Effects of surface treatment, hydration and application method on the bond strength of a silorane adhesive and resin system to dentine

Abstract

Objectives: To evaluate the effects of surface treatment, surface hydration (SH) and application method (AM) on the tensile bond strength of the Silorane Adhesive System (SAS) to dentine.

Methods: Ninety bovine teeth were used. For the control group (n=10), each dentine surface was treated according to the manufacturer's instructions of the SAS. The remaining teeth were randomly distributed into two groups (n=40), according to the type of dentine surface treatment (ST)-37% phosphoric acid or Er:YAG Laser prior to the application of the SAS. Each group was further divided into 2 subgroups (n=20), according to the SH status: dry (D) or wet (W). Each subgroup was further divided into 2 subgroups (n=10), according to the application method [AM: Active (AC) mode or Passive (PA) mode]. A coat of resin composite (Filtek P90) was applied on the surface. Artificial ageing was performed with a thermo-mechanical cycling machine. The specimens were sectioned into 1mm×1mm×10mm sticks and stressed to failure using a universal testing machine. The remaining teeth in each group were used for Scanning Electron Microscopy to examine the fractured area. Data were subjected to a three-way ANOVA, Tukey's test and Dunnet's test (α=0.05).

Results: The ANOVA showed significant differences for SH and AM, but not for ST. For SH, the results of Tukey's test were (in MPa): D - 14.9(±3.8)(a), W - 17.1(±4.3)(b); and for AM: PA - 14. 9(±4.2)(a), AC - 17.1(±3.9)(b).

Conclusions: Acid etching, when combined with a moist dentine surface and the use of primer agitation, improves the bond strength of the SAS to dentine.

Clinical significance: According to the results of the present in vitro study, modification of the application protocols for the silorane-based adhesive system may improve its clinical performance.