Purpose: Implant component fractures are one of the most serious complications in implant treatment. With a better understanding of the risk factors for fracture in the preoperative, surgery, superstructure, and post-loading phases of implant treatment, low-risk treatment could reduce implant component fractures, leading to a better prognosis. The aim of this study was to clarify the risk factors for abutment and implant fractures that occur after loading, and to perform a retrospective, approximately 10-year follow-up study to explore the risk factors in each treatment phase. Methods: Subjects were fitted with an implant prosthesis between January 2008 and December 2009. In total, 1,126 Ankylos implants in 430 patients were included for analysis. Binary logistic regression analysis was performed to extract factors related to non-fracture and fracture of the abutment or implant as a dependent variable.

The aim of this study was to show the reaction varieties of human tooth enamel and dentin with a carbonated soft drink, Sprite. After one week exposing into the soft drink, the sliced tooth specimens were examined by macroscopic and microscopic and then carried out the micro X-ray diffraction analysis using a 100 m diameter X-ray beam. The macroscopic and microscopic results showed the wide varieties from the one showing a very slight increase white-spot areas in the enamel to the another showing almost complete decay of the enamel. The crystallites in the examined enamel and dentin changed drastically as follows; the one enamel sample showed the decrease of crystal amount and some ionic substitutions, and the another dentin sample showed the increase in crystallinity and ionic substitutions. These results clearly showed that the original tooth enamel and dentin had their own crystallographic properties differing from each others. This study provided a crystallographic basic data which will be applied to a tayler-made individual preventive dentistry in near future.

The purpose of this study was to evaluate the correlation and distribution of dental postgraduate residents, dentists and clinical training facilities in each prefecture to analyze the regional distribution and supply of dentists in Japan. The results were also compared with referential data for medicine. The coefficient of correlation between the dentist index and dental postgraduate resident index was r = 0.76 (P < 0.001) in 2006. The distribution (coefficient of variation) was greatest for the dental postgraduate resident index. The numbers of dentists per 100,000 population in prefectures with dental colleges were significantly higher in 1986, 1996 and 2006 for each comparison (P < 0.001). Coefficients of correlation between dentist index and dental postgraduate resident index were r = 0.

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Multi-observer assessment involves the assessment of a personʼs work behavior by more than one colleague at the same time for the purpose of human resource development and capacity building. In the medical field, multi-observer assessment is employed to provide formative feedback during regular one-on-one meetings in order to increase the professional competence of medical residents, but it is rarely used in dental medicine. This report describes multi-observer assessment of the performance of trainee dentists at cooperative-type facilities. A total of 70 trainee dentists were assessed in the present study.For method of an investigation, a supervising dentist, a dental hygienist, and a receptionist assessed the professionalism and communication skills of the trainee dentists. There were significant differences of the average scores of assessment about the professionalism of the trainee dentist by all reviewers (p < 0.01, p < 0.05). There was a positive correlation between the average scores assigned by the supervising dentist and the dental hygienist (r = 0.62, p < 0.001,), as well as between the scores assigned by the dentist and receptionist (r = 0.53, p < 0.001,) or the dental hygienist and receptionist (r = 0.78, p < 0.001). These results suggest that there is a strong correlation between assessment by dentists, dental hygienists, and receptionists. The assessment that includes the perspective of the healthcare service recipients (patients) is needed in the future.

Background: Public oral health surveys have shown that the prevalence of dental caries in adults is increasing worldwide, resulting in increased workload and costs of dental and other clinical oral health services. Total streptococci are broadly grouped into mutans streptococci and three other species. They constitute a majority of bacteria found in the mouth. Of the total streptococci, the group of bacteria that primarily causes dental caries is mutans streptococci, which consists of seven species. Streptococcus mutans (S. mutans) is the mutans streptococcus most strongly associated with dental caries. To date, no simple culture assay (kit) has been developed for detecting S. mutans using plaque samples for caries risk assessment. This study aimed to evaluate the association between S. mutans and dental caries in adults based on the number and proportion of cariogenic bacteria in toothbrush plaque samples by culture methods to obtain basic data to develop clinical and chairside culture assay for caries risk assessment.

No abstract

Marsupials were mammals whose young were born in an undeveloped stage and attached to the mother's nipples, usually in a pouch. Despite, these jaw elements to suckle and digestive system must develop early. Previously we have reported that the morphology of the salivary glands in the gray short-tailed opossums (Monodelphis domestica). This opossum, a kind of marsupial, has three large salivary glands which include the parotid, submandibular and sublingual glands. Parotid glands consist only of serous acinar cells. Submandibular and sublingual glands consist of seromucous secretory end pieces and the submandibular and sublingual glands were mixed glands. This study was purpose to investigate the localization of cytokeratin19 (CK19), aquaporin5 (AQP5) and alpha smooth muscle actin (SMA) in the gray short-tailed opossum parotid, submandibular and sublingual glands. These proteins localization was determined by immunohistochemistry on paraffin sections. Submandibular and sublingual glands showed a broadly similar staining pattern. CK19 was localized to the acinar cells and ductal cells in three major salivary glands. AQP5 was expressed in the luminal only of serous cells. Alpha-SMA was observed around the secretory end pieces. These results are thought to reflect the characteristic of the opossum salivary glands. Further studies are required to unravel obscure matters with cell differentiation and physiological functions of salivary glands among the mammals.