Dentin dysplasia

Type I has been known as radicular dentine dysplasia because the teeth have undeveloped root(s) with abnormal pulp tissue. Morphology and colour of the crown mostly appear normal, but occasionally teeth appear slightly amber-coloured or bluish-brown shine in primary teeth with no or only immature root development. The teeth are mostly maligned and have a higher risk of fracture.[12]

In other words, affected primary teeth usually have abnormal -shaped or shorter than normal roots. “Crescent/half-moon shaped” pulp chamber remnant in permanent teeth can be seen on x-rays. The roots may appear to be darker or radiolucent/pointy and short with apical constriction. Dentine is laid down abnormally and causes excessive growth within the pulp chamber. This will reduce the pulp space and eventually cause incomplete and total pulp chamber obliteration in permanent teeth.[12][13] Sometimes periapical pathology or cysts can be seen around the root apex.[11] Most cases of DD associated with peri-apical radiolucency/ pathology have been diagnosed as radicular cysts, but some of them have been as diagnosed peri-apical grauloma instead.[14]

Type II would mostly cause discolouration to the primary teeth. Affected teeth usually appear as brownish-blue, brown or yellow. Translucent “opalescence” is often one of the characteristics to describe teeth with DD-2. In some cases, teeth might show slightly amber-coloured, but in most of the cases permanent teeth are unaffected and appear normal regardless of colour, shape and size. Dental X-rays are the key to diagnosing dentine dysplasia, especially on permanent teeth. Abnormalities of the pulp chamber is the main characteristic to make a definitive diagnosis.[15][16]

In the primary teeth, coronal dentin dysplasia may appear similar to Dentinogenesis Imperfecta type II (DG-II) but if abnormalities features appear to be more pronounced in the permanent teeth, then consider changing the diagnosis to DGI-II instead of DD-2.[5]

In the coronal type, teeth show normal roots containing enlarged pulp with abnormal extensions towards the roots, which is often described as “thistle tube” shaped on dental radiographs. As well as this, numerous pulp stones can often be found in the pulp chambers due to abnormal calcifications.[15] In primary teeth, the pulp chamber is usually completely obliterated but in permanent teeth, the pulp may become partially obliterated after the eruption.[11]

There are a few studies and proposals that were designed to explain the pathogenesis of DD but the main reason of the cause still remains unclear in the dental literature. Logan et al.,[17] suggested that dental papilla is the cause of abnormal root growth or development. They also proposed that the calcification of multiple degenerative foci within the papillae reduces the growth and eventually leads to pulpal obliteration. Wesley et al.,[18] suggested that odontoblasts with abnormal function and/ or differentiation are mainly due to atypical interaction between odontoblasts and ameloblasts. Histopathologically, the deeper layer of the teeth shows abnormal dentine tubular pattern with unstructured, unorganised, atubular areas with a normal enamel appearance. The Globular or small mass of rounded or irregular shape of atypical dentine is often seen in the pulp.[19]

Stainless steel crowns which also known as "hall crowns" can prevent tooth wear and maintain the occlusal dimension in affected primary teeth. However, if demanded, composite facings or composite strip crowns can be added for aesthetic reasons.[11]

Endodontic intervention can help conserve the existing health of affected permanent teeth. It is difficult to perform endodontic therapy on teeth that develop abscesses as a result of obliteration of the pulp chambers and root canals. An alternative to conventional therapy would be retrograde filling and periapical curettage. However, these therapies are not recommended for teeth with roots that are too short.[14]

Teeth with short, thin roots and marked cervical constrictions are less favourable for indirect restorations such as crown placements. If endodontics treatment fails, and an abscess develops around the root apex, extraction of the affected teeth would be the best treatment option. Dentures or over-dentures can be considered as rehabilitation until growth is completed. Cast partial dentures could also be an alternative treatment option and it only works if there are a few teeth that have enough root length to serve a retentive purpose.[11]

Dental implant is one of the treatment options that can be considered when growth is fully attained. For patients who experience maxillo-mandibular alveolar atrophy due to early loss of teeth, an alveolar ridge augmentation procedure is recommended prior to the implant placement. Both onlay bone grafting and sinus lift techniques can be carried out together to accomplish implant placement.[20]