Assessment of the functional efficacy of root canal treatment with high-frequency waves in rats.

The purpose of this study was to develop a high-frequency wave therapy model in rats and to investigate the influence of high-frequency waves on root canal treatment, which may provide a novel strategy for treating apical periodontitis. Root canal treatments with and without high-frequency wave irradiation were performed on the mandibular first molars of 10-week-old male Wistar rats. The mesial roots were evaluated radiologically, bacteriologically, and immunohistochemically. At 3 weeks after root canal treatment, lesion volume had decreased significantly more in the irradiated group than in the non-irradiated group, indicating successful development of the high-frequency therapy model. The use of high-frequency waves provided no additional bactericidal effect after root canal treatment. However, high-frequency wave irradiation was found to promote healing of periapical lesions on the host side through increased expression of fibroblast growth factor 2 and transforming growth factor-ß1 and could therefore be useful as an adjuvant nonsurgical treatment for apical periodontitis.

Multicenter study on caries risk assessment in adults using survival Classification and Regression Trees.

Dental caries is an important public health problem worldwide. This study aims to prove how preventive therapies reduce the onset of caries in adult patients, and to identify patients with high or low risk of caries by using Classification and Regression Trees based survival analysis (survival CART). A clinical data set of 732 patients aged 20 to 64 years in nine Japanese general practices was analyzed with the following parameters: age, DMFT, number of mutans streptococci (SM) and Lactobacilli (LB), secretion rate and buffer capacity of saliva, and compliance with a preventive program. Results showed the incidence of primary carious lesion was affected by SM, LB and compliance with a preventive program; secondary carious lesion was affected by DMFT, SM and LB. Survival CART identified high-risk patients for primary carious lesion according to their poor compliance with a preventive program and SM (≥10(6) CFU/ml) with a hazard ratio of 3.66 (p = 0.0002). In the case of secondary caries, patients with LB (≥10(5) CFU/ml) and DMFT (>15) were identified as high risk with a hazard ratio of 3.50 (p < 0.0001). We conclude that preventive programs can be effective in limiting the incidence of primary carious lesion.

Multicenter study on caries risk assessment in Japanese adult patients.

OBJECTIVES: This study was conducted to identify significant risk factors for the onset and the accumulation of new caries in adult patients undergoing regular preventive therapy. METHODS: The data of 732 patients from nine Japanese general dental practices were retrospectively analyzed. Classification and regression tree (CART) analysis was applied to develop a caries prediction model using the following patient parameters: age, number of teeth with caries experience (DMFT), levels of mutans streptococci (SM) and lactobacilli (LB), saliva flow rate and buffer capacity, and compliance with a preventive program. Poisson regression analysis was conducted to identify factors affecting caries accumulation within three years. RESULTS: CART analysis identified patients at high risk for primary caries with an odds ratio of 3.08 (95%CI, 1.55-5.79; p=0.0018) according to SM levels and compliance; and those for secondary caries with an odds ratio of 3.69 (95%CI, 2.29-5.91; p<0.0001) according to LB and SM levels. Poisson regression analyses showed that accumulation of primary caries was affected by compliance (p<0.001), SM (p<0.001) and LB (p=0.013). Accumulation of secondary caries was affected by DMFT (p<0.001), SM (p<0.001) and LB (p<0.001). CONCLUSIONS: CART is an important tool in identifying the risk of caries development in individual adult patients. Cariogenic bacteria are important factors for both the onset and accumulation of primary and secondary caries. CLINICAL SIGNIFICANCE: Participation in a regular preventive program limits the onset and the accumulation of primary caries in adult patients.

Dentistry in the 21st century: challenges of a globalising world.

Oral health is - literally - vital to good general health, not least because the mouth is the sentinel of the body. Dentistry, the Cinderella of health care, faces immense challenges of globalisation. Governments, having spent freely on everything from defence to social security, face mountains of debts which make budget cutbacks essential. Simultaneously, most developed countries have to pay increasing costs of caring for rapidly ageing populations. Dentistry is being pulled two ways: wealthy members of society demand high-end expensive treatment, much of it cosmetic rather than necessary to deal with disease, whereas many millions of poor people in developing countries cannot afford basic dental treatment and may never see a dentist. Too many governments and dentists persist with the expensive and destructive regime of 'drill and fill (and bill)'. International advances in care may not reach the clinician's chair because treatment guidelines and payments are set locally. An international symposium to celebrate Mikako Hayashi becoming Professor of Restorative Dentistry and Endodontology at Osaka University concluded that dentistry should move from an increasingly un-affordable curative model to a cost-effective evidence-based preventive model. The goal is to help people retain healthy natural teeth throughout their lives, as an essential part of enhancing their general health.

Risk assessment of dental caries by using Classification and Regression Trees.

OBJECTIVES: Being able to predict an individual's risks of dental caries would offer a potentially huge natural step forward toward better oral heath. As things stand, preventive treatment against caries is mostly carried out without risk assessment because there is no proven way to analyse an individual's risk factors. The purpose of this study was to try to identify those patients with high and low risk of caries by using Classification and Regression Trees (CART). METHODS: In this historical cohort study, data from 442 patients in a general practice who met the inclusion criteria were analysed. CART was applied to the data to seek a model for predicting caries by using the following parameters according to each patient: age, number of carious teeth, numbers of cariogenic bacteria, the secretion rate and buffer capacity of saliva, and compliance with a prevention programme. The risks of caries were presented by odds ratios. Multiple logistic regression analysis was performed to confirm the results obtained by CART. RESULTS: CART identified high and low risk patients for primary caries with relative odds ratios of 0.41 (95%CI: 0.22-0.77, p = 0.0055) and 2.88 (95%CI: 1.49-5.59, p = 0.0018) according the numbers of cariogenic bacteria. High and low risk patients for secondary caries were also identified with the odds ratios of 0.07 (95%CI: 0.01-0.55, p = 0.00109) and 7.00 (95%CI: 3.50-13.98, p < 0.0001) according the numbers of bacteria and existing caries. CONCLUSIONS: Cariogenic bacteria play a leading role in the incidence of caries. CART proved effective in identifying an individual patient's risk of caries.