Immunohistochemical study of dental pulp applied with 4-META/MMA-TBB adhesive resin after pulpotomy

The purpose of this study was to investigate nerve regeneration and prolife rative activity in amputated pulp tissue after the application of 4-META/MM A-TBB adhesive resin (4-META resin). Calcium hydroxide was used as a contro l material. At 3 days, fibroblast-like cells were positive for proliferatin g cell nuclear antigen (PCNA) in both 4-META resin- and calcium hydroxide-t reated groups and were located mainly within 0.5 mm from the cut surface. O nly a few fragmented neurofilament protein (NFP)-positive nerve fibers were observed in this area. At 7 and 14 days, the number of PCNA-positive cells had gradually decreased and regenerated NFP-positive nerve fibers were obs erved close to the cut surface of the pulp in both groups. At 21 days in th e experimental group, several PCNA-positive cells were still found in the a rea 0.5 mm from the cut surface, and NFP-positive nerve fibers were detecte d about 0.15-;0.2 mm from the cut surface. In contrast, a dentin bridge was produced under the necrotic layer at 21 days in the control group. PCNA-po sitive cells were not found underneath the dentin bridge, but NFP-positive nerve fibers had regenerated close to it. These results suggest that althou gh cell differentiation and nerve regeneration are delayed, wound healing o ccurred even after the application of 4-META resin to exposed pulp surface the same as calcium hydroxide application. (C) 2000 John Wiley & Sons, Inc. J Biomed Mater Res, 51, 241-248, 2000.