Yoshinobu Maki

A Semi-Quantitative Determination of Streptococcus mutans Using Its Adherent Ability in a Selective Medium

A method differentiating the critical level of Streptococcus mutans in whole saliva was developed. The procedure is as follows: 100 μl whole saliva is inoculated into 2 ml of MSB broth, the test tube is set tilted at a 60° angle and incubated aerobically at 37 °C for 24 h. The degree of adherence is then scored. When the adherence score is + + +, S. mutans may be assumed to be present at a level higher than 105/ml of whole saliva. On the other hand, if adherence is scored – or + S. mutans is present at a level lower than 104/ml of whole saliva. The method is useful for handling many samples in preventive practice and epidemiological studies, because of its simplicity.

A Rapid and Quantitative Detection System for Streptococcus mutans in Saliva Using Monoclonal Antibodies

A new semiquantitative enumeration system was developed to detect Streptococcus mutans in saliva. Using species-specific monoclonal antibodies, the system quickly detected salivary S. mutans in 30 min and classified the results into three levels. In this study, saliva samples collected from 28 young adults aged between 22 and 24 years were subjected to the monoclonal antibody-based detecting system and selective medium-based detecting methods. The results generated from the PCR-confirmed culture method indicated the mean salivary S. mutans counts at level 1, 2 and 3 were 5.7 × 104, 1.3 × 105 and 3.4 × 106 CFU/ml, respectively. The differences between level 3 and 1 and level 3 and 2 were statistically significant (one-way ANOVA; p < 0.01). The results generated from the system were consistent with the data generated from two culture-based commercial products.

Effect of pH on Acid Production from Sorbitol in Washed Cell Suspensions of Oral Bacteria

The acid production from sorbitol and glucose was studied under anaerobic conditions in resting cell suspensions of bacteria from the predominant sorbitol-fermenting human dental plaque flora, belonging to the genera Streptococcus, Lactobacillus and Actinomyces. The acid production activity of the bacterial cells was followed by titration with alkali, at environmental pH 7.0, 6.0 and 5.0 after addition of carbohydrate solution. The metabolic end products formed in the suspensions were analyzed thereafter by isotachophoretic and enzymatic methods. The results showed that sorbitol was fermented at a slower rate than glucose. Lowering the environmental pH decreased the acid production activity from the two carbohydrates. Compared with glucose, the catabolism of sorbitol was affected to greater extent by the pH conditions. The total amount of acids formed from sorbitol was considerably less than from glucose. Lactic acid, which was the major end product in glucose-challenged suspensions, was produced only in low concentrations from sorbitol by all strains tested. The ratio strong (formic + lactic)/weak acids was moreover lower for sorbitol than for glucose. The present results further illustrate some of the mechanisms behind the low cariogenic potential of this sugar substitute.

Evaluation of a Japanese “Prevention of Long-term Care” project for the improvement in oral function in the high-risk elderly

Aim:  The purpose of this study was to analyze the improvement in oral function and environment in high‐risk elderly persons participating in a program to improve oral function organized by their local government.

Evaluation of a dysphagia screening system based on the Mann Assessment of Swallowing Ability for use in dependent older adults

Dysphagia is common in dependent older adults. Thus, a method of evaluating eating and swallowing functions that can be used to diagnose and manage dysphagia in a simple and robust manner is required. In 2002, the Mann Assessment of Swallowing Ability (MASA) was introduced to identify dysphagia in acute‐stage stroke patients. As the MASA enables easy screening, it might also be applicable to dependent older adults if appropriate MASA cut‐off values and the most useful assessment items could be determined. In the present study, we attempted to determine suitable MASA cut‐off values, and the most useful assessment items for predicting aspiration and pharyngeal retention in dependent older adults.

Comparison of the oral health problems and behavior of male daytime-only and night-shift office workers: An Internet survey.

The aim of this study was to compare the oral health problems and behavior of full‐time male daytime‐only and night shift office workers.

Comparison of Dental Explorers and CPI-probes in Diagnosing Dental Caries

The primary aim of the present study was to compare efficiency in detecting suspected caries requiring observation (CO) and decayed teeth (DT) between dental explorers and Community Periodontal Index (CPI)-probes in school dental examinations and evaluate the effect of their respective use on Decayed, Missing, Filled Teeth (DMFT) Index scores. A total of 126 elementary and high school students were examined. All the clinical findings were obtained by a pair of trained dentists examining each student at routine annual school dental examinations. A dental explorer or CPI-probe and dental mirror were used for the examination. One dentist used the dental explorer, while the other used the CPI-probe. The choice of which instrument to use by the first dentist to examine the student was made at random. A comparison of the explorers and CPI-probes revealed that the numbers of patients and permanent teeth classified as CO were greater with the former in 6th-grade elementary and high school students (p<0.05). The Kappa value for CO and DT was 0.560 for 6th-grade elementary school and 0.846 for high school students. All DMFT scores were higher with the explorers than with the CPI-probes in the 6th-grade elementary school students. No significant difference was observed between the explorers and CPI-probes in any of the DMFT scores in any group, however. The present results indicate that as long as the low rate of caries in Japanese school children is maintained, the epidemiological data on this disease should not show any significant change if a CPI-probe is used instead of an explorer in school dental examinations.

Adhesiveness of Foods and Their Retention in the Mouth

食品の齲蝕誘発能は, 食品の齲蝕誘発病に与える基質としての性質と, その基質としての性質の作用時間とで評価することが, 可能であることを著者らは提唱してきた。本報では, 食品の物理的性状によって影響されると考えられる食品の作用時間としての性質を測定することをその目的とした。食品の作用時間としての性質は, 摂取中の作用時間と嚥下後の作用時間とに分けられ, 前者は, 食品単位重量あたりの摂取時間で, 後者は, 食品の付着性を23種の食品について測定し, その結果から, 食品の物理的性状よりその齲蝕誘発能を評価する方法について次のような考察を得た。1) 従来の報告で食品の作用時間としての性質が正しく評価されていない種類の食品についても, 食品の作用時間としての性質を二つに分けて行なう本研究方法によって, その評価が可能であることが明らかとなった。2) 本研究方法は, 従来の方法と比較して簡単であり, 被験者間の個人差もみられない。3) レオメーターによる食品の物理的性状の測定は, 齲蝕誘発能の評価のための指標として有用であることが, 示唆された。