RESUMO
Replacement of a fractured metal-ceramic restoration is not possible in some cases.combination of different surface treatments and repair systems have been recommended for this purpose. The present study assessed the shear bond strength of three intra-oral metal-ceramic repair systems. In this in vitro study, 30 cylindrical metal specimens and 30 porcelain specimens were fabricated. The specimens were embedded in a ring, after surface treatment, the specimens received one of the following repair systems including Ultradent, Ivoclar Vivadent and Clearfil Multi-Purpose according to the manufacturers' instructions. The specimens were stored in incubator then thermal cycled. The shear bond strength of the specimens and failure types was determined. The data were analyzed. On porcelain substrate, the mean and standard deviation of shear bond strength using Ultradent, Clearfil and Ivoclar Vivadent repair systems were 12.16 [ +/- 4.59], 10.19 [ +/- 4.18] and 12.68 [ +/- 4.89] while the rates were 14.32 [ +/- 3.15], 24.66 [ +/- 3.25] and 13.32 [ +/- 3.83] in the metal substrate. The bond strength of Clearfil system was significantly higher than others in the metal substrate [both: p<0.0001] while no other significant differences was noted in the paired comparisons, all metal specimens showed adhesive failures while the porcelain specimens demonstrated more cohesive failures. Although, replacement of the fractured metal-ceramic restorations is the ideal treatment modality, in the porcelain substrate all repair systems can be used. Clearfil repair system was associated with higher bond strength in the metal substrate