BONE RESORBING ACTIVITY OF GINGIVA FROM BEAGLE DOGS FOLLOWING METRONIDAZOLE AND INDOMETHACIN THERAPY

Twenty-four beagle dogs were divided into 3 groups of 8 dogs each. Periodontitis was induced in 3 of the dental quadrants of each dog using wire ligatures while 1 quadrant was not ligated and was kept cleaned. One group of dogs received no additional treatment, 1 group received systemic metronidazole and the 3rd group received systemic indomethacin [chemotherapeutics]. The in vitro bone resorbing activity of extracts from freeze-dried gingiva from the groups was compared. Extracts of gingiva from ligated teeth produced significant bone resorption. Metronidazole treatment suppressed this ligature-induced bone resorbing activity while indomethacin had no effect. Extracts from gingiva from around clean nonligated teeth had somewhat less activity than extracts from gingiva of ligated teeth, although some significant resorption remained in all treatment groups. Bacterial cultures from metronidazole-treated groups showed a change from a predominantly Gram negative obligatory anerobic flora (Bacteroides asaccharolyticus), to one predominated by Gram negative, facultative anaerobes (Capnocytophaga and Campylobacter). Metronidazole evidently suppressed bone resorbing activity by inducing a change in the flora of the gingival crevice.