Effect of different factors on microleakage and fracture strength of CAD-CAM produced inlays

PurposeTo investigate the effects of occlusal finish line, material, cement, and aging type on the microleakage and fracture strength of inlay restorations in vitro. Materials and MethodsMesio-occluso-distal (MOD) inlay cavities were prepared in all teeth with an occlusal finish line in the form of a butt joint (BJ) or hollow-ground chamfer (HC) in one wall (buccal) (n = 80 each). Inlay restorations were designed using a computer-aided design and computer-aided manufacturing (CAD-CAM) device and milled from blocks (lithium disilicate ceramic [IPS e.max CAD] [LD] and resin nanoceramic [Lava Ultimate] [RN] [n = 40 each]). Inlay restorations were cemented to each tooth with dual-cure resin cement (RelyX Ultimate) (RU) or dual-cure self-adhesive resin cement (RelyX U200) (RU2) (n = 20 each). Specimens were divided into two groups (control [C] and thermomechanical aging [TM]) (n = 10 each). Microleakage and fracture strength tests were performed. The failure types were determined. Microleakage data (mm3) and fracture strength data (N) were analyzed by 4-way analysis of variance (ANOVA). Pairwise comparisons were made by Bonferroni testing. Fisher-Freeman-Halton testing was used to examine the relationship between categorical data. The correlation between microleakage and fracture strength was analyzed using Pearson's correlation analysis (p = 0.05). ResultsAlthough the occlusal finish line, cement, and aging type affected the microleakage (p < 0.001), only the occlusal finish line type affected the fracture strength (p = 0.007). Relationships between the microleakage and fracture strength data were nonsignificant in all subgroups. ConclusionsFor inlay restorations, an HC finish line and RU resin cement can be recommended.