CAD/CAM-fabricated inlay restorations: Can the resin-coating technique improve bond strength and internal adaptation?

This study assessed the effect of the resin-coating technique on the bond strength and internal adaptation of computer-aided design/computer-aided manufacturing (CAD/CAM)-fabricated inlays. Seventy-two mesio-occlusal-distal (MOD) cavities were prepared and distributed into 3 groups according to the resin-coating technique utilized: uncoated group, G-Premio Bond (1-step) group, and Clearfil SE Bond 2+Clearfil Majesty ES Flow (2-step+Flow) group. The MOD inlays were fabricated and cemented with RelyX Ultimate (RXU), G-CEM LinkForce (LinkForce), or Panavia V5 (PV5). After 5,000 thermal cycles, each specimen was sectioned and subjected to microtensile bond strength (MTBS) testing and an internal adaptation evaluation. For the uncoated group, RXU exhibited higher MTBS than LinkForce and PV5 (p<0.05). The MTBS of all 1-step and 2-step+Flow groups was greater than 30 MPa. Resin coating did not influence the MTBS of RXU, whereas resin coating increased the MTBS of LinkForce and PV5. More than 95% gap-free margins were found in all groups.