The effects of different tetracyclines on the dentin root surface of instrumented, periodontally involved human teeth: A comparative scanning electron microscope study

This in vitro study compares, by scanning electron microscope (SEM) examination, the surface effects of various topical applications of tetracycline on the instrumented dentin root surface of human teeth. Eighty- two (82) dentin samples were prepared from periodontally-compromised teeth planned for extraction. Solutions of tetracycline HCI, doxycycline, minocycline, sumycin, and a saline control were prepared and applied to the dentin samples for 0.5, 1, 3, 5, and 10 minutes. Each solution pH was measured: tetracycline HC1 (pH 1.6), doxycycline (pH 2.2), minocycline (pH 3.8), sumycin (pH 4.4), and saline (pH 5.1). A tetracycline periodontal fiber was also evaluated at 1, 4, 7, and 10 days of exposure for dentin surface effects. Tetracycline HC1 removed the dentin smear layer leaving clean and open tubules significantly better than other solutions tested in as little as 30 seconds. Doxycycline and minocycline produced similar results to each other, which were significantly better than sumycin and saline, but not as effective as tetracycline HC1. Smear layer removal was attained by doxycycline and minocycline in five to ten minutes; however, sumycin and the saline control ineffectively removed the surface smear layer and dentinal tubules remained partially to totally occluded by debris. The periodontal fiber did not significantly alter the surface smear layer. Results of this study suggest that tetracycline HC1 is the best current tetracycline form for root surface conditioning as measured by its ability to affect both dentin smear layer removal and dentin tubule exposure.