The effects of different handpieces and distances of Er∶YAG laser irradiation on dentinal tubule sealing-an in vitro study

YANG Jiu-hui; LIU Yan-li; ZHANG Min; LI Qiang; CHEN Yong-jin

doi:10.15956/j.cnki.chin.j.conserv.dent.2017.012.001

Abstract：AIM:To compare the effects of different irradiation modes and distances of Er∶ YAG laser irradiation on dentinal tubule sealing with focusing handpiece (R02) and the defocusing handpiece (R14) of Fotona laser therapeutic instrument.METHODS:90 dentin discs with the thickness of 2 mm were prepared and etched with 0.5 mol/L EDTA to establish the dentine hypersensitivity models.Then the discs were randomly divided into a blank control group and 8 experimental groups (n =10).The R02 and the R14 were used to deliver Er∶YAG laser irradiation to the dentin discs at the distance of 1 cm,2 cm,3 cm and 4 cm respectively.The dentinal tubule were observed with SEM,and the exposed area and the sealed rate of dentinal tubules were evaluated with Image-Pro Plus 6.0 software.RESULTS:The dentinal tubules in the control group were intact and open uniformly,while the dentinal tubules were destroyed when the dentin discs were exposed to the Er∶YAG laser at 1 cm whether with R02 or with R14.In the 2 cm group,the dentinal tubules were still open with R02 while they were closed with R14.The dentinal tubules were sealed well and the melt layer formed over the dentin when exposed to the Er∶ YAG laser at 3 cm and 4 cm with both handpieces.The exposure area of the dentinal tubules decreased and the seal rate of dentinal tubules increased with the Er∶ YAG laser irradiation by R02 or R14 and with the distance increase(For the exposur area and seal rate,between the controlgroup and 2 cm,3 cm or 4 cm groups,P ＜0.05).Moreover,the sealing effects with R14 at 2 cm were better than that with R02 at 2 cm (P ＜ 0.05).CONCLUSION:Er∶ YAG laser irradiation can seal the dentinal tubules,and the immediate sealing effects can be influenced by irradiation handpiece and irradiation distance.