Er:YAG Laser Versus Sandblasting for Build-Up Conditioning in Adhesive Cementation: A Retrospective Study of 187 Posterior Indirect Restorations

<b>Background</b>: Adhesive indirect restorations have become increasingly common in daily clinical routine in most dental practices. Before etching and adhesive application, a sandblasting procedure is essential to clean and increase the microporosity of the surface. Air abrasion with aluminum oxide particles significantly improves the bond strength. However, this procedure may have some limitations, such as the presence of powder particles. Recently, the Er:YAG laser in QSP mode has been proposed for conditioning build-ups prior to adhesive cementation. The aim of this study was a retrospective analysis of adhesive indirect restoration in which build-up was conditioned or using a traditional sandblaster with alumina powder or using the Er:YAG laser in QSP mode. <b>Methods</b>: 187 posterior indirect adhesive restorations were cemented using two different conditioning techniques: in 96 cases (51.34%) build-up conditioning was performed using an intraoral sandblaster with alumina oxide (Microetcher CD, Kavo, Biberach, Germany); in 91 cases (48.66%) build-up conditioning was performed using the Er:YAG laser (Fotona LighWalker^®, Ljubljana, Slovenia) in QSP modality (1 W, 10 Hz, 100 mJ). The clinical efficacy of the two techniques was evaluated and compared, assessing the occurrence of complications such as debonding, fracture, secondary leakage, and hypersensitivity over time. <b>Results</b>: The frequency of secondary complications was very low in both groups. Only one case of debonding and one case of restoration cracking was observed in the sandblasting group, with none in the laser group (<i>p</i> = 0.329). Secondary caries occurred in both groups. A difference was observed in postoperative hypersensitivity: 6% in the sandblasting group and 1% in the laser group (<i>p</i> = 0.064). The Kaplan-Meier curves of the two conditioning techniques showed comparable survival over time (Log-rank test χ² = 2.4864/<i>p</i> = 0.1148). The mean follow-up was 30 months. <b>Conclusions</b>: The success rates of these restorations are very high if adhesive cementation steps are properly followed. Conditioning the build-up before etching is essential. Among these, the Er:YAG laser in QSP mode seems to provide excellent results in the absence of dust and smear layer. Recurrence rates of complications such as decementation, leakage, and cracking resulted in less than 1%. Furthermore, it is interesting to note that using the laser to condition the build-up appears to reduce the recurrence of post-cementation hypersensitivity. These data require confirmation through prospective clinical trials.