The effect of elapsed time following alumina blasting on adhesion of CAD/CAM resin block to dentin.

The aim of this study was to evaluate the time elapsed bond strength of the CAD/CAM resin block (CRB) to bovine dentin after alumina blasting. CRB (KATANA AVENCIA BLOCK) slices were ground with #600-SiC paper and divided into three groups according to alumina blasting pressure -0.1 MPa, 0.2 MPa or untreated- and then divided into two subgroups according to the time elapsed after alumina blasting -same-day or one-week "dry-storage" at controlled laboratory conditions before cementation. The CRB slices were then cemented to bovine dentin with Panavia V5 (Kuraray Noritake Dental), and divided into two subgroups -light curing or chemical curing. After 24 h storage in distilled water at 37°C, the specimens were then subjected to micro-tensile bond strength (µTBS) testing. One-week group showed a significant decrease in µTBS. The µTBS values showed that CRBs must be cemented with light curing immediately after alumina blasting at 0.1 or 0.2 MPa to obtain a stable adhesion.