OBJECTIVETo observe the histological and immunohistochemical characteristics of the pulp of teeth after pulpotomy.

METHODSTwenty-nine permanent anterior teeth with completely formed roots after pulpotomy due to dental trauma were selected. Thirty permanent premolars with completely formed roots served as control, which were extracted for orthodontic treatment. HE stain and immunohistochemical study of collagen I and collagen III were performed on the root pulp of these two groups.

RESULTSThere were degenerative changes in root pulp of the teeth after pulpotomy, such as vacuolization and homogenization of the odontoblasts, cell reduction, fibrosis, hyaline degeneration and calcification. In healthy root pulp, collagen I had a dispersed distribution, calcification substance was stained positive, but collagen III weakly stained in the extreme at peripheric pulp, and calcification substance stained negative. While in pulp of teeth after pulpotomy, both types of collagens had increased expression, fibers aggregated forming thick fiber bundles. In the wall of blood vessels collagen I had increased expression, but collagen III decreased.

CONCLUSIONSThe root pulp below dentin bridge after pulpotomy was different from the healthy pulp, and there were some histological degenerative changes in the pulp of the immature anterior teeth after pulpotomy. It is suggested that root canal treatment should eventually be performed on these teeth.