Comparative SEM study on the effect of acid etching with tetracycline HCl or citric acid on instrumented periodontally-involved human root surfaces.

This study compared the surface characteristics of periodontally diseased single-rooted human teeth extracted after treatment with either tetracycline HCl or citric acid solutions. The study group was comprised of 30 teeth from 22 patients with advanced periodontal disease extracted before the start of periodontal therapy. Diseased surfaces were identified, outlined, and root planed by hand curet or finishing bur. The teeth were sectioned and solutions of tetracycline HCl or citric acid (pH 1) were applied to the surfaces with cotton pellets for 5 minutes. Extracted teeth were processed and root surface samples then examined by scanning electron microscope. The surfaces of both acid-treated sets of specimens differed considerably from specimens treated with root planing alone, regardless of root planing method. Acid-treated specimens exhibited dentinal tubules exposed by the removal of the smear layer, surfaces devoid of the debris normally present in root planed-only specimens, and the dense network of collagen fibers that make up the dentin structure. Although differences were seen in surface depressions and fiber-like structures among some specimens, the tetracycline HCl and citric acid solutions produced comparable morphologic characteristics.