Er: YAG Laser Contact and Non-Contact Delivery Systems Cavity Preparation and Sonic-Activated Bulk Composite Restoration

Introduction: The comparison of tissue quality and its restoration after contact, and non-contact Er: YAG (2940 nm) laser radiation ablation was evaluated. Methods: Laser setting for contact ablation was 250 mJ/pulse, pulse repetition rate 15 Hz, average power 3.75 W. For non-contact ablation these values were: 600 mJ/pulse, 6 Hz, 3.6 W. Structure of enamel and dentin after laser ablation was analyzed in scanning electron microscope. All cavities were filled by sonic-activated composite resin. Chemical and mechanical bond was observed in scanning electron microscope.Microleakage was assessed quantitatively by the degree of methylene blue dye penetration. Fischer exact test (p < 0.05) was used for statistical evaluation. Results: Contact and non-contact laser treatments prepared similar cavities (5167.31 μm versus 5356.31 μm). Defocusing of non-contact therapy has direct influence on the dye penetration microleakage presence (481.19 μm versus 611.94 μm) but this increase was not statistical significant. Conclusion: Cavity prepared by contact mode with sonic-activated composite filling protects microleakage formation.