Fracture resistance of single-tooth implant-supported zirconia-based indirect composite-layered molar restorations

Objectives This study evaluated the fracture resistance of single‐tooth implant‐supported zirconia‐based indirect composite‐layered molar restorations. Material and methods Forty‐four titanium abutments (GingiHue Post) were placed on dental implants (Osseotite Implant). Standardized single‐tooth cement‐retained implant‐supported mandibular molar restorations were fabricated for each of four test groups (n = 11) as follows: porcelain‐fused‐to‐metal crowns (PFM), zirconia‐based all‐ceramic crowns (ZAC), zirconia‐based indirect composite‐layered crowns primed with Estenia Opaque Primer for zirconia frameworks (ZIC‐E), and zirconia‐based indirect composite‐layered crowns (ZIC). The crowns were luted with a glass‐ionomer cement (Ketac Cem Easymix). Fracture resistance (N) was determined by force application of a perpendicular load to the crowns with a universal testing machine. One‐way analysis of variance (ANOVA) and the Tukey's HSD test were used to assess differences in fracture resistance values (α = 0.05). Results Mean fracture resistances (SD) were 3.09 (0.22) kN, 3.11 (0.34) kN, 2.84 (0.21) kN, and 2.50 (0.36) kN for the PFM, ZAC, ZIC‐E, and ZIC groups, respectively. Fracture resistance in the ZIC specimens was significantly lower (P