Comparative study of bond strength of tubes bonded to a resin surface on the buccal aspect of molars using Empress Direct resin and Transbond XT resin: an ex vivo study

Resumen

Objective: To assess the detachment of tubes bonded to the first molars on a resin surface without surrounding dental enamel, which were bonded with the same restorative resin Empress Direct and the Transbond XT resin, testing three preparation methods of the resin surface. Material and methods: The sample consisted of 120 third molars, which were prepared with cavities in the buccal aspect and restored with Empress Direct, which in turn, were divided into six groups. In the case of groups I and II 37% phosphoric acid was placed on the surfaces of the resin restorations; the tubes were bonded on the surface using for group I Empress Direct resin and for group II, Transbond XT. On groups III and IV phosphoric acid and silane were placed; the tubes were bonded with the two types of resin in the same way as in groups I and II. In groups V and VI the resin surface was sandblasted with 50 μ aluminum oxide and conditioned with 37% phosphoric acid and silane. Finally, we evaluated the tubes bond strength. Results: Group I, in which 37% phosphoric acid was used, the bond strength was 2.71 ± 1.06 (MPa) and for Group II, it was 3.32 ± 1.06 (MPa). Group III, in which phosphoric acid and silane was used had a bond strength of 4.45 ± 1.46 (MPa) and group IV showed a bond strength of 6.64 ± 1.93 (MPa); for group V which used sandblasting, orthophosphoric acid and silane, bond strength was 9.55 ± 3.0 (MPa) and for group VI it was 10.56 ± 3.88 (MPa). Conclusions: The bond strength of tubes increases when the resin surface is prepared with sandblasting, 37% phosphoric acid and silane with both Empress Direct and Transbond XT resins.