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

## TL;DR

This study examines how ultrasonic scaling affects the microleakage of lithium disilicate crowns bonded with different resin cements.

## Contribution

The study evaluates the effect of ultrasonic scaling on microleakage in lithium disilicate crowns using three types of resin cements.

## Key findings

- Ultrasonic scaling did not significantly affect microleakage in any cement group.
- Total-etch cement showed the highest microleakage, while self-etching cement showed the lowest.
- There was no significant difference in microleakage among the three types of resin cements.

## Abstract

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.