Neuroregulation of protein synthesis in odontoblasts of the first molar of the rat after wounding.

Odontoblasts respond to occlusal trauma by increased elaboration of a matrix which is subsequently calcified to form reparative dentin. The purpose of the present study was to analyze quantitatively and compare the ability of odontoblasts to synthesize collagen after wounding in rats with an intact innervation (baseline) and in rats with sensory (inferior alveolar nerve, IAN) and/or sympathetic (superior cervical ganglion, SCG) surgical denervation. Surgery was performed 7 days prior to wounding. All rats had 1 mm of enamel and dentin removed from the occlusal surface of the first mandibular molar (resected side) with the contralateral tooth serving as a control. Rats were killed 1 h after injection with 3H-proline on days 0, 5, 10 or 15 after wounding, and mandibles were removed and processed for autoradiography. Grain counts were performed over odontoblasts throughout the pulp horns for each time period and for control and experimental molars in intact (baseline) and denervated groups. When compared to the control baseline, the experimental baseline data showed increased 3H-proline uptake throughout the study with a peak at 5 days. When compared to the baseline data, IAN and SCG results demonstrated a delay or attenuation of the protein synthetic response. The results indicate that the sensory and sympathetic neural components may regulate odontoblastic response to wounding.