Akiyuki Maeda

Three-dimensional Assessment of the Accuracy of Maxillary Repositioning by Le Fort I Osteotomy with Emphasis on Maxillary Backward Transference

Objective: To evaluate the accuracy of repositioning of the maxilla by Le Fort I osteotomy with emphasis on maxillary backward transference. Materials and Methods: Thirty patients with jaw deformity who underwent Le Fort I osteotomy were enrolled in the study. The patients were divided into 3 groups: backward transference group, in whom both molar regions were moved >2 mm in the posterior direction; forward transference group, in whom both molar regions were moved >2 mm in the anterior direction; and minor transference group, in whom both molar regions were moved <2 mm. The 3-dimensional position of the maxillary central incisor (U1) and both first molars (R6, L6) were measured on presurgical, surgical, and post-surgical dental models. The difference between planned and actual movements was analysed using Wilcoxon signed-rank test. Results: In the backward transference group, the maxilla was moved backward to excess, probably because of a preconception that forward movement after the operation due to occlusal force will occur. In the forward transference group, the maxilla was located more forward as a consequence of being excessively moved upwards. In the horizontal direction, influence of the operators position and the plate fixation method were thought to explain the differences between the backward transference group and the forward transference group. Conclusion: To perform the operation more precisely, additional reference points with a plane factor are needed for Le Fort I osteotomy. In the future, the infrared sensor might be useful and effective.

Condylar Reconstruction by Vertical Sliding Ramus Osteotomy

Abstract A convenient method for condylar reconstruction through vertical ramus sliding osteotomy after condylectomy of the mandible is described. The method utilises the submandibular approach enabling a modification of the intracapsular temporomandibular joint arthroplasty and avoidance of excessive exposure of the temporomandibular joint capsule. This appears to prevent mandibular dysfunction postoperatively while maintaining the restored vertical dimension of the ramus.

Involvement of Chemokine Receptor 4/Stromal Cell-derived Factor 1 System in Human Salivary Gland Carcinoma Motility

Abstract Salivary gland carcinoma such as adenoid cystic carcinoma (AdCC) is characterized by slow growth, diffuse invasion and lung metastasis, which determine the patients prognosis. It is important to clarify an attractant molecule leading tumor cells to migrate. We examined the effects of stromal cell-derived factor (SDF)-1, a chemokine, on salivary gland carcinoma cell clone HSG and its subclone HSG-AZA3. SDF-1 promoted the invasion and migration of HSG and HSG-AZA3 cells dose-dependently. Immunocytostaining and RT-PCR indicated that HSG and HSG-AZA3 cells expressed SDF-1 receptor, CXCR4, both in protein and mRNA level, respectively. CXCR4 was present on the cell surface of HSG cells, was downregulated by SDF-1 addition. Finally, we confirmed that CXCR4 was expressed in the tissue of AdCC. Our study suggests that SDF-1 and CXCR4 play a role in the migration of carcinoma of salivary gland origin.

Salivary Duct Carcinoma of the Minor Salivary Glands

Abstract Salivary duct carcinoma is characterised by aggressive behaviour, with a high risk of local recurrence, and regional and distant metastasis. This report describes a patient with salivary duct carcinoma that originated in the minor salivary glands of the mucosa over the maxilla. Microscopically, vascular invasion varied from 4 to 5 per 10 high-power fields, and immunohistochemical staining with E26 transformation specific-1 was demonstrated in the tumour cells. Ki67 positivity was also revealed in 52% of the specimens examined. These results suggest that salivary duct carcinoma is a highly aggressive malignant salivary gland tumour due to proliferative cell activity, angiogenesis, and vascular invasion.