Regional odontodysplasia (ORPHA:83450)
A rare orodental disease characterized by localized developmental anomaly of the dental tissues, with enamel and dentin hypomineralization affecting one (odontodysplasia) or several (regional odontodysplasia; ROD) teeth (deciduous and permanent, with teeth of the maxilla more frequently involved).
Epidemiology
The prevalence is unknown but around 180 cases have been reported in the literature so far.
Clinical description
The defects involve both primary and permanent dentitions in the majority of the cases. The teeth of individuals with ROD are usually hypoplastic, small and atypically shaped with surface pits and grooves and a yellowish or brownish discoloration. Early loss of primary teeth is described. The condition usually affects the maxilla more than the mandible and is generally unilateral. Other common features include eruption failure or delay, and facial swellings (cellulitis), abscesses or fistulae in the absence of caries. Radiographic examination reveals a lack of contrast between enamel and dentin, with very thin (ghost-like) layers. Both dentin and enamel are hypomineralized. The pulp looks large and pulp stones or denticles can be seen. Histological features include mixed areas of cellular, amorphous and interglobular dentin. The enamel is hypoplastic, and hypocalcified areas and invaginations from the enamel surface into the dentin layer have been observed and may result in bacterial contamination of the pulp, leading to pulpitis or necrosis. The bone itself is not affected.
Etiology
The underlying cause of ROD is still a matter of debate but various etiological factors have been suggested such as local circulatory disorders, viral infections, local trauma, pharmacotherapy during pregnancy, facial asymmetry or a combination of these factors. Some familial cases may also point towards a genetic etiology.
Diagnostic methods
Diagnosis should be suspected on the basis of the clinical aspect of the teeth, or upon presentation with failure of eruption, or pulpitis or necrosis in absence of caries. The diagnosis may be confirmed by radiography revealing the typical ''ghost-like'' appearance of the teeth and the presence of enamel and dentin with similar radiodensities.
Differential diagnosis
The differential diagnosis includes dentinogenesis imperfecta, dentin dysplasia and amelogenesis imperfecta.
Management and treatment
Management is mainly conservative and includes treatment of the pulpitis and necrosis when necessary, with the aim of trying to maintain the affected teeth as long as possible to permit normal jaw development. If extraction is required, the extracted teeth should be replaced with removable appliances to maintain aesthetic appearance and function, and to avoid overeruption of opposing teeth and preserve the normal vertical dimension. Some patients benefit from autotransplants. Prosthesis and implants can be considered when craniofacial development is complete.
Prognosis
The prognosis for patients is good, especially when the condition is diagnosed and managed during the early stages. Life-long treatment is expected.

                            Last update: 
                            November 2023


                            - Expert reviewer(s): 
                            Pr Agnès BLOCH-ZUPAN | ERN CRANIO*


                                * European Reference Network