Evaluation of Er:YAG and Er,Cr:YSGG laser irradiation for the debonding of prefabricated zirconia crowns

BACKGROUND Reduced tooth structure in the pediatric and adolescent population is frequently restored with prefabricated zirconia crowns. On permanent teeth, these restorations may need to be removed replaced restorations. OBJECTIVES To explore compare use of 2 high-powered erbium lasers for removing crowns from molar teeth as a non-invasive alternative rotary instruments. MATERIAL AND METHODS Twenty-five molars were prepared dentin all-ceramic fitted cemented resin modified glass ionomer (RMGI) cement. The randomly assigned into one retrieval treatment groups: erbium-doped yttrium, aluminum garnet (Er:YAG) laser group (G1; n = 12) or erbium, chromium-doped scandium, gallium (Er,Cr:YSGG) (G2; 13). operating parameters Er:YAG 300 mJ, 15 Hz, 4.5 W, 50-microsecond pulse duration (SSP mode); Er,Cr:YSGG laser, they 20 water/20 air, 5 50 water/50 60-microsecond (H mode). experiment was repeated twice. surface area volume measured cement space calculated. time temperature changes tested recorded. data analyzed t-test. surfaces crown each further examined using scanning electron microscopy (SEM). RESULTS average removal 1 min 32.7 s; it 3 13.9 s (p < 0.0001). mean 1.41 ±1.36°C 2.2 ±0.99°C 0.0321). SEM examination showed no damage major structural caused by either erbium-family laser. CONCLUSIONS Both are effective, tools remove should considered viable alternatives instrumentation.