A Comparative Study of a New Microtensile Testing Device for Dental Research

Aims: This study aimed to compare the performance of a new microtensile bond strength (µTBS) testing device, called the Flextest device.

Study Design: This is an experimental randomised study in which composite resin/dentin stick-shaped specimens were submitted to a microtensile bond strength test in both Flextest device and Bencor Multi-T device.

Place and Duration of Study: University of Brasília (Brasília, Brazil). The duration of this study is 2 years.

Methodology: Fifteen human third molars were submitted to dentin surface exposure, polishing, bonding treatment, and composite blocks that were built up and sectioned to obtain composite resin/dentin stick-shaped specimens with a cross-sectional area of approximately 0.9 mm². One hundred composite resin/dentin specimens were assigned randomly to the Bencor Multi-T device (Danville Engineering, San Ramon, CA, USA) group (n = 50) and the Flextest device group (n = 50). Tensile bond testing was performed by a universal testing machine (MTS, Eden Prairie, MN, USA) at a crosshead speed of 1.0 mm/min. The intragroup and intergroup µTBS comparisons, and the ratios of the types of failure in each group were analysed by factorial analysis of variance, Fisher`s test, and the Chi square test at 5% significance.

Results: Both devices showed significant intragroup differences. However, the differences were not significant between the devices.

Conclusion: The new Flextest device and the Bencor Multi-t device had similar microtensile bond strength test results; however, a lower standard deviation was observed in the Flextest device group.