Objectives: Our goal is to develop tooth-restorative materials that induce dentin regeneration biologically. Phosphophoryn, a member of SIBLING family, is thought to be involved in dentin biomineralization. Previously we reported that phosphophoryn induces apatite induction only when covalently cross-linked to type I collagen fibrils. The objective of this study was to examine whether phosphophoryn-collagen composite induces reparative dentin formation in rat. Methods: The purified phosphophoryn (2 µg) was cross-linked to atelocollagen (Cellmatrix Type I-P, Nitta Gelatin) fibrils (75µg) using divinyl sulfone (Sigma). Multi-Cal™ (Pulpdent) was used as a conventional material. Phosphophoryn-collagen composite (PP-Col) and Multi-Cal™(Ca) were placed onto the exposed pulp in maxillary first molar of 8 week-old wistar rats. Rats were sacrificed 1, 2 and 3 weeks after the direct pulp capping. Teeth were fixed in 10% neutral buffered formaldehyde, demineralized in EDTA, and embedded in paraffin. Four µm sections were stained with hematoxylin-eosin. In histological observation of the sections, the area and dense of newly formed dentin were measured, and degree of pulp inflammation was evaluated. Results: PP-Col induced reparative dentin formation intensively. The amount of dentin formed by PP-Col was 1.4 times more than that by Ca at 2 weeks. The dense rate of reparative dentin formed by PP-Col was 95% and 98% at 2 and 3 weeks respectively while that by Ca was 88% even at 3 weeks. In Ca group, reparative dentin having tunnel-shaped defect was formed as reported previously. Slight pulp hyperemia was observed throughout the whole experimental period in PP-Col group. On the other hand, strong inflammatory reaction was observed in pulp tissue at 1 and 2 weeks in Ca group. Conclusion: These findings suggest that phosphophoryn-collagen composite is a promising material for dentin regeneration in new vital pulp therapy. Supported by Grant-in-Aid for Exploratory Research #16659525 in Japan.

Back to the Pulp Biology & Regeneration Research Program
Back to the IADR/AADR/CADR 85th General Session and Exhibition (March 21-24, 2007)

Top Level Search