Dentin disorders: anomalies of dentin formation and structure

Abstract

Dentin defects represent a cluster of relatively rare heritable disorders affecting the formation and mineralization of dentin. Major clinical features include loss of enamel with extreme wear of exposed dentin, opalescent tooth discoloration, short roots with pulpal calcification and increased tooth mobility, and frequent periapical radiolucencies. Historically, these inherited conditions have been classified by Shields et al. (1) as either dentinogenesis imperfecta (DGI) types I, II and III, or dentin dysplasia (DD) types I and II. DGI type I is now universally designated as osteogenesis imperfecta with dentinogenesis imperfecta (OI/DGI) and is caused by type I collagen mutations. Among the genes expressing the non‐collagenous proteins in dentin, only the DSPP gene has been implicated in the etiology of DD type II and all DGI types, suggesting that heritable dentin defects can be viewed as a continuum rather than as distinct disease entities. Dental treatment strategies should aim to preserve the affected dentitions by protecting teeth from wear, restoring them to compliance with the specific structural characteristics of the defective dentin, and anticipating early tooth loss. Endodontic treatment of the affected teeth is very challenging because of the peculiar pulp morphology and most often has poor prognosis. If conventional therapy is not an option, periapical curettage and retrograde filling is a possible alternative, except in the case of teeth with short roots.

Developmental defects of enamel and dentine: challenges for basic science research and clinical management

“…It is caused by a mutation in the DSPP gene . The clinical and radiographic features are similar to dentinogenesis imperfecta type I, but are expressed more consistently . Dentinogenesis imperfecta type III is also caused by the same DSPP mutation as type II, but shows variable discolouration and morphology of the teeth, ranging from normal appearing teeth to shell teeth with reduced dentine formation .…”

The expression and role of Lysyl oxidase (LOX) in dentinogenesis

“…It is possible that the collagen matrix maturation is not as essential for proper mineralized dentine formation as previously believed, because in spite of impaired aggregation of collagen in LOX-depleted mice, the gross histology and morphology seemed to remain unaltered. This is supported by differential clinical and histological findings in patients with collagen mutations and disorders (Kratochwil et al 1989, De Coster et al 2007, De Coster 2012. It is also possible that the absence of functional LOX gene may be, at least partially or with delay, compensated by lysyl oxidase isoenzymes.…”

“…, De Coster et al . , De Coster ). It is also possible that the absence of functional LOX gene may be, at least partially or with delay, compensated by lysyl oxidase isoenzymes.…”

“…). Collagen‐related disorders with hard tissue involvement, such as osteogenesis imperfecta (OI) or Ehlers‐Danlos syndromes (EDS) present variable spectrum of dentinal disorders, and cases with apparent OI skeletal appearance and dentinal disorders without collagen alterations have been reported (De Coster ). Therefore, the absolute importance of collagen matrix organization remains open.…”

“…Most of those crystals are closely associated with collagen fibrils, and the proper organization of collagen matrix is believed to be essential for the formation of high-quality mineralized dentine (Tjäderhane & Haapasalo 2012), even though the scientific evidence is somewhat contradictory (Kratochwil et al 1989, De Coster et al 2007). Collagen-related disorders with hard tissue involvement, such as osteogenesis imperfecta (OI) or Ehlers-Danlos syndromes (EDS) present variable spectrum of dentinal disorders, and cases with apparent OI skeletal appearance and dentinal disorders without collagen alterations have been reported (De Coster 2012). Therefore, the absolute importance of collagen matrix organization remains open.…”