Fluoride Release of Fresh and Aged Glass Ionomer Cements after Recharging with High-Fluoride Dentifrice.

OBJECTIVE: This study aimed to evaluate F release from GICs before and after recharging with F-dentifrices and after aging process. METHODS: Fifteen specimens of GICs (conventional, resin modified, and high viscosity) and composite resin were stored individually in a polystyrene tube containing 2 ml of deionized water (DW), with water replacement every 24 hours. After 15 days, the specimens were treated with a dentifrice suspension (1 : 3 by volume) containing 0 µg F/g (n = 5), 1,100 µg F/g (n = 5), or 5,000 µg F/g (n = 5). After 3 min, the specimens were rinsed and replaced in new tubes with 2 ml of DW. This procedure was performed 2x/day for 2 days. The readings were taken on days 1, 5, 10, and 15 before and after the treatments. A second experiment was performed, using the same specimens of the previous study that were submitted to an aging process (specimens were kept in 2 ml of DW, remaining at 37°C for 36 weeks). Readings using specific electrode for F detection were taken on days 1, 5, 10, and 15 after treatment of the samples as described above. Data were analyzed by ANOVA and Tukey's test with α fixed at 5%. RESULTS: It was observed that the highest release of F for all the GICs occurred on the first day after the treatments, especially when using a high-fluoride dentifrice, with decreasing release over time. Also, although aged GICs still recharge with F treatments, the amount of F released was lower than fresh materials. CONCLUSION: GICs present a high F recharge and release capacity, especially in the first 24 hours and after the treatment with a high-fluoride dentifrice, even after material aging.

Effect of Sweeteners on Root Dentine Demineralization Using a Microcosm Biofilm Model / Efecto de los Edulcorantes en la Desmineralización de la Dentina Radicular Utilizando un Modelo de Biofilm Microcosmo

ABSTRACT: The aim of the present study was to evaluate the effect of commercial sweeteners on root dentin demineralization using a microcosm biofilm model. Bovine dentin specimens with pre-determined surface hardness were randomized into six groups according to the studied sweeteners: sucralose, stevia, saccharin, aspartame. Sucrose was used as a positive control and an untreated group as a negative control. The specimens were submitted to biofilm development from one saliva donor and the cariogenic challenge occurred on subsequent five days, twice a day. At the end, the percentage of surface hardness loss (%SHL) and biomass was determined and submitted to ANOVA followed by Tukey's test. Sucrose presented the highest rate of demineralization, however, all sweeteners tested lead to a statistically higher root demineralization compared to the negative control (p <0.05). Sucrose caused greater demineralization in root dentin, however, the sweeteners were also able to induce it under this biofilm model.

RESUMEN: El objetivo del presente estudio fue evaluar el efecto de los edulcorantes comerciales en la desmineralización de la dentina radicular utilizando un modelo de biofilm microcosmo. Se asignaron al azar muestras de dentina bovina con una dureza de la superficie predeterminada de acuerdo con los edulcorantes estudiados: sucralosa, estevia, sacarina, aspartame. La sacarosa se utilizó como control positivo y un grupo no tratado como control negativo. Las muestras se enviaron al desarrollo de biopelículas de un donante de saliva y el desafío cariogénico se produjo en los siguientes cinco días, dos veces al día. Al final, se determinó el porcentaje de pérdida de dureza de la superficie (% PDS) y biomasa y se aplicó un estudio estadístico de ANOVA seguido de la prueba de Tukey. La sacarosa presentó la mayor tasa de desmineralización; sin embargo, todos los endulzantes probados condujeron a una desmineralización de la raíz estadísticamente mayor en comparación con el control negativo (p<0,05). La sacarosa causó una mayor desmineralización en la dentina de raíz, sin embargo, los edulcorantes también fueron capaces de inducirla bajo este modelo de biofilm.

Association of chlorhexidine and high fluoride dentifrice on Streptococcus mutans viability using an in vitro biofilm model / Associação de clorexidina e dentifricio com alta concentração de flúor na viabilidade de Streptococcus mutans em um modelo de biofilmes in vitro

Objective: this in vitro study investigated the effect of high-fluoride dentifrice, Chlorhexidine (CHX), and their association on the viability of Streptococcus mutans using a biofilm model. Material and Method: biofilms were anaerobically grown on glass slides that were vertically suspended in 24-well plates for 5 days. After 48 h of initial growth, biofilms were treated for the next 72 h, 2x/day with 0.12% CHX and 2%, F as 0.08% and 0.4% NaF and their association. Results: CHX treatment decreased the bacteria counts either alone or in association with both F concentrations, when compared with control group and the F treatments alone (p < 0.05). Conclusion: no additional effect was observed when CHX and F were used in combination, when compared with CHX used alone.

Objetivo: este estudo avaliou, o efeito do dentifrício com alta concentração de fluor (F), da clorexidina (CHX) e da associação destes na viabilidade de Streptococcus Mutans (SM) utilizando um modelo de biofilme in vitro. Materiais e Métodos: biofilme cresceram anaerobicamente em lamínulas de vidro suspensas, verticalmente, em placas de 24 poços por 5 dias. Após 48h do crescimento inicial, o biofilme formado foi submetido a um tratamento por 72h, 2x/ dia com CHX 0.12%, F na forma de NaF a 0.08% e 0.4%, suas associações, CHX 2% (controle positivo) e solução salina (controle negativo). Os dados obtidos foram transformados e submetidos ao ANOVA e teste de Tukey e em seguida analisados por meio do SAS, com significância fixada em 5%. Resultados: isolada ou em associação com as diferentes concentrações de F, a CHX demonstrou maior potencial em reduzir os níveis de SM quando comparada ao uso isolado de F em ambas concentrações ou com o controle negativo (p < 0,05). Conclusão: o uso da combinação de F e CHX não apresentou efeito adicional na redução dos níveis de SM quando comparado ao uso isolado de CHX.