Biomechanical and Morphological Studies on the Periodontal Ligament of the Rat Molar after Treatment with α-amylasein vitro

Biomechanical properties and morphological features of the rat molar periodontal ligament were examined after treatment with alpha-amylase. Treatment with alpha-amylase induced dose-dependent decreases in the maximum shear stress, tangent modulus, and failure strain-energy density of the periodontal ligament; in addition, it weakened the alcian-blue staining of the periodontal ligament and exposed periodontal collagen fibrils as revealed by scanning electron microscopy. Azan staining and polarized microscopic observations of the periodontal collagen fibers were not markedly different between the control and alpha-amylase treated specimens. These results suggest that decreases in the strength of the periodontal ligament due to alpha-amylase digestion are largely due to removal of interfibrillar substances such as acid glycosaminoglycans and neutral polysaccharides from the periodontal ligament. It is also suggested that the interaction of the interfibrillar substances with collagen fibrils is involved the biomechanical properties of the periodontal ligament.