Evaluation of the marginal and internal fit of CAD/CAM Experimental Resin Block Restorations

Abstract

The purpose of this study was to compare marginal and internal fit between Lava Ultimate (3M ESPE, St Paul, MN, USA) and an experimental nano-hybrid composite resin block (Vericom Co., Anyang, Korea) in two preparation types, single crown and inlay with one cusp capping design. Extracted maxillary and mandibular teeth were prepared as single crown and inlay. After preparation, abutment impression was taken and poured with epoxy resin to make replicas (n = 20). 3M Lava ultimate blocks (LU) and Experimental Resin blocks (EB) were milled using CEREC MC XL with the CEREC 3D system (CEREC AC, software package 4.00, Bensheim, Germany) to construct 10 crowns and inlays for each group. The milling parameters were set as 140 ㎛ for spacer and 50 ㎛ for marginal width. After milling, sample restorations were assessed for proper fit and cemented with resin material (RelyX™ Ultimate Clicker™ Adhesive Resin Cement, 3M ESPE). To measure marginal gap, milled restorations were examined under dental surgical microscope with scale under 40× magnifications, captured images with digital camera and measured using Adobe Photoshop. For internal gap, specimens were embedded in acrylic resin and sectioned bucco-lingually and mesio-distally with water cooled low speed diamond blade in 0.5 mm thickness (n = 20) and evaluated with cement gap was evaluated. The statistical analysis was performed for significant differences of marginal and internal gap between different restoration design and different restoration material. In our study, the means of crown marginal gap before cementation were significantly lower than after cementation (p < 0.05), but there was no statistically significant difference at inlay groups. And the mean values of marginal gap between EB and LU showed no significant difference regardless of restoration design. Internal gap of LU inlay was significantly lower than EB inlay (p < 0.05), but no internal gap difference was found in the internal gaps between crown groups.