Effects of desensitizing agents on human dentin permeability

Purpose: To compare the in vitro effects of three desensitizing agents on h ydraulic conductance of human dentin: Protect (n=10), Gluma Desensitizer (n =10), MS Coat (n=10) (Pain-Free in the USA). Materials and Methods: Dentin discs were prepared from 40 freshly extracted normal human third molars. Th e pulpal side of the dentin discs was etched with 37% phosphoric acid for 1 5 s and then rinsed under tap water. The coronal side was sequentially grou nd and the dentin discs were sonicated for 30 min. The hydraulic conductanc e was measured filtering 20% serum in phosphate buffered saline under a pre ssure of 15 cm H2O. The hydraulic conductance of each dentin specimen was m easured before using the desensitizing agent and this value was designated as 100%. Thirty dentin discs were treated, the hydraulic conductance was re measured and expressed as a percentage of the hydraulic conductance of that specimen before treatment. The teeth were stored for 1 month at 37 degrees C in deionized water and the hydraulic conductance of the 40 dentin discs was recorded again. Ten dentin discs were left untreated to serve as a cont rol. Results: No statistical difference was found between the immediate hyd raulic conductance of the three groups after treatment. After 1-month stora ge, the control group showed a statistically higher hydraulic conductance t han the three treated groups. There was no statistical difference between t he three dentin desensitizing agents evaluated.