Er:YAG laser and low-speed handpiece-comparison of ablative potential"

Objectives: The aim of this in vitro study was: 1) to compare ablated volume and dentin ablation rate using three different pulses of Er:YAG laser and a low-speed handpiece and 2) to examine the effects of the Er:YAG and a steel bur ablation on dentin surface using SEM. Materials and Methods: The experiment was conducted on 48 extracted human molar teeth which were divided into four experimental groups. Cavity preparations were made in dentin with three different pulses of the Er:YAG (SSP- Super Short Pulse: 50 sec ; MSP- Medium Short Pulse: 100 sec ; SP-Short Pulse ; 300 sec) and low-speed handpiece at different time intervals. A laser triangulation profilometer was used to determine cavity volumes. SEM was used to examine the surface of cavity preparations in all experimental groups. Results: There were no statistically significant differences in ablated volume or ablation rate for steel bur, SSP, MSP and SP groups for time intervals of 1 and 2 seconds (p>0.05). In 5 seconds interval, greater volume of dentin was removed and with higher ablation rate using steel bur in comparison to SSP (p=0.006), MSP (p=0.003) and SP (p=0.002) groups. In all laser groups, dentin surface was free of smear layer, with open dentinal tubules and this was most pronaunced for SSP and MSP groups. Conclusions: In time intervals of 1 and 2 seconds SSP, MSP, SP and steel bur were equally efficient in dentin removal. In 5 seconds interval, steel bur was more efficient in dentin removal in comparison to SSP, MSP and SP. In all laser groups, dentin surface was free of a smear layer.