King Chong Chan

Radiographic Evaluation of Maxillary Sinus Lateral Wall and Posterior Superior Alveolar Artery Anatomy: A Cone-Beam Computed Tomographic Study

OBJECTIVE The purpose of the current study is to assess the thickness of the maxillary sinus lateral wall in dentate and edentulous patients using cone beam computed tomography (CBCT). This study also provides information about the diameter, prevalence, and course of the posterior superior alveolar artery (PSAA), and its relation to the maxillary sinus floor. MATERIALS AND METHODS Four hundred and thirty CBCT scans of the maxillofacial complex (860 maxillary sinuses) were reviewed. Measurements of the lateral wall of the maxillary sinus and PSAA were performed on the CBCT images. RESULTS Statistical analysis showed that dental status (edentulous, non-edentulous) of the patients had no significant effect on the lateral wall thickness. The mean thickness of the lateral wall of the maxillary sinus was 1.21 ± 1.07 mm at the second molar (M2), 1.98 ± 1.87 mm at the first molar (M1), 2.02 ± 1.53 mm at the second premolar (P2) and 2.16 ± 1.25 mm at the first premolar (P1). There was statistically significant difference between the left and right sides of the maxillary sinus only at P2 (p =.043). Detection rate of the PSAA on CBCT was reported as 60.58%. The mean diameter of the artery was 1.17 mm (range 0.4-2.8 mm). There was no significant correlation between age and the size of the PSAA. The most frequent path of the PSAA was intraosseous (69.6%), followed by intrasinusal (24.3%) and superficial (6.1%). The overall mean distance of the PSAA from the floor of the maxillary sinus is 8.16 mm. CONCLUSIONS The results from this study suggest that using CBCT prior to the surgery provides valuable diagnostic information. However, undetected intraosseous canal in CBCT does not exclude its existence. Alteration in the lateral window design and the use of piezoelectric instruments are recommended if intraoperative complications are expected.

A radiographic study of permanent molar development in wild Virunga mountain gorillas of known chronological age from Rwanda

OBJECTIVES While dental development is important to life history investigations, data from wild known-aged great apes are scarce. We report on the first radiographic examination of dental development in wild Virunga mountain gorillas, using known-age skeletal samples recovered in Rwanda. MATERIALS AND METHODS In 43 individuals (0.0-14.94 years), we collected radiographs of mandibular molars, and where possible, cone beam CT scans. Molar crown and root calcification status was assessed using two established staging systems, and age prediction equations generated using polynomial regression. Results were compared to available data from known-age captive and wild chimpanzees. RESULTS Mountain gorillas generally fell within reported captive chimpanzee distributions or exceeded them, exhibiting older ages at equivalent radiographic stages of development. Differences reflect delayed initiation and/or an extended duration of second molar crown development, and extended first and second molar root development, in mountain gorillas compared to captive chimpanzees. However, differences in the duration of molar root development were less evident compared to wild chimpanzees. DISCUSSION Despite sample limitations, our findings extend the known range of variation in radiographic estimates of molar formation timing in great apes, and provide a new age prediction technique based on wild specimens. However, mountain gorillas do not appear accelerated in radiographic assessment of molar formation compared to chimpanzees, as they are for other life history traits. Future studies should aim to resolve the influence of species differences, wild versus captive environments, and/or sampling phenomena on patterns observed here, and more generally, how they relate to variation in tooth size, eruption timing, and developmental life history.

Salivary duct carcinoma ex pleomorphic adenoma of the palate: a case report.

Carcinoma ex pleomorphic adenoma is a rare malignancy of the head and neck, particularly in the minor salivary glands. Most cases arise in the major salivary glands, most commonly in the parotid gland, followed by the submandibular gland. The malignant component of the tumor varies, but can be salivary duct carcinoma, adenoid cystic carcinoma, mucoepidermoid carcinoma, squamous cell carcinoma, or adenocarcinoma, not otherwise specified. Primary salivary duct carcinoma is also a rare malignancy of the head and neck. Similar to carcinoma ex pleomorphic adenoma, it is more common in the major salivary glands, with the parotid gland accounting for 88% and the submandibular gland for 10% of cases. To date, only 25 known cases of primary salivary duct carcinoma arising in the minor salivary glands have been documented, with most arising in the palate. Salivary duct carcinoma ex pleomorphic adenoma of the minor salivary glands appears to be even rarer. Our case of salivary duct carcinoma ex pleomorphic adenoma of the palate is the first complete report, to our knowledge, in the English-language scientific literature.

Does Fluorodeoxyglucose Positron Emission Tomography With Computed Tomography Facilitate Treatment of Medication-Related Osteonecrosis of the Jaw?

PURPOSE There is considerable controversy over the treatment of medication-related osteonecrosis of the jaw (MRONJ) and growing interest and debate related to the timing, type, technique, and goals of surgical intervention. The specific aim was to evaluate the predictive value of fluorodeoxyglucose (FDG) positron emission tomography (PET) with computed tomography (CT) on healing outcomes in patients undergoing surgery for MRONJ of the mandible. MATERIALS AND METHODS A retrospective cohort study of 31 patients with 33 MRONJ lesions of the mandible who had undergone surgery using FDG PET-CT was conducted. Data were collected on FDG uptake patterns, healing, follow-up, demographics, lesion characteristics, antiresorptive therapy, and adjunctive therapy. Panoramic and/or periapical radiographs were used to identify non-restorable teeth and PET-CT images were used to identify sequestra and FDG uptake. Above the mandibular canal, surgery consisted of marginal resection and/or debridement of clinically involved bone and exposure of clinically uninvolved bone identified by FDG uptake. Below the mandibular canal, mobile segments of bony sequestra were removed, but areas of clinically uninvolved bone with FDG uptake were not. Patients who did not heal underwent segmental resection and reconstruction with rigid fixation and a local or regional soft tissue flap or free fibular flap. The primary predictor variable was the FDG uptake pattern for each patient. The outcome variable was postoperative healing defined by mucosal closure without signs of infection or exposed bone at the time of evaluation. RESULTS Two risk groups were identified based on FDG uptake pattern. The low-risk group, type A, included 22 patients with activity limited to the alveolus, torus, and/or basal bone superior to the mandibular canal. The high-risk group, type B, included 11 patients with type A FDG activity with extension inferior to the mandibular canal. Treatment of type A MRONJ lesions was more successful than treatment of type B MRONJ lesions (100 vs 27%; P < .001). Seven of the type B failures were successfully retreated by segmental resection and reconstruction (1 patient refused further treatment). CONCLUSION These results showed that low-risk FDG PET-CT findings predicted successful healing with surgery above the mandibular canal. In contrast, high-risk FDG findings were associated with a greater than 50% risk of failure for treatment that extended below the mandibular canal. Although these failures suggest that FDG uptake indicates infected tissue, further research is needed to identify which high-risk patients are most likely to benefit from a conservative treatment protocol.