Anesthesia serves two purposes: to prevent pain during surgery, and to get presurgical hemostasis in the area.
Lidocaine (2%) with 1:50,000 epinephrine is the anesthetic of choice, because it causes activation of alpha receptors, that are in the majority in arteriolar muscles, submucosa and periodontium, causing vasoconstriction. Epinephrine is a safe drug1’2 and allergies to it are extremely rare. It is contraindicated only in severe cardiovascular disorders.
The keys to the injection technique are the sites chosen and the speed of infusion. The sites are multiple, peripheral, supraperiosteal injections at the level of the root apices. Slow injection is painless, allowing an adequate diffusion along normal tissue planes. It does not cause postinjection discomfort and, most importantly, provides a tremendous safety margin against adverse drug reactions, particularly in the event of inadvertent intravascular injection.
This allows the injected solution to be spread over a broad surface area, promotes rapid and extensive diffusion into adjacent tissues, and predictably produces maximum hemostasis and prolonged, profound anesthesia3.
One cartridge is slowly (1-2 mL/min) injected into connective tissue at the apical level of the tooth to be treated, and half a cartridge in the mesial and distal teeth. Ten minutes later, another half cartridge is injected in a palatal-lingual site, in order to get uniform hemostasis in the surgical area.
For mandibular teeth, one cartridge can be injected at a distance in order to have nerve block.
There should be 15 minutes of total waiting time to allow the anesthetic to be effective, because an anesthetic injection after the incision has been made is ineffective for hemostasis4.
If a special flap design is programmed, anesthesia should cover it.
The patient must rinse his or her mouth with chlorhexidine solution in order to decrease the bacterial load, and an assistant should rub all teeth in the surgical area with a gauze soaked with chlorhexidine.