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Dentin dysplasia | |
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Preoperative panoramic radiographs showing features of dentin dysplasia type I | |
Specialty | Dentistry |
Dentin dysplasia (DD) is a rare genetic developmental disorder affecting dentine production of the teeth, commonly exhibiting an autosomal dominant inheritance that causes malformation of the root. It affects both primary and permanent dentitions in approximately 1 in every 100,000 patients. [1] It is characterized by the presence of normal enamel but atypical dentin with abnormal pulpal morphology. Witkop [1] in 1972 classified DD into two types which are Type I (DD-1) is the radicular type, and type II (DD-2) is the coronal type. DD-1 has been further divided into 4 different subtypes (DD-1a,1b,1c,1d) based on the radiographic features. [2]
Clinically the teeth look normal in colour and morphologic appearance; however, they are commonly very mobile and exfoliated prematurely. [3]
Both primary and permanent dentitions can be affected by either type I or type II dentin dysplasia. However, deciduous teeth affected by type II dentin dysplasia have a characteristic blue-amber discolouration, whilst the other dentition appears normal. [3]
The mutation in collagen type 1 (COL1 A1, COL1 A2) causes DI-1. It is similar to the systemic condition dental features known as osteogenesis imperfect. [4] [5] [6] DI-2, DI-3 and DD-2 share the same genetic mutation of dentin sialophosphoprotein, that is located on chromosome 4. They are autosomal-dominant diseases with complete penetrance and variable expressivity. [1] [7] Due to the same genetic mutation, these diseases would often result in overlapping clinical and radiographic features. [8] [9] Therefore, prevailing theories suggest that DI-2, DI-3 and DD-2 are categorized as a single disease entity with variable severity of expression. [10] However, the causes of DD-1 have yet to be theorized.
Diagnosis is mostly based on general examination and radiographs, and it should be taken when abnormality of the teeth is suspected as most of the affected teeth have a normal clinical appearance. [1]
Differential diagnosis is very important to have a definitive diagnosis as some radiographic or histologic features of dentine dysplasia may bear a resemblance to different disorders: [11]
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 granuloma 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]
With various options available to dentists, the treatment of this condition can still be difficult. Endodontic treatment is not advised for teeth with complete obliteration of root canals and pulp chambers. [3] An alternative treatment for teeth with periapical abscesses and pulpal necrosis is dental extraction. Retrograde fillings and periapical surgery is a treatment option for teeth with longer roots, as well as orthodontic treatment. However, orthodontic treatment can lead to even more resorption of the roots, which could lead to further tooth mobility and premature exfoliation. [3] Another proposed treatment, for successful oral rehabilitation, is to extract all teeth, curette any cysts and provide the patient with a complete denture. A combination of bone grafting and a sinus lift technique can also be successful to accomplish implant placement. [3]
The best method of maintaining the health of teeth is to practice exemplary oral hygiene. More tooth loss is likely to occur if intervention takes place. However, factors such as present complaint, patient age, severity of the problem, can affect the treatment plan or options. [11]
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]
Human teeth function to mechanically break down items of food by cutting and crushing them in preparation for swallowing and digesting. As such, they are considered part of the human digestive system. Humans have four types of teeth: incisors, canines, premolars, and molars, which each have a specific function. The incisors cut the food, the canines tear the food and the molars and premolars crush the food. The roots of teeth are embedded in the maxilla or the mandible and are covered by gums. Teeth are made of multiple tissues of varying density and hardness.
Dentin or dentine is a calcified tissue of the body and, along with enamel, cementum, and pulp, is one of the four major components of teeth. It is usually covered by enamel on the crown and cementum on the root and surrounds the entire pulp. By volume, 45% of dentin consists of the mineral hydroxyapatite, 33% is organic material, and 22% is water. Yellow in appearance, it greatly affects the color of a tooth due to the translucency of enamel. Dentin, which is less mineralized and less brittle than enamel, is necessary for the support of enamel. Dentin rates approximately 3 on the Mohs scale of mineral hardness. There are two main characteristics which distinguish dentin from enamel: firstly, dentin forms throughout life; secondly, dentin is sensitive and can become hypersensitive to changes in temperature due to the sensory function of odontoblasts, especially when enamel recedes and dentin channels become exposed.
Toothache, also known as dental pain or tooth pain, is pain in the teeth or their supporting structures, caused by dental diseases or pain referred to the teeth by non-dental diseases. When severe it may impact sleep, eating, and other daily activities.
The pulp is the connective tissue, nerves, blood vessels, and odontoblasts that comprise the innermost layer of a tooth. The pulp's activity and signalling processes regulate its behaviour.
Dentinogenesis imperfecta (DI) is a genetic disorder of tooth development. It is inherited in an autosomal dominant pattern, as a result of mutations on chromosome 4q21, in the dentine sialophosphoprotein gene (DSPP). It is one of the most frequently occurring autosomal dominant features in humans. Dentinogenesis imperfecta affects an estimated 1 in 6,000-8,000 people.
Dens invaginatus (DI), also known as tooth within a tooth, is a rare dental malformation and a developmental anomaly where there is an infolding of enamel into dentin. The prevalence of this condition is 0.3 - 10%, affecting males more frequently than females. The condition presents in two forms, coronal involving tooth crown and radicular involving tooth root, with the former being more common.
Dens evaginatus is a rare odontogenic developmental anomaly that is found in teeth where the outer surface appears to form an extra bump or cusp.
Regional odontodysplasia is an uncommon developmental abnormality of teeth, usually localized to a certain area of the mouth. The condition is nonhereditary. There is no predilection for race, but females are more likely to get regional odontodysplasia. The enamel, dentin, and pulp of teeth are affected, to the extent that the affected teeth do not develop properly. These teeth are very brittle. On radiographs the teeth appear more radiolucent than normal, so they are often described as "ghost teeth". Most cases are considered idiopathic, but some cases are associated with syndromes, growth abnormalities, neural disorders, and vascular malformations. Permanent teeth usually show effects of regional odontodysplasia if the deciduous tooth was affected. Many of these teeth do not erupt, and those that do have an increased risk of caries and periapical inflammation.
Root canal treatment is a treatment sequence for the infected pulp of a tooth which is intended to result in the elimination of infection and the protection of the decontaminated tooth from future microbial invasion. Root canals, and their associated pulp chamber, are the physical hollows within a tooth that are naturally inhabited by nerve tissue, blood vessels and other cellular entities. Together, these items constitute the dental pulp.
Dental pertains to the teeth, including dentistry. Topics related to the dentistry, the human mouth and teeth include:
Pulpotomy is a minimally invasive procedure performed in children on a primary tooth with extensive caries but without evidence of root pathology. The minimally invasive endodontic techniques of vital pulp therapy (VPT) are based on improved understanding of the capacity of pulp (nerve) tissues to heal and regenerate plus the availability of advanced endodontic materials. During caries (cavity) removal, this results in a carious or mechanical pulp exposure (bleeding) from the cavity. During pulpotomy, the inflamed/diseased pulp tissue is removed from the coronal pulp chamber of the tooth, leaving healthy pulp tissue which is dressed with a long-term clinically successful medicament that maintains the survival of the pulp and promotes repair. There are various types of medicament placed above the vital pulp such as Buckley's Solution of formocresol, ferric sulfate, calcium hydroxide or mineral trioxide aggregate (MTA). MTA is a more recent material used for pulpotomies with a high rate of success, better than formocresol or ferric sulfate. It is also recommended to be the preferred pulpotomy agent in the future. After the coronal pulp chamber is filled, the tooth is restored with a filling material that seals the tooth from microleakage, such as a stainless steel crown which is the most effective long-term restoration. However, if there is sufficient remaining supporting tooth structure, other filling materials such as amalgam or composite resin can provide a functional alternative when the primary tooth has a life span of two years or less. The medium- to long-term treatment outcomes of pulpotomy in symptomatic permanent teeth with caries, especially in young people, indicate that pulpotomy can be a potential alternative to root canal therapy (RCT).
Resorption of the root of the tooth, or root resorption, is the progressive loss of dentin and cementum by the action of odontoclasts. Root resorption is a normal physiological process that occurs in the exfoliation of the primary dentition. However, pathological root resorption occurs in the permanent or secondary dentition and sometimes in the primary dentition.
Dentin sialophosphoprotein is a precursor protein for other proteins found in the teeth. It is produced by cells (odontoblasts) inside the teeth, and in smaller quantities by bone tissues. It is required for normal hardening (mineralisation) of teeth. During teeth development, it is broken down into three proteins such as dentin sialoprotein (DSP), dentin glycoprotein (DGP), and dentin phosphoprotein (DPP). These proteins become the major non-collagenous components of teeth. Their distribution in the collagen matrix of the forming dentin suggests these proteins play an important role in the regulation of mineral deposition. Additional evidence for this correlation is phenotypically manifested in patients with mutant forms of dentin sialophosphoprotein. Such patients suffer dental anomalies including type III dentinogenesis imperfecta.
Amelogenesis imperfecta (AI) is a congenital disorder which presents with a rare abnormal formation of the enamel or external layer of the crown of teeth, unrelated to any systemic or generalized conditions. Enamel is composed mostly of mineral, that is formed and regulated by the proteins in it. Amelogenesis imperfecta is due to the malfunction of the proteins in the enamel as a result of abnormal enamel formation via amelogenesis.
Pulp stones are nodular, calcified masses appearing in either or both the coronal and root portion of the pulp organ in teeth. Pulp stones are not painful unless they impinge on nerves.
Regenerative endodontic procedures is defined as biologically based procedures designed to replace damaged structures such as dentin, root structures, and cells of the pulp-dentin complex. This new treatment modality aims to promote normal function of the pulp. It has become an alternative to heal apical periodontitis. Regenerative endodontics is the extension of root canal therapy. Conventional root canal therapy cleans and fills the pulp chamber with biologically inert material after destruction of the pulp due to dental caries, congenital deformity or trauma. Regenerative endodontics instead seeks to replace live tissue in the pulp chamber. The ultimate goal of regenerative endodontic procedures is to regenerate the tissues and the normal function of the dentin-pulp complex.
Pulp capping is a technique used in dental restorations to protect the dental pulp, after it has been exposed, or nearly exposed during a cavity preparation, from a traumatic injury, or by a deep cavity that reaches the center of the tooth, causing the pulp to die. Exposure of the pulp causes pulpitis. The ultimate goal of pulp capping or stepwise caries removal is to protect a healthy dental pulp, and avoid the need for root canal therapy.
Tricho–dento–osseous syndrome (TDO) is a rare, systemic, autosomal dominant genetic disorder that causes defects in hair, teeth, and bones respectively. This disease is present at birth. TDO has been shown to occur in areas of close geographic proximity and within families; most recent documented cases are in Virginia, Tennessee, and North Carolina. The cause of this disease is a mutation in the DLX3 gene, which controls hair follicle differentiation and induction of bone formation. All patients with TDO have two co-existing conditions called enamel hypoplasia and taurodontism in which the abnormal growth patterns of the teeth result in severe external and internal defects. The hair defects are characterized as being rough, course, with profuse shedding. Hair is curly and kinky at infancy but later straightens. Dental defects are characterized by dark-yellow/brownish colored teeth, thin and/or possibly pitted enamel, that is malformed. The teeth can also look normal in color, but also have a physical impression of extreme fragility and thinness in appearance. Additionally, severe underbites where the top and bottom teeth fail to correctly align may be present; it is common for the affected individual to have a larger, more pronounced lower jaw and longer bones. The physical deformities that TDO causes become more noticeable with age, and emotional support for the family as well as the affected individual is frequently recommended. Adequate treatment for TDO is a team based approach, mostly involving physical therapists, dentists, and oromaxillofacial surgeons. Genetic counseling is also recommended.
Tooth discoloration is abnormal tooth color, hue or translucency. External discoloration is accumulation of stains on the tooth surface. Internal discoloration is due to absorption of pigment particles into tooth structure. Sometimes there are several different co-existent factors responsible for discoloration.
Periapical granuloma, also sometimes referred to as a radicular granuloma or apical granuloma, is an inflammation at the tip of a dead (nonvital) tooth. It is a lesion or mass that typically starts out as an epithelial lined cyst, and undergoes an inward curvature that results in inflammation of granulation tissue at the root tips of a dead tooth. This is usually due to dental caries or a bacterial infection of the dental pulp. Periapical granuloma is an infrequent disorder that has an occurrence rate between 9.3 to 87.1 percent. Periapical granuloma is not a true granuloma due to the fact that it does not contain granulomatous inflammation; however, periapical granuloma is a common term used.
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