Tooth dentin defects reflect genetic disorders affecting bone mineralization

Abstract

Several genetic disorders affecting bone mineralization may manifest during dentin mineralization. Dentin and bone are similar in several aspects, especially pertaining to the composition of the extracellular matrix (ECM) which is secreted by well-differentiated odontoblasts and osteoblasts, respectively. However, unlike bone, dentin is not remodelled and is not involved in the regulation of calcium and phosphate metabolism. In contrast to bone, teeth are accessible tissues with the shedding of deciduous teeth and the extractions of premolars and third molars for orthodontic treatment. The feasibility of obtaining dentin makes this a good model to study biomineralization in physiological and pathological conditions. In this review, we focus on two genetic diseases that disrupt both bone and dentin mineralization. Hypophosphatemic rickets is related to abnormal secretory proteins involved in the ECM organization of both bone and dentin, as well as in the calcium and phosphate metabolism. Osteogenesis imperfecta affects proteins involved in the local organization of the ECM. In addition, dentin examination permits evaluation of the effects of the systemic treatment prescribed to hypophosphatemic patients during growth. In conclusion, dentin constitutes a valuable tool for better understanding of the pathological processes affecting biomineralization.

SPR4-peptide alters bone metabolism of normal and HYP mice

“…In X-linked and autosomal recessive rickets there are high levels of circulating ASARM-peptides (6, 8, 13). In vitro and in vivo (bolus and infusion) administration of ASARM-peptides and transgenic mice over expressing ASARM-peptides cause mineralization defects and hypophosphatemia (2–5, 7–14, 26, 33–35, 40–42); (11) The pleiotropic effects of SPR4- peptide occurs because SPR4-peptide also binds and neutralizes ASARM-peptides; (1, 11, 12 & 13) Thus, under conditions of ASARM depletion and/or acute bolus administration of SPR4, the formation of the trimeric complex is favored because of reduced ASARM-peptides (neutralized by SPR4); (2 & 3) This in turn results in reduced FGF23 expression hyperphosphatemia and increased mineralization. This model also explains the different effects of SPR4-peptide administration in wild-type and HYP mice since HYP-mice have defective PHEX and increased circulating ASARM-peptides.…”

Occlusal features and need for orthodontic treatment in persons with osteogenesis imperfecta

“…Dentinogenesis imperfecta has been associated with OI, regarding dental–facial manifestations (Lin et al, 2009; Opsahl Vital et al, 2012; Saeves, Axelsson, Wekre, & Storhaug, 2006). Other oral problems of persons with OI are also reported in the literature.…”

Type VII collagen is enriched in the enamel organic matrix associated with the dentin–enamel junction of mature human teeth

“…In contrast, the underlying dentin, which is similar to bone in composition [3], is a calcified, collagen-rich ectomesenchymal tissue that serves to support the outer, more brittle enamel [4]. The interfacial region coupling these dissimilar mineralized phases is known as the dentin-enamel junction (DEJ), which optically appears as an abrupt transition.…”