal nerve area

2. Mental Nerve Block
a) Terminal branch of the inferior alveolar
nerve, exits the mandible via the mental
foramen
b) The position of this foramen is most
frequently near the apex of the mandibular 2nd
premolar
c) The foramen open upward and slightly
posteriorly!

a) Anesthetized 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

3. Lingual Nerve Block
a) Nerve passes from the infratemporal fossa into
the floor of the mouth, in the vicinity of the 2nd and
3rd molars, is quite vulnerable
b) Is anesthetizes during the inferior alveolar
nerve block or with a bolus of anesthetic solution
injected after an inferior alveolar nerve block
a) Anesthetized anterior ⅔ of the tongue, lingual
gingiva and adjacent mucosa

4. Buccal Nerve Block
a) Arises in the infratemporal fossa and crosses
the anterior border of the ramus to give multiple
branches
b) 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
Lingual
nerve
Inferior
alveolar
nerve
Mental
nerve

Reported Reasons for Mandibular
Anaesthesia Failure
1. Operator Inexperience
2. Armamentarium: Deflection of the needle tip
3. Patient factors:
1. Variations in anatomy
2. Accessory innervation
3. Unpredictable spread of LA
4. Local infection
5. Pulpal inflammation
6. Psychological issues

■ What about experienced operators?

■ Always use a long 25 gauge needle (the red
one)
■ 2 reasons:
■ 1. Less deflection
■ 2. Less false negative aspiration

■ Decrease in the pH locally
■ Can influence the amount of LA available in
the lipophilic form to diffuse across the
nerve membrane
■ Result is less drug interference of sodium
channels
■ Less likely to influence mandibular block
anaesthesia

Pulpal Inflammation
■ Causes activation and sensitization of
peripheral nociceptors
■ Causes sprouting of nerve terminals in the
pulp
■ Causes expression of different sodium
channels: TTX-resistant class of sodium
channels are 4 times as resistant to blockade
by lidocaine and their expression is doubled
in the presence of PGE2

Adjunctive Strategies
■ Additional Anaesthetic
■ PDL Injection
■ Intraosseous Injection
■ Intrapulpal Injection
■ Different anaesthetic
■ Retest using the CC

■ Higher injection
■ Gow Gates
■ Akinosi
■ Nerve to mylohyoid
■ PDL Injection

Maximum Doses LA
■ % means g/dL
■ Example:
■ 1% = 1 g/dL
■ 1% = 10g/L
■ 1% = 10 mg/mL
■ Therefore:
■ 2% = 20 mg/mL

Maximum Doses LA
■ A cartridge contains 1.8 mL
■ Therefore a cartridge of 2% local anaesthetic
contains 20 mg/mL X 1.8 mL = 36 mg of
local anaesthetic

Maximum Doses LA
■ How much LA can you give?
■ 193 lb 33 yo male
■ Lidocaine 2% 1:100K
■ Articaine 4% 1:200K
■ 2.2 lbs = 1 kg
■ 193 lbs = 88 kg

Maximum Doses LA
■ Lidocaine 2%
■ Max dose = 7 mg/kg
■ 7mg/kg X 88=616 mg
■ 36 mg/1.8 mL
■ 616mg/36mg/cart.=
■ 17 cartridges **
■ Articaine 4%
■ Max dose 7 mg/kg
■ 7 X 88 = 616 mg
■ 72 mg/1.8mL
■ 616 mg/72 mg/cart. =
■ 9 cartridges

Maximum Doses Epi
■ % = 1/100 = g/dL
■ Therefore:
■ 1/100 = 1% = 1g/dL = 10 mg/mL
■ 1/1000 = 0.1% = 0.1 g/dL = 1 mg/mL
■ 1/10000 = 0.01% = 0.01 g/dL = 0.1 mg/mL
■ 1/100000 = 0.001% = 0.001 g/dL = 0.01mg/mL
■ A cartridge contains 1.8 mL
■ Therefore a cartridge of 1:100 000 epi contains 0.01
mg/mL X 1.8 mL = 0.018 mg
(or about 0.02 mg)

Maximum Doses Epi
■ Cardiovascular patient 0.04 mg
■ Healthy patient 0.2 mg

Maximum Doses LA
■ Lidocaine 2%
■ Max dose = 7 mg/kg
■ 7mg/kg X 88=616 mg
■ 36 mg/1.8 mL
■ 616mg/36mg/cart.=
■ 17 cartridges **
■ 10-11 cartridges (epi)
■ Articaine 4%
■ Max dose 7 mg/kg
■ 7 X 88 = 616 mg
■ 72 mg/1.8mL
■ 616 mg/72 mg/cart. =
■ 9 cartridges

Pregnant Patients
■ Which Local Anaesthetic to use?
■ Articaine 4% 1:200 000 epi
■ Lidocaine 2% 1:100 000 epi
■ Mepivacaine 2% 1:20 000 levo
■ Mepivacaine 3% plain

FDA categories (based on risk of fetal
injury)
■ A: controlled studies in humans—no risk to
fetus demonstrated
■ B: animal studies show no risk, no human
studies; or animal studies have shown a risk
but human studies have shown no risk
■ C: animal studies show risk, no human
studies; or no animal or human studies

Pregnant Patients
■ Which Local Anaesthetic to use?
■ Articaine 4% 1:200 000 FDA category C
■ Lidocaine 2% 1:100 000 FDA category B
■ Mepivacaine 2% 1:20 000 FDA category C
■ Mepivacaine 3% plain FDA category C

Advantages of Injecting “Higher”
■ Failure to achieve profound local anaesthesia
attributed to being “too low” and “too far
forward”
■ Injecting superiorly and more distally may
block accessory innervation
■ 3 nodes of Ranvier may not be true

Gow-Gates Technique
■ Landmarks:
■ Corner of the mouth (contralateral side)
■ Tragus of the ear
■ Disto palatal cusp of the maxillary second molar
■ AIMING FOR THE NECK OF THE CONDYLE

Akinosi Technique
■ Closed-mouth technique
■ Does not rely on a hard-tissue landmark
■ Parallel to occlusal plane, height of the
mucogingival junction
■ Advanced until hub is level with distal surface
of maxillary second molar
■ Delayed onset of anaesthesia

Nerve to Mylohyoid
■ Deposit ¼ cartridge of LA on lingual surface
of tooth in alveolar mucosa
■ Goal is to bathe the nerve as branches of it
enter the lingual surface of the mandible

■ PDL Injection

PDL Injection
■ Technique:
■ needle inserted into the gingival sulcus at a 30
degree angle towards the tooth
■ bevel placed towards bone
■ advanced until resistance felt
■ anaesthetic injected with continuous force for
about 15 seconds.
■ approx. 0.2 mL of solution
■ 25 vs. 30 gauge needle

Intraosseous Injection
■ Technique for mandibular infiltration
■ Perforate the cortical plate to introduce LA in
medullary bone
■ Bathes the periradicular region in LA
■ 2 commercial systems available:
■ Stabident (Patterson)
■ X-Tip (Tulsa Dentsply)

■ Additional Block (higher injection)
■ PDL Injection

Intrapulpal Anaesthesia
■ VanGheluwe and Walton 1997:
■ under back-pressure, efficacy of LA=saline
injection
■ Conclusion: back-pressure is the key to
intrapulpal anaesthetic success

Articaine
■ Reputation for improved local anaesthetic
effect—short linear molecule
■ Amide local, contains a thiophene ring
instead of a benzene ring
■ Partial hydrolysis by plasma esterases
■ 4% solution—concern with toxicity
■ Potential for methemoglobinemia (like
prilocaine)

Articaine
■ More effective than other local anaesthetics?
■ No difference found:
■ Haas et al. 1990 (vs. prilocaine)
■ Vahatalo et al. 1993 (vs. lidocaine)
■ Malamed et al. 2000 (vs. lidocaine)
■ Donaldson et al. 2000 (vs. prilocaine)
■ Claffey et al. 2004 (vs. lidocaine)
■ Mikesell et al. 2005 (vs. lidocaine)

Articaine
■ Claffey et al. 2004:
■ Articaine vs. lidocaine IANB for irreversible pulpitis
of mandibular teeth
■ Articaine 9/37 (24%)
■ Lidocaine 8/35 (23%)
■ (all subjects had subjective lip anaesthesia)

Articaine
■ Paraesthesia?
■ Haas and Lennon 1995: higher incidence of
paraesthesia associated with prilocaine and
articaine. Attributed to the higher concentration of
drug required for comparable clinical effect
■ 14/11 000 000 injections
■ Statistically higher
■ Clinical relevance? Claffey et al 2004 “clinically rare
event”

Articaine
■ Paraesthesia?
■ Dower 2003 (Dentistry Today)
■ Review article
■ Paraesthesia rates up to 2-4% when using
articaine for lingual blocks or IANBs

Articaine
■ Hillerup and Jensen 2006:
■ Danish population—all cases in Denmark referred
to authors for evaluation
■ 54 injection injuries in 52 patients
■ 54% of all nerve injuries associated with articaine
■ Substantial increase in number of injection injuries
following introduction of articaine to Danish market
in 2000.

Articaine
■ What about a mandibular infiltration?
■ Recommended by Steve Buchanan
■ Kanaa et al. 2006
■ Cross-over design comparing articaine and
lidocaine for mandibular infiltration for first molars
■ Anaesthesia measured by maximal EPT X2
■ Lidocaine 38% effective
■ Articaine 65% effective

Mandibular anesthesia techniques

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