ABSTRACT
ABSTRACT Objective: To evaluate the effect of thermocycling on the Knoop internal microhardness of high- and low viscosity bulk fill resins applied in Class I cavities. Methods: Thirty third molars with Class I cavity preparations were randomly divided into 3 groups according to the restorative system: nanoparticulated composite resin (Filtek™ Z350 XT 3M ESPE) (oblique increments of 2mm); low viscosity bulk fill resin (Filtek™ Bulk fill Flow, 3M ESPE) (3mm increments covered with a 1-mm layer of nanoparticulated resin); high viscosity bulk fill resin (Filtek™ Bulk fill, 3M ESPE) (single 4-mm increment). After 24h, half of samples was submitted to thermocycling (1,000 cycles). All samples (n=5) were sectioned in half to measure the internal microhardness at bottom and top of restoration. Results: Analysis of variance indicated that, for nanoparticulated composite resin, without thermocycling, the microhardness at the top was statistically lower than at the bottom. After thermocycling, there was no difference in microhardness between the top and the bottom. For low viscosity bulk fill resin, without thermocycling, there was no significant difference in microhardness means between the top and the bottom. After thermocycling, significantly higher microhardness was found at the top than at the bottom (p <0.05). For high viscosity bulk fill resin there was no significant difference between the microhardness values at the top and bottom, regardless of thermocycling (p> 0.05). In all composite resins, an increase in microhardness was observed after thermocycling (p <0.05). Conclusion: Thermocycling increased the internal microhardness of resin restorations, and, for the low viscosity bulk fill resin, the microhardness at the top was higher than at the bottom after thermocycling.
RESUMO Objetivo: Avaliar o efeito da termociclagem na microdureza Knoop interna de resinas bulk fill de alta e baixa viscosidade aplicadas em cavidades classe I. Métodos: Trinta terceiros molares com cavidades Classe I foram divididos aleatoriamente em três grupos de acordo com o sistema restaurador: Resina composta nanoparticulada (Filtek™ Z350 XT 3M ESPE) (incrementos oblíquos de 2mm); resina bulk fill de baixa viscosidade (Filtek™ Bulk fill Flow, 3M ESPE) (incremento de 3mm mais 1mm de resina nanoparticulada); resina bulk fill de alta viscosidade (Filtek ™ Bulk fill, 3M ESPE) (único incremento de 4mm). Após 24h, metade das amostras foi submetida a termociclagem (1.000 ciclos). Todas as amostras (n=5) foram seccionadas ao meio para mensuração da microdureza interna na base e topo da restauração. Resultados: Análise de variância indicou que, para a resina composta nanoparticulada e antes da termociclagem, a microdureza no topo foi estatisticamente inferior do que na base (p<0,05). Após a termociclagem, não houve diferença entre topo e base. Já para a resina bulk fill de baixa viscosidade, antes da termociclagem, não se constatou diferença significativa nos valores de microdureza entre topo e base. Após termociclagem, valores significativamente mais elevados de microdureza foram encontrados no topo do que na base (p<0,05). Para resina bulk fill de alta viscosidade, não houve diferença significativa na microdureza entre topo e base, realizando-se ou não termociclagem (p>0,05). Em todas as resinas compostas foi verificado aumento de microdureza após termociclagem (p<0,05). Conclusão: A termociclagem aumentou a microdureza para todas as resinas compostas, sendo que para a resina bulk fill de baixa viscosidade a microdureza no topo foi maior do que na base após termociclagem.
ABSTRACT
BACKGROUND: The assessment of oral health should consider clinical and biopsychosocial aspects. AIM: To evaluate the impact of untreated dental caries on the quality of life of children. DESIGN: A cross-sectional study was conducted with 647 Brazilian children. The Child Perceptions Questionnaire (CPQ8-10 ) and the 'oral health' global indicator were administered to the children and used as the outcomes. Parents answered a general questionnaire, and oral clinical examinations were performed. Data analysis involved descriptive statistics, chi-squared test, Mann-Whitney test, and Poisson's regression analysis (α = 5%). The psychometric properties of the CPQ8-10 were tested for younger age group (6/7 years). RESULTS: Untreated caries was a predictor of impact on quality of life for the following items: 'pain in teeth/mouth' (PR = 1.69; 95% CI: 1.41-2.04), 'difficulty biting/chewing hard foods' (PR = 1.28; 95% CI: 1.05-1.56), 'difficulty eating what you wanted to eat' (PR = 1.61; 95% CI: 1.29-2.02), 'trouble sleeping' (PR = 1.64; 95% CI: 1.27-2.13), 'missed school' (PR = 1.62; 95% CI: 1.24-2.12), 'trouble doing homework' (PR = 1.61; 95% CI: 1.12-2.31), and 'difficulty paying attention in class' (PR = 1.41; 95% CI: 1.01-1.96). CONCLUSION: Children with untreated dental caries feel greater negative impacts on quality of life than children without untreated caries.
