Real-time measurement of dentinal fluid flow during laser irradiation and desensitizing agents application

Abstract

Objectives. The objective of this study was to evaluate the effects of lasers (Nd:YAG and Er:YAG) and of topical desensitizing agents on dentinal tubule occlusion by measuring real-time dentinal fluid flow (DFF). Methods. Thirty-two molars were prepared with V-shape cavity at the cervical area, acid-etched, water rinsed, blotted dry, and treated with 1) Nd:YAG laser

2) Er:YAG laser

3) SuperSeal, a desensitizing agent

4) ClinproXT, a resin modified glass ionomer (RMGI) varnish (n=8 each). A real-time fluid flow measuring instrument (nano-Flow) was used to measure the DFF throughout the procedures. The DFF rates before and after the treatment were compared. Moreover, the surface topography of dentinal tubules after each desensitizing method was examined using SEM. Results. DFF varied among the groups. The DFF rate was significantly reduced after laser irradiation/application of the desensitizing agents (p<0.05). ClinproXT showed the greatest reduction of DFF rate (71.9%), followed by SuperSeal (34.8%) and laser groups (p<0.05). However, there was no significant difference between the Nd:YAG (24.1%) and Er:YAG (20.6%) groups (p>0.05). In SEM images, narrowed dentinal tubules were observed in both lased groups and SuperSeal group. In ClinproXT group, the occluded dentinal tubules by the RMGI covering were observed. Conclusion. The fluid flow measuring instrument could clearly show the changes of DFF rate during laser irradiation/application of the desensitizing agents in real-time. ClinproXT, a RMGI varnish and SuperSeal, an oxalate-based desensitizing agent showed better results than the Nd:YAG and Er:YAG lasers in the reduction of DFF rate.