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 HCl,
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 HCI (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 HCI 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 HCl.
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 HCl 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.