title: Osteopetrosis, osteopetrorickets and hypophosphatemic rickets differentially affect dentin and enamel mineralization.
abstract: Osteopetrosis (OP) is an inherited disorder of defective bone resorption, which can be accompanied by impaired skeletal mineralization, a phenotype termed osteopetrorickets (OPR). Since individuals with dysfunctional osteoclasts often develop osteomyelitis of the jaw, we have analyzed, if dentin and enamel mineralization are differentially affected in OP and OPR. Therefore, we have applied non-decalcified histology and quantitative backscattered electron imaging (qBEI) to compare the dental phenotypes of Src(-/-), oc/oc and Hyp(-/0) mice, which serve as models for OP, OPR and hypophosphatemic rickets, respectively. While both, Src(-/-) and oc/oc mice, were characterized by defects of molar root formation, only oc/oc mice displayed a severe defect of dentin mineralization, similar to Hyp(-/0) mice. Most importantly, while enamel thickness was not affected in either mouse model, the calcium content within the enamel phase was significantly reduced in oc/oc, but not in Src(-/-) or Hyp(-/0) mice. Taken together, these data demonstrate that dentin and enamel mineralization are differentially affected in Src(-/-) and oc/oc mice. Moreover, since defects of dental mineralization may trigger premature tooth decay and thereby osteomyelitis of the jaw, they further underscore the importance of discriminating between OP and OPR in the respective individuals.
authors.affiliation: Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
authors.forename: Till
authors.initials: T
authors.lastname: Koehne
authors.forename: Robert P
authors.initials: RP
authors.lastname: Marshall
authors.forename: Anke
authors.initials: A
authors.lastname: Jeschke
authors.forename: Bärbel
authors.initials: B
authors.lastname: Kahl-Nieke
authors.forename: Thorsten
authors.initials: T
authors.lastname: Schinke
authors.forename: Michael
authors.initials: M
authors.lastname: Amling
mesh_terms: D000818:Animals; D002113:Calcification, Physiologic; D003743:Dental Enamel / Q000502:physiology*; D003804:Dentin / Q000502:physiology*; D007015:Hypophosphatemia, Familial / Q000503:physiopathology*; D051379:Mice; D018345:Mice, Knockout; D010022:Osteopetrosis / Q000503:physiopathology*; D012279:Rickets / Q000503:physiopathology*; D014078:Tooth Eruption