Abstract
The aim of the present study was to evaluate the effects of root conditioning with citric acid (pH 1, 2, 3, or 4) and tetracycline hydrochloride solution (pH 2, 3, or 4) on root and calculus surfaces. Eighty root tips (5×5×1mm) with subgingival calculus were prepared for this experiment. Forty tooth root tips were carefully planed with hand curets until dentin could be seen, and the planed and the unplaned root tips were separated into 8 groups each. Each group of tip was fixed on slide glasses with twe-side adhesive tape. Root tips treated by curettage and those with calculus were conditioned with citric acid solution (pH 1, 2, 3, or 4), tetracycline hydrochloride solution (pH 2, 3, or 4), and distilled water (control) for 3 minutes by using cotton pellets, that were changed every 30 seconds. After conditioning, the root tips were irrigated with distilled water for 1 minutes. And then freezedried with tert butyl alcohol, and coated with sputtered gold. All specimens were examined by scanning electron microscopy. The higher concentrations of both citric acid solution (pH 1 or 2) and tetracycline hydrochloride solution (pH 2) had the strongest demineralizing effect on the dentinal surfaces. Citric acid solution and tetracycline at pH 3 and 4 produced a milder changes in dentin than higher concentrations, and differences were recognized between those and samples conditioned with distilled water. Mineralized objects and many rods were observed on every unplaned root surfaces, at all concentrations of citric acid and tetracycline hydrochloride, the same as in the control. Higher concentrations of citric acid and tetracycline hydrochloride (pH 1 or 2) shold be used for conditioning to demineralize root surfaces. It was concluded that citric acid causes greater degrees of morphologic change in root dentin than tetracycline hydrochloride. The layers of calculus were so thick, however that could not be removed by root conditioning with either citric acid or tetracycline hydrochloride.
