Characterization of Mechanical Properties, Fluoride Release and Colour Stability of Dental Sealants

Objective: To compare the mechanical properties, fluoride release, colour stability and spreading characteristics of glass ionomer cement (GIC), compomer (CO), chemical (CR) and light-cured resin based (LR) fissure sealants. Material and Methods: Cylinders were prepared to determine mechanical properties by diametral tensile strength tests (stored for 24h in distilled water at 37°C) and fluoride release (24 hours, 3, 7 and 15 days; deionised water). Disk shaped specimens were prepared to determine colour stability (1 week in pigmenting solution; 37°C; CIE L*a*b*; ΔE). A simplified method of a spreading test was proposed to predict viscosity characteristics of the tested materials. Data were analysed using one-way ANOVA followed by T-test (p<0.05). Results: Results showed differences between materials regarding all tested properties. CO was statistically more resistant than the other materials (p<0.05), but no difference was observed between CR and LR. The fluoride release of GICs was significantly higher than the other materials (p<0.05). CO showed lower ΔE than the other materials in the following order: CO

Variations of salivary flow rates in Brazilian school children.

The salivary flow rate (SFR) in healthy individuals may vary according to different factors. There is a scarcity of studies from different geographical areas that analyze SFR variations in children. The aim of this study was to verify stimulated salivary flow rate (SFR) variations in 6 to 12-year-old children, from four different public schools of Rio de Janeiro and correlate these data to gender, age, type of dentition, and health status. Clinical data were taken from the children's medical records that were kept at those schools. Oral examination and sialometry were performed in every child. Salivary flow rate was obtained by chewing-stimulated whole saliva under standard conditions. There were significant differences in SFR according to age (p = 0.0003). Six and 12-year-old children showed the lowest SFR, and when they were excluded from the analysis, no significant differences were found (p = 0.21). There were also significant differences in SFR among children from different public schools (p = 0.0009). The gender did not show any correlation to SFR, even when children were stratified by age (p = 0.36). Correlation between SFR and deciduous, mixed or permanent dentition was not found as well. These results show that the analyzed clinical variables did not seem to influence SFR in this children population.

Variations of salivary flow rates in Brazilian school children

O fluxo salivar (FS) em indivíduos saudáveis pode variar em função de diversos fatores. Dados sobre a análise das variações do FS em crianças de diferentes regiões geográficas são escassos na literatura. O objetivo deste trabalho foi estudar possíveis variações do FS em crianças de quatro escolas públicas do Rio de Janeiro, apresentando entre 6 e 12 anos de idade, além de correlacionar esses dados com gênero, idade, tipo de dentição e estado de saúde. A história médica das crianças foi obtida dos registros nas escolas. Em todas as crianças foram realizados exame bucal e sialometria. O FS foi obtido pelo método de saliva total estimulada mecanicamente, em condições padronizadas. Houve diferenças no FS em relação à idade (p = 0,0003). Crianças de 6 e 12 anos mostraram as menores médias de FS, mas quando estas crianças foram eliminadas da análise, não houve mais diferenças significativas no FS em relação à idade (p = 0,21). Houve também diferenças significativas nas médias dos FS entre as escolas (p = 0,0009). Não houve correlação do FS com gênero, mesmo quando as crianças foram agrupadas em relação à idade (p = 0,36). Também não houve correlação entre FS e as dentições decídua, mista ou permanente. Esses resultados mostram que na população de crianças estudada não houve influência das variáveis clínicas analisadas sobre o FS.