[Recognition on dentin dysplasia type â ¡].

Dentin dysplasia type Ⅱ (DD-Ⅱ) is a subtype of hereditary dentin disorders. The dentin sialophosphoprotein (DSPP) gene has been revealed to be the causative gene, whose mutations could affect the normal tooth development process. The lesions involve both deciduous and permanent dentition, mainly manifested as tooth discoloration, attrition and even the subsequent malocclusion. If not treated in time, it will significantly affect the physical and psychological health of patients. The disease is difficult to be diagnosed in clinic accurately as its low incidence and hidden manifestations. The present article aims to discuss the clinical and radiographic characteristics, diagnosis, treatment of DD-Ⅱ, in order to improve the overall understanding on DD-Ⅱ for clinicians.

Dentinogénesis Imperfecta y Displasia Dentinaria. A propósito de un caso / Dentinogenesis Imperfecta and Dentin Dysplasia. Case Report

La flexibilidad de la dentina permite resistir las fuerzas masticatorias. Esta propiedad hace que el esmalte subyacenteno se fracture. En los casos de dentinogénesis imperfecta y displasia dentinaria los pacientes tienen mas riesgo de fracturas y atriciones dentarias en edades muy tempranas. Se presenta un caso clínico de un paciente varón de 3,7 años que acude por primera vez a la consulta por dolor. A la exploración presenta múltiples caries, absceso de origen dentario, atriciones, dimensión vertical disminuida y dentinogénesis imperfecta. En los casos leves de osteogénesis imperfecta es posible que la dentinogénesis imperfecta sea la primera manifestaciónen ser detectada, por lo tanto, el odontólogo debe estar capacitado para saber diagnosticar y derivar al paciente al especialista para permitir un diagnóstico precoz de la enfermedad. La primera visita odontológica del niño/aal cumplir el año de vida es necesaria para detectar cualquier anomalía en el crecimiento de los dientes, huesos y establecer una relación entre el niño/a, el especialista y su entorno. (AU)

The flexibility of dentin allows it to resist masticatory forces. This property prevents the underlying enamel from fracturing. In cases of dentinogenesis imperfecta and dentin dysplasia, patients have a higher risk of fractures and dental attrition at a very early age. A clinical case of a 3.7-year-old male patient who comes to the clinic for the first time due to pain is presented. On examination he presented multiple caries, abscess of dental origin, attrition, decreased vertical dimension and dentinogenesis imperfecta. In mild cases of osteogenesis imperfecta, it is possible that dentinogenesis imperfecta is the first manifestation to be detected, therefore, the dentist must be trained to know how to diagnose and refer the patient to the specialist to allow an early diagnosis of the disease.The first dental visit of the child at the ageof one year is necessary to detect any anomaly in the growth of the teeth, bones and establish a relationship between the child, the specialist and their environment (AU)

[Mutation of dentin sialophosphoprotein and hereditary malformations of dentin].

The classification as well as the clinical manifestations of hereditary malformations of dentin are of great concern and have been deeply elucidated. The understanding of its genetic basis also increases progressively. Dentin sialophosphoprotein (DSPP) is the pathogenic gene of dentinogenesis imperfecta type Ⅱ, dentinogenesis imperfecta type Ⅲ and dentin dysplasia type Ⅱ. In this article, the classification of DSPP mutations as well as the resultant dysfunction of the mutant DSPP are summarized respectively and the corresponding clinical manifestations are analyzed. This work will provide a reference for the diagnosis and treatment of hereditary malformations of dentin.

Mutation of dentin sialophosphoprotein and hereditary malformations of dentin / 中华口腔医学杂志

The classification as well as the clinical manifestations of hereditary malformations of dentin are of great concern and have been deeply elucidated. The understanding of its genetic basis also increases progressively. Dentin sialophosphoprotein (DSPP) is the pathogenic gene of dentinogenesis imperfecta type Ⅱ, dentinogenesis imperfecta type Ⅲ and dentin dysplasia type Ⅱ. In this article, the classification of DSPP mutations as well as the resultant dysfunction of the mutant DSPP are summarized respectively and the corresponding clinical manifestations are analyzed. This work will provide a reference for the diagnosis and treatment of hereditary malformations of dentin.

Full Mouth Rehabilitation of Two Siblings with Dentinogenesis Imperfecta Type II Using Different Treatment Modalities.

BACKGROUND: Dentinogenesis imperfecta (DGI) is a complex anomaly, not only by its structure but by treatment approach. The treatment protocol depends on the severity, behavior, and the age of the patient. CASE DESCRIPTION: This paper presents two siblings' cases of DGI type II (DGI-II) with different treatment based on the patient's clinical severity, behavior, and age (mixed versus primary dentition). The first case involves a patient in the primary dentition with severe attrition leading to a reduction in the vertical dimension of occlusion (VDO) treated by the fabrication of complete overlay dentures. The second case involves a patient in the early mixed dentition treated with restorations and extractions. CONCLUSION: Full mouth rehabilitation in the two patients dramatically improves function, aesthetics, and proved to be a significant psychological boost to the patient's well-being. PRACTICAL IMPLICATIONS: Early diagnosis and a multidisciplinary approach for patients with DGI to preserve the remaining teeth and rehabilitation for their function and aesthetics are essential for obtaining a favorable prognosis.

Pathogenic variants in the TRIP11 gene cause a skeletal dysplasia spectrum from odontochondrodysplasia to achondrogenesis 1A.

The thyroid hormone receptor interactor 11 (TRIP11) gene encodes the Golgi microtubule-associated protein 210 (GMAP-210), a protein essential for the operation of the Golgi apparatus. It is known that null mutations in TRIP11 disrupt Golgi function and cause a lethal skeletal dysplasia known as achondrogenesis type 1A (ACG1A), however recently, hypomorphic mutations in that gene have been linked to odontochondrodysplasia (ODCD), a nonlethal skeletal dysplasia characterized by skeletal changes in the spine and in the metaphyseal regions, associated with dentinogenesis imperfecta. Here we present two patients reflecting the phenotypic spectrum related to different TRIP11 variants. The first is a female child with ODCD, for whom a homozygous in-frame splicing mutation in intron 9 of TRIP11 was identified. The mutation appears to lead to the expression of an alternative TRIP11 transcript, that may explain the less severe radiological alterations in ODCD. The second is a fetus with classical form of ACG1A, associated with typical molecular findings (frameshift) in exon 11 of TRIP11, both novel mutations. The two patients reported here represent the TRIP11 spectrum of skeletal dysplasia ranging from mild to lethal phenotypes, thereby enabling one to suggest a genotype-phenotype correlation in these diseases.

A novel hypothesis based on clinical, radiological, and histological data to explain the dentinogenesis imperfecta type II phenotype.

Purpose/Aim: The aim of this study was to explore whether dentinogenesis imperfecta (DGI)-related aberrations are detectable in odontogenic tissues. Materials and Methods: Morphological and histological analyses were carried out on 3 teeth (two maxillary 1st molars, one maxillary central incisor) extracted from a patient with DGI Type II. A maxillary 2nd molar teeth extracted from a healthy patient was used as control. A micro-computed tomographic (µCT) data-acquisition system was used to scan and reconstruct samples. Pentachrome and picrosirius red histologic stains were used to analyze odontogenic tissues and their collagenous matrices. Results: Our findings corroborate DGI effects on molar and incisor root elongation, and the hypo-mineralized state of DGI dentin. In addition to these findings, we discovered changes to the DGI pulp cavity: Reactionary dentin formation, which we theorize is exacerbated by the early loss of enamel, nearly obliterated an acellular but still-vascularized DGI pulp cavity. We also discovered an accumulation of lamellated cellular cementum at the root apices, which we hypothesize compensates for the severe and rapid attrition of the DGI tooth. Conclusions: Based on imaging and histological data, we propose a novel hypothesis to explain the complex dental phenotypes observed in patients with DGI Type II.

Una nueva imagen en osteogénesis imperfecta: "nube de humo" / A new radiological image in osteogenesis imperfecta: "Smoke cloud"

No disponible

Complete overdenture fabrication for a 12-year-old child with dentinogenesis imperfecta type 2.

Dentinogenesis imperfecta type 2 (DI-2), also known as hereditary opalescent dentin, is a rare, genetically linked condition that affects both primary and permanent teeth. Severe attrition requiring full-mouth rehabilitation is a common finding associated with DI-2. Dental rehabilitation options include a variety of invasive and noninvasive restorative techniques dictated by the age of the patient. Growth and development must be considered and may result in a restorative challenge for the dental practitioner, particularly when the patient in question is a child. This case report describes the fabrication of an overdenture to reestablish function, esthetics, and self-esteem in a 12-year-old patient. A 2-stage restorative treatment was followed by a satisfactory 6-month recall examination, indicating that the prostheses provided a successful outcome until more definitive restorative treatment can be accomplished in adulthood.

Osteogenesis imperfecta with ectopic mineralizations in dentin and cementum and a COL1A2 mutation.

We report a Thai father (patient 1) and his daughter (patient 2) affected with osteogenesis imperfecta type IV and dentinogenesis imperfecta. Both were heterozygous for the c.1451G>A (p.Gly484Glu) mutation in COL1A2. The father, a Thai boxer, had very mild osteogenesis imperfecta with no history of low-trauma bone fractures. Scanning electron micrography of the primary teeth with DI of the patient 2, and the primary teeth with DI of another OI patient with OI showed newly recognized dental manifestations of teeth with DI. Normal dentin and cementum might have small areas of ectopic mineralizations. Teeth affected with DI have well-organized ectopic mineralizations in dentin and cementum. The "French-fries-appearance" of the crystals at the cemento-dentinal junction and abnormal cementum have never been reported to be associated with dentinogenesis imperfecta, either isolated or osteogenesis imperfecta-associated. Our study shows for the first time that abnormal collagen fibers can lead to ectopic mineralization in dentin and cementum and abnormal cementum can be a part of osteogenesis imperfecta.

The Prosthodontic Pathway for Patients with Anomalies Affecting Tooth Structure.

There are a number of anomalies that affect the structure of the dental hard tissues which impact upon the form, function and aesthetics of the dentition. Understanding the challenges these conditions pose will enable dentists to manage the functional and aesthetic problems with restorative techniques better. This article will present cases that demonstrate the different conditions, the restorative challenges experienced and a variety of restorative treatments in the management of these conditions. Clinical relevance: Awareness of different anomalies affecting tooth structure that may present to the dental practitioner is necessary. Clinicians should appreciate the specific restorative challenges that may arise in treating such patients and the possible treatment options that may be available.

Microscopic study of dental hard tissues in primary teeth with Dentinogenesis Imperfecta Type II: Correlation of 3D imaging using X-ray microtomography and polarising microscopy.

OBJECTIVES: The aim of this study was to examine the histological appearance of dental hard tissues in primary teeth from children with DI using conventional polarised light microscopy and correlate that with 3D imaging using X-ray microtomograpy (XMT) to gain a further understanding of the dentine structure of teeth diagnosed with dentinogenesis imperfecta. DESIGN: Undecalcified sections of primary teeth from patients diagnosed with Dentinogenesis Imperfecta Type II were examined using polarised light microscopy. XMT was employed for 3D-imaging and analysis of the dentine. RESULTS: The polarised light microscopy and XMT revealed tubular structures in the dentine seen as vacuoles coinciding with the path of normal dentinal tubules but not continuous tubules. The size of the tubules was close to that of capillaries. The largest tubular structures had a direction corresponding to where the pulp tissue would have been located during primary dentine formation. The dysfunctional mineralisation of the dentine and obliteration of the pulp evidently leaves blood vessels in the dentine which have in the main been tied off and, in the undecalcified sections, appear as vacuoles. CONCLUSIONS: Although from radiographs, the pulp in teeth affected by Dentinogenesis Imperfect type II appears to be completely obliterated, a network of interconnected vessels may remain. The presence of large dentinal tubules and blood vessels, or the remnants of blood vessels, could provide a pathway for bacteria from the oral cavity. This might account for why some of these teeth develop periapical abscesses in spite of apparently having no pulp.

Immunocytochemical detection of dentin matrix proteins in primary teeth from patients with dentinogenesis imperfecta associated with osteogenesis imperfecta.

Dentinogenesis imperfecta determines structural alterations of the collagen structure still not completely elucidated. Immunohistochemical analysis was used to assay Type I and VI collagen, various non-collagenous proteins distribution in human primary teeth from healthy patients or from patients affected by type I dentinogenesis imperfecta (DGI-I) associated with osteogenesis imperfecta (OI). In sound primary teeth, an organized well-known ordered pattern of the type I collagen fibrils was found, whereas atypical and disorganized fibrillar structures were observed in dentin of DGI-I affected patients. Expression of type I collagen was observed in both normal and affected primary teeth, although normal dentin stained more uniformly than DGI-I affected dentin. Reactivity of type VI collagen was significantly lower in normal teeth than in dentin from DGI-I affected patients (P<0.05). Expressions of dentin matrix protein (DMP)-1 and osteopontin (OPN) were observed in both normal dentin and dentin from DGI-I affected patients, without significant differences, being DMP1 generally more abundantly expressed. Immunolabeling for chondroitin sulfate (CS) and biglycan (BGN) was weaker in dentin from DGI-I-affected patients compared to normal dentin, this decrease being significant only for CS. This study shows ultrastructural alterations in dentin obtained from patients affected by DGI-I, supported by immunocytochemical assays of different collagenous and non-collagenous proteins.

Evaluation of vitamin D receptor (VDR) gene polymorphisms (FokI, TaqI and ApaI) in a family with dentinogenesis imperfecta.

Dentinogenesis imperfecta Type II (DGI-II) is a condition inherited as an autosomal dominant trait and characterized by abnormal dentine structure affecting both the primary and secondary dentitions. The genetic etiology of the disease still remains unclear, suggesting a genetically heterogeneous background. The aim of this study is to manifest briefly DGI-II and to investigate the association between BsmI, TaqI and FokI polymorphisms of Vitamin D receptor (VDR) gene and dentinogenesis imperfecta type II in a Turkish family by PCR-RFLP methodology. The affected mother and her two affected daughters were bb for BsmI polymorphism, whereas her unaffected son and her husband were Bb for the same polymorphism. One of the affected children was tt, the rest of the family were Tt for TaqI polymorphism, and all of the enrolled subjects were FF for FokI polymorphism. As a conclusion, BsmI polymorphism bb seems to be associated with (DGI-II), but should be examined in larger numbers in order to be considered as a risk factor.

Dentinogenesis imperfecta type II: ultrastructure of teeth in sagittal sections.

The morphological abnormalities of the teeth of patients affected by dentinogenesis imperfecta type 2 (DI-II) may underlie the difficulties with the clinical restoration of such teeth. We therefore performed a scanning electron microscopy (SEM) study of four permanent first mandibular molars of four DI-II patients with periapical pathosis. The teeth were prepared for SEM evaluation by standard methods. In the crown, the enamel presented a highly irregular surface with a number of cracks and crevices. In some places, only granular remains of the enamel were found, while in other parts of the crown, the enamel was absent. SEM examination revealed the structural changes responsible for the lower enamel's hardness and resistance to attrition, and for tooth wear, while the structural changes in the dentin may explain the failure of some adhesive restorative materials. This SEM study thus revealed structural defects which underlie the problems of attrition and restoration loss found in patients with this genetic dental condition.

Diseases of the tooth: the genetic and molecular basis of inherited anomalies affecting the dentition.

In humans, inherited variation in the number, size, and shape of teeth within the dentitions are relatively common, while rarer defects of hard tissue formation, including amelogenesis and dentinogenesis imperfecta, and problems associated with tooth eruption are also seen. In many cases, these anomalies occur in isolation, but they can also present as a feature of numerous well-characterized developmental syndromes. Complex reiterative signaling between the epithelium and mesenchyme is a feature of normal tooth development in the embryo, occurring from early patterning through morphogenesis, hard tissue formation and during root development. Significant events also occur during postnatal development of the dentition, including hard tissue maturation and tooth eruption. In the last decade, advances in human and mouse genetics have meant that in many cases candidate genes have been identified for these anomalies. These genes have provided a useful platform for developmental biologists, allowing them to begin elucidating how these signals interact to generate a functional dentition and understand the mechanisms underlying many of the anomalies that are seen in human populations. In this article, we review current concepts relating to the developmental biology of tooth number, size, and shape, formation of the dental hard tissues and eruption of the tooth into the oral cavity. We will focus on the molecular mechanisms underlying these processes in both health and disease.

Capdepont's teeth - a hereditary dentin defect: case report & review / IDientes de capdepont - un defecto de dentina hereditario. reporte de caso y revisión de la literatura

Dentinogenesis imperfecta is an autosomal dominant genetic disorder with abnormal dentin structure affecting both primary and permanent dentitions leading to discolouration and attrition of teeth. Diagnosis is usually based on family history, a detailed clinical examination and pedigree construction. Treatment involves preservation of teeth, removal of infection, restoration of function and esthetics.

La dentinogénesis imperfecta es un trastorno genético autosómico dominante, caracterizado por una estructura anormal de la dentina, que afecta tanto la dentición temporal como permanente, generando decoloración y desgaste de los dientes. El diagnóstico generalmente se basa en la historia familiar, el examen clínico detallado y la construcción de pedigrí. Su tratamiento implica la conservación de los dientes, eliminación de infección, y la restauración de la función y la estética.

Transcriptional repression of the Dspp gene leads to dentinogenesis imperfecta phenotype in Col1a1-Trps1 transgenic mice.

Dentinogenesis imperfecta (DGI) is a hereditary defect of dentin, a calcified tissue that is the most abundant component of teeth. Most commonly, DGI is manifested as a part of osteogenesis imperfecta (OI) or the phenotype is restricted to dental findings only. In the latter case, DGI is caused by mutations in the DSPP gene, which codes for dentin sialoprotein (DSP) and dentin phosphoprotein (DPP). Although these two proteins together constitute the majority of noncollagenous proteins of the dentin, little is known about their transcriptional regulation. Here we demonstrate that mice overexpressing the Trps1 transcription factor (Col1a1-Trps1 mice) in dentin-producing cells, odontoblasts, present with severe defects of dentin formation that resemble DGI. Combined micro-computed tomography (µCT) and histological analyses revealed tooth fragility due to severe hypomineralization of dentin and a diminished dentin layer with irregular mineralization in Col1a1-Trps1 mice. Biochemical analyses of noncollagenous dentin matrix proteins demonstrated decreased levels of both DSP and DPP proteins in Col1a1-Trps1 mice. On the molecular level, we demonstrated that sustained high levels of Trps1 in odontoblasts lead to dramatic decrease of Dspp expression as a result of direct inhibition of the Dspp promoter by Trps1. During tooth development Trps1 is highly expressed in preodontoblasts, but in mature odontoblasts secreting matrix its expression significantly decreases, which suggests a Trps1 role in odontoblast development. In these studies we identified Trps1 as a potent inhibitor of Dspp expression and the subsequent mineralization of dentin. Thus, we provide novel insights into mechanisms of transcriptional dysregulation that leads to DGI.

Frameshift mutations in dentin phosphoprotein and dependence of dentin disease phenotype on mutation location.

We describe results from a mutational analysis of the region of the dentin sialophosphoprotein (DSPP) gene encoding dentin phosphoprotein (DPP) in 12 families with dominantly inherited dentin diseases. In eight families (five mutations in the N-terminal third of DPP), the clinical and radiologic features were uniform and compatible with dentin dysplasia type II (DD-II) with major clinical signs in the deciduous dentition. In the other families (four mutations in the more C-terminal part), the permanent teeth also were affected, and the diseases could be classified as variants of dentinogenesis imperfecta. Attrition was not prominent, but periapical infections were common. Discoloring with varying intensity was evident, and pulps and root canals were obliterated in the permanent dentition. All mutations caused a frameshift that replaced the Ser-Ser-Asx repeat by a code for a hydrophobic downstream sequence of approximately original length. We conclude that frameshift mutations in DSPP explain a significant part of dentin diseases. Furthermore, we propose that the location of the mutation is reflected in the phenotypic features as a gradient from DD-II to more severe disease that does not conform to the classic definitions of DI-II.

Novel dentin phosphoprotein frameshift mutations in dentinogenesis imperfecta type II.

The dentin sialophosphoprotein (DSPP) gene encodes the most abundant non-collagenous protein in tooth dentin and DSPP protein is cleaved into several segments including the highly phosphorylated dentin phosphoprotein (DPP). Mutations in the DSPP gene have been solely related to non-syndromic form of hereditary dentin defects. We recruited three Korean families with dentinogenesis imperfecta (DGI) type II and sequenced the exons and exon-intron boundaries of the DSPP gene based on the candidate gene approach. Direct sequencing of PCR products and allele-specific cloning of the highly repetitive exon 5 revealed novel single base pair (bp) deletional mutations (c.2688delT and c.3560delG) introducing hydrophobic amino acids in the hydrophilic repeat domain of the DPP coding region. All affected members of the three families showed exceptionally rapid pulp chambers obliteration, even before tooth eruption. Individuals with the c.3560delG mutation showed only mild, yellowish tooth discoloration, in contrast to the affected individuals from two families with c.2688delT mutation. We believe that these results will help us to understand the molecular pathogenesis of DGI type II as well as the normal process of dentin biomineralization.