Effects of denervation on 3 H-fucose incorporation by odontoblasts in the mouse incisor

The present study was designed to determine the effects of denervation on glycoprotein synthesis in the predentinal matrix of the mouse incisor. The inferior alveolar nerve (IAN), superior cervical ganglion (SCG) or both (IAN+SCG) were unilaterally resected in adult mice with the contralateral side remaining intact as a control. Fourteen days after surgery and 4 h prior to killing, 0.2 mCi of 3 H-fucose was injected intravenously and mandibles were processed for standard histological and autoradiographic techniques. Silver halide grains were counted over the predentin matrix for 2000 μm per tooth. The results showed that the IAN and SCG resection affected 3 H-fucose incorporation into the predentinal matrix; however, the highest absolute mean grain counts occurred after IAN+SCG resection. SCG resection increased the amount of 3 H-fucose incorporated into the predentinal matrix by 48%, that of IAN by 24% and that of IAN+SCG by 14% as compared to contralateral controls. These data indicate a regulatory role for the nervous system and a possible interaction of neural components in the control of glycoprotein synthesis by odontoblasts in the mouse incisor.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47677/1/441_2004_Article_BF00216039.pd

Characterization of Cellular Responses Involved in Reparative Dentinogenesis in Rat Molars

During primary dentin formation, differentiating primary odontoblasts secrete an organic matrix, consisting principally of type I collagen and non-collagenous proteins, that is capable of mineralizing at its distal front. In contrast to ameloblasts that form enamel and undergo programed cell death, primary odontoblasts remain metabolically active in a functional tooth. When dentin is exposed to caries or by operative procedures, and when exposed dentinal tubules are treated with therapeutic dental materials, the original population of odontoblasts is often injured and destroyed. The characteristics of the replacement pool of cells that form reparative dentin and the biologic mechanisms that modulate the formation of this matrix are poorly understood. Based on the hypothesis that events governing primary dentinogenesis are reiterated during dentin repair, the present study was designed to test whether cells that form reparative dentin are odontoblast-like. Cervical cavities were prepared in rat first molars to generate reparative dentin, and animals were killed at various time intervals. In situ hybridization with gene-specific riboprobes for collagen types I and III was used to study de novo synthesis by cells at the injured dentin-pulp interface. Polyclonal antibodies raised against dentin sialoprotein (DSP), a dentin-specific protein that marks the odontoblast phenotype, were used in immunohistochemical experiments. Data from our temporal and spatial analyses indicated that cells forming reparative dentin synthesize type I but not type III collagen and are immunopositive for DSP. Our results suggest that cells that form reparative dentin are odontoblast-like.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67273/2/10.1177_00220345950740021301.pd