Comparitive effects of tetracyclines and citric acid on dentin root surface of periodontally involved human teeth: A scanning electron microscope study

Periodontal diseases produce physical and chemical alterations in the root cementum. Various topical applications as root conditioning agents have been recommended as an adjunct to mechanical root surface debridement to remove smear layer, endotoxins and to expose collagen fibers on dentin surface. The objectives were to compare dentin surface changes following applications of tetracyclines and citric acid to the instrumented root surface of periodontally involved human teeth under scanning electron microscope. The study group comprised of 80 dentin samples, which were prepared from periodontally-compromised teeth, planned for extraction. Diseased surfaces were root planed. The teeth were sectioned and solutions of tetracycline HCl, minocycline, doxycycline and citric acid were applied to the surfaces with cotton pellets for 5minutes.The root surface samples were then examined by scanning electron microscope. Removal of smear layer in all the four groups was near total except a few areas. All four groups showed slight difference in mean number of total dentinal tubules. Minocycline and doxycycline showed no significant difference. The proportion of patent dentinal tubules was (74%) in tetracycline HCl group compared to minocycline (48.3%), doxycycline 42%), citric acid (52%), showing the differences statistically significant. Tetracycline group showed higher number of patent tubules when compared to minocycline, doxycycline and the difference was statistically significant. Results of this study suggest that tetracycline is the best current tetracycline form for root surface conditioning as measured by its ability to affect both dentin smear layer removal and tubule exposure.