Avaliação da influência do tratamento de superfície na resistência à flexão biaxial de cerâmicas vítreas cimentadas ao G10

Abstract

The present study aimed to evaluate the influence of surface treatment on the biaxial flexural strength of strengthened ceramics under mechanical fatigue stress. According to the type of ceramic material: lithium disilicate (IPS e.max CAD, IvoclarVivadent), leucite-reinforced ceramic (IPS empress cad cerec, Ivoclar-Vivadent) and resin-infiltrated ceramic (Enamic, Vita Zahnfabrik), the samples were randomly divided. Fifteen samples of each ceramic material analyzed received three types of surface treatments (n=15), namely: hydrofluoric acid 5% 20 seconds and silane (HF 5%20s + Sil); hydrofluoric acid 5% 60 seconds and silane (HF 5%60s + Sil) and application of Monobond Etch & Prime (Monobond), making a total of 09 experimental groups, namely: Enamic HF 5% 20s + Sil; Enamic HF 5%60s + Sil;Enamic Monobond; Empress HF 5% 20s + Sil; Empress HF 5%60s + Sil; Empress Monobond; eMaxHF 5% 20s + Sil; eMAx HF 5%60s + Sil; eMax Monobond. For further qualitative analyses, three samples were made and added to each group, and therefore not subjected to mechanical cycling, in addition to samples in which no surface treatment had been performed, to evaluate the pure structure. Thus, the three extra samples were essential for the analyses, involving the recognition of the chemical and microscopic characteristics of the materials used. IPS.emax CAD, Empress cad and Enamic were cemented on G10 (NEMA grade, G10 - 1.2 mm / 2.3 mm), dentin analog, with Relyx Ultimate resin cement (3M ESPE) after each surface treatment and were subjected to mechanical cycling for 1.0x106 cycles and subsequently to biaxial flexural testing (ISO 6872) immersed in water. The samples assigned the qualitative analyses were submitted to optical profilometry, scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The data obtained in this study were submitted to the statistical model of analysis of variance (ANOVA) and Tukey's multiple comparison test. For all groups involved, the Empress Monobond, eMax Monobond and Enamic Monobond groups showed higher biaxial flexural strength than the respective groups, revealing that treatment with Monobond Each and Primer positively influences the strength of these ceramics. The Weibull modulus was significantly higher for the Empress Monobond and Enamic Monobond groups. The groups with surface treatment HF60 + silane showed higher roughness than the others. Conclusion: Monobond each and primer treatment is most indicated for lithium disilicate, polymerinfiltrated lithium silicate and leucite-reinforced lithium silicate ceramics.