RESUMO
OBJECTIVE: The aim of this study to investigate the effects of different polymerization protocols on the cuspal movement in class II composite restorations. MATERIALS AND METHODS: Human premolar teeth were prepared with class II cavities and then restored with composite and three-step and two-step etch-and-rinse adhesive systems under different curing techniques (n = 10). It was used a light- emitting-diode curing unit and the mode of polymerization were: standard (exposure for 40 seconds at 700 mW/cm(2)), pulse-delay (initial exposure for 6 seconds at 350 mW/cm(2) followed by a resting period of 3 minutes and a final exposure of 37 seconds at 700 mW/cm(2)) and soft-start curing (exposure 10 seconds at 350 mW/cm(2) and 35 seconds at 700 mW/cm(2)). The cuspal distance (µm) was measured before and after the restorative procedure and the difference was recorded as cuspal movement. The data were submitted to two-way ANOVA and Bonferroni test (p < 0.05). RESULTS: The type of adhesive system did not influenced the cuspal movement for all the curing methods. Standard protocol showed the highest values of cuspal movement and was statistically different from the pulse-delay and soft-start curing modes. CONCLUSION: Although the cuspal displacement was not completely avoided, alternative methods of photocuring should be considered to minimize the clinical consequences of composites contraction stress.
Assuntos
Dente Pré-Molar/anatomia & histologia , Resinas Compostas/química , Materiais Dentários/química , Restauração Dentária Permanente/classificação , Cura Luminosa de Adesivos Dentários/métodos , Coroa do Dente/anatomia & histologia , Condicionamento Ácido do Dente/métodos , Fenômenos Biomecânicos , Bis-Fenol A-Glicidil Metacrilato/química , Lâmpadas de Polimerização Dentária/classificação , Preparo da Cavidade Dentária/classificação , Humanos , Cura Luminosa de Adesivos Dentários/instrumentação , Teste de Materiais , Polimerização , Doses de Radiação , Cimentos de Resina/química , Estresse Mecânico , Propriedades de Superfície , Fatores de TempoRESUMO
Introdução: As cerâmicas são consideradas uma excelente alternativa como material estético restaurador, entretanto questões relevantes, como adaptação marginal, exigem um maior critério na confecção quando comparadas aos sistemas convencionais. Objetivo: Este trabalho avaliou a adaptação marginal de uma coroa In-Ceram confeccionada sobre um dente que, após 3 anos, teve sua extração indicada pela ortodontia. Material e métodos: A avaliação deu-se por meio de microscópio eletrônico de varredura. Resultados e conclusão: Foram encontrados valores de falta de adaptação entre 157 e 390 um, obtendo uma média estatística acima do considerado aceitável clinicamente pela literatura.
Introduction: Ceramics are considered an excellent choice as esthetic restorative material, but relevant questions like marginal fit require more attention in manufacturing than conventional systems. Objective: This work evaluated the marginal adaptation of an In-Ceram crown over a tooth that, after three years, had been indicated to extraction by orthodontics. Material and methods: The evaluation was by mean scanning electron microscope. Results and conclusion: It was found values of gaps between 157 and 390 um, getting a statistic average considered greater than the accepted by literature.