DKK1 and Oligodontia: The mutation of Dkk1 may cause oligodontia and short root anomaly.27,66 Researchers observed that strong expression of Dkk1 was localized in preodontoblasts on the labial side of the incisors.67 At postnatal day 2, Dkk1 is prominently expressed in the preodontoblasts and odontoblasts in mouse molar germs.68 In Dkk1 transgenic mice, overexpression of Dkk1 in pulp and odontoblast cells delayed the maturation of dentinogenesis during post-natal development.69 The dental crown begins to form in the late bell stage (P1).