Influence of method and period of storage on the microtensile bond strength of indirect composite resin restorations to dentine

This study evaluated the influence of the method and period of storage on the adhesive bond strength of indirect composite resin to bovine dentin. Ninety bovine incisors were stored in three different solutions: 0.2 percent thymol, 10 percent formalin, and 0.2 percent sodium azide, during 3 periods of storage: 7 days, 30 days and 6 months, resulting in 9 groups (n = 10). The roots were cut off and the buccal surface was ground with #600-grit silicon carbide paper. The surface was conditioned with 37 percent phosphoric acid for 15 s and a composite resin restoration (TPH Spectrum) was fixed using a one-bottle adhesive system (Adper Single Bond) and a dual-cured resinous cement (Rely X ARC) under a load of 500 g for 5 minutes. The samples were serially cut perpendicular to the bonded interface to obtain slices of 1.2 mm in thickness. Each slab was trimmed with a cylindrical diamond bur resulting in an hourglass shape with a cross-sectional area of approximately 1 mm². The microtensile bond strength (μTBS) testing was performed in a testing machine (EMIC 2000 DL) at a 0.5 mm/minute crosshead-speed until failure. After fracture, the specimens were examined under SEM to analyze the mode of fracture. μTBS Means were expressed in MPa and the data were analyzed by two-way ANOVA (3X3) and the Tukey test (α = 0.05). The storage times of 7 and 30 days produced no significant difference irrespective of the solution type. The formalin and thymol solutions, however, did have a negative influence on bond strength when the teeth were stored for 6 months.

Análise comparativa do diagnóstico clínico, radiográfico e macroscópico da cárie dentária em cicatrículas e fissuras / Comparative analyze of clinical radiographic and optical diagnosis of dental caries in pit and fissure

Este trabalho se propõe a comparar os métodos de diagnóstico clínico e radiográfico da cárie na região de cicatrículas e fissuras em 30 dentes posteriores humanos, realizados por 15 Cirurgiões-dentistas e 15 acadêmicos de odontologia. Os dentes foram montados em blocos de cera, radiografados de forma padronizada e submetidos à avaliação clínica e radiográfica de superfície oclusal, afirmando ou rejeitando a presençça de cárie. Posteriormente, os dentes foram seccionados ao meio, no sentido mésio-distal, planificados e, então, analisados em lupa estereoscópica em aumento de 40X para validação da presença de cárie. A análise dos dados demonstrou que a experiência profissional não interferiu no percentual de acertos do exame clínico e que o exame radiográfico pouco contribuiu para a detecção da cárie oclusal. O índice de acerto, tanto para profissionais, quanto para acadêmicos foi maior no exame clínico que no radiográfico.