Dayse Andrade Romão

Effect of Fluoride Concentration on Reduction of Enamel Demineralization According to the Cariogenic Challenge

Fluoride present in toothpaste at 1,100 µg/g is considered effective on caries control. However, under high cariogenic challenge due to increasing sugar exposure, higher fluoride concentration (5,000 µg/g) could be necessary to compensate the unbalance on caries process. This was tested in a pH-cycling regimen, which evaluated the effect of fluoride concentration relative to toothpaste on reduction of enamel demineralization under conditions of two levels of cariogenic challenge. Enamel slabs (n=20) were subjected to two pH-cycling regimens, simulating 8x and 16x/day sugar exposure and were treated with solutions containing: 0 (no fluoride), 275 or 1,250 µg F/mL, resulting in 6 treatment groups: 4-h/0-F; 8-h/0-F; 4-h/275-F; 8-h/275-F; 4-h/1,250-F and 8-h/1,250-F. The 275 and 1,250 µg F/mL concentrations simulate mouth salivary dilution when 1,100 and 5,000 µg/g toothpastes are used. Enamel demineralization was assessed by surface (%SHL) and cross-sectional hardness. Fluoride taken up by enamel was also evaluated. Data were analyzed by ANOVA one-way and Tukeys test. The treatment with 1,250 µg F/mL significantly reduced %SHL compared with 275 µg F/mL (p<0.05), irrespective the level of cariogenic challenge (4-h/1,250-F vs. 4-h/275-F and 8-h/1,250-F vs 8-h/275-F comparisons, respectively). These data were supported by fluoride concentration found in enamel. These findings suggest that higher fluoride concentrations could partly compensate the greater caries risk under higher cariogenic challenge due to increasing sugar exposure.

Experiência de cárie dentária em usuários de drogas psicoativas

1Universidade Federal de Alagoas, Maceió/AL, Brasil. 2Universidade Estadual de Campinas, Piracicaba/SP, Brasil. RESUMO| Introdução: O uso de substâncias psicoativas tem aumentado mundialmente e tem se tornado um problema de saúde pública. A falta de autocuidado nessa população a coloca em maior risco para o desenvolvimento da cárie dentária. Objetivo: Verificar a experiência de cárie dentária em usuários de substâncias psicoativas. Métodos: Foi realizada uma revisão narrativa da literatura por meio das bases de dados PubMed, Embase e Scopus, utilizando-se os termos: drug users, drug abusers, drug addicts, dental caries, unidos pelo operador booleano AND, período entre os anos 2000 e 2015, uso do Índice de dentes permanentes cariados, perdidos e obturados (CPO-D) e de língua inglesa. Resultados: Foram encontrados 181 artigos; desses, 136 foram excluídos após referências em duplicata entre as combinações das palavras-chave e entre bases de dados; 45, selecionados para leitura de títulos e resumos, e apenas 7 artigos foram selecionados para esta revisão por avaliarem a experiência de cárie em usuários de álcool e de outras drogas. Foi identificado que os drogaditos podem fazer uso isolado ou associado entre diferentes tipos de drogas. Conclusão: De acordo com esta revisão narrativa, os resultados sugerem que os usuários de álcool e de outras drogas são acometidos pela doença cárie dentária e se apresentam como um grupo de risco que necessita de cuidado odontológico.

Development of caries adjacent to composite restorations after exposure to dentifrices with different fluoride concentrations

Objective To evaluate the development of recurrent caries after exposure to fluoride dentifrices with different concentrations. Material and method: 48 samples of bovine incisors (4x4mm2) were exposed to pH cycling for 7 days before the preparation of the cavities (2mm deep). The samples were restored with a microhybrid resin composite. Then, the samples were exposed to thermal cycling (350 cycles) and they were randomly allocated into 4 treatment groups (n = 12): Group A - non-fluoridated dentifrice (negative control); Group B - 500 ppm dentifrice; Group C - 750 ppm dentifrice; group D - 1100 ppm dentifrice (positive control). The samples were treated with solutions of each dentifrice (9.6 ml water/1.6 g dentifrice) for 60 seconds and then were immersed in demineralizing (3 h) and remineralizing (2 h) solutions 3 times a day. Next, the samples were immersed in a remineralizing solution for 18 hours. Then, the blocks were sectioned for examination of the length of the outer caries lesion, using polarized light microscopy. The ANOVA parametric test complemented by the Tukey test with a confidence level of 95%, were used in the statistical analysis. Result: A smaller lesion length was observed in the group treated with the fluoride concentration of 1100 ppm F, but there were no differences between toothpastes with fluoride concentrations of 500 and 750 ppm F. Conclusion: The use of fluoride dentifrices (1100 ppm) reduces the development of caries adjacent to dental restorations.