Transmission of Er:YAG Laser Energy Through Different Dental Ceramics

Laser debonding procedure of adhesively luted all-ceramic restorations is based on the transmission of laser energy through the ceramic and the ablation of resin cement because of the transmitted laser energy.  The aim of this study was to determine the Er:YAG laser transmission ratio through different dental ceramics with different thicknesses.

Method:

Five different dental ceramics were evaluated in this study: sintered zirconium-oxide core ceramic, monolithic zirconium-oxide ceramic, feldspathic ceramic, leucide-reinforced glass ceramic and lithium disilicade-reinforced glass ceramic. Two ceramic discs with different thicknesses (0.5 mm and 1mm) were fabricated for each group. Ceramic discs were placed between the sensor membrane of a laser power meter and the tip of the contact handpiece of an Er:YAG laser device with the aid of a custom made acrylic holder. The transmission ratio of Er:YAG laser energy (200 mJ, 5 Hz, 1W) through different ceramic discs was measured with the powermeter. Ten measurements were made for each group and the results were analyzed with two-way ANOVA and Tukey-HSD tests.

Result:

The highest transmission ratio was determined for lithium disilicade-reinforced ceramic with 0.5 mm thickness (88%) and the lowest was determined for feldspathic ceramic with 1 mm thickness (44%). The differences among the different ceramics and between the different thicknesses were significant (p<0.05).

Conclusion:

Ceramic type and thickness should be taken into consideration to adjust the laser irradiation parameters during laser debonding of adhesively luted all-ceramic restorations.