Safety evaluation was made on Biological canal paste (BCP), one of newly developed endodontic pastes used for Ultrasonic Bio-Mechanical Obturation System. BCP was characteristic of a high content of thymol to show extreme antimicrobic action. The basic biological tests on cytotoxicity, systemic toxicity, mutagenicity and dermal sensitization were carried out in this study. On potency of cell growth inhibition in vitro, BCP was as same as Canals-N^[○!R] and much less than Canals^[○!R]. As neither death nor toxic syndrome in mice was found from administration of BCP in oral maximal dose of 1.0mg/kg, it was estimated that LD_<50> of BCP should be not less than the value of 'slightly toxic' classified by Deichmann. BCP showed negative results in mutagenicity examined by Ames test, and also in delayed type allergenicity by Adjuvant and patch test. From the above it was suggested that BCP was possibly safe so far as it was used properly for dental therapy.

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The purpose of this study was to evaluate the clinicopathologic factors associated with late cervical metastases developing at high rate in 6 of 11 patients (54.5%) with stage IドI tongue carcinoma following partial glossectomy alone at Department of Oral Surgery, Health Insurance AMAKUSA CHUO General Hospital between 2002-2004. Those 6 patients had more than 5mm in thickness and exceeded grade 3 (Mode of invasion, Yamamoto, 1984) of the primary tongue tumor. As a small number of cases including decisive predictive values of the late cervical metastasis have used in this study, it demonstrated the late cervical metastasis at high rate. All patients who developed late cervical metastases have recieved delayed radical neck dissection, there were no recurrences at the cervical region after surgery, but the distant metastasis occurred in one case.

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Objective Structured Clinical Examination (OSCE) of dental education in Japan will be executed in 2005. Recently, we analyzed the questionnaire surveys of students participating in OSCE trial of Kyusyu Dental College in 2002. Almost all students answered that the participation to the OSCE trial was useful for their reviews of lectures, and motivated for their future clinical practices. On the other hand, students doubted the meaning of the OSCE trial, and also expressed that the curriculums of the clinical practices were not enough for increasing their clinical skills. Although the curriculums for dental education of our college should be considered, the OSCE trial appears to be useful for the motivation of the students before the clinical practices.

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Lingual osseous choristoma is a rare lesion. A case of lingual osseous choristoma was found in a 20-year-old female. The lesion was a hard pedunculated mass measuring about 14×13×8mm in the right side posterior region of the tongue. The tumor was excised under general anesthesia. Histological finding showed a well circumscribed mass of dense lamellar bone with Haversian canals. It was covered with normal squamous epithelium.

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