engleski

Ablative potential of Er:YAG laser: quantum square pulse mode versus new digitally controlled dental laser handpiece (X-runner)

Objectives: The primary objective of this in vitro study was to compare ablated volume and dentin ablation rate of quantum square pulse (QSP), using two different pulse energy settings, and a new digitally controlled dental laser handpiece (X- runner) in QSP mode. The secondary objective was to examine the effects of the ablation with different Er:YAG laser modes on dentin surface using SEM. Methods: Freshly extracted human molars (n=36) were divided into three experimental groups. Cavity preparations were made in dentinas follows: 1) QSP with pulse energy of 250 mJ ; 2) QSP with pulse energy of 500 mJ and 3) X-runner in QSP mode with pulse energy of 250 mJ, at time intervals of 1, 2 and 5 seconds. A laser triangulation profilometer was used to determine cavity volumes and SEM analysis was performed to examine the surface of cavity preparation surfaces in all experimental groups. Results: There was asignificant difference in ablated volume and ablation rate for QSP (pulse energy 250 mJ) and X- runner groups and between QSP (pulse energy 500 mJ) vs. QSP mode (pulse energy 250 mJ) for all examined time periods (p<0.05). There was no significant difference in ablated volume and ablation rate between X-runner and QSP mode (pulse energy 500 mJ), (p>0.05). In all laser groups, except the group where X- runner was used, dentin surface was free of smear layer, exhibiting open dentinal tubules. Conclusions: A larger volume of dentin was removed and with higher ablation rate in X-runner group in comparison to QSP mode with pulse energy of 250 mJ. There was no difference in ablated volume and ablation rate between X- runner and QSP mode with pulse energy of 500 mJ. Out of all the examined laser groups, only the X-runner group exhibited smear layer and closed dental tubules in the SEM analysis.

Er:YAG laser ; ablation rate ; x-Runner

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