Lecture of local anesthesia

1. Local anesthesia

2. Pain
It is an unpleasant sensation following the application of noxious stimuli
Pain
fibers
Thin +
unmylelinated
Easily
blocked by
anesthesia

3. Nerve transmission

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5. How local anesthesia interrupts this process ?
In order to accomplish this feat, the anesthetic
molecules must actually enter through the cell
membrane of the nerve.
Here lies the differences in
1- The potency
2- Time of onset
3- Duration

6. Local anesthesia
■ Is any technique to render part of the body insensitive to
pain without affecting consciousness. It allows patients to
undergo surgical and dental procedures with reduced pain
and distress

7. Aromatic group (the benzene ring lipid soluble)
An intermediate chain, either an ester or an amide
Amine group (water soluble)
Composition

8. Requirements of an ideal LA
1- Effective
2- Rapid onset and prolonged duration
3- Reversible
4- Selective action on sensory nerves
5- Water soluble
6- Non irritant
7- compatible with the salt used to form isotonic sol.
8- sterilized without deterioration
9- No effect on healing
10- No systemic side effects
11- have a vasoconstrictor action if not add
12- Stable
13- Not expensive

9. Management of patients
Preanesthetic
evaluation
Techniques
Prevention of
complications

10. A- Pre- anesthetic evaluation
1- Case history
2-Evaluation of the general
3- Systemic condition
4- Local examination

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5- Premedication
Sensitivity test
Tranquilizers
Barbiturates
Antibiotics

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Nerve supply:
Maxilla
⦿ Posterior superior alveolar nerve: Molars
⦿ Middle superior alveolar nerve: Premolars
⦿ Anterior superior alveolar nerve: Canines and Incissor
⦿ Sensory supply of palate from greater and lesser palatine nerves as well

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Mandibular nerve:
● Lingual nerve
● Inferior alveolar nerve : Enters the mandibular
canal

14. Techniques

15. Topical anesthesia
Infiltration anesthesia
Injectable
Needless anesthesia ( jet injection)
Nerve block anesthesia

16. Maxillary injection techniques

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20. Infraorbital block
Just inferior to the infraorbital notch
⦿ Teeth affected
● Incisors
● Canines
● premolars

23. Main Types of Maxillary Injections:
1) Local Infiltration
2) Field Block
3) Nerve Block

24. Local Infiltration
■ Incision (treatment) is done in the same area in which the
local anesthetic was deposited (interproximal papilla before
Scaling and Root Planing)

25. Field Block
• Local anesthetic is deposited toward larger nerve terminal branches
• Treatment is done away from the site of local anesthetic injection
• Maxillary injections administered above the apex of the tooth to be
treated are properly referred to as field blocks not local infiltrations

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Nerve Block
• Local anesthetic is deposited close to a main nerve
trunk, usually at a site removed from the area of
treatment (PSA, IANB, NPB)

27. Posterior Superior Alveolar
Nerve Block (PSA)

29. Middle Superior Alveolar
Nerve Block (MSA)

30. Anterior Superior Alveolar
Nerve Block (ASA)

31. Palatal Anesthesia Greater Palatine Nerve Block

34. Nasopalatine Nerve Block

35. Local Infiltration of the Palate

36. P-ASA

38. Maxillary Nerve Block
1) Greater Palatine Approach
2) High Tuberosity Approach

41. Mandibular Injection Techniques

42. NERVE SUPPLY OF THE TEETH
INFERIOR ALVEOLAR N.
V3 (POST. DIVISION)
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Temporalis fascia
and m.
Anterior division (V3) (mostly motor)
Posterior division (V3) (mostly sensory)
Foramen ovale
Auriculotemporal n.
Inferior alveolar n. (cut)
Inferior alveolar n. (cut)
Lingual n.
Chorda tympani n.
Posterior and
anterior deep temporal nn.
Masseteric n.
Lateral
pterygoid n.
and m.
Buccal n.
Mylohyoid m. (cut)
Digastric m. (anterior belly)
Mylohyoid n.
Mental n.

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Temporalis fascia
and m.
Anterior division (V3) (mostly motor)
Posterior division (V3) (mostly sensory)
Foramen ovale
Auriculotemporal n.
Inferior alveolar n. (cut)
Inferior alveolar n. (cut)
Lingual n.
Chorda tympani n.
Posterior and
anterior deep temporal nn.
Masseteric n.
Lateral pterygoid n.
and m.
Buccal n.
Mylohyoid m. (cut)
Digastric m. (anterior belly)
Mylohyoid n.
Mental n.
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Lingual n.
3rd Molar

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INFERIOR ALVEOLAR NERVE BLOCK
Pterygomandibular raphe
Lingual n.
Sphenomandibular ligament
Medial pterygoid m.
Parotid gl.
& facial n.
Inferior alveolar n.
Ramus of mandible
Temporalis m. insertion
Masseter m.
Buccinator m.

52. Remember – Always aspirate before injection!

54. Supplemental Injection Techniques
Infilteration
Periodontal ligament injection (PDL)
Intraseptal
Intraosseous (IO) technique
Intrapulpal injection

55. ■ A noninvasive method to block pain
electronically by using a low current of
electricity through contact pads that target a
specific electronic waveform directly to the
nerve bundle at the root of the tooth.
■ Benefits to the patient:
– No needles.
– No post-operative numbness or swelling.
– Chemical-free method of anesthesia.
– No risk of cross-contamination.
– Reduces fear and anxiety.
– Patients have control over their own
comfort level.
Electronic Anesthesia

56. ■ Nitrous oxide/oxygen (N²O/O²) is a combination
of these gases that the patient inhales to help
eliminate fear and to help the patient relax.
■ History
– Dates back to 1844.
– Dr. Horace Wells first used it on his patients.
■ Effects
– Non addictive.
– Easy onset, minimal side effects, and rapid
recovery.
– Produces stage I anesthesia.
– Dulls the perception of pain.
Inhalation Sedation

57. ■ For the relief of anxiety.
■ Sedatives
■ Criteria for use:
– Patients are very nervous about a procedure.
– Procedures are long or difficult.
– Mentally challenged patients.
– Very young children requiring extensive
treatment.
Antianxiety Agents

58. ■ Commonly prescribed:
– Secobarbital sodium (Seconal)
– Chlordiazepoxide HCl (Librium)
– Diazepam (Valium)
– Chloral hydrate (Noctec): For children
Sedatives

59. ■ Antianxiety drugs that are administered
intravenously continuously throughout a
procedure at a slower pace, providing a
deeper stage I analgesia.
Intravenous Sedation

60. ■ A controlled state of unconsciousness in
which there is a loss of protective reflexes,
including the ability to maintain an airway
independently and to respond appropriately
to physical stimulation or verbal command.
This controlled state in loss of
consciousness, produces stage III general
anesthesia.
General Anesthesia

61. ■ Always document the following
measures and observations:
– Review of patient’s medical history.
– Preoperative and postoperative vital signs.
– Patient’s tidal volume if using inhalation
sedation.
– Time anesthesia began and ended.
– Peak concentration administered.
– Amount of postoperative time (in minutes) for
patient recovery.
– Adverse events or patient complaints.
Record Keeping for Sedation Methods

62. Local Anesthesia
Complication

63. LOCAL COMPLICATION OF LOCAL
ANESTHESIA
1. Complications arising from drugs or chemicals
used for local anesthesia
2. Complications arising from injection techniques
3. Complications arising from both

64. Complications arising from drugs or
chemicals used for local anesthesia
1. Soft tissue injury
2. Sloughing of tissues (Tissue ischemia and
necrosis)

65. SOFT TISSUE INJURY
■ Causes
1. It is seen in the form of
self-inflicted trauma to lips,
tongue and cheek
2. It is common in children
and mentally retarded
adults

66. 2- Sloughing of Tissues
(Tissue Ischemia and Necrosis)
Causes
1. predisposition: Commonly in
hard palate, as in the region of
distribution of nasopalatine
and greater palatine nerves,
because mucoperiosteum is
firmly attached to the bone.
2. Deposition of excessive volume
of local anesthetic agent with
high concentration of
vasoconstrictors
3. Rapid deposition of the local
anesthetic solution with undue
pressure
4. Application of topical local
anesthetic agent for prolonged
period (epithelial desquamation)

67. COMPLICATIONS ARISING
FROM INJECTION TECHNIQUES

68. COMPLICATIONS ARISING FROM
INJECTION TECHNIQUES
1. Breakage of anesthetic cartridge
2. Breakage of needle
3. Needle-stick injuries
4. Hematoma
5. Failure to obtain local anesthesia

69. Breakage of Anesthetic Cartridge
■ Causes
It occurs when there is
resistance to flow of local
anesthetic solution in to
the tissues
It occurs due to following
reasons:
1. Blockage of the needle
2. Too rapid injection;
especially during
administration of palatal
injection.

70. Breakage of Needle
■ Its very rare since the
introduction of sterile,
stainless steel disposable
needles
■ Causes :
Primary cause: Sudden
unexpected movements
by the patient

72. Needle-stick Injuries
■ It’s an accidental injuries
occurring to dental staff caused by sharp
instruments such as needles, blades, scalpels,
explorers, root canal instruments, and wires, etc
■ These injuries are not usually serious, unless, the
instruments used were contaminated by blood from
patients with conditions such as Hepatitis B virus
HBV Infection, Hepatitis C virus HCV Infection, A IDS

73. Failure to Obtain Local Anesthesia
■ Causes
1. OPERATOR-DEPENDENT
I. Selection of local anesthetic agent (type and dose; too
small a dose)
II. Use of a local anesthetic solution which has crossed its
date of expiry
III. Improper injection technique:
a. Wrong technique: Inaccurate placement of solution
b. Not waiting long enough for anesthesia to act; before
commencing the surgery
IV. Intravascular administration
V. Intramuscular administration

74. 2- PATIENT - DEPENDENT
I. Anatomical:
a. Barriers to diffusion
b. Anatomical aberrations
c. Additional innervations
II. Psychological:
Fear and apprehension : unco-operative
patient, inadequate opening of the mouth,
movement by the patient

75. COMPLICATIONS ARISING FROM LOCAL
ANESTHETIC SOLUTION AND INJECTION
TECHNIQUE

76. PAIN ON INJECTION
■ This increases patient’s anxiety;
and may lead to a sudden unexpected
movement by the patient and increases the
risk of needle breakage.
■ Management
Not required. However, steps should be
taken to avoid pain associated with
injection of local anesthetic agent

77. PAIN ON INJECTION
■ Causes
1. Careless injection technique
2. Dull needles
3. Rapid deposition of local anesthetic solution
4. Needles with barbs: There is pain while withdrawal of
the needle from the tissues
5. Temperature: Extremes of temperature such as warm
or hot or very cold (refrigerated) local anesthetic
solution

78. TRISMUS
■ Trismus is the inability to normally open the mouth
■ It is a fairly common complication of local anesthesia,
particularly while giving pterygomandibular block

79. MUCOSAL BLANCHING
■ It is caused by the spasm of the artery
accompanying
the nerve at the point of injection
Causes
1. Use of excessive amount of vasoconstrictor
2. Deposition of excessive volume of local
anesthetic solution in firm or tight tissue

80. PERSISTENT ANESTHESIA OR
PARESTHESIA (NERVE INJURIES)
■ Persistent paresthesia can lead to self-inflicted
injury. Biting, or thermal or chemical insults can
occur without the patients awareness
■ The condition is more frequent as a result of
operative procedure than injection itself
■ The sensory nerves most frequently traumatized
are inferior alveolar nerve, lingual nerve, and
mental nerves in lower jaw; and infraorbital nerve
in upper jaw

81. POST-INJECTION HERPETIC LESIONS OR
POST-ANESTHETIC INTRAORAL LESIONS
■ Patients’ reporting of development
of ulcerations around the site of
injection a few days after intraoral
injection of local anesthetic agent.
Patient complains of intense pain
■ Cause
❑ Recurrent Aphthus Stomatitis
(RAS): It is a frequent
manifestation, developing in
gingival tissues (movable part, i.e.
not attached to the bone)

83. FACIAL NERVE PARALYSIS
■ Paralysis of some of the muscles of facial
expression which are supplied by some of
the terminal branches of facial nerve, when
the solution is deposited in their vicinity

84. Thank you
•Islam Kassem
• ikassem@dr.com
• 00201222209842
• 002034810481
• 00201091472244
www.kmaxfacs.com