Controversy exists in the literature regarding the most optimal repair procedure for improving the adhesion between the repair resin and the existing resin composite materials. This systematic review analyzed the adhesion potential of resin-based composites to similar and dissimilar composites. Original scientific papers on adhesion to composites published in MEDLINE (PubMed) database between 1 January 1955 and 1 June 2010 were included in this systematic review. Bond-strength data were evaluated for different factor levels, namely surface conditioning methods (control, physical, chemical, physicochemical), substrate-adherent type (being of the same kind or dissimilar), substrate aging (thermocycling or water storage), and test methods (macroshear, microshear, macrotensile, microtensile). The selection process resulted in the final sample of 41 studies. In total, 160 different surface conditioning methods, being mainly combinations of the use of etching agents, application of grinding or air-abrasion protocols, and adhesive promoters (silanes, adhesive resins), have been investigated. When substrate is aged with thermocycling, bond-strength results for composite-composite combinations of the same material were significantly influenced by the surface conditioning method (p = 0.010) and with the test method (p = 0.014), but for dissimilar composite-composite combinations, only test method (p = 0.000) showed a significant effect on the results. When substrate is aged with water storage, bond-strength results for composite-composite combinations of the same material were significantly influenced by the surface conditioning method (p = 0.000), but for dissimilar material combinations only test method showed a significant effect (p = 0.000) on the results. For the composite combinations of the same kind, the impact of surface conditioning type and the test method in thermocycled group was higher on the results.

This study evaluated the effect of contamination media on the adhesion of resin cement to resin composites. Specimens of direct (DRC) (Quadrant Photo Posterior) and indirect resin composite (IRC) (Gradia) (N = 300, n = 15 per group) were prepared. Except the control group (C), the specimens of DRC and IRC were contaminated with one of the following media: (a) saliva (S), (b) silicon (SI), (c) dental stone (D), and (d) isolation medium (I). While one half was only rinsed with water, the other half was silica coated (30 m SiO2, Siljet). All specimens were silanized (Monobond Plus) and coated with adhesive resin (Heliobond). Resin cement (Variolink II) was bonded to the substrates and photopolymerized for 40 s. After thermocycling (x5.000, 5-55°C), composite-cement interface was loaded under shear in a Universal Testing Machine (1 mm/min). Data (MPa) were analyzed using Univariate analysis, Tukey's and Dunnett-T3 tests. Both contamination media (p = 0.000) and surface conditioning (p = 0.005) significantly affected adhesion to DRC and IRC. No significant difference was found between the DRC and IRC (without: p = 0.098; with: p = 0.084). Significantly lower results were obtained after SI (DRC: 0.66 ± 0.6; IRC: 0.8 ± 1.3) followed by I contamination (DRC: 2.1 ± 2.6; IRC: 0.8 ± 1.3) (p < 0.05). Regardless of contamination medium, surface conditioning significantly increased the results for both DRC (15.1 ± 6.1-23.6 ± 3.7) and IRC (20.3 ± 5.4-25.1 ± 3.6) (p < 0.05). Weibull distribution increased after surface conditioning for both DRC (without: 1.33-3.27; with: 2.55-9.34) and This study evaluated the effect of contamination media on the adhesion of resin cement to resin composites. Specimens of direct (DRC) (Quadrant Photo Posterior) and indirect resin composite (IRC) (Gradia) (N = 300, n = 15 per group) were prepared. Except the control group (C), the specimens of DRC and IRC were contaminated with one of the following media: (a) saliva (S), (b) silicon (SI), (c) dental stone (D), and (d) isolation medium (I). While one half was only rinsed with water, the other half was silica coated (30 μm SiO 2 , Siljet). All specimens were silanized (Monobond Plus) and coated with adhesive resin (Heliobond). Resin cement (Variolink II) was bonded to the substrates and photo-polymerized for 40 s. After thermocycling (x5.000, 5-55 °C), composite-cement interface was loaded under shear in a Universal Testing Machine (1 mm/min). Data (MPa) were analyzed using Univariate analysis, Tukey's and Dunnett-T3 tests. Both contamination media (p = 0.000) and surface conditioning (p = 0.005) significantly affected adhesion to DRC and IRC. No significant difference was found between the DRC and IRC (without: p = 0.098; with: p = 0.084). Significantly lower results were obtained after SI (DRC: 0.66 ± 0.6; IRC: 0.8 ± 1.3) followed by I contamination (DRC: 2.1 ± 2.6; IRC: 0.8 ± 1.3) (p < 0.05). Regardless of contamination medium, surface conditioning significantly increased the results for both DRC (15.1 ± 6.1-23.6 ± 3.7) and IRC (20.3 ...