Influence of number of surfaces on microleakage of ceramic inlays

Objectives: The aim of this study was to verify the influence of the number of surfaces and the loca-tion of cervical margin on the microleakage of ceramic inlays. Methods: Forty extracted human bicuspids, without previous restoration and decay were stored in tap water at room temperature. Standardized Class II preparations, designed for porce-lain inlays, were made under copious water spray with diamond burs at high-speed handpiece. The teeth were divided into four experimental groups (n=10): Group I – Class II cavities (MOD), cervical margins 1 mm above the CEJ, limited within enamel; Group II - Class II cavities (OD), cervical margins 1 mm above the CEJ; Group III - Class II cavities (MOD), cervical margins 1 mm below the CEJ, and Group IV - Class II cavities (OD), cervical margins 1 mm below the CEJ. After impression procedures, inlays were fabricated with IPS Empress System (Ivoclar Vivadent, Schaan, Liechten-stein) following manufacturer's instructions. The teeth were submitted to thermocycling (500 cycles, 5°C to 55°C), coated with nail polish 2 mm away from the restoration mar-gins and sectioned mesiodistally. The sections were evaluated for dye penetration (0.5% basic fuchsin) and scored from 0 to 4. Results: Non-parametric Kruskall-Wallis test showed statistical difference among groups (p=.0208). Mann-Whitney test showed that the number of surfaces (OD or MOD) did not influence marginal infiltration (GI and GII, p=.942; GIII and GIV, p =.831). In con-trast, the cervical margin location (enamel or dentin) had significant influence on micro-leakage (GI and GIII, p =.016; GII and GIV, p= .05). The greater degree of dye penetra-tion was measured in dentin. Conclusions: However, none of groups showed complete inhibition of marginal infiltration.