INJURIES TO ADJACENT STRUCTURES
During the process of tooth extraction, it is possible to injure adjacent tissues. The prudent surgeon preoperatively evaluates all adjacent anatomic areas and designs a surgical procedure to prevent injury to these tissues.
Injury to Regional Nerves
The branches of the fifth cranial nerve, which provide innervation to the mucosa and skin, are the structures most likely to beinjured during extraction. The most frequently involved specific branches are the mental nerve, the lingual nerve, the buccal nerve, and the nasopalatine nerve. The nasopalatine and buccal nerves are frequently _.sectioned during the creation of flaps for removal of impacted teeth. The area of sensory innervation of these two nerves is relatively small, and reinnervation of the
affected area usually occurs rapidly. Therefore the nasopalatine and long buccal nerves can be surgically sectioned without sequelae or complications. Surgical removal of mandibular premolar roots or
impacted mandiputar premolars and periapical surgery in
Prevention of Nerve Injury
1. Be aware of nerve anatomy in surgical area.
2. Avoid making incisions or affecting periosteum in· nerve area.
performed with great care. If the mental nerve is injured, the patient will have an anesthesia or paresthesia of the lip and chin. If the injury is the result of flap reflection or simple manipulation, the altered sensation usually disappears in a few weeks to a few months. If the mental nerve is sectioned at its exit from the mental foramen or torn along its course, it is likely that mental nerve function, will not return, and the patient will have a per.manent state of anesthesia. If surgery is to be performed in the area of the mental nerve or the mental foramen, it is imperative that surgeons have a keen awareness of the potential morbidity from injury to this nerve (Box 11-6). If surgeons have any question concerning their ability to perform the indicated surgical procedure, they should refer the patient to an oral and maxillofacial surgeon. If a three-corner flap is to be used in the area of the mental nerve, the vertical releasing incision must be placed far enough anterior to avoid severing any portion of the mental nerve: Rarely is
it advisable to make the vertical releasing incision at the inter dental papilla between the canine and first premolar. The lingual nerve is anatomically located directly against the lingual aspect of the mandible in the retromolar pad region. The lingual nerve rarely regenerates if it is severely
traumatized, Incisions made in the retro molar pad region of the mandible should be placed to avoid severing this nerve. Therefore incisions made for surgical exposure of impacted third molars or of bony areas in the posterior molar region should be made well to the buccal aspect of the mandible.
Prevention of injury to the lingual nerve is of paramount importance far controlling this difficult complication. Finally, the inferior alveolar nerve may be traumatized along the course of its intrabony canal. The most common place of injury is the area of the mandibular. third molar. Removal of impacted third molars may crush or sharply . injure the nerve in its canal. This complication is common enough during the extraction of third molars that it Is important to inform patients on a routine basis that it is a
possibility. The surgeon must then take every precaution possible to avoid injuring the nerve during the extraction.
Injury to .Temporomandibular Joint
Another major structure that can be traumatized during an extraction procedure in the mandible is the temporo-: mandibular .joint (TMJ). Removal of mandibular molar teeth frequently requires the application of a substantial amount of force. If the jaw is inadequately supported diuing
the extraction, the patient may experience pain in this region. Controlled force and adequate support of the jaw prevents this. The use of a bite block on the contralateral
Prevention of Injury to Temporomandibular Joint
1. Support mandible during extraction.
2. Do-not open mouth too widely.
side may provide adequate balance of forces so that injury and pain do not occur (Box 11-7). The surgeon must also support the jaw as described earlier. If the patient complains of pain in the TMJ immediatefy after the extraction procedure, the surgeon should recommend the use of moist heat, rest for the jaw, a soft diet, and 1000 mg of aspirin every 4 hours for several days. Patients who cannot tolerate aspirin should be given an aspirin substitute, such as other NSAIDs or acetaminophen.