The effect of endodontic materials on periodontal ligament cell proliferation, alkaline phosphatase activity, and extracellular matrix protein synthesis in vitro

Recent studies have demonstrated that periodontal ligament-derived (PDL) cells have the potential to regenerate a complete periodontal connective tissue attachment apparatus on both root and artificial substrates. To study the characteristics of endodontic materials conducive to periodontal regeneration, we have established an experimental model using PDL cell cultures that express a 42 kDa protein (CP42) associated with cementum extracellular matrix. In this report, the effect of gutta percha, dental amalgam, composite and calcium hydroxide on PDL cell proliferation, collagen and noncollagen protein synthesis, alkaline phosphatase activity, and CP42 expression are presented. While all substrates supported PDL cell attachment and proliferation, highest levels of alkaline phosphatase activity, collagen and noncollagen protein synthesis were observed in control cultures. Lowest levels of the above parameters were observed with gutta percha while amalgam, composite and calcium hydroxide had intermediate levels. Only control PDL cultures demonstrated CP42 expression. These data suggest that culture substrate can markedly influence periodontal extracellular matrix gene expression in vitro and provide an experimental model to select and develop endodontic materials compatible with periodontal regeneration in vivo.