The document defines local anesthesia and describes the desirable properties of local anesthetics, including that they should not be irritating, cause permanent nerve damage, or have high systemic toxicity. It also discusses the components, actions, dosages, techniques, and complications of various local anesthetic injections used to anesthetize the maxillary teeth and surrounding tissues, such as infiltration, posterior superior alveolar nerve block, and anterior superior alveolar nerve block injections. Contraindications to local anesthetics include allergies and risk of overdose.

2. Definition:
Local anaesthesia 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.

4. Desirable properties of LA
• Should not be irritating to the tissues to which it is applied
• Should not cause any permanent alteration of nerve
structure
• Systemic toxicity should be low
• Time of onset of anaesthesia should be as short as possible
• The duration of action must be long enough to permit
completion of the procedure yet not so long to require and
extended recovery
• Should be free from producing allergic reactions
• Should be stable in solution and readily undergo
biotransformation in the body

5. Composition of local
anaesthetics
Local anaesthetic agent:Lignocaine Hydrochloride-
2%(20mg/ml)
Reducing agent:Sodium meta-bisulphite-(0.5mg)
Preservative:Methylparaben-0.1%(1mg)
Diluting agent:Distilled water
Fungicide:Thymol
Isotonic solution:Sodium chloride or Ringer’s
Solution-6mg
Vasoconstrictor:adrenaline-1:80,000(0.012mg)
To adjust pH-Sodium hydroxide
Nitrogen bubble-1-2mm in diameter and is present to
prevent oxygen from being trapped in the cartridge
and potentially destroying the Vasopressor.

6. Actions of :
Vasoconstrictor:Decreased blood flow to the
site of injection,absorption of L.A by
cardiovascular system is solved,decrease the
risk of local toxicity,higher volume of local
anaesthetic agent remain in and around the
nerve for longer period,thereby increasing the
duration of action,vasoconstrictor decreases
bleeding at the site of their administration.
Preservative:Stability of modern L.A is
maintained by adding caprylhydro-cuprienotoxin
which includes xylotox and
methyl paraben.

7. Reducing agent:These act as
preservatives for the vasoconstictor
agents.Vasoconstrictors are unstable in
solution and may oxidize,especially on
exposure to prolonged sunlight.Sodium
metabisulphite which competes for the
available oxygen is added in the
concentration between 0.05% and 0.1%
Vehicle:The isotonic vehicle reduces
discomfort during injection.

8. B.R.I.T:
Bi-Rotational Insertion
Technique:
The operator rotates the needle in a back-and-
forth rotational movement while
advancing the needle through the tissues;
results in less deflection, less force is needed
for needle penetration.

9. Dosages:
To calculate the recommended dose,the
following must be known:
Concentration of the L.A
Dilution percentages of vasoconstrictors
Standard cartridge volume
Maximum recommended dose
Patients weight and general health
status,including medications.

10. Maximum recommended
doses:
Lignocaine hydrochloride with
epinephrine:7mg/kg
Articaine:6.4mg/kg
Bupivicaine:6.66 mg/kg

11. A 100% solution has 1000mg of L.A per ml.Therefore a 2%
solution has....
20mg/ml
A cartridge of 2ml,therefore has 40mg of L.A.
M.L.D for lignocaine hydrochloride is 7mg/kg.
For a 70kg man,the maximum dosage of L.A he can recieve
is-7*70kg =490mg.
In 1 cartridge there is 2ml of L.A which contains 40mg of
L.A,therefore the number of cartridges needed to achieve
maximum lethal dose is 12.25 cartridges.(490*1/40)

12. Anatomical considerations
Branches of maxillary nerve:

13. Injections used to anaesthetize
the maxillary teeth,soft and
hard tissues:
Infiltration(supraperiosteal injection)
Posterior superior alveolar nerve block(PSA)
Middle superior alveolar n.b(MSA)
Anterior superior alveolar n.b(ASA)(Infraorbital
nb)
Greater palatine nb
Nasopalatine nb
2nd division nb(maxillary nb)
Anterior middle superior alveolar nb(AMSA)
Palatal-(PASA)

14. Infiltration:
Infiltration is a technique used to
achieve pulpal anaesthesia for one or
two maxillary teeth at a time.
The area anaesthetised are the
pulp,bucal soft and hard tissues of the
anaesthetised teeth.
Recommended needle-27 gauge short

15. Technique:
Site of insertion-Height of the
mucobuccal fold,at the apex of the tooth.
The needle is inserted parallel to the
maxillary bone and inserted till the
needle tip is at or above the apex of the
root.
After two negative aspirations,1/3rd of a
cartridge of L.A is injected.

16. Posterior superior alveolar
nerve block(PSA
Provides pulpal anaesthesia to the three
maxillary molars and supporting buccal
soft tissue and bone.
In 28% of patients,the mesiobuccal root
of the maxillary first molar is not
anaesthetised by this technique.
Recommended needle-27 gauge short.

17. Technique:
Site of insertion-Height of the buccal
fold,adjacent to the maxillary second
molar,with the syringe held in an
upwards,inwards and backwards
direction,and inserted to a depth of
16mm
After two negative aspirations,1/2 a
cartridge of L.A is injected,over 30
seconds.

18. Middle superior alveolar
n.b(MSA)
Provides pulpal anaesthesia to the
maxillary premolars and the
mesiobuccal root of the maxillary first
molar,and supporting buccal soft and
hard tissues.
Recommended needle-27 gauge short.

19. Technique:
Site of insertion-Height of the buccal
fold,adjacent to the maxillary second
premolar.Needle is inserted till its tip is
located way above the apex of the
second premolar.
After 2 negative aspirations,1/2 a
cartridge of local anaesthetic is slowly
injected.

20. Anterior superior alveolar
n.b(ASA)(Infraorbital nb)
Provides pulpal anaesthesia to five
maxillary anterior teeth-The
incisors,canine and two premolars,and
also anaesthetises the buccal
supporting soft tissue and bone,the skin
of the lower eyelid,the lateral side of the
nose,upper lip.
Recommended needle-25 gauge long.

21. Technique:
The infraorbital foramen is palpated,lip
retracted,the needle is inserted at the
height of the buccal fold,adjacent to the
maxillary first premolar.
The needle is held parallel to the maxillary
bone and inserted till bone is contacted at
the roof of the infraorbital foramen.
After 2 negative aspirations,1/2-1/3rd of a
cartridge is deposited over 30-40 seconds.

22. Greater palatine nb(Anterior
palatine nb)
Provides anaesthesia to the posterior
portion of the hard palate and its
overlying soft tissues extending
anteriorly as far as the first premolar and
medially to the midline.
Recommended needle-27 gauge short

23. Technique:
The greater palatine foramen is
palpated(cotton swab may be used for
this),the needle is inserted into the soft
tissue,just anterior to the greater
palatine foramen.
As the needle is advance,L.A is
deposited slowly,upon contacting
bone,1/4th-1/3rd a cartridge of L.A is
deposited,over 15-20 seconds.

24. Nasopalatine nb
Provides anaesthesia to the anterior
portion of the hard palate,affecting both
soft and hard tissues,from the mesial of
the right first premolar to the mesial of
the left first premolar.

25. Technique:
Traditional-The needle is inserted,just lateral to
the incisive papilla,advanced till bone is
contacted,after 2 negative aspirations,0.3 ml of
L.A is deposited.
Multipl injection technique-1st injection is an
infiltration of 0.3ml to the labial soft tissues
between the central incisors.2nd injection is an
infiltration to the now limp papilla between the
two central incisors.L.A is administered as the
needle is advanced,until blanching is noted on
the palatal soft tissues.3rd injection is a
traditional Nasopalatine nb.

26. 2nd division nb(maxillary nb)
Provides anaesthesia to the pulp of the
teeth of that side of the maxilla,
supporting hard and soft buccal tissues,
the soft tissues and bone of the hard
palate and some of the soft palate
medially till the midline, the skin of the
lower eyelid, lateral side of the nose,
cheek,upper lip.
Recommended needle-25 gauge long.

27. Technique:
The needle is inserted into the greater
palatine foramen,and advanced to a
depth of 30mm.After 2 negative
aspirations,1.8ml of L.A is deposited
slowly over at least 60seconds.

28. Anterior middle superior
alveolar nb(AMSA)
Provides pulpal anaesthesia to the
incisors,canine and premolars of that
side,buccal soft tissue and bone,palatal
soft tissue and bone.
Recommended needle-27 gauge short

29. Technique:
The needle is inserted at a point halfway
along the line between the premolars
and the midline of the palate.
1.4-1.8ml of L.A is slowly deposited.

30. Palatal-(PASA)
Provides pulpal anaesthesia to both
central incisors,both lateral incisors and
to a lesser degree,both canines,as well
as the labial and palatal soft and hard
tissues of these teeth.
Recommended needle-27 gauge short

31. Technique:
The needle is inserted lateral to the
incisive papilla,slowly to a depth of 6-
10mm into the incisive canal.Following
negative aspiration,1.4-1.8ml of local
anaesthetic is administered slowly.

32. Contraindication to local
anaesthetics

33. Local complication of LA
Needle breakage
Paraesthesia
Facial nerve paralysis
Trismus
Soft tissue injury
Haematoma
Pain on injection
Burning on injection
Infection
Edema
Sloughing of tissues
Post anaesthetic intra oral lesions

34. Systemic complications
Overdose
Allergy
idiosyncrasy

35. References:
Malamed, Stanley. Handbook of Local
Anesthesia. 5th Edition. Mosby. 2004

36. Dr.Vikram Perakath
B.D.S