1. Oral Surgery Local Anesthesia

2. Local anesthesia (L.A) : could be defined as a loss of sensation in a circumscribed area of the body caused by a depression of excitation in nerve ending or inhibition of the conduction process in peripheral nerves.

3. Terminology:
Pain: unpleasant physical sensation experienced followed the application of noxious stimuli; although the supporting tissues of the teeth can themselves give rise to pain most of the nerve endings in the periodontal membrane are proprioceptive.
Anesthesia: means loss or abolition of all modalities of sensation which includes pain and touch.
Analgesia: means loss of pain sensation only.
Paresthesia: means altered sensation (tingling sensation) and this may occur when a damaged nerve is regeneration or when a local anesthesia is either starting to work or its effect is wearing off.

4. The effect of a local anesthetics on nerve fiber has been shown
to be dependent on:
1. The duration of exposure of local anesthesia.
2. Concentration.
3. Volume of the solution.

5. Relative analgesia: is a sedation technique in which the patient remains conscious but mental relaxation is induced by inhalation of a mixture nitrous oxide, oxygen and air. local anesthesia used when necessary.
Depolarization: when a stimulus excites a nerve this will lead to an increase in permeability of the membrane to Na ions, the rapid influx of Na ions to the interior of the nerve will cause depolarization of the never membrane from the resting level to its firing threshold.

6. uses of local anesthesia Local anesthesia use for: a- Diagnostic uses b- Therapeutic uses c- preoperative uses d- postoperative uses

7. a- Diagnostic uses
administration of (L.A) can be a useful way of finding the source of patients pain an example of this is the pain of pulpitis which can be very difficult for both the patient and the dentist to isolate because of its tendency to be referred to other part of the mouth or face , so (L.A) can distinguish between maxillary and mandibular sources , and between individual upper teeth provided they are not immediately adjacent ,

8. b- Therapeutic uses
(L.A) can by itself constitute part of treatment for painful surgical conditions, for example the use of block technique to eliminate the pain of dry socket can be helpful in the management of this very painful condition particularly in the first few days.

9. c- preoperative uses
the provision of pain – free operative surgery is by far the most common use of (L.A) and provides effective and safe method for almost all outpatient dentoalveolar oral surgical procedures, it can in conjunction with sedation techniques allow more difficult procedures to be carried out without the additional risks of general anesthesia and this is particularly of value in patients with significant cardio – vascular or air way diseases .

10. additionally however , (L
additionally however , (L.A) is often given to patient undergoing oral and maxillofacial surgery under general anesthesia this serves the following purposes:
1. It reduce the depth of general anesthesia needed .
2. It reduce the errhythemias which are noted on electrocardiogram during the surgery when significant stimulation is taking place , this can be seen for example when a tooth is being elevated .
3. It also provides local homeostasis to the operative site and provides immediate postoperative analgesia

11. d- postoperative uses
after surgery with either local or general anesthesia the continuing effect of the anesthesia is most beneficial way of reducing patients discomfort , it help to reduce or even eliminate the need for stronger systemic analgesic .

12. Indications of local anesthesia
local anesthesia is indications in almost all the dental procedures , it is used to render the teeth and supporting tissue and structures insensitive to painful procedures ,it is used in oral surgery for extraction of teeth and fractured roots , and for all other surgical procedures as surgical removal of teeth , apicoectomy , incisions and drainage of localized abscesses , removal of cysts , ranula and salivary calculi , and for all other surgical procedures .

13. local anesthesia is used also for the conservative treatment as for cavity preparation , crown and bridges abtment preparation , pulp treatments as root canal filling , pulpotomy or pulpoctomy .
local anesthesia is used for the surgical treatments of the periodontal diseases deep scaling and prophylaxis treatment , mucogingival surgical procedures .
it is also used some time in prosthodontic treatment and some of the orthodontic treatments .

14. Contraindications Of Local Anesthesia
These can be divided into two groups:
1. Absolute contraindications such as
A- History of allergy to local anesthetic agent
Local Anesthesia agents belonging to the same chemical group should not be used however , local Anesthesia agents in the different chemical group can be used . in case , a patient gives history of allergy to an amide local anesthetic agent , an ester local anesthetic agent can be used

15. B- Documented allergy to other constituents of the local anesthetic solution when the patient has a history of allergy to any of the constituent of the local anesthetic solution the solution containing should be avoided , an alternate solution should be used if possible .

16. 2. Relative contraindication as
A- Fear and apprehension : where the patient is uncooperative for local anesthesia .
B- Presence of acute inflammation or supportive infection at the site of insertion of the needle where their will be increase chances for the spread of infection with the passages of the needle from the abscess area to the deeper tissue .
C- Infant or small children : these patients lack reasoning and understanding

17. D- Mentally retarded patients : these patients are unable to cooperate
E- Patients with significant medical diseases as cardiovascular diseases , hepatic dysfunction , renal dysfunction , and clinical hyperthyroidism .
F- Restricted mouth opening : when the patient cannot open his mouth sufficiently , in situation such as trismus , also in partial or complete ankyloses of the temporomandibular joint .
G- Major surgical procedures .

18. Advantages of local anesthesia
These are follows :
1- No special preparation of the patient is needed .
2- No complicated apparatus or bulky gas cylinders are needed .
3- There is no risk of respiratory obstruction .
4- Anesthesia lasts for at least an hour .
5- the patient remains a wake and cooperative and need no after care .

19. 6- seriously ill patient such as those with heart diseases can usually tolerate local anesthesia without any risk .
7- an anesthetist and other additional trained personnel not required .
8- technique is not difficult to master .
9- low percentage of failure .
10- no additional expense to the patient .

20. dis Advantages of local anesthesia
No true dis Advantages to the use of local anesthesia when the patient is normal and there is no contraindications to its use so in every instance when satisfactory anesthesia can be achieved and patient is cooperative , local anesthesia is the method of choice .

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