Humoral immune response to active root resorption with a murine model

A depression in autoantibody titers to tooth root antigens has been shown to coincide with active root resorption in the dog. Since a murine model would facilitate immunologic studies of root resorption because of the availability of syngeneic and immunodeficient strains, the objectives of this study were to develop a quantitative mouse model for root resorption and to determine if a similar drop in tooth root autoantibodies coincides with active root resorption in this species. Uniform areas of necrosis were created in the periodontal ligaments of lower incisors of 36 male Swiss albino mice by inserting a cryoprobe through a skin incision (-80 degrees C; 5 minutes). Contralateral incisors served as controls. At 0, 3, 5, 7, 10, 14, and 21 days; six mice were killed, and blood and incisors were collected. Relative surface areas of root resorption were quantified with micrographs taken at a standardized position, tilt, and magnification with a scanning electron microscope. Serum autoantibody titers were determined with an enzyme-linked immune sorbent assay with antigen prepared from a 5 mol/L guanidine-HCl-EDTA (pH 5.0) extract of incisor roots that were harvested from syngeneic mice. ANOVA and the paired Student t test were used to compare data at the various time points. No root resorption was evident on control teeth. Localized lesions on treated teeth were found to be of significant size between 7 and 14 days (p less than 0.05), but most of these erupted into the mouth by 21 days.(ABSTRACT TRUNCATED AT 250 WORDS)