Local Anaesthesia, properties, types, uses and techniques in dentistry.

1. LOCAL
ANESTHESI
A
Presented by:
Dr. Rajvi Nahar
PG 1st Year

2. CONTENT
 History
 Definition
 Chemistry
 Properties of Local Anesthetics
 Classification of LA
 Composition of LA
 Mechanism of Local Anesthetics
 Pharmacological Actions
 Pharmacokinetics
 The Armamentarium
 Techniques of Local Anesthesia

3.  Basic Injection Techniques
 Maxillary and Mandible Injection Techniques
 Local Anesthesia in Prosthodontics
 Local and Systemic Complications
 Conclusion
 References

4. History
 The first people, as far as we know, with
knowledge of local anaesthesia were the
inhabitants of Peru. They had long known that
chewing on coca leaves caused a numbing of the
mucous membrane in the mouth.
 In the later half of the 19th century the research
into this effect was conducted in Europe. This
lead to the first eye operation under local
anesthesia by the eye surgeon, Kol Ier in Vienna
in 1884.
 The anesthesia was achieved using cocaine.
Following this first successful operation cocaine
was increasingly administered as a local
anesthetics.

5.  Before long, the disadvantages of cocaine became
self-evident. Toxicity, a short lasting effect and
addiction were problematic. However, the local
anesthesia phenomenon had become well known
and greatly appreciated.
 A need arose however to find alternatives for
cocaine as a local anesthetic due to the negative
side effects of cocaine usage. An alternative
appeared in 1905 in the form of Procaine.
 It is a cocaine derivative, meaning that it is
chemically related to cocaine, with similar
characteristics, but without the toxicity, with a
longer lasting effect and without the problems of
addiction.

6.  The issue of hypersensitivity reactions attributed
to ester-type anesthetics (cocaine derivatives)
contributed to their demise and prompted the
search for new substances with less chances of
allergic reactions.
 A new substance, lidocaine was first developed in
1943 and marketed in 1947 under the name,
Xylocaine. It was the first amide-type local
anesthetic.
 Lidocaine is generally well tolerated by patients, is
mildly toxic, has a sufficiently long lasting effect
and is non-addictive. The only disadvantage of
lidocaine is that it is slow in taking effect.

7. Definition
 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
 The order of blockade of the nerve function
proceeds in the following manner: pain,
temperature, touch, pressure and finally skeletal
muscle power.

8.  LOCAL ANAESTHETICS (LAS) are the drugs,
when applied topically or injected locally, block
nerve conduction and cause reversible loss of
all sensation in the part supplied by the nerve.

9. Chemistry
 LAs are weak bases .
 They consist of three parts-
1. Hydrophillic Amino group
2. Lipophilic Aromatic group
3. Intermediate Ester or Amide linkage.

10. IDEAL
PROPERTIES OF
LOCAL
ANESTHETICS.
Non irritating to
the tissue to
which it is
applied.
Do not cause
any permanent
alteration of the
nerve structure.
Low systemic
toxicityShort time of
onset .
Non-allergic.
Stable in
solution.
Long duration of
action
Readily undergo
biotransformation
inside the body.
Effective at low
concentrationsBe either sterile
or capable of
being steriled by
heat without
deterioration.
Effective in both
topical and
injectable forms

11. Classification of LAs
1. According to Structure:
(a)Esters: Cocaine, Procaine, Chloroprocaine,
Benzocaine, Tetracaine.
(b)Amides: Lignocaine, Mepivacaine, Bupivacaine,
Prilocaine, Articaine, Ropivacaine.

12. 2. According To Clinical Use:
(a) Surface Anesthetics: Cocaine, Ligocaine,
Tetracaine, Benzocaine, Benoxinate, Dyclonine,
Butylaminobenzoate.
(b) Injectable Anesthetics:
(I)Short Acting With Low Potency: Procaine,
Chloroprocaine
(II)Intermediate Acting With Intermediate Potency:
Lignocaine, Mepivacaine, Prilocaine
(III)Long Acting With High Potency: Tetracaine,
Bupivacaine, Dibucaine, Ropivacane

13. Composition of LAs
 Local Anesthetic Agent: Lignocaine
Hydrochloride 2% - Conduction blockade.
 Vasoconstrictor: Adrenaline 1:80,000 - decreases
absorption of LA into blood, thus increasing
duration of anesthesia and decreases toxicity of
anesthetic agent.
 Reducing Agent: Sodium meta-bisulphite –
Antioxidant for vasoconstrictor.
 Preservative: Methylparaben- preservative to
increase shelf life and is bacteriostatic.

14.  Isotonic solution: Sodium Chloride or Ringer’s
solution- reduces discomfort during injection.
 Diluting agent: Distilled water
 Sodium Hydroxide: to adjust pH .
 Nitrogen bubble: 1-2mm in diameter bubbles are
added to prevent oxygen from being trapped in the
cartridge and potentially destroying the
vasopressor or vasoconstrictor.
 Fungicide: Thymol

15. Maximum Recommended Dose
 In 2% concentration:
 LA with vasoconstrictor: 7.0mg/kg body
weight but it should not exceed 500mg.
 LA without vasoconstrictor: 4.4mg/kg body
weight but should not exceed 300mg.

16. Mechanism of Action
 Main site of action of LA is the cell membrane.
 The LAs in “unionized” form easily penetrate the
nerve sheath and the axon membrane.
 Within the axoplasm, the molecules become
“ionized” and block the voltage-gated Na+
channels.

17. Penetrate the nerve membrane
Partly unionized LA ions
Enter the axon (axonal pH is low)
Re-ionization of Local Anesthetics
LAs block the voltage-gated Na+ channel from inside
No entry of Na+ ions into the neuron : DEPOLARIZATION
No generation of action potential
No generation and conduction of impulses to CNS
LOCAL ANAESTHESIA

18. Pharmacological Actions
 Nervous system:
(a) Peripheral nerves- The order of nerve affected
is autonomic fibres, pain, temperature, touch,
pressure and motor fibres.
(b) CNS: Most of the LAs cross the BLOOD-BRAIN
BARRIER(BBB)- initially they cause CNS
stimulation and then depression in higher doses.
They cause excitement , tremor, twitching,
restlessness and convulsions. Large doses can
cause respiratory depression, coma and death.

19.  Cardiovascular System:
(a) Heart- LAs, by blocking
Na+ channels, decrease
contractility, conductivity,
excitability, heart rate,
cardiac output, and
increase effective refractory
period.
(b)Blood- LAs produce
hypotension due to
vasodilatation and
myocardial depression.

20. Pharmacokinetics
 Most of the ester-linked LAs are rapidly
metabolized by plasma cholinesterase whereas
amide-linked drugs are metabolized mainly in
liver.
 LAs (procaine, lignocaine ,etc) are not effective
orally because of high first-pass metabolism.
 In liver diseases, the metabolism of lignocaine
may be impaired ; hence dose must be reduced
accordingly.

21. The Armamentarium
 The Syringe
 The Needle
 The Cartridge
 Other materials:
1.Topical Anaesthetic agents- ointments,
gels, pastes or sprays
2.Applicator sticks
3.Cotton gauze

22. Syringes
 They must be durable and able to withstand
repeated sterilization without damage.
 They should be inexpensive, self contained ,
light weight and simple to use with one hand.
 They should be capable of accepting a wide
variety of cartridges and needles.
 They should provide for effective aspiration and
be constructed so that blood may be easily
observed in the cartridge.

23. Types Of Syringes Available in
Dentistry
 1. Non Disposable syringes:
 a.Breech-loading,metallic,cartridge-type,aspirating
 b.Breech-loading,plastic,cartridge-type, aspirating
 c.Breech –loading,metallic,cartridge-type,self-
aspirating
 d.Pressure syringe for periodontal ligament
injection.
 e.Jet injector (needle less syringe)

24.  2.Disposable syringes
 3.Safety syringes
 4.Computer-controlled local anaesthetic
delivery systems.

25. The Needle
 The needle is composed of a single piece of
tubular metal around which is places plastic or a
metal syringe adaptor and a needle hub.

26.  The needle gauge: The larger the gauge the
smaller the internal diameter of the needle. The
gauges 25, 27 & 30 are commonly used.
 Length- (a) Long- approx 40 mm – used for
nerve blocks
(b) Short- 20-25mm
(c) Extra short- approx 15mm for
Periodontal ligaments

27. The Cartridge
 The dental cartridge is a glass cylinder
containing the local anaesthetic drug, among the
other ingredients.
 The glass cylinder itself holds 2ml of the
solution.

28.  Components: 1. Cylindrical glass tube
2. Stopper
3. Aluminum cap
4. Diaphragm

29. Techniques of Local Anesthesia
 Surface Anesthesia/ Topical
Anesthesia: It is applied on the abraded skin
and mucous membrane of the oral cavity, nose,
eyes, throat, upper respiratory tract, esophagus,
urethra, ulcers, burns etc.
 Tetracaine 2%, Lignocaine 2-10% , Benzocaine
1-2% etc are used as topical agents.

30.  They are available as solutions, ointment, gel,
patch, cream, spray, lozenges.
 They are useful before injecting a local anesthetic,
subgingival and periodontal scaling.

31. APPLICATION OF TOPICAL ANAESTHETIC.

32.  Infiltration Anesthesia: It is injected
directly into the tissues to be operated; it blocks
small sensory nerve endings in the area.
 Lignocaine 0.5-1% ,articaine, procaine, and
bupivacaine are used
 They are suitable for small areas and the main
disadvantage is the requirement of large doses
to anaesthetize a relatively small area.

33.  They can be used in drainage of abscess,
gingivectomy, excision of small swellings,
suturing of cut wounds before root canal
treatment.
 Infiltration is contraindicated if there is a local
inflammation and clotting disorders.

34.  Conduction Block:
1.Field block anesthesia: It is achieved by injecting the
local anesthetic near the apex of the tooth- blocks
larger terminal nerve endings at the apex.
This technique is used around the tooth which is to
be treated, in case of minor procedures of scalp,
anterior abdominal wall, etc.

35. 2. Nerve Block Anesthesia: LA is injected very
close to or around the peripheral nerve or nerve
plexuses. It produces larger areas of anesthesia
than field block.
In nerve block, requirement of LA is less than field
block and infiltration.

36.  Spinal Anesthesia: LA is injected into the
subarachnoid space to anaesthetize spinal roots.
 It is injected into the space
between L2-L3 and L3-L4
below the lower end of the
spinal cord.
 Lignocaine, tetracaine,
bupivacaine, etc are used.
 It is used in surgical procedures
below the level of umbilicus,
i.e. lower limb surgery,
caesarean section, Obstetric
procedures , appendicectomy.

37.  Epidural Anesthesia: LA is injected into the
epidural space, where it acts on spinal nerve roots.
 Lignocaine and Bupivacaine are commonly used.
 Epidural Anesthesia is
safer and slower in
onset than spinal
anesthesia.
 It requires larger
amount of drug.
 It is used in obstetric
analgesia.

38. Basic Injection Technique
 There are two components to an atraumatic
injection: a technical and a communicative
aspect.
 The atraumatic injection technique was given by
Dr. Nathan Friedman and the Department of
Human Behavior at the University of Southern
California School of Dentistry.
 The technique is as follows:

40. Maxillary Injection Techniques
 POSTERIOR SUPERIOR ALVEOLAR NERVE
BLOCK:
 It is also called as Tuberosity block, Zygomatic
block.
 A 27-guage short needle is recommended.
 0.9-1.8ml is inserted.

41.  LANDMARKS:
1.Mucobuccal fold
2. Zygomatic process of Maxilla
3. Infratemporal surface of maxilla
4. Anterior border and coronoid process of
ramus of mandible
5.Tuberosity of maxilla

43.  Nerves Anaesthetized: PSA and branches.
 Areas Anaesthetized: 1. Pulp of maxillary third,
second and first molars (except mesiobuccal root )
2. Buccal periodontium and bone overlying these
teeth.

44.  Indications:
1.When treatment involves two or more maxillary
molars.
2. When supraperiosteal inj. is contraindicated or
proved ineffective.
 Contraindications: When the risk of hemorrhage
is too high, in such cases supraperiosteal or PDL
injection is recommended.

45.  ANTERIOR SUPERIOR ALVEOLAR NERVE
BLOCK: (INFRA-ORBITAL NERVE BLOCK)
 It is indicated in the procedures involving more
than two maxillary teeth and their overlying
buccal tissues.
 MSA & ASA together comprise to a block called
as INFRA-ORBITAL NERVE BLOCK.
 The 25 or 27 gauge long needle is
recommended.
 0.9-1.2 ml is inserted.

46. LANDMARKS of MSA & ASA( INFRA-ORBITAL
NERVE BLOCK):
1. Mucobuccal fold of premolar teeth
2. Infra-orbital ridge
3. Infra-orbital depression
4. Supra-orbital notch
5. Infra-orbital notch
6. Anterior teeth
7. Pupil of the eye

47.  Nerves Anaesthetized: Anterior superior alveolar,
Middle superior alveolar, Infraorbital- (a)Inferior
palpebral (b) Lateral nasal (c) Superior labial.
 Areas Anesthetized: 1. Pulps of maxillary central
incisors through the canine on injected side.
2. Pulps of maxillary first and second premolars and
the mesiobuccal root of maxillary 1st molar.
3. Buccal periodontium and bone of the same teeth.
4. Lower eyelid, lateral aspect of the nose and upper
lip.

49.  Indications:
1. Dental procedures involving more than two
maxillary teeth and their overlying buccal tissues.
2. Inflammation or infection, if a cellulitis is present,
the maxillary nerve block may be indicated.
3. When supraperiosteal injections have been
ineffective because of dense cortical bone.
 Contraindications:
1. Discrete treatment areas.
2. Hemostasis of localized areas, when desirable,
cannot be adequately achieved by this method
thus local infiltration is indicated.

50.  GREATER PALATINE NERVE BLOCK:
 The GP nerve block is useful for dental procedures
involving the palatal soft tissues distal to the
canine.
 The 27-gauge needle is recommended.
 0.4-0.6 ml is inserted.
 LANDMARKS:
1. Greater palatine foramen and junction of the
maxillary alveolar process and Palatine bone.
2. A line approximately 1cm from the palatal gingival
margin towards the midline of the palate.

51.  Nerves Anaesthetized: Greater Palatine
 Areas Anaesthetized: The posterior portion of the
hard palate and its overlying soft tissues, anteriorly
as far as the first premolar and medially to the
midline.

53.  Indications:
1. When palatal soft tissue anesthesia is necessary
for restorative therapy on more than two teeth.
2. For pain control during periodontal or oral
surgical procedures involving palatal soft and
hard tissues.
 Contraindications:
1.Inflammation or infection at
the injection site.
2.Smaller areas of therapy.

54.  NASOPALATINE NERVE BLOCK:
 It is also called as Incisive nerve block.
 The 27 gauge short needle is recommended.
 LANDMARKS:
1. Central incisor
2. Incisive papilla in the middle of the palate.

55.  Nerves Anesthetized: Nasopalatine nerves
bilaterally.
 Areas Anesthetized: Anterior portion of hard palate
bilaterally from the mesial of the right first premolar
to the mesial of the left first premolar.

57.  Indications:
1.When palatal soft tissue anesthesia is
necessary for restorative therapy on more than
two teeth.
2. For pain control during periodontal or oral
surgical procedures involving palatal soft and
hard tissues.
 Contraindications:
1.Inflammation or infection at the injection site.
2.Smaller areas of therapy.

58. Mandibular Injection Techniques
 INFERIOR ALVEOLAR NERVE BLOCK:
 It is also called as mandibular nerve block.
 The most important injection technique in
mandibular blocks.
 The 25 or 27 gauge long needle is recommended.
 1.5-1.8ml is inserted.

59.  LANDMARKS:
1. Mucobuccal fold
2. Anterior border of ramus of mandible
3. External oblique ridge
4.Retromolar triangle
5.Internal oblique ridge
6.Pterygomandibular Ligament
7. Buccal sucking pad
8. Pterygomandibular space

60.  Nerves Anesthetized: Inferior Alveolar nerve,
Incisive nerve and Mental nerve.
 Areas Anesthetized: 1. Mandibular teeth to the
midline.
2. Body of the mandible, inferior portion of the
ramus.
3. Buccal mucoperiosteum, mucous membrane
anterior to the mandibular first molar.
4. Anterior two thirds of the tongue and floor of
oral cavity.
5. Lingual soft tissues and periosteum.

62.  Indications:
1.Procedures on multiple mandibular teeth in one
quadrant.
2.When buccal soft tissue anesthesia is necessary.
3.When lingual soft tissue anesthesia is necessary.
 Contraindications:
1. Infection or acute inflammation in the area of
injection.
2. Patients who might bite either the lip or the tongue,
for instance, a very young child or a physically or
mentally handicapped child or adult.

63.  BUCCAL NERVE BLOCK:
 It is also called as Long buccal nerve block.
 It is common for the buccal nerve block to be
routinely administered after IANB.
 The 25-27 gauge long needle is recommended.
 0.3ml is recommended.

64.  LANDMARKS:
1.External Oblique ridge
2. Retromolar triangle
 Nerve Anaesthetized: Buccal nerve.
 Areas Anaesthetized: Soft tissue and
periosteum buccal to the mandibular molar
teeth.

66.  Indications: When buccal soft tissue anesthesia is
necessary for dental procedures in the mandibular
molar region.
 Contraindications: Infection or acute inflammation
in the area of injection.

67.  MENTAL NERVE BLOCK:
 It is the terminal branch of the Inferior Alveolar
Nerve.
 There is very little indication for use of the mental
nerve block.
 The 25-27 gauge short needle is recommended.

68.  LANDMARKS:
1.Mandibular bicuspids and mucobuccal fold.
 Nerve Anaesthetized: Mental nerve
 Areas Anaesthetized: Buccal mucous
membrane anterior to the mental foramen to
the midline and the skin of the lower lip.

70.  Indications: When buccal soft tissue anesthesia
is necessary for procedures in the mandible
anterior to the mental foramen, such as : Soft
tissue biopsies and suturing of soft tissues.
 Contraindications: Infection or acute
inflammation at the injection site.

71.  GOW-GATES TECHNIQUE:
 It is a true mandibular nerve block as it provides
sensory anesthesia to virtually the entire division
of V3.
 A 25-27 gauge long needle is used.
 LANDMARKS:
1.Lower border of tragus.
2.Corner of the mouth.
3. Mesiopalatal cusp of
Maxillary second molar

72.  Nerves Anesthetized: Inferior alveolar, Mental,
Incisive, Lingual, Mylohyoid, Auriculotemporal,
Buccal ( in 75% cases).
 Areas Anesthetized: 1. Mandibular teeth to the
midline.
2. Body of the mandible, inferior portion of the
ramus.
3. Buccal mucoperiosteum, mucous membrane on
the side of injection.
4. Anterior two thirds of the tongue and floor of oral
cavity.
5. Lingual soft tissues and periosteum.
6. Skin over zygoma, posterior portion of the cheek,
Temporal regions.

74.  INDICATIONS:
1. Multiple procedures on mandibular teeth.
2.When buccal soft tissue anesthesia is necessary.
3.When lingual soft tissue anesthesia is necessary.
4. When a conventional inferior nerve block is
unsuccessful.
 CONTRAINDICATIONS:
1. Infection or acute inflammation in the area of
injection.
2. Patients who might bite either the lip or the tongue,
for instance, a very young child or a physically or
mentally handicapped child or adult.
3. Patients who are unable to open their mouth wide.

75.  VAZIRANI-AKINOSI TECHNIQUE:
 Also called as Tuberosity technique, Closed Mouth
Mandibular Nerve Block.
 A 25 gauge long needle is used.
 1.5ml to 1.8ml is deposited.
 LANDMARKS:
1. Mucogingival junction
of the maxillary third
or second molar.
2. Maxillary tuberosity.

76.  Nerves Anesthetized: Inferior Alveolar, Incisive,
Mental, Lingual, Mylohyoid.
 Areas Anesthetized: 1. Mandibular teeth to the
midline.
2. Body of the mandible, inferior portion of the
ramus.
3. Buccal mucoperiosteum, mucous membrane
anterior to the mandibular first molar.
4. Anterior two thirds of the tongue and floor of oral
cavity.
5. Lingual soft tissues and periosteum.

78.  INDICATIONS:
1. Limited mandibular opening.
2. Multiple procedures on mandibular teeth.
3. Inability to visualize landmarks for IANB.
 CONTRAINDICATIONS:
1. Infection or acute inflammation in the area of
injection.
2. Patients who might bite either the lip or the
tongue, for instance, a very young child or a
physically or mentally handicapped child or
adult.
3. Inability to visualize or gain access to the
lingual aspect of the ramus.

79. Local Anesthesia IN FPDs
Anesthetic Application
 Applying topical anesthetic to the injection sites
after drying the mucosa will provide patient
comfort during the injections.
 After the teeth to be prepared have been
anesthetized, the
dentist will use burs in
a high-speed
handpiece to reduce
and shape the teeth

80. Local Anesthetics in Implants
 A local anesthetic (Novocaine, more likely
lidocaine) is usually all that's needed for a
person's implant procedure.
 "Locals" are administered by way of giving an
injection.
 For patients who have anxiety about their
proposed surgery, a decision might be made to
use conscious sedation
technique during their
procedure so they are
more relaxed.

81.  Some implant cases may benefit from the use
of general anesthesia. With this technique, a
medication is used that places the patient in a
state of deep sleep.
 For simple dental implant surgeries, such as the
placement of one or two implants, the use of a
local anesthetic, alone, is probably all that's
needed.
 For more complex cases, and those requiring
longer surgical times, both the patient and the
surgeon may benefit from the use of conscious
sedation or general anesthesia technique.

82. Local and Systemic Complications
CLASSIFICATION:
 PRIMARY OR SECONDARY:A Primary
complication is one that is caused and manifested
at the time of anesthesia. Secondary complication
is one that is manifested later, even though it may
be caused at the time of insertion of needle and
injection of solution.

83.  MILD OR SEVERE: A Mild complication is one that
exhibits a slight change from the normally expected
pattern and reversed itself without any specific
treatment. A Severe complication manifests itself
by a pronounced deviation from the normally
expected pattern and requires a definite plan of
treatment.
 TRANSIENT AND PERMANENT: A Transient
complication is one that, although severe at the
time of occurrence , leaves no residual effect. A
Permanent complication would, ofcourse, leave a
residual effect, even though mild in nature.

84.  Complications arising from drugs or chemicals
used:
 SOFT TISSUE INJURY: Self inflicted injury, most
common in children and mentally or physically
challenged adults.
 Prevention: Warn the patient or the
parents/guardians about
tongue and lip biting.
 Management: Comprises
of analgesics, antibiotics
and topical anesthetic gel
for relief of pain.

85.  SLOUGHING OF TISSUES: Commonly seen in
hard palate as in the region of nasopalatine and
greater palatine nerves, because the
mucoperiosteum is tightly attached to the bone.
It is related to volume of solution injected.
 Prevention: Use LA agent with short duration of
action. Warn the pt. against application of hot
items.
 Management: Consists of
analgesics, topical
anesthetics and bland
diet etc. Usually resolves
within 1-2 weeks. An
established abscess may
require incision and drainage.

86.  Complication arising from injection technique:
 NEEDLE STICK INJURY: Careless technique.
 Prevention: Careful of sharp instruments.
Prophylactic vaccination of HBV infection to be
taken and maintained.
 Management: If injury involves a patient with AIDS,
then
1. The concerned authority
should be informed.
2. Post exposure
prophylaxis to be
considered.

87.  NEEDLE BREAKAGE: Due to sudden movement
by patient. Breakage is common in small needles.
Defect in manufacturing. Redirection of needle
inside the tissue.
 Prevention: Inform the pt. about the technique.
Use proper gauge of
needle. Use good quality
of needle.
 Management: Do not panic.
Remain calm. If needle is
visible and is outside
the soft tissue, catch it with
a hemostat and remove it.
If not visible refer to Oral
and Maxillofacial Surgeon.

88.  HEMATOMA:
 Prevention: Good knowledge of anatomy. Use short
needle for posterior alveolar nerve block. Minimize
the number of needle penetration.
 Management: 1.Immediate: If the area is
accessible, application of pressure for 2-3 minutes.
Observe pt. for at least 12 hours.
2. Delayed: Assurance to the pt. , external ice
application, symptomatic
treatment comprising
analgesics, muscle relaxant,
and antibiotic coverage.

89.  INFECTION: Contamination of needle, improper
preparation of site, needle passing through
infection site, LA solution deposited under
pressure.
 Prevention: Preparation of site prior to penetration,
careful handling of needles. Avoid multiple
injections with same needle. Use disposable
needles. Proper handling of cartridges.
 Management: Analgesics, Antibiotics,
Physiotherapy, Muscle relaxants, Incision and
drainage if required.

90.  FAILURE TO OBTAIN LOCAL ANALGESIA: Faulty
technique like deposition of LA away from nerve,
accidental intravascular administration. Anatomical
Variations. Injecting in infected area. Abnormal
reaction to LA agent.
 Prevention: Good knowledge of anatomy, Good
surgical technique.
 Management: Not required. Repeat the injection. In
case of infection, repeat higher block techniques.

91.  POST-INJECTION HERPETIC LESIONS:
Reactivation of dormant herpes virus particles
by trauma of injection.
 Prevention: Pre-anesthetic assessment: history
of recurrent herpes infection. Delay surgical
intervention in the active stage.
 Management: Symptomatic.

92.  Complication arising from both:
 PAIN ON INJECTION: Careless injection. Blunt
needles. Rapid deposition of LA solution. Needles
with barbs. High temperature of LA solution.
 Prevention: Use sharp needles. Proper technique.
Use sterile LA solution. Use topical LA agents
prior to injection. Inject LA slowly. Avoid using
refrigerated cartridges.
 Management: Not required.

93.  BURNING ON INJECTION: Rapidity of injection.
Contamination of LA Cartridge. High temperature
LA solution. Altered pH of solution.
 Prevention: Slow injection. Cartridges to be stored
at room temperature.
 Management: Not required.

94.  TRISMUS: Trauma to muscles and blood vessels
in infratemporal and pterygomandibular fossae.LA
agents are mild myotoxic. Hemorrhage leads to
irritation of muscles. Low grade infection.
 Prevention: Use sharp, sterile and disposable
needles. Proper handling of needles. Avoid
contamination of needles. Avoid multiple injections
into the same area.
 Management:
Physiotherapy. Heat
therapy. Warm saline
rinse. Analgesics.
Muscle relaxants.

95.  EDEMA: Trauma during injection. Infection.
Allergy. Hemorrhage. Injection of irritating solution.
 Prevention: Preoperative assessment. Careful
handling of LA armamentarium. Atraumatic
technique.
 Management: Find out cause. Basic life support
instituted. Administration of epinephrine,
antihistaminics, and
corticosteroids. Refer to
Oral and Maxillofacial
Surgeon.

96.  BLANCHING OF SKIN: Trauma to blood vessels
by needle. Intravascular administration.
 Prevention: Use of aspiration technique, and
avoid intra-arterial administration of local
anesthetic agents.
 Management: Usually a transient phenomenon.
Treatment is not required.

97.  PERSISTENT PARESTHESIA: Injection of LA
solution near a nerve with contaminated LA
solution with cold sterilizing solution. Trauma to
nerve sheath. Hemorrhage in and around nerve
sheath.
 Prevention: Strict adherence to injection protocol.
Careful surgical technique. Proper handling of
dental cartridges.
 Management: Reassurance to the pt. Prescribe
B1, B6 , B12 vitamin tabs. Observe pt. for two
months, if no improvement, refer to Oral And
Maxillofacial Surgeon.

98.  FACIAL NERVE PARESIS/ PARALYSIS: Injection
of LA solution in the capsule or deeper lobe of
parotid gland. Injection superficially, into muscles
of facial expression.
 Prevention: Good knowledge of anatomy. Follow
the standard protocol for LA technique.
 Management: Explanation and assurance to the
pt. Inability to voluntarily close the eye- Eye-
dressing is given, contact lenses should be
removed.

99.  PERSISTENT (PROLONGED) PAIN: Poor
surgical technique. Needle tip with barbs.
Ischemic necrosis.
 Prevention: Good surgical technique. Avoid
needles with barbs. Use vasoconstrictors with
maximum dilution.
 Management: Symptomatic.

100. Conclusion
 Local anesthetics can and should be
administered in a nonpainful, or atraumatic
manner.
 Not only can the injection of local anesthetic
produce pain and fear, it is also a factor in the
occurrence of emergency medical situation.
 Thus, the operator should make any possible
minor changes in the technique that will cause
less pain to the patients and be aware of the
complications that can occur.

101. References
 Shanbhag’s Pharmacology for dentistry, 2nd ed.
 KD Tripathi, Essentials of Pharmacology for
Dentistry, 2nd ed.
 Stanley Malamed , Handbook of Local
Anesthesia, 5th ed.
 Neelima Malik , Textbook of Oral and
Maxillofacial Surgery, 3rd ed.

105. Properties of LA
 It should not be irritating to the tissue to which it is
applied.
 It should not cause any permanent alteration of the
nerve structure.
 Its systemic toxicity should be low.
 Time of onset of anesthesia should be as short as
possible.
 It should be relatively free from producing allergic
reactions.
 It should be stable and readily undergo
biotransformation inside the body.

106.  Duration of action must be long enough to permit
completion of the procedure yet not as long as to
require an extended recovery.
 It should be effective regardless of whether it is
injected into the tissue or applied locally to the
mucous membrane.
 It should have the potency sufficient to give
complete anesthesia without the use of harmful
concentrated solutions.
 It should be either sterile or capable of being
steriled by heat without deterioration.

107.  STEP 1- Use a sterilized sharp needle.
 STEP 2 -Check the flow of Local
anesthetic solution.
 STEP 3- Determine whether to warm the
anaesthetic cartridge or syringe.
 STEP 4 -Position the patient.

108.  STEP 5 -Dry the tissues.
 STEP 6 -Apply topical antiseptic
(optional)
 STEP 7a- Apply topical anesthetic
 STEP 7b-Communicate with the
Patient.
 STEP 8- Establish a firm hand rest.

109.  STEP 9- Make the tissue taut.
 STEP 10- Keep the syringe out of the
patients line of sight.
 STEP 11a- Insert the needle into the
mucosa.
 STEP 11b -Watch and communicate with
the patient.

110.  STEP 12- Inject several drops of local
anesthetic solution(optional).
 STEP 13- Slowly advance the needle
towards the target.
 STEP 14- Deposit several drops of LA
before touching the periosteum.

111.  STEP 15- Aspirate.
 STEP 16a- Slowly deposit the local
anesthetic solution.
 STEP 16 b- Communicate with the
patient.
 STEP17- Slowly withdraw the syringe.
Cap the needle and discard.

112.  STEP 18- Observe the patient after the
injection.
 STEP 19- Record the injection on the
patients chart.