Effect of Surface Treatment and Aging on the Shear Bonding Strength of Interim Restoration Materials

Abstract

@font-face { font-family: Calibri; }@font-face { font-family: BatMincho; }@font-face { font-family: Malgun Gothic; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 10pt; line-height: 115%; font-size: 11pt; font-family: Times New Roman; }div.Section1 { page: Section1; } Statement of Problem Interim restorations are required for extended periods as complex treatment is being established or to assess long-term prognosis of teeth. The reparability of interim restorations relies on adhesion of the repair material onto the parent restorative material. Purpose The purpose of this study was to investigate the shear bonding strength of bis-acryl composite resins compared to autopolymerizing polymethyl methacrylate (PMMA) under different surface treatments and environmental conditions. Material and Methods Eighty cylindrical specimens fabricated from PMMA and bis-acryl received one of the following of environmental treatments: no surface treatment, surface roughening with SiC paper, grinding with bur or chemical treatment. One group was stored in water for 24 h (37 °C, distilled water) and the other group was stored in coffee for 24 h (37 °C). Shear bond strength was determined by loading the specimens to failures with a 10 kN load cell and a 0.5 mm/min crosshead speed. The statistical significances were evaluated by Kruskal-Wallis one-way ANOVA . Every analysis was approved with 95% reliance. Results For PMMA stored in water, there was no statistical difference between different surface treatments. For PMMA stored in coffee, surface roughening treatment with SiC paper had the highest average bonding strength and was significantly better than no surface treatment or surface treatment with bur. For bis-acryl stored in water, surface roughening with SiC paper had the highest average bonding strength and was significantly better than no surface treatment. Surface treatment with bur was also significantly better than no surface treatment. For bis-acryl stored in coffee, the highest average bonding strength was for surface treated specimens with SiC and this was significantly better than surface treatment with bonding agent. Whether specimens were stored in water or coffee, PMMA was significantly better than bis-acryl in all surface treatment groups. Conclusions In all environmental conditions including no surface treatment, surface roughening with SiC paper, grinding with bur, or chemical treatment, and in all storage media, PMMA has better bonding strength compared to bis-acryl. For bis-acryl specimens, surface roughening with SiC paper improved bonding strength of the repair material to the parent material.