Fibroblast growth factor 23 overexpression impacts negatively on dentin mineralization and dentinogenesis in mice

1. Though previous studies have shown that fibroblast growth factor 23 (FGF23) mRNA expression localizes in ameloblasts and odontoblasts in teeth, it is unclear what effect FGF23 overexpression has on dentin mineralization and dentinogenesis. Toward this end, the phenotypes of mandibles and teeth were compared between 6-week-old FGF23 transgenic mice and their wild-type littermates by radiography, microcomputed tomography scanning, histology, histochemistry and immunohistochemistry. 2. The mineral density was reduced in all teeth, including molars and incisors, and in the mandible, and the mineralized tooth volume in incisor and molars, and the mineralized cortical and alveolar bone volume in mandibles were decreased in FGF23 transgenic mice compared with their wild-type littermates. The dental volume, reparative dentin area, the expression of dentin sialoprotein in dentin, and the deposition of type I collagen and osteocalcin in the dental matrix were significantly reduced. However, the predentin volume and the expression of biglycan in dentin were increased in FGF23 transgenic mice compared with their wild-type littermates. 3. The results of the present study show that FGF23 overexpression plays a negative regulatory role on dentin mineralization and dentinogenesis.