Experimental study of periodontal tissue regeneration after the application of enamel matrix derivative in rat periodontal defects

The purpose of this study was to evaluate periodontal wound-healing after the application of enamel matrix derivative (EMD) in rats. Periodontal defects were surgically created on the mesial side of the first maxillary molar of 24 male Long-Evans rats. EMD was applied to cover the denuded root surfaces in the experimental group. The contralateral molar was used for the control group, which received the same treatment without EMD. The rats were sacrificed at 2 weeks (8 rats), 4 weeks (8 rats), and 8 weeks (8 rats) after the surgery. Demineralized paraffin sections were stained with Masson's trichrome. Histological analysis and histomorphometric measurements were performed on the periodontal sections. Using an immunohistochemical technique, the localization of osteocalcin (OC) was also examined. The formation of new cementum was statistically significant in the experimental group, especially new cementum with extrinsic fiber. Both acellular and cellular cementum were also rather strongly observed in the experimental group. Epithelial down growth was also strongly inhibited in the experimental group at 8 weeks after the surgery. OC-positive cells and matrix were limited at the bottom of the defects in the control group, while positive reaction was detected not only at the bottom but also spreading to the coronal portion of the defects in the experimental group. These results suggest that EMD has potential to promote cementum regeneration, especially fiber-inserted cementum, and to create a favorable environment that will promote periodontal regeneration.