A Method for the Rapid Cultivation of Desulfovibrio aestuarii on Filter Membranes

The cultivation of sulfate-reducing bacteria on agar plates is a somewhat involved and time-consuming process. This is partly due to the requirement for fairly strict anaerobic conditions but mainly because of the length of the incubation period which may vary from 6 days to weeks with the resulting delay of the required information. The work reported herein was undertaken in an attempt to apply the advantageous features of the membrane filter method to the detection of anaerobic organisms. As originally developed, the membrane filter (Goetz and Tsuneishi, 1951; Clark et al., 1951) permits the recovery of small numbers of organisms from large volumes of water and the rapid cultivation of many aerobic bacteria. The ultimate purpose was to develop a method which would not require more complex manipulation than the membrane procedure according to Standard Methods for the Examination of Water, Sewage, and Industrial Wastes (A.P.H.A. 1955) and to reduce the incubation period for anaerobic bacteria

Reasons for Tooth Extractions in Japan: The Second Nationwide Survey

BACKGROUND: More than 10 years have passed since the first nationwide study on the reasons for tooth extraction in Japan. In the present study, we conducted the second nationwide survey to update the previous data. METHODS: This was a descriptive study. A sample population consisting of 5,250 dentists was selected by systematic random sampling using the 2018 membership directory of the Japan Dental Association. The reason for each permanent tooth extraction was documented by each dentist during a period of 1 week from June 4 to June 10, 2018. A questionnaire was provided for documentation. Reasons for tooth extraction were categorised into 6 groups as follows: caries, periodontal disease, fracture, orthodontics, impacted teeth, and others. RESULTS: A total of 2345 identified dentists responded to the questionnaire (recovery rate: 44.8%). Information on 7809 extracted teeth from 6398 patients was obtained. Periodontal disease was the main reason for tooth extraction for both sexes (men: 40.4%, women: 34.9%). Caries accounted for 30.2% of tooth extractions among men and 29.0% among women. Periodontal disease was predominant in the groups older than 55 years of age. Dental fracture accounted for 16.8% of tooth extractions among men and 19.2% among women. CONCLUSIONS: Caries and periodontal disease are still the main reasons for tooth extraction in Japan. Moreover, dentists should note that fractures accounted for approximately one-fifth of permanent tooth extractions after the age of 45 years

Self-Reported Diabetes Mellitus and Tooth Extraction Due to Periodontal Disease and Dental Caries in the Japanese Population

Diabetes mellitus is closely related to oral health. We aimed to determine the relationship between diabetes mellitus and tooth extraction due to periodontal disease and dental caries. Japan’s second nationwide survey data collected from 4 June to 10 June 2018 was used to identify reasons for tooth extraction among patients aged > 40 years. General dentists collected information on patients who underwent tooth extraction procedures, and the presence of diabetes mellitus was determined through interviews. Multivariable logistic regression was performed to investigate the relationship between diabetes mellitus and the reasons for tooth extraction, including periodontal disease and dental caries. In total, 2345 dentists responded to the survey (response rate 44.8%). We analyzed data on 4625 extracted teeth from 3750 patients (1815 males and 1935 females). Among patients with self-reported diabetes mellitus, 55.4% had extractions due to periodontal disease compared to 46.7% of such extractions among those without self-reported diabetes mellitus. Self-reported diabetes mellitus was significantly associated with tooth extraction due to periodontal disease. No significant differences were observed in dental caries according to self-reported diabetes mellitus status. This study provides further evidence of a significant association between diabetes mellitus and tooth extraction due to periodontal disease