Although Streptococcus anginosus is a part of the normal flora found in human dental plaque, recent studies indicate that S. anginosus infection in oral mucosa can be associated with oral squamous cell carcinoma. The organism possesses a number of pathogenic properties, however, the adhesive mechanism that mediates the initial process of S. anginosus infection to oral mucosal epithelial cells remains to be elucidated. In this study, the adhesive abilities of S. anginosus to mucosal epithelial cells of a human larynx carcinoma cell line (HEp-2 cells) and a gingival epithelial cell line (GE1 cells) as well as the immobilized fibronectin were investigated. The results indicated that S. anginosus can adhere to both mucosal epithelial cells as other oral streptococci do, and that the adhesive ability could be ascribable to mainly its fibronectin-mediated adherence to the mucosal epithelial cells. It was also indicated that the adhesive ability to HEp-2 cells of the S. anginosus isolates from oral cancer tissues was significantly higher than that of the isolates from the plaque sample of healthy subjects. Although the cell-surface expression of fibronectin in HEp-2 cells was augmented by the bacterial adhesion itself and the autocrine activation of TGF-β 1 induced by the bacterial adhesion, the addition of exogenous fibronectin (10nM) enhanced the S. anginosus adherence to HEp-2 cells. Furthermore, the pretreatments with fibronectin of the bacterial cells as well as HEp-2 cells enhanced the S. anginosus adherence, and the enhancements were abrogated by the addition of anti-fibronectin antibodies, suggesting the coexistence of a direct adhesion of S. anginosus to the fibronectin of HEp-2 cell surfaces and another fibronectin-mediated adhesion mechanism involving a fibronectin bridge between the S. anginosus fibronectin-binding molecule(s) and the integrins of HEp-2 cells. Moreover, the adhesive ability of the oral cancer isolates of S. anginosus was markedly higher than those of the plaque sample isolates and of the laboratory strain of S. anginosus. Taken together, the present findings suggest that S. anginosus could adhere to mucosal epithelial cells via multiple adhesion mechanisms, and the adhesive ability to fibronectin could be involved in the pathogenicity of S. anginosus, leading to the onset of oral squamous cell carcinoma.

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In November 1994, the Oral Implant Room was established as a clinic at the Dental Hospital of Iwate Medical University School of Dentistry. Since then, with the cooperation of the implant committee members recommended from each hospital department, we have performed treatment for the recovery of stomatognathic function. Therefore, with the goal of understanding the results of the Oral Implant Center, the clinical statistics of the treatment provided in the 14 years and 5 months between its opening and March 2009 were assembled, and the following results were obtained. 1. There were 148 cases of implantation involving 129 patients (54 men, 75 women). 2. Mean age at time of implantation was 50.6 years. Individuals in their 50s outnumbered those of other decades, and women outnumbered men. 3. A total of 513 implants were implanted (192 maxilla, 321 mandible), with an average of 3.5 implants per person. 4. The average time between primary surgery and secondary surgery was 5 months 24 days for the maxilla and 3 months 17 days for the mandible. 5. Regarding the distribution of implants, 52.6% were mandibular free-end and 29.3% were in the anterior maxilla. 6. Of the implant patients, 10.7% were smokers and 24.8% were drinkers. 7. The survival rate for the implants was 97.9%.

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