Immunohistochemical study on cell adhesion molecule in the rat root during tooth movement

Abstract

Cell-adhesive glycoprotein, which is in the cell and extracellular matrix, may be di-rectly involved with attachment of odontoclasts to the root surface. The left maxillary first molars of 12- to 13-week-old Wister rats were moved by the Waldo method to observe root resorption and localization of vitronectin immunohistochemically on the tension side of the molars. The teeth were divided into two groups according to the thickness of elastic bands used. Group A had 1mm×1mm×0.65mm bands, and group B had 1mm×1mm×1mm bands. Vitronectin was not detected on the tension side after 1 or 3 days tooth movement in either group. After 5 and 7 days, odontoclasts were observed on root surfaces of the tension side and vitronectin was detected ; the former, on the circle of spot-like absorption, and the latter, con-tinuously, on the surface of widespread absorption. Root resorption was less frequent in group B, while the amount of vitronectin detected was the same in both groups. Although, vitronectin was not detected the control side in either group, there was widespread bone resorption by osteoclasts in both. Thickness of the elastic bands had little effect on the localization of vitronectin. It was con-cluded that root resorption and the subsequent localization of vitronectin on the root surfaces at the tension side was more influenced by time than by strength of the orthodontic force.