Effects of orthodontic tooth movement on the Alcian blue staining patterns of rat alveolar bone: an histochemical study

There is little information available concerning the effects of orthodontic forces on glycosaminoglycans (GAG) of alveolar bone. The present study identifies changes in Alcian blue staining intensity in rat alveolar bone undergoing resorption resulting from a heavy (25g) tipping force applied to the adjacent teeth by a separating spring. One day after force application, bone from treated animals (internal control and experimental sides) demonstrated more intense staining with Alcian blue, pH 1.0 (p less than 0.005) and pH 2.5 (p less than 0.05) than external controls (untreated animals). By day 3, the intensity of Alcian blue staining of treated alveolar bone was similar to untreated. Chondroitinase AC, ABC and testicular hyaluronidase predigestion did not completely block the staining reaction, suggesting that both GAG and noncollagenous proteins were demonstrated. Mean cross-sectional areas of the interdental septum of the experimental side were nearly 44% less than that of the internal control side after 3 days and nearly 62% less after 5 days. The study suggested that alterations in bone GAG levels occurred prior to tooth movement as histochemical changes occurred after force application but before initiation of significant septal resorption. A precise appraisal of the types of macromolecules effected awaits future biochemical analysis. The results of the present work strongly suggest the use of an external control group for future studies, as Alcian blue staining reactions of the internal control side of treated animals were not similar to those of external controls.