Local Anasthesia in dentistry

Dr.Mohamed Rhael Ali

2016 - 2017

Terminology

Pain ; unpleasant physical sensation experienced followed the application of noxious stimuli

Analgesia ; loss of pain sensation only

Anesthesia ; loss of all modalities of sensation which include pain and touch

Parasthesia ; 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

• Depolarization; rapid influx of Na ions to the interior of the nerve

• Repolarization;  reestablishment of polarity, especially  the return of a cell's membrane potential to resting potential after depolarization. This occur by the movement of positively charged K+ ions out of the cell.

local anesthesia

Definition loss of sensation in a circumscribed area of the body

caused by depression of excitation in nerve endings or inhibition of the conduction process in peripheral nerves

differ from general anesthesia by which the loss of sensation occur without loss of consciousness.

Requirement of local anesthesia it should not be irritating to the tissue to which it is applied it should not cause any permenant alteration to the nerve structure its systemic toxicity should be low the time of onset of anesthesia should be as short as possible the duration of action must be long enough to permit completion of

the procedure it should be free from producing allergic reactions it should be either sterile or be capable of being sterilized by the

heat without deterioration it should have potency sufficient to give anesthesia without using

harmful concentration it must be effective regardless of wether it is injected into the

tissue or applied locally to mucous membranes. It should be stable in solution and readily under go transformation

in the body

Uses of local anesthesia

Diagnostic uses

Therapeutic uses

Preoperative uses

postoperative uses

Indications of local anesthesia

Almost all dental procedures …..a. in oral surgery for extraction of teeth, apicoectomy,

incisions and drainage of abscesss , removal of cysts, ranula and all other surgical procedures.

b. In conservative treatment c. periodontal diseases

d. some cases of prosthodontics and orthodontic treatments

Contraindications for local anesthesia

• Absolute contraindication ; as in patients with history of allergy to local anesthesia

• Relative contraindications ; as in presence of acute inflammation at the site of injection ,or in patients with significant medical diseases as cardiovascular diseases,clinical hyperthyroidism

Advantages of local anesthesia

• No special preparation of the patient is needed• No complicated apparatus are needed• No risk of respiratory obstraction• Anesthesia last for at least an hour• Patient remains awake and cooperative and no need for

care posoperatively• Seriously ill patient as with heart diseases can usually

tolerate local anesthesia without any risk.

Disadvantages of local anesthesia

No true disadvantages to the use of local anesthesia when the patient is normal and there is no

contraindications to its use