Impact of Ultrasonic Scaling on Microleakage in Lithium Disilicate Crowns Luted With Different Resin Cements

To assess the impact of ultrasonic scaling on the microleakage at the lithium disilicate crown margins with three different techniques of resin cements.

Forty-eight human teeth were fixed in acrylic resin mold within 2 mm away from the cementoenamel junction. A 1.5 mm occlusal and axial surface preparation with 12° taper and heavy chamfer of 1 mm thickness was performed. E-max CAD/CAM crown was fabricated for each sample. Samples were categorized according to the cement used into: Group 1 (n = 16) cemented with self-etching, Group 2 (n = 16) cemented with self-adhesive, and Group 3 (n = 16) cemented with total-etch cement. Each group was subsequently divided into two equal subgroups: one undergoing water aging (10,000 thermocycles) without ultrasonic scaling (n = 8) and the other subjected to both water aging (10,000 thermocycles) and ultrasonic scaling. All samples were then examined under microscopes (n = 8).

The overall comparison of microleakage among the three cements was not statistically significant (p=0.49). The highest microleakage was observed in total-etching cement (5.69), while the lowest was in self-etching cement without scaling (0.88). No significant difference was found between nonscaling and scaling within the same cement group: Group 1 (p=0.92), Group 2 (p=0.64), and Group 3 (p=0.89).

No statistically significant differences were found in microleakage around lithium disilicate crowns cemented with various types of resin cements, nor between groups subjected to ultrasonic scaling and those that were not.