Reliability and correlation between microshear and microtensile bond strength tests of composite repairs.

The aim of this study was to evaluate the reliability of microshear (µSBS) and microtensile (µTBS) bond strength tests on composite repairs using universal adhesives with or without the application of additional silane. Cylindrical (µSBS) and block-shaped (µTBS) specimens were fabricated using nanofilled (F-Filtek One Bulk Fill) and nanohybrid (T-Tetric EvoCeram Bulk Fill) bulk-fill composites. The specimens were aged by thermocycling (5,000 cycles, 5-55 °C), sandblasted, and then divided into three groups (n = 30) as follows: non-repaired (FC and TC), repaired with universal adhesives (FA, Scotchbond Universal; and TA, Adhese Universal), and with the previous application of silane (FS and TS). After 48 h, the specimens were repaired using the same composite. The µSBS and µTBS specimens exhibited bonded areas of 1 mm2 and were subjected to shear stress and tension until failure, at a crosshead speed of 0.5 mm/min in a universal testing machine. Weibull analyses and Pearson correlation (α = 0.05) were applied to the data. At characteristic strength, FC, FA, and FS exhibited significantly higher µSBS when compared with TA and TS (p < 0.05). However when tested by µTBS at the same parameter, FA presented significantly lower bond strength when compared to FC, FS, and TA (p < 0.05). The correlation between Weibull modulus was strongly negative and not significant (p > 0.05). Both bond strength tests exhibited a material-dependent behavior. The microtensile bond strength test demonstrated more reliability than the microshear test for composite repair evaluation.

Achieving Better Function through Combining Orthodontics and Restorative Dentistry in the Case of Dental Abrasions.

This case report describes the orthodontic treatment used to prepare for restorative dentistry, aimed at the functional rehabilitation of an adult patient with Class I malocclusion, right posterior crossbite, and significant tooth wear on the palatal face of the maxillary canine to canine. The orthodontic treatment was performed with a total fixed appliance mini-expandex-type expander, associated with vertical elastics. Good dental intercuspation was obtained and enabled conditions for the restoration of the abrasions on the palatal surfaces of the maxillary incisors and canines and the tips of the buccal cusps of the maxillary right premolars and first molar. Excellent results were found during a 37-month follow-up.