Effect of Two Immediate Dentin Sealing Approaches on Bond Strength of Lava™ CAD/CAM Indirect Restoration

The study was conducted according to the guidelines of the Declaration of Helsinki, and approved by the Ethics Committee of the University of Granada (Spain) (protocol code #1005/CEIH/2019 approved on 13 January 2020).Informed consent was obtained from all subjects involved in the studyThe objective of this work was to compare the micro-tensile bond strength (mu TBS) of CAD/CAM (Computer-Aided Design/ Computer-Aided Manufacturing) specimens cemented with different pairing of adhesives and resin-cements using two Immediate Dentin Dealing (IDS) approaches in comparison with Delay Dentin Sealing (DDS). Coronal dentin from 108 molars were divided into nine groups (n = 12) depending on the adhesive/resin-cement (A-C) assigned. Lava (TM) Ultimate (4 x 10 x 10 mm) was cemented according to different strategies: IDS1(cementation after dentin sealing), DDS (dentin sealing and cementation at 2-weeks), IDS2 (immediate dentin sealing and cementation at 2-weeks). Samples were sectioned and tested until failure to determine the mu TBS. Failure mode was categorized as dentin/cement (DC), at Lava (TM) Ultimate/cement (LC) and hybrid (H). Kruskal-Wallis and Mann-Whitney U tests and influence of the type of failure on the mu TBS by survival analysis with competing risk was explored. Mostly, mu TBS values were equal or higher in IDS2 than DDS. In general, A-Cs that showed higher mu TBS, have high percentages of LC failure. Survival analysis with competing risk between DC + H and LC values showed that some A-Cs would significantly increase the mu TBS values for IDS2. A-Cs with the highest adhesion values showed a high percentage of fractures at the LC interface, suggesting that the adhesion at the adhesive/dentin interface would be higher