This document summarizes local and general complications that can occur from local anesthesia in dentistry. For local complications, it discusses failure to obtain anesthesia, pain during/after injection, hematoma formation, intravascular injection, blanching, trismus, facial paralysis, lip trauma, prolonged impairment of sensation, broken needles, and infection. For general complications, it mentions fainting, drug interactions, homologous serum jaundice, sensitivity reactions, occupational dermatitis, and cardio-respiratory emergencies. Causes and treatments are provided for many of the complications.
4. Failure to obtain anasthesia
It may be complete or partial
Causes :
Operator experience
Inadequate amount of the local anasthesia
Injection in to the blood vessel
Presence of infection
Expire date of local anasthesia solution
Patient response to drugs
5. pain during and after injection
Suggested causes :
a. Injection of either non isotonic or contaminated
solutions .
b. Neurological pain during injection due to
penetration of nerve sheath by the needle
c. Use of excessive force during deposition of
anasthesia solution
9. Hematoma formation
Mainly occure with block injection
• Mostly superior posterior block injection
• Less common inferior alveolar and infa-orbital block
injection
• Bleeding from pterygoid venous plexus clinically appear as
swelling in the cheek followed by discoloration of the
overlying skin due to break down of the blood within 24 -48
hours .
• Bleeding from the infraorbital vessels appear as above with
black eye
• Bleeding in to the pterygo-mandibular space not show any
swelling in the cheek but it may show trismus
10. Management :
• Reassurance of the patient
• Antibiotic to avoid infections
• Follow - up
Hematoma formation
11. Intra – vascular injection
• Result in Increase the toxicity of
local anasthetic solution or
vasoconstrictor in the blood .
• Clinically patient may show
fainting , pale,clammy skin and
even decrease in the level of
consciousness .
• Can be avoided by using
aspiration injection technique
12. Blanching at the site of injection
Ischemia of the area as aresult of decrease in
blood supply
13. Causes :
• Increase tissue tension due to the deposition
of fluid .
• Local effect of local anasthesia
Blanching at the site of injection
15. Blanching at the site remote from
that of injection
Causes :
• Intra-vascular injection
• Interferance with the autonomic nerve supply of
the blood vessels
Treatment :
• No treatment is needed just reassurance to the
patient . Its usually transit
17. Causes :
Injection in to the medial pterygoid muscle may cause injury to
the blood vessels inside the muscle and hematoma formation or
infection
Inflamation in the pterygomandibular space
Blood that escape during injection in the pterygomandibular
space may cause irritation to the muscle and produce trismus
• Note : if trismus associated with pain ,fever so its due to
infection and should treated by drainage of pus , antibiotic , and
mouth wash by warm saline
Trismus
19. Causes :
Due to deposition of anasthetica solution in the
parotid which occure when the tip of needle
inserted too far back and behind the ramus
Facial paralysis
21. Prolonged impairment of sensation
Occure due to nerve injury
Main causes :
Direct trauma from the nerve
Injection of a solution contaminated with a
neurotoxic substances as alcohol
Hemorrhage and infection near the nerve
Surgery near the nerve fibers as mental nerve
22. Prolonged impairment of sensation
• Testing the degree and extent of parasthesia or
anasthesia can done by measuring the reactions to pin –
prinks and passing of cotton wall wisps over the skin
23. Prolonged impairment of sensation
Treatment :
In case of infection .. Drainage of pus and
anti-biotic coverage
Follow up to check the improvement
If no improvement then refer the patient to a
specialist
24. Broken needles
Prevention
• The needle must kept straight during injection .
• If resistance is encounterd , force must not be
applied to overcome it .
• The direction of the needle should not changed
within the tissue .
• Bending of the needle should be avoided .
• The needle should never embeded completely
within the tissue , at least 5 mm must project from
the mucosal surface .
25. Broken needles
Treatment
• If fracture occure the patient should told to stop any
movment to prevent displacemnt of needle within
the tissue .
• The needle graspes by artery forceps or pleir and
withdrawn .
• If the needle displaced within the tissue then its
position must determined radiographically ( two x-
ray films must be taken one perpendicular to other )
to confirm the exact position of needle and then
removed it surgically by dental surgeon .
26. infection
• Use of contaninated needle may cause infection
especially in pterygomandibular space during inferior
alveolar nerve block
27. Lip trauma
• Anasthetised lip after injection may suffer
from trauma by chewing it espcially in
children or thermal injury by hot drink or
cigarrete in adult .
28. Visual disturbance
• Rare complication of unknown causes but
suspected to be due to vascular spasm or
accidental intra-arterial injection
Treatment
• Reassurance , usually normal vision retained
within 30 minute