Narges Naghsh
Reza Birang
Fahimeh Shafiei
Fatemeh Ghorbani
Norbert Gutknecht
Jaber Yaghini

Abstract Background: The tooth root surfaces are modified by different agents for better removal of the smear layer, formation of fibrin clots and attachment of blood cells. This in vitro study compared removal of the smear layer, formation of fibrin clots and attachment of blood cells after exposing periodontally compromised root surfaces to ER:YAG and CO۲ laser beams.Methods: Eighteen dentin block samples were prepared from freshly extracted periodontally compromised teeth that were deemed hopeless, and divided into ۳ groups; exposed to Er:YAG laser beams, exposed to CO۲ laser beams and the control group. The samples were evaluated using scanning electron microscopy and micrographs were taken. Smear layer removal and blood cell attachment were scored. Data were analyzed with SPSS using Kruskal-Wallis and Mann-Whitney tests.Results: In the Er:YAG laser group, the smear layer was removed completely. In the specimens exposed to blood, better fibrin clot formation and blood cell attachment were observed in the Er:YAG laser group. In the CO۲ laser group, the smear layer was also removed; however, there were no significant differences between the CO۲ laser and control groups in fibrin clot formation and blood cell attachment.Conclusion: Application of Er:YAG laser to the root dentin appears to result in the formation of a suitable surface for fibrin clot formation and blood cell attachment. Further clinical studies are necessary to support these results. Keywords: CO۲ laser Er YAG laser Root planing