Fig. 1.

Bone loss in the rat oral cavity. (A) Schematic of the molars of the left rat maxilla viewed buccal to lingual. “Front” denotes the area closest to the front of the mouth (anterior). The solid line labeled ABC represents the alveolar bone crest in the diseased animals. Shaded area below the line indicates the area evaluated for bone loss; the solid line labeled CEJ represents the cemental–enamel junction. Letters A–F indicate the sites that were evaluated for bone loss (shaded areas). (B) Mean bone loss from all sites by rat group. Bar heights represent the combined area bone loss per rat group as cm² in the projected radiograph image (see Materials and Methods). Error bars represent SD. The wild-type strain produces significantly greater (P = 0.046) total bone loss as determined by ANOVA. (C) Average bone loss at different sites in the evaluated left rat maxillae. Letters correspond to those regions presented in Fig. A. Bar heights represent area of bone loss (cm² as measured from the projected radiograph; see Materials and Methods). Error bars represent SD. The wild-type strain produces significantly greater (P = 0.004) bone loss at site B by ANOVA. (D) Radiograph of the left maxilla of a rat from the uninoculated control group (Left) and from the group that was fed wild-type A. actinomycetemcomitans (Right). The amount of bone loss indicated by the arrow was not typical of all samples, and represents an obvious case of bone loss.