Shield classification (1973) This is the most widely used classification for<unk> , and sub-divides the condition into 3 types: Type I<unk>  associated with Osteogenesis Imperfecta (OI). Type of<unk>  with similar dental abnormalities usually an autosomal dominant trait with variable expressivity but can be recessive if the associated osteogenesis imperfecta is of recessive type. Recent genetic studies have identified that mutations in the genes coding for the collagen type 1 proteins, COL1A1 and COL1A2, are associated with this type of<unk> . Not all individuals with OI have<unk> , and the prevalence of<unk>  varies depending on the sub-type of OI: * Higher prevalence of<unk>  among individuals with OI type III and IV at 43-82% and 37-100%, respectively * Lower prevalence of<unk>  among individuals with OI type I at 8-40% * No data available for other OI sub-types Type II<unk>  not associated with OI. Occurs in people without other inherited<unk> sorders (i.e. Osteogenesis imperfecta). It is an autosomal dominant trait. A few families with type II have progressive hearing loss in addition to dental abnormalities. Also called hereditary opalescent dentin. Type III Brandywine isolate. This type is rare with occurrences only in the secluded populations in Maryland, USA. Similar to<unk>  type II, this type is also not associated with OI. Its predominant characteristic is bell-shaped crowns, especially in the permanent dentition. Unlike Types I and II, it involves teeth with shell-like appearance and multiple pulp exposures. Mutations in the gene coding for the dentine sialophosphoprotein (DSPP) are associated with<unk>  type II and III. DSPP is a polypeptide which gives rise to 3 proteins; dentine sialoprotein (DSP), dentine glycoprotein (DGP), and dentine phosphoprotein (DPP). The DPP protein is thought to contribute to hydroxyapatite crystal formation and growth, a fundamental crystal which is widely<unk> stributed in mineralised dentine and enamel. The function of the DGP and DSP proteins is not well understood. Genetic studies have shown that type II and III may be the same sub-type of<unk> ,<unk> ffering only by the severity. de La Dure-Molla, Foruner and Berdal (2015) de La Dure-Molla, Foruner and Berdal (2015) have proposed a new classification to supersede the Shield Classification (1973). This new classification is designed to overcome the shortcomings of its predecessor, mainly the clinical<unk> fficulty in using the Shield classification due to the overlapping signs & symptoms between the sub-types. In this classification, the authors propose that the DSPP (dentine sialophosphoprotein)<unk> seases, that is<unk>  and dentine dysplasia, are jointly named<unk> ", and sub-types are determined according to the severity of the condition. There are a few exceptions: * Shields' Dentine Dysplasia type I - this condition is unique in that it only affects root development, and is separately termed "radicular dentin dysplasia" in the new classification. * Shields'<unk>  type I - this sub-type is not acknowledged in this new classification as the authors deem it a<unk> fferent<unk> sease since it is a syndrome of osteogenesis imperfecta Mild type Primary (baby) teeth are moderately affected. Permanent (adult) teeth are not<unk> scoloured, or the<unk> scolouration is mild (grey colour). Little or no attrition (tooth wear) is evident. The crown of the teeth may be bulbous and markedly constricted at the cemento-enamel junction (CEJ). Radiographically, evidence of partial pulp obliteration with a "thistle-shaped appearance". Moderate type Teeth are moderately<unk> scoloured (blue, grey or amber opalescent). More attrition is evident with shortening of crown height. Crowns may appear bulbous with prominent constriction at the CEJ. Radiographically, the pulp is small or is totally obliterated. Roots appear thinner and shorter than average. There may be periapical pathology. Severe type Teeth are markedly<unk> scoloured (brown opalescent). The crowns are very short due to severe attrition. Crowns may appear bulbous with prominent constriction at the CEJ. Radiographically, pulp appears large and the dentine layer is thin ("shell teeth" as described in Presentation section). Roots are thin and short. There may be multiple periapical pathologies. Radicular dentin dysplasia This sub-type is used in place of Shields' dentine dysplasia type I, in which only the roots of the teeth are affected. Both primary and permanent teeth are affected. The teeth appear normal clinically. Radiographically, the roots are shorter and fused together with a rounded apex.
Dentinogenesis imperfecta
Kyrle disease
Osteogenesis imperfecta
Rhizomelic chondrodysplasia punctata
Chondrodysplasia punctata
Fuchs' dystrophy
Thiel–Behnke dystrophy
Iododerma