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The concept of socket preservation by placing a particulate bone allograft or xenograft into a tooth socket or on the alveolar ridge after tooth removal remains a somewhat controversial topic. The concept is that it will preserve the ridge from resorption and such that subsequent implant insertion will be easier, with fewer complications. However, one particular issue is that these materials, although not directly neurotoxic, appear to be an irritant to the nerves if they come in contact with them. We present a case series demonstrating this complication., (Copyright © 2017 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Permanent nerve involvement has been reported following inferior alveolar nerve blocks. This study provides an update on cases reported to one unit in the preceding six years. Lidocaine was associated with 25 percent of cases, articaine with 33 percent of cases, and prilocaine with 34 percent of cases. It does appear that inferior alveolar nerve blocks can cause permanent nerve damage with any local anesthetic, but the incidences may vary.

Purpose: The arrangement of the structures within the inferior alveolar neurovascular bundle has not been clearly defined. Because this could be of importance in surgery involving the inferior alveolar canal, a study was undertaken., Materials and Methods: The inferior alveolar neurovascular bundle was dissected from 8 cadaveric mandibles and examined for the arrangement of the inferior alveolar artery, vein, and nerve. Histologic sections were taken for examination, and simultaneously, the bundle was exposed as part of a clinical surgical procedure for a marginal resection of the mandible., Results: All 3 studies confirm that the inferior alveolar vein lies superior to the nerve and that there are often multiple veins. The artery appears to be solitary and lies on the lingual side of the nerve, slightly above the horizontal position. This position appeared to be consistent in all cases., Conclusions: Knowledge of the arrangement of the inferior alveolar artery vein and nerve within the inferior alveolar canal can be of importance in surgical procedures that may involve these structures. Dentoalveolar surgery, implant-related surgery, and surgery for trauma or pathology could involve these structures.

Background: An explanation for the predominance of injuries to lingual nerves over those to inferior alveolar nerves as a result of inferior alveolar nerve blocks may be due to the nerves' fascicular pattern. A unifascicular nerve may be injured more easily than a multifascicular nerve., Methods: The authors unilaterally dissected lingual and inferior alveolar nerves from 12 cadavers. They cut the specimens 2 millimeters above the lingula for both the lingual nerve and inferior alveolar nerve and opposite the site of the middle of the third molar for the lingual nerve, and they counted the number of fascicles at each site., Results: For the lingual nerve at the lingula, the mean number of fascicles was three (range, one to eight). Four of the 12 nerves (33 percent) were unifascicular at this point. Opposite the third molar, the lingual nerve had a mean of 20 fascicles (range, six to 39). In every case, there were more fascicles in the third molar region than above the lingula in the same nerve. At the lingula, the inferior alveolar nerve had a mean of 7.2 fascicles (range, three to 14)., Conclusion: This study may explain the observation that when an inferior alveolar nerve block causes permanent nerve impairment, the lingual nerve is affected about 70 percent of the time and the inferior alveolar nerve is affected only 30 percent of the time. In 33 percent of cases, the lingual nerve had only one fascicle at the lingula; a unifascicular nerve may be injured more easily than a multifascicular one., Clinical Implications: There is no known way to avoid the remote possibility of nerve damage resulting from an inferior alveolar nerve block. The lingual nerve may be predominantly affected because of its fascicular pattern.

Purpose: The goal was to evaluate the experience of one surgical unit during a 5-year period in the evaluation and management of patients with injuries of the inferior alveolar and lingual nerve with particular reference to indications for and results of microneurosurgery., Patients and Methods: This study includes all patients referred with a diagnosis of injury to the inferior alveolar or lingual nerve during 5-year period from January 1, 1994, to January 1, 1999. All patients were evaluated with Frey's hairs for touch and direction sense, 2-point discrimination, and hot and cold water and Minnesota thermal discs for temperature sensation. Patients who fulfilled certain specified criteria were offered microneurosurgery, and the results were evaluated for those who underwent microneurosurgery., Results: The study consisted of 880 consecutive patients; 96 were thought to fulfill the criteria for microneurosurgery. Of these, 51 underwent microneurosurgical exploration and repair. In 5 patients, no injury could be detected at surgery, and no corrective surgery was performed other than decompression. In 26 patients, excision and direct anastomosis were performed, and in an additional 20 patients, nerve gap reconstruction was performed. In 16 of these 20 patients, reconstruction was performed with an autogenous vein graft, and in 2 patients, a Gore-Tex tube graft (W.L. Gore & Associates, Inc, Flagstaff, AZ) was used to bridge the nerve gap. In 2 patients, an autogenous nerve was used. Thirty-four of the repairs were made on the lingual nerve, and 17 were made on the inferior alveolar nerve. With the use of established criteria, 10 patients were considered to have had a good improvement in sensation, 18 patients were considered to have had some improvement in sensation, and 22 patients were considered to have had no improvement in sensation; 1 patient reported an increase in dysesthesia after surgery. The semiobjective assessment of patients did not always correspond with the patients' subjective evaluation., Conclusion: In a relatively small study in selected cases, microneurosurgery can provide a reasonable result in improving sensation in the inferior alveolar and lingual nerve. More than 50% of patients experienced some improvement in sensation, and dysesthesia did not develop after surgery in any patient who did not have it before surgery., (Copyright 2002 American Association of Oral and Maxillofacial Surgeons)

Purpose: This study evaluated whether an autogenous vein graft forms a satisfactory conduit for nerve regeneration., Patients and Methods: Fifteen patients received a total of 16 autogenous vein grafts to repair continuity defects of the inferior alveolar (6) and lingual nerves (10) nerves. All were treated between 4 and 10 months after injury. At surgery, the postresection defects ranged from 2 to 14 mm. All lingual nerves were repaired with saphenous vein grafts from an intraoral approach and all inferior alveolar nerves were repaired with facial vein grafts inserted from an extraoral approach., Results: Lingual nerve repair in 3 cases where the gap between the nerve ends was 5 mm or less resulted in some return of sensation. In 7 cases where the gap was between 5 and 14 mm, there was no return of sensation. In the 6 inferior alveolar nerve repairs there was some return of sensation in all cases and there was good return of sensation in 3 cases. One patient redeveloped dysesthesia in the inferior alveolar nerve and subsequently had a neurectomy. Histologic material was available from this case., Conclusions: It appears that a vein graft can form a physiologic conduit for nerve regeneration. The results are more successful with shorter gaps, which indicates that, in some respects, the vein acts like a barrier membrane. The increased success rate in the inferior alveolar nerve repair may be because the vein remains straight and patent in the inferior alveolar canal. The lack of success with a long lingual nerve gap repair may be because the vein is collapsed or kinked by movement of the tongue, which may inhibit neural regeneration. Therefore, vein grafts should not be used for long lingual nerve continuity defects., (Copyright 2001 American Association of Oral and Maxillofacial Surgeons)

Purpose: This study tested the hypothesis that some sensory innervation to the lower incisor teeth comes from reentry of the terminal branches of the mental nerve through the labial plate of the anterior mandible., Patients and Methods: Ten cadaveric heads (20 sides) were dissected and studied to determine whether the mental nerve crossed the midline or reentered the labial plate. Using careful dissection, the most posterior branch of the nerve was exposed from its point of emergence at the mental foramen to its insertions, and any entries into the labial plate were recorded and photographed., Results: Three of 20 (15%) specimens showed unequivocal evidence of nerve reentry into the labial plate. Five specimens displayed strong evidence of nerve fibers reentering the plate, but these were too fragile to be dissected through the periosteum without breaking. In 12 of 20 (60%) specimens, there were no branches identified that reentered the bone plate. Of the eight specimens showing evidence of reentry, four had substantial midline crossover., Conclusions: The finding that branches of the mental nerve may reenter the labial plate to supply the lower incisors explains the phenomenon of crossover innervation from the contralateral mental nerve and the fact that a labial infiltration injection will anesthetize the lower incisor teeth.

Normal somatosensory evoked potentials were obtained from the lower lip of 40 volunteers. Efforts were made to exclude artefact. A consistent triphasic wave form of three peaks and troughs was defined. There were greater variations in amplitude than latency between subjects. Statistically, one side of the lower lip can be used as a control for the contralateral side, but it may not be possible to have reliable normal values between subjects. Somatosensory evoked potentials may however represent an objective method of evaluating trigeminal sensory nerve function.