Newer Class I cavity preparation for permanent teeth using air abrasion and composite restoration

This study attempts to determine a more effective cavity preparation design, material selection and preparation technique for reducing microleakage in posterior Class I esthetic restorations. An in vitro study using four different cavity designs, for Class I restorations on permanent molars, prepared with two different methods, and restored with three different restorative materials (hybrid composites) was done to evaluate marginal microleakage, and voids occurrence. Two hundred and forty extracted permanent molars were chosen and evaluated for caries, visually, with a dental explorer, and with caries detector dye. The teeth were then randomly divided in two groups (n = 120). In the first group, Class I cavity preparations were performed with air-abrasion. In the second group Class I cavity preparations were performed with #330 bur. The results revealed that cavity preparations prepared with air-abrasion with or without chamfer, and for cavity preparations done with a #330 bur with chamfer and restored with Tetric Flow, had zero microleakage. Cavity preparations done with air-abrasion, without chamfer, and for cavity preparations prepared with #330 bur with chamfer and restored with Tetric Ceram, had zero microleakage score. Cavity preparations done with air-abrasion with chamfer and restored with Herculite had one tooth out of twenty with microleakage, and for cavities without chamfer two teeth had microleakage. Cavity preparations prepared with a #330 bur, without chamfer, and restored with Herculite XRV had four teeth out of twenty with microleakage, and with a chamfer, two teeth had microleakage. These differences were not statistically significant. When comparing Tetric Flow versus Herculite XRV for void formation in cavity preparations prepared with Air-abrasion and a chamfer, Tetric Flow had significantly less voids, p < 0.001. When comparing Tetric Ceram versus Herculite XRV for cavity preparations prepared with Air-abrasion and a chamfer, Tetric Ceram had significantly less void formation, p < 0.01 > 0.001. When comparing Tetric Flow versus Herculite XRV for cavity preparations prepared with #330 bur and without a chamfer, Tetric Flow had significantly less void formation, p < 0.02 > 0.01. When comparing Tetric Flow versus Herculite XRV for cavity preparations prepared with #330 bur and a chamfer, Tetric Flow had significantly less void formation, p < 0.001 > 0.001. Caries detection results revealed that the caries detector dye method had significantly higher caries detection scores than explorer p < 001, and than visual inspection p < 0.001. Also inspection with explorer had significantly higher scores than visual inspection p < 0.001.