Iranian Dental Association Journal of Iranian Dental Association 3060-8201 32 1-2 2020 01 01 Effect of Er:YAG Laser Irradiation on Shear Bond Strength of Two Porcelain Laminate Veneers Bonded to Tooth Surface 21 29 10.30699/jidai.32.1.2.21 EN Ehsan Morshedi https://orcid.org/0000-0003-2763-8138 Maryam Azimi Zavaree Seyed Mohammad Reza Hakimaneh https://orcid.org/0000-0003-3306-357X Sayed Shojaedin Shayegh https://orcid.org/0000-0003-3513-5848 Maryam Pirmoradian Sara Torabi Sina Jafari https://orcid.org/0000-0001-9268-1146 Journal Article 10.30699/jidai.32.1.2.21 2020 11 19 2020 01 20 Background and Aim: The conventional procedure for removal of porcelain laminate veneers (PLVs) is time-consuming and inconvenient. The purpose of this study was to evaluate the efficacy of Er:YAG laser for debonding of PLVs.<br> Materials and Methods: Forty-eight intact extracted human maxillary anterior teeth received discoid PLVs (24 feldspathic and 24 e-max ceramic). The PLVs had 0.7 mm thickness and 4 mm diameter. After cementation of all PLVs with a light-cure cement, samples were stored at 37ºC distilled water for 48 h. Samples of each ceramic were randomly divided into 3 groups of 8 samples. Then, laser was irra-diated on the cemented PLVs as follows: (I) feldspathic PLVs without laser irradiation (control group), (II) feldspathic PLVs with laser irradiation (6 s, 10 Hz, 200 mJ, 2 W), (III) feldspathic PLVs with laser irradiation (6 s, 10 Hz, 300 mJ, 3 W), (IV) e-max PLVs without laser irradiation (control group), (V) e-max PLVs with laser radiation (6 s, 10 Hz, 200 mJ, 2 W), (VI) e-max PLVs with laser irradiation (6 s, 10 Hz, 300 mJ, 3 W). The shear bond strength of all samples was measured using a universal testing machine. We used Mann-Whitney and Kruskal-Wallis tests for data analysis (P<0.05).<br> Results: Laser irradiation decreased the shear bond strength of both ceramics. But this decrease was only significant for the e-max group (P<0.05). No significant difference was found between different laser irradiation powers in the two ceramic groups.<br> Conclusion: Er: YAG laser is effective for debonding of e-max PLVs.