Kanae Niimi

Vascular invasion in squamous cell carcinomas of human oral mucosa

The process of vascular invasion of human oral squamous cell carcinomas was histologically and immunohistochemically studied in surgical and autopsy specimens. Hematoxylin-eosin, Massons trichrome, and immunohistochemical stainings for Ulex europaeus I lectin binding, CD31, and type IV collagen were done to differentiate lymphatic and blood vessels and to demonstrate basement membranes in vascular walls and around carcinoma cell nests was observed. With growth of tumor, there was mechanical disruption of vascular walls and endothelial cells by carcinoma cell nests. After disrupting vascular walls, they invaded into the lumen as clusters, not as single cells. At the blood vessel invasion sites, inflammatory reactions were seen around carcinoma cell nests inside as well as outside lumina with microthrombotic reactions due to endothelial injury. At the lymphatic invasion sites, carcinoma cell nests maintained their volume inside the lumen and the cells adhered tightly to each other, and inflammatory reaction was scarcely seen. These findings showed that mechanical pressure has an important role in the vascular invasion of human oral squamous cell carcinoma.

Prognostic factors for autotransplantation of teeth with complete root formation.

OBJECTIVES The aim of the present study was to evaluate the factors affecting the prognosis of the autotransplantation of teeth with complete root formation. STUDY DESIGN A total of 259 transplanted teeth were studied. The significance of each of the prognostic factors was examined in 2 ways, first in a univariate analysis and then in a multivariate analysis. The comprehensive risk combining these factors that remained after multivariate analysis was calculated. RESULTS Among 259 transplanted teeth, 27 (10.4%) were judged as unsuccessful cases. In the multivariate analysis, history of root canal treatment of donor tooth, multirooted, maxillary tooth as a donor, and duration of tooth absence at recipient site remained significantly associated with unsuccessful transplantation. Multifarious combination of the significant prognostic factors can decrease the comprehensive risk. CONCLUSIONS Minimizing the comprehensive risk by combining significant prognostic factors improved the prognosis of autotransplantation of teeth with complete root formation.

A simple technique for repositioning of the mandible by a surgical guide prepared using a three-dimensional model after segmental mandibulectomy

BackgroundMandibular reconstruction is performed after segmental mandibulectomy, and precise repositioning of the condylar head in the temporomandibular fossa is essential for maintaining preoperative occlusion.MethodsIn cases without involvement of soft tissue around the mandibular bone, the autopolymer resin in a soft state is pressed against the lower border of the mandible and buccal and lingual sides of the 3D model on the excised side. After hardening, it is shaved with a carbide bar to make the proximal and distal parts parallel to the resected surface in order to determine the direction of mandibular resection. On the other hand, in cases that require resection of soft tissue around the mandible such as cases of a malignant tumor, right and left mandibular rami of the 3D model are connected with the autopolymer resin to keep the preoperative position between proximal and distal segments before surgical simulation. The device is made to fit the lower border of the anterior mandible and the posterior border of the mandibular ramus. The device has a U-shaped handle so that adaptation of the device will not interfere with the soft tissue to be removed and has holes to be fixed on the mandible with screws.ResultsWe successfully performed the planned accurate segmental mandibulectomy and the precise repositioning of the condylar head by the device.ConclusionsThe present technique and device that we developed proved to be simple and useful for restoring the preoperative condylar head positioning in the temporomandibular fossa and the precise resection of the mandible.