Investigation of Coronal Leakage of Root Fillings after Smear Layer Removal with EDTA or Er,Cr:YSGG Laser through Capillary Flow Porometry

摘要

Erbium lasers are mostly used because of their photoablative action similar to that of cavity preparation (thermome-chancal tissue interaction). Because water has the strongest absorption peak for electromagnetic radiation at around 2,900 nm, erbium lasers (EnYAG-2,940 nm; Er,Cr:YSGG-2,796 nm) emitting at around this wavelength are a suitable instrument for ablation of dentin [1-3].Experimental studies when using the Er.YAG laser fiber for direct exposure to root canal walls have demonstrated that this type of laser is more effective in removing the smear layer than other laser types and endodontic irrigants [4, 5]. The dentinal walls mostly show open tubules [6-8] and are free of debris or a smear layer [6,7]. As the laser fiber is used in a circular motion whilst withdrawing the optical fiber (this withdrawal might otherwise have been slower or even have halted in certain areas), in some of the areas irradiated, not all of the tubules are completely open [9, 10]. Differences in power settings do not appear to result in significant differences in efficacy for removing the smear layer [7,11,12]. Although Er:YAG laser irradiation is reported to be effective for removing debris and the smear layer [6, 7], a better apical seal is not necessarily achieved [13,14].