The natural history of periodontal bone loss in germfree and gnotobiotic rats infected with periodontopathic microorganisms.

Abstract

A new technique for evaluating the vertical component of bone loss in rats is described in which silicone base impression material is utilized. The extent and pattern of bone loss in germfree rats is compared to the bone loss in gnotobiotic animals infected with either Streptococcus mautans strain 6715 or with Actinomyces naeslundii strain I or with Actinomyces viscosus strain T 14. In general, after approximately 60 days of infection the gnotobiotic animals demonstrated patterns of bone loss similar to germfree animals although the extent of loss was more marked. The major increases in bone loss (both horizontal and vertical) were observed in the period between 60 and 90 days of infection. The major destruction offurs on the lingual aspects of maxillary molars. Vertical bone loss was greater in A. naeslundii infected animals than in S. mutans infected animals.