Block anesthesia in dentistry

Apparatus
Local analgesia cartridges are of 2 sizes --- 1.8 and 2.2 ml. They come pre-sterilised and the most common solution used is lignocaine 2% with adrenaline 1:80,000. A latex-free version is available for patiens with latex allergies.Cartridge syringes used with ultra-fine disposable needles.lignocaine/adrenaline most commonly used preparation (2% lignocaine, 1:80,000 adrenaline).Gives pulpal analgesia for 1 ½ hours and altered soft tissue sensation for up to 3 hours. Extremely safe, maximum dose is 800mg ! (10 x 2.2ml carts).Prilocaine/ octapressin – similar to last but slighty less duration and effect compared to lignocaine/adrenaline. Maximum safe dose is 600mg ( 8 x 2.2ml carts).Other solutions used include mepivacaine, bupivacaine and articaine.

One cartridge + one needle PER PERSON. The cartridge Is to be discarded if precipitate is seen in it somehow or if air bubbles are present.Warm cartridge to decrease discomfort and load it into the syringe immediately prior to use and ASPIRATE before using.

Techniques
(ifsupplemented with infiltrations). The aim is to deposit solution around inferior alveolar nerve as it enters the mandibular foramen underneath the lingual. Palpate the landmarks of external and internal oblique ridges and note the line of the pterygomandibular raphe. With the palpating thumb lying in the retromolar fossa the needle should be inserted at the midpoint of the tip of the thumb slightly above the occlusal plane lateral to the pterygomandibular raphe. The needle is inserted ~0.5cm and if a lingual nerve block is required 0.5ml of LA (local analgesic) is injected at this point. The syringe then moved horizontally ~40 degrees across the dorsum of the tongue and advanced to make contact with lingual. Once bony contact is made the needle is withdrawn slightly and the remainder of the anesthetic is injected
 * 1) IDB (inf. Alveolar block): used for mandibular molars, premolars canines and incisors.


 * 1)  Gow Gates technique: Blocks sensation to mandibular branch of trigeminal nerve by disposing anesthetic at the head of condyle.


 * 1) Nasopalatine block: Profound anesthesia can be achieved by passing needle thru the incisive papilla and injecting a small amount of solution BUT IT IS VERY PAINFUL


 * 1) Infraorbital block: where anesthetic is deposited around the infra orbital nerve about 1cm below orbit – RARELY INDICATED

INFILTRATIONS
the aim is to deposit anesthetic supraperiosteally in as close proximity as possible to the apex of the tooth to be anesthetized


 * 1) Intraligamentary analgesia: individual teeth are anesthetized by injecting a small amount of anesthetic along the periodontal membrane via a specially designed system. High pressure syringe + ultra fine needles


 * 1) Electronic dental anesthesia: uses electrodes, bucally and lingually which carry electrical current to interfere with local nerve induction and therefore pain appreciation/sensation

Benefits of local anesthesia include:
 * 1) cooperative patient -> helps with patient - dentist communications/relationship?
 * 2) salivation control
 * 3) hemostasis – temporary reduction in blood flow and volume in tissue