Enamel and dentin irradiation with 9.6 micros COsub(2) and 2.94 microns Er:YAG lasers

Abstract

: Background and objective: The objective of this study was to evaluate the bond strength between a composite resin and dental hard tissues, which have been previously irradiated with an Er:YAG (2.94 µm) or CO2 (9.6 µm) laser. Materials and methods: A total of 156 bovine teeth were divided into 6 groups: Group 1 – Enamel control: acid etched enamel (Single Bond); Group 2 – Dentin control: acid etched dentin (Single Bond); Group 3 – Irradiated enamel (CO2 laser – 3 W) followed by acid etching; Group 4 – Irradiated dentin (CO2 laser – 3 W) followed by acid etching; Group 5 – Irradiated enamel (Er:YAG laser – 0.16 W) followed by acid etching; Group 6 – Irradiated dentin (Er:YAG laser – 0.16 W) followed by acid etching. Results: Treatment only with acid etching and also the Er:YAG laser irradiation followed by acid etching showed the highest bond strength value while the CO2 laser irradiation followed by acid etching treatment produces the lowest bond strength values in both tissues. Conclusion: Acid etching of non-irradiated and Erbium YAG laser irradiated tissues produces better adhesion than acid etching of CO2 laser irradiated surfaces. Dentin surface after CO2 laser irradiation (150 mJ, 20 Hz, 212.2 J/cm2, 3 W) followed by acid etching, the smooth melting pattern is removed and the dentin tubules are exposed with a similar aspect as the acid etching only.