A comparative scanning electron microscopic study on the characteristics of demineralized dentin root surface using different tetracycline HCl concentrations and application times

Background: The use of demineralizing agents has been reported to enhance t he degree of connective tissue attachment to denuded roots. Of the agents u sed, tetracycline HCl has received the most attention. Methods: The purpose of this study was to evaluate and compare the SEM surf ace morphology of human root dentin following various concentrations and ap plication times of tetracycline HCl. The surface characteristics were compa red and the width of dentin tubule orifices were measured and analyzed. Twe lve human teeth were collected and stored in distilled water after soft tis sue removal using hand instruments. The apical third of each root was remov ed and remaining mid-root region was sectioned longitudinally through the r oot canal following removal of its cementum with a fine diamond bur. A tota l of 48 dentin specimens were randomly divided into 8 groups for conditioni ng at different tetracycline HCl concentrations, at 0, 10, 25, 50, 75, 100, 125, and 150 mg/ml. Application times for each group were 1, 3, and 5 minu tes. Immediately following treatment procedures, the specimens were rinsed, fixed in GTA-PBE dehydrated, and prepared for SEM. Each specimen was exami ned at 2 magnification values, representative fields photographed, and data tested by one-way ANOVA and paired t test statistical analysis. Results: Our results indicate that the use of tetracycline HCl solution bet ween 50 mg/ml and 150 mg/ml showed a statistically significant opening of d entin tubules. All tetracycline HCl groups at 1, 3, and 5 minutes show smea r layer removal from the dentin surface. Conclusions: Dentin demineralization is not time dependent at all concentra tions of tetracycline HCl.