Immediate and delayed repair bond strength of a new ormocer resin restorative material as a function of mechanical and chemical surface conditioning methods

Abstract

This study evaluated the μ-shear repair bond strength (μSBS) of a new ormocer restorative material as a function of repair time and repair protocol. Ormocer disks (N = 140) (Admira Fusion, Voco) were prepared and divided into 14 groups: Factor 1: Bonding protocol (No Conditioning, Admira Bond, Futurabond M+, Silane/Admira bond, Silane/Futurabond M+, Ceramic repair system, Silane/Cimara bond) and Factor 2: Repair procedure time (immediate versus delayed). Each disk received two ormocer micro-cylinders. Half of the disks were repaired immediately (24 h) and the other half after six-month water storage. Shear test was run at cross-head speed of 0.5 mm/min. Debonded specimens were evaluated for failure mode and SEM analysis was performed. Data were analyzed using two-way ANOVA and Tukey’s tests (p < 0.05). Both the repair time and the surface conditioning method showed a significant effect on the repair μSBS (MPa) of the ormocer material (p = 0.000). When immediate repair strengths were considered, all repair protocols tested reached the mean bond achieved based on oxygen-inhibited layer (10.8 ± 2.4 MPa), except. Futurabond M+(13.9 ± 3.4) and Silane/Cimara adhesives (16.3 ± 2.9) showed significantly higher μSBS (p = 0.001 and p = 0.000, respectively). For the delayed repair, non-conditioned (5 ± 1.7), showed significantly lower values compared to those of the other protocols (p < 0.05). Failure modes were predominantly adhesive type (immediate:95% and delayed:90%). No cohesive failures were observed either in the substrate or in the repair material.