Objective: to evaluate quantitative and qualitatively the effect of 3% potassium oxalate (KOx - experimental gel), 4% titanium tetrafluoride (TiF4) (experimental solution) and glutaraldehide/HEMA/Fluoride gel (GHF) (Biodinâmica Química e Farmacêutica Ltd. Brazil) on hydraulic conductance of human dentin before and after acid challenge. Methods: Forty eight dentin discs 1.00±0.08mm in thickness, obtained from no irrupted human molars were randomly distribute (13 discs) among the experimental groups. Three extra discs for each treatment group were analyzed under SEM, for comparison of tubular obstruction. The methodology used for the measurement of dentin hydraulic conductance (Lp) was based on the model suggested by Pashley, Stewart and Galloway, 1984. ANOVA and Turkey (p<0.05) were used for intra and intergroups comparison of dentin hydraulic conductance. Results:
Treatment Experimental Phases | KOx | TiF4 | GHF |
| |||
Smear layer | 0.033a±0.033 (14.6%) | 0.016a ±0.012 (9.3%) | 0.026a±0.018 (18.8%) |
H3PO4 | 0.226b ±0.084 (100%) | 0.172b ±0.058 (100%) | 0.138b ±0.060 (100%) |
Treatment | 0.017a ±0.011 (7.5%) | 0.155b±0.052 (90.1%) | 0.137b±0.064 (99.3%) |
Citric acid | 0.017a ±0.011 (7.5%) | 0.154b±0.054 (89.5%) | 0.137b±0.064 (99.3%) |
Intragroup Lp – horizontally, different letters = statistical difference.
Intergroup Lp – vertically, different letters = statistical difference
OxK: crystals were observed inside the dentin tubule apertures. After acid challenge these crystals remained visible. TiF4: tubules were widely opened with collagen fibrils exposed on tubule walls; tubules became even larger after acid challenge with no visible collagen fibrils. GHF: No crystals were detected on or inside tubule openings, matching the appearance of etched dentin. Conclusions: The potassium oxalate proved to be effective in reducing dentin hydraulic conductance and to be resistant to the acid challenge. TiF4 and GHF were both not able to reduce the dentin permeability.