Overexpression of Sp7 in odontoblasts results in dentinogenesis imperfecta due to the inhibition of odontoblast maturation

These results indicate that sustained Sp7 expression in differentiated odontoblasts inhibits odontoblast maturation and reduces the expression of dentin matrix proteins; however, it fails to induce the transdifferentiation of odontoblasts into osteoblasts, which occurs in Runx2 transgenic mice. Therefore, Sp7 expression needs to be down-regulated to an appropriate level for odontoblast maturation.