The effects on dentin tubules of two desensitising agents in combination with Nd:YAG laser: An <i>in vitro</i> analysis (CLSM and SEM)

Abstract

Objectives: The aim of this study was to assess in vitro the effects of two desensitising agents containing calcium phosphate and nano-hydroxyapatite, applied alone or with Nd:YAG laser, on dentin tubule occlusion, and to determine the penetration depth. Methods: 75 extracted human 3rd molar teeth were used. The effects of desensitising treatments and erosion resistance were evaluated on dentin tubule occlusion via SEM and the dentin tubule penetration depth via CLSM. Two desensitising agents-Teethmate (TMD), (Kuraray, Japan) and Professional Oral Care Nano-hydroxyapatite (Nhap) Desensitiser (Miromed Group SA, Italy)-were used. Study groups were designated as Group 1(Control), Group 2(TMD), Group 3(TMD+Nd:YAG), Group 4(Nhap) and Group 5(Nhap+Nd:YAG) and were assigned 10 dentin discs per group. After treatment with desensitising agents and laser, dentin discs were exposed to artificial saliva for one night in samples prepared to be without erosion and a sample prepared as with erosion was exposed 3 times per day for 5 days to 0.3% citric acid cycles. The Image J programme was used to scale the images of SEM analyses. The agents were mixed with 0.1% Rhodamine B for testing penetration depth and samples were analysed with CLSM after applying with and without laser. The obtained images were evaluated using the Zeiss ZEN Lite, Zeiss Microscopy programme (Carl Zeiss, Germany). Data were analysed with MannWhitney U and Kruskal Wallis tests (p < 0.05). Results: Statistically significant differences from the control group were found in all treatment groups. The TMD +Nd:YAG group had the lowest number of open tubules before and after erosion and the highest penetration depth. The Nd: YAG laser markedly increased the efficiency of the desensitising agents.