The induction of reparative dentine by enamel proteins

This study was designed to examine whether enamel matrix derivative (EMD) could induce reparative dentine formation without eliciting adverse side-effects in pulpotomized teeth in the miniature swine.

Pulpotomy was performed in 36 mandibular incisor teeth from 11 adult miniature swine. Following the surgical procedure, the exposed pulp tissue was treated with EMD or covered with a calcium hydroxide preparation (Dycal). Following an observation period of 3, 4 and 8 weeks, the experimental teeth were extracted and examined using light microscopy and histometric analysis. The total amount of reparative dentine formed in the EMD-treated teeth was calculated as total area using digital histomorphometry analysis of the five central-most sections from each experimental tooth.

In the EMD-treated teeth, substantial amounts of dentine-like tissue formation consistently led to a complete hard-tissue bridging of the defects. The onset of hard tissue formation could be observed after 2 weeks and was located only on the pulpal wound. More limited dentine formation was also observed in Dycal-treated teeth. However, in these teeth the new hard tissue formed at the expense of pulp chamber width, causing narrowing of root canals. The total amount of reparative dentine formed in the EMD-treated teeth was significantly higher (P<0.005) than in the Dycal-treated specimens.

These results demonstrate the potential of EMD as a biologically active pulp-dressing agent that specifically induces pulpal wound healing and dentine formation in the pulpotomized teeth without affecting the normal function of the remaining pulp.