Macroscopic and microscopic features of the mandibular condyle in autopsied elderly individuals.

Many studies have attempted to classify the macroscopic shapes of the mandibular condyle in humans; however, no consensus has yet been reached because the shapes vary. One problem is that classification of macroscopic morphological changes of the condylar surface has been largely based on bones from ancient people, with few bones from modern people covering many different age groups. In this study, 144 condyles from 78 cadavers (40 men, 38 women; age at death: >70 years) were investigated. The macroscopic shapes of the condyles were classified from posterior and lateral views into four types: convex, flattened, angled, and irregular. Of the 144 condyles, 25 were investigated microscopically. On macroscopic examination, in both posterior and lateral views, convex-type condyles were most frequently observed. Most posterior convex-type condyles were also categorized as the lateral convex type. On histological examination, we observed an increase in cartilage cells (7 condyles, 28%), a decrease in cartilage cells (3 condyles, 12%). Increases in cartilage cells were seen only in angled and irregular types (P = 0.001), whereas decreases in cartilage cells were only observed in the flattened type (P = 0.01). A convex macroscopic form appears to be standard for human mandibular condyles, even in the elderly. The histological findings suggest that mandibular condyles tend to not only undergo flattening, but also undergo progressive changes toward protrusion with age due to increased numbers of cartilage cells. In other words, this study suggests that there is potential for progressive alterations in mandibular condyles in the elderly.

Clinical assessment of the relationship between the third molar and the inferior alveolar canal using panoramic images and computed tomography.

PURPOSE: To predict the relationship between lower third molars and the inferior alveolar canal (IAC) from panoramic radiographs, and to establish criteria for using computed tomography (CT). MATERIALS AND METHODS: A retrospective cohort study was performed involving 443 patients (695 teeth). Predictor variables were the distance between the third molar and the IAC, and findings according to the Rood's criteria. Outcome variables were the absence of cortication between the third molar and the IAC on the CT image, and injury of the inferior alveolar nerve (IAN). Statistical analysis was performed to assess the relationship between predictor and outcome variables. RESULTS: All patients had preoperative panoramic radiographs, and 71 patients (119 teeth) also had CT images. On CT examination, 48 teeth (40.3%) showed absence of cortication. Injury of the IAN was reported in 7 cases (1.0%), 5 of which exhibited absence of cortication; the remaining 2 did not have CT scans. Five of the 48 cases showing absence of cortication exhibited IAN injury, and none of the cases with cortication exhibited IAN injury. On the panoramic images, the following signs were strongly correlated with absence of cortication: a superimposed relationship between the third molar and the IAC; darkness of the root; and diversion and narrowing of the IAC. CONCLUSION: Presence of Rood's criteria was a predictor for a contact relationship between the third molar and the IAC, and an indication for CT examination. However, a superimposed relationship and the absence of Rood's criteria did not necessarily signify a separate relationship between third molar and the IAC.

[Osteomyelitis of the jaw in breast cancer patients receiving bisphosphonate therapy].

Osteonecrosis of the jaw is a severe new complication in cancer patients with bone metastases receiving bisphosphonate. Currently, there is no effective treatment for bisphosphonate-related osteonecrosis of the jaw, and the pathogenesis of this complication has not been completely elucidated. It has been shown that a potential risk factor for the complication is dentoalveolar trauma including extraction of teeth during bisphosphonate therapy. Attention should be paid to dental care in patients prior to the initiation of bisphosphonate therapy, and extraction of teeth during bisphosphonate therapy should be avoided to prevent this complication. Therefore, the communication between general physicians prescribing bisphosphonate and dentists is important.