Evaluation of bond strength in different CAD/CAM laminate veneer restorations with ceramic and resin content

Aim: In recent years, computerized milling-based CAD/CAM restorations have become popular. Zirconia has been used in esthetic cases often. Because of its brittleness new materials are developed like hybrid ceramic and resin nano ceramic. The aim of this study examine and evaluate bond strenght of eight different CAD/CAM restoration materials was restored with the help of an optical reader by milling the blocks in an advanced lathing machine by means of information recorded in the computer memory by measurements taken directly from the preparation teeth (Cerec in Dental Office). Material and Method: In this study, 80 freshly extracted, non-decayed, non-restorated and no cracks maxillar central teeth has been used. Teeth before use, stored in 10% neutral formalin and distilled water solutions until cavity preparation is made, polishing was made to clean soft tissue on all teeth and to remove the storage solution using micromotor mounted tires with pumice brush. Chamfer style standard cavities was prepared 0,5mm on labial surfaces of all teeth, 0,2mm on mesial and distal contact points, 0,3mm in gingival step. 80 anterior teeth which are prepared cavities, has been divided into nine groups that a different CAD/CAM blocks to be used in each group and each group was restored in accordance recommended procedures by the manufacturer. After cementation of restorations, all samples has been subjected to 1000 cycles in the thermal cycle device which remained open the crowns of the teeth has been embedded vertically into acrylic blocks and subjected to shear forces in the Instron tester, tearing resistance value was determined in Newton. Results were evaluated at statistical significance level of p<0,05. Results and Conclusion: A statistically significant difference was observed between the ANOVA One-Way Variance Analysis and TUKEY HSD tests in terms of fracture resistance (P<0,05). The material with the highest bond strength average was determined as Lava Ultimate. Keywords: CAD/CAM, laminate veneer, ceramic block, resin block, bond strength