Resumo

GARCIA, Rubens Nazareno et al. Bond strength and degradation of a self-adhesive flowable composite in dental substrates and a restorative composite. RFO UPF [online]. 2016, vol.21, n.1, pp. 61-68. ISSN 1413-4012.

Objective: This study aimed to assess the shear bond strength (SBS) of a self-adhesive flowable composite in four substrates used in the direct technique, with one week and one year of storage in distilled water. Materials and method: Ninety-six samples (5-mm wide / 15-mm long / 2-mm thick) of bovine teeth - uncut enamel, cut enamel, medium dentin - and direct restorative composite/CD Filtek Z350XT™ (3M ESPE) were used; there were 24 samples per substrate. The samples were divided into two groups according to storage time. Two flowable composites (Control/FF - Filtek Z350 XT Flow™/3M ESPE, and the self-adhesive/DF - Dyad Flow™/Kerr) were bonded to the four substrates (n=6). Four tubings were positioned on each sample, filled with FF/DF composites, and light-cured for 20 s. The tubings were removed to expose the specimens (24 per group) and stored in distilled water at 37±2°C for one week and one year. After each period, the specimens were subjected to the Shear Bond Strength (SBS) test (speed of 1.0 mm/min). The results were analyzed by Anova and Tukey's test (p<0.05). Results: For the one- -week tests with DF composite, cut enamel and direct restorative composite showed higher SBS, with no difference between themselves. Uncut enamel and medium dentin presented lower SBS, with no significant difference. For the one-year test with DF composite, the behavior was similar, however uncut enamel and medium dentin showed lower SBS. Conclusion: The results show that Dyad Flow™ composite, after one year of storage in distilled water, showed higher shear bond strength in cut enamel and direct composite substrates.

Palavras-chave : Composite resins.; Dental enamel.; Dentin.; Shear strength..