Long term effect of systemic tetracycline administration on the severity of induced periodontitis in the rat.

The present investigation was undertaken to determine the influence of systemically administered tetracycline on periodontitis in the rat. Thirty Sprague-Dawley rats were arranged into two groups, one group received 21 mg of tetracycline hydrochloride each day for 10 weeks in the drinking water. Periodontitis was induced in the maxillary left segment with a 0.008 inch stainless steel ligature wire and by modifying the normal diet with sucrose. The direct microscopic and histometric measurements obtained were analyzed for statistical significance, which revealed the following: 1. Tetracycline-treated animals demonstrated significantly less resorption of the buccal alveolar bone. There were no statistical differences however, in the amount of alveolar bone resorption palatally or interdentally. 2. Tetracycline-treated animals demonstrated significantly less apical migration of the junctional epithelium on the distal root of the maxillary first molar tooth. 3. Tetracycline-treated animals demonstrated significantly fewer inflammatory cells. In conclusion, long term systemic administration of tetracycline in the rat may be of value in reducing the amount of tissue destruction in experimentally induced periodontitis.