Evaluation of the Weakest Interface in the Adhesive Luting of a Computer-aided Design/ Computer-aided Manufacturing Composite Resin

• Published in: Journal of international oral health 2016-04, Vol.8 (4), p.465
• Main Authors: Souza, Ivana Agnoletto, Stona, Deborah, Burnett, Luiz Henrique, Spohr, Ana Maria
• Format: Article
• Language: English
• Subjects: Adhesives; Bond strength; Cement; Dentin; Enamel; Failure; Knee; Manufacturers; Teeth; Values
• ISSN: 0976-7428; 0976-1799
• DOI: 10.2047/jioh-08-04-11

The aim of the study was to evaluate, in vitro, the weakest bond interface of lava ultimate onlays luted with Scotchbond Universal and RelyX Ultimate. A total of 56 Lava Ultimate onlays were milled and divided into eight groups according to the luting procedure to the human teeth (n = 7): G1 and G2 - Scotchbond Universal using the etch-and-rinse technique; G3 and G4 - Scotchbond Universal using the self-etch technique; G5 and G6 - Scotchbond Universal using the etch-and-rinse technique + adhesive application on the onlay; G7 and G8 - Scotchbond Universal using the self-etch mode + adhesive application on the onlay. The onlays were luted with RelyX Ultimate. Only the samples from G2, G4, G6 and G8 were submitted to cyclic loading. Beams with a cross section area of ~0.80 mm2 were obtained and submitted to microtensile bond strength (µTBS) test in a universal testing machine. The types of failure were observed in optical microscope. According to three-way analysis of variance, there was a significant interaction between the three factors (P = 0.006). The µTBS means (MPa) followed by the same letter represent no statistical difference by Tukey's post-hoc test (P < 0.05): G6 = 34.64a, G1 = 34.48^sup a^, G2 = 31.94^sup ab^, G5 = 30.88^sup abc^, G7 = 26.66^sup bc^, G8 = 24.03^sup cd^, G4 = 18.81^sup de^, G3 = 14.64^sup e^. Most failures were at the resinous agent-restoration interface. The resinous agent-restoration interface corresponded to the weakest interface. The application of Scotchbond Universal on the internal surface of the onlay was not a relevant procedure.