Electrophysiologic evaluation of inferior alveolar nerve regenerated by bifocal distraction osteogenesis in dogs.

BACKGROUND: Bifocal distraction osteogenesis has been shown to be a reliable method for reconstructing missing bone segments. However, there are no reports regarding inferior alveolar nerve regeneration during bifocal distraction. In the present study, the authors evaluated the function of inferior alveolar nerve regenerated by bifocal distraction after segmental resection in the mandibles of dogs. METHODS: Using a bifocal distraction osteogenesis method, the authors produced a 10-mm mandibular defect and distracted the transport disk at a rate of 1 mm/day. The regenerated inferior alveolar nerve was evaluated by electrophysiologic analysis that was performed on all dogs after euthanasia at 3, 6, and 12 months after the first operation. RESULTS: At 6 and 12 months, stable evoked potential measurements were obtained from the nerves throughout the study on electrophysiologic analyses. CONCLUSIONS: The authors' results indicate that the inferior alveolar nerve regenerated by bifocal distraction osteogenesis functioned electrophysiologically at 6 months after the first operation. Although our research is still at the stage of animal experiments, future application in humans is considered to be possible.

Intraductal papilloma arising from sublingual minor salivary gland: case report and immunohistochemical study.

Intraductal papilloma is a rare benign salivary gland tumor. This lesion is commonly observed in the duct of the minor salivary gland, predominantly in lip and buccal mucosa, but the case in the sublingual region is quite rare. This report shows a first case of intraductal papilloma developed in minor salivary gland of sublingual region. A 47-year-old Japanese male was referred to our hospital with painless submucosal nodule in the right sublingual region beside Wharton's duct orifice. The excised specimen was histologically diagnosed as intraductal papilloma of minor salivary gland, according to the microscopic finding of the papillary growth of ductal epithelium into the ductal space with fibrovascular core. Immunohistochemical study showed the tumor cells originated from ductal luminal cells because of positive Cytokeratin 18 and 7 staining in both types of cells.

Breakage of internal maxillary distractor: considerable complication of maxillary distraction osteogenesis.

Maxillary distraction osteogenesis using intraoral distractors is now one of the standard treatments of maxillary retrusion. This report shows 2 cases of breakage of this internal maxillary distractor in patients with cleft lip and palate; one was observed during the distraction period and the other was during the retention period. The first case required a rotational movement of the distraction segment, and this movement caused the laterally dislocation of the posterior part of the distractor, where the distractor suffered some mechanical forces by mouth opening. In the latter case, breakage of distractor was observed on the radiographs taken 3 months after distraction and this complication may have been caused by mechanical force by occlusion and mastication. Both breakages were found at the joint of the anchorage plate and the extension rod, which has some flexibility for adjusting the plate to the bone surface. Therefore, surgeons should pay special attention for this mechanical weak area in this distractor not only during the advancement period, but also during the retention period and should avoid unnecessary frequent bending for adopting the bone surface, which directly weakens the joint.