The aim of this study was to determine the effect of restoration design on the fracture resistance of different computer-aided design/computer-aided manufacturing (CAD/CAM) ceramics and investigate the marginal leakage of endocrowns according to different types of cement. In total, 96 extracted mandibular first premolars were used for fabrication of endocrowns; 48 of the endocrowns were divided into 6 groups (n = 8) according to intracoronal cavity depth (2 and 3 mm) and CAD/CAM ceramics (lithium disilicate IPS e.max-CAD, zirconia-reinforced glass-ceramic Vita Suprinity, and poly-ether-ether-ketone (PEEK)). Teeth were subjected to a fracture resistance test with a universal test machine following thermo-cycling. Failure modes were determined by stereomicroscope after the load test. The rest of the endocrowns (n = 48) were produced by Vita Suprinity ceramic and divided into 6 groups (n = 8) according to the cement used (Panavia V5, Relyx Ultimate, and GC cement) with intracoronal cavity depths of 2 and 3 mm. Microleakage tests were performed using methylene blue with stereomicroscope after thermo-cycling. Numerical data for both fracture resistance and microleakage tests were obtained and evaluated by three-way ANOVA. PEEK endocrowns had higher fracture resistance compared to lithium disilicate and Vita Suprinity. Panavia V5 cement had the lowest degree of microleakage, while GC cement had the highest. Different intracoronal cavity depths had no correlation with fracture resistance and microleakage.

BackgroundDespite the wide use of implants in dentistry, there is insufficient information about the ideal cement for retention.PurposeTo determine the cement bond strength and marginal leakage of crown and partial denture cemented to implant abutments by four different types of cement.Materials and MethodsEighty‐four direct abutments were divided into eight groups (n = 7). Fifty‐six crown and bridge restorations were cemented using zinc phosphate (ZM), temporary cement (TM), resin‐modified glass‐ionomer cement (GM), and self‐adhesive resin cement (RM). After cementation, thermal cycling and incubation in basic fuchsin dye was applied. The maximum load to failure, marginal leakage, and fracture modes were evaluated.ResultsThe mean of retention strength for the bridges (874 N) was higher than the crown samples (705 N) (P = .005). The mean of retention strength for each cement group was ZM = 1298, RM = 1027, GM = 646, and TM = 187 N (P ≤ .0001). Marginal leakage was recorded in majority of the samples; the highest incidence was detected for ZM samples. The cement fracture was mostly adhesive in nature.ConclusionSelf‐adhesive resin and resin‐modified glass ionomer cement had better mechanical properties to retain implant supported restorations.

No abstract