Disrupted odontoblast differentiation and dentin dysplasia in Epiprofin-deficient mice.

Tooth formation is a process tightly regulated by reciprocal interactions between epithelial and mesenchymal tissues. These epithelial-mesenchyme interactions regulate the expression of target genes via transcription factors. Among the regulatory elements governing this process, Epiprofin/Sp6 is a zinc finger transcription factor which is expressed in the embryonic dental epithelium and in differentiating pre-odontoblasts. Epiprofin knockout (Epfn-/-) mice present severe dental abnormalities, such as supernumerary teeth and enamel hypoplasia. Here, we describe dentin defects in molars and incisors of Epfn-/- mice. We observed that in the absence of Epfn, markers of early odontoblast differentiation, such as alkaline phosphatase activity, Dsp/Dpp expression, and Collagen Type I deposition, are downregulated. In addition, the expression of tight and gap junction proteins was severely impaired in the predontoblastic cell layer of developing Epfn-/- molars. Altogether, our data shows that Epfn is crucial for the proper differentiation of dental mesenchymal cells towards functional odontoblasts and subsequent dentin-matrix deposition.

Type I Dentin Dysplasia: The Literature Review and Case Report of a Family Affected by Misrecognition and Late Diagnosis.

Background and Objectives: Type I dentin dysplasia (DD-I) is a rare genetic disorder with autosomal dominant or recessive inheritance at risk of late or long-misunderstood diagnosis because the teeth, compared to other degenerative dentin diseases, do not have coronal defects and/or alterations but only at the root level (absent, conical, pointed roots, and obliterated pulp canals). The first radiographic suspicion often occurs only in case of sudden mobility and/or abscesses of the permanent teeth. Genetic tests confirm the diagnosis. Case Presentation: This case report describes the oral and radiographic characteristics of two siblings, 12 and 10 years old, a male and a female, at an early age affected by DD-I, whose diagnosis was made for a first orthodontic visit. The father and the older child had already undergone dental and orthodontic treatments, respectively, without the disease being suspected by the dentist. Results: Genetic tests support the diagnosis of DD-I. Following the diagnosis, the patients began a process of close periodic checks every 3-4 months to monitor their situation. The male child lost upper lateral incisors, which were then replaced with a light nylon removable prosthesis. Conclusions: The ability to recognize the radiographic features characteristic of DD-I is very important to avoid prejudicial diagnostic delays and to be able to plan the long-term treatment of these patients better, especially when the pathology was primarily misrecognized in the family.

[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)

A novel DSPP frameshift mutation causing dentin dysplasia type 2 and disease management strategies.

The present study aims to investigate the mutation in a Chinese family with dentin dysplasia type II (DD-II) and to summarize mutation hotspots, clinical manifestations, and disease management strategies. Phenotype analysis, clinical intervention, mutation screening, and cosegregation analysis within the enrolled family were performed. A summary of the reported mutations in the dentin phosphoprotein (DPP) region of dentin sialophosphoprotein (DSPP) was analyzed. Pathogenicity prediction analysis of the physical properties and function of DSPP variants was performed by bioinformatic processing. Clinical management strategies are discussed. A novel pathogenic mutation (c.2035delA) in the DPP region of DSPP was identified, which was cosegregated in the family. The immature permanent teeth of patients with DD-II presented with X-shaped root canal phenotypes. Most of the identified mutations for DD-II were clustered in the DPP region between nucleotides 1686-2134. Points of differential diagnosis, clinical interventions, and management strategies are proposed. This study revealed a novel DSPP frameshift mutation and presented new clinical features of DD-II. The locus involving nucleotides 1686-2134 of DSPP may represent a mutational hotspot for the disease. Appropriate management of DD-II at different stages is important to avoid the development of secondary dental lesions.

Generalized Dentin Dysplasia in a Four-Year-old dog.

Dentin dysplasia is an autosomal-dominant genetic abnormality that occurs in humans and results in diffuse radiographic dental abnormalities and variable tooth discoloration due to an underlying defect in secondary dentinogenesis. This case report presents distinctive radiographic and histopathologic dental abnormalities in a dog that are consistent with generalized dentin dysplasia. These findings are similar to but not completely analogous to any specific clinical type of dentin dysplasia in humans. Grossly, the majority of the teeth in this case were discolored and most were determined to be vital. Dentin dysplasia should be included in the list of differential diagnoses of discolored teeth and notably this form of discoloration does not necessarily indicate loss of vitality.

Displasia dentinária Tipo I: relato de caso clínico / Dental dysplasia Type I: a clinical case report

As anomalias de desenvolvimento dos dentes, como a displasia dentinária, podem ser observadas durante os exames clínicos e radiográficos em alguns pacientes. O presente relato de caso discute sobre a Displasia Ectópica Dentinária (DD), sendo um distúrbio de desenvolvimento relacionado a formação da dentina que possui obliteração da polpa e defeito da formação da raiz. Descrita como uma condição rara e transmitida geneticamente. Ela pode ser dividida em tipos I e II, uma vez que ambas podem afetar as dentaduras decídua e permanente. O tratamento clínico transformou-se com o passar dos anos, sendo que o protocolo indicava a necessidade de exodontia para um tratamento menos invasivo, utilizando métodos que consistem na manutenção da higiene oral, a idade do paciente, a gravidade da doença, a extensão dos sintomas e atendimento odontológico regular. Este trabalho tem como objetivo apresentar o caso clinico de um menino de 8 anos, diagnosticado com displasia dentinária do tipo I e com presença de restaurações insatisfatórias na dentição mista. Dessa forma é significativo o planejamento adequado, em favor de melhorias na manutenção profilática... (AU)

Anomalies in the development of teeth, such as dentin dysplasia, can be observed during clinical and radiographic examinations in some patients. The present case report discusses Dentinal Dysplasia Ec topic (DD), being a developmental disorder related to the formation of dentin that has pulp oblitera tion and root formation defect. Described as a rare and genetically transmitted condition. It can be divided into types I and II, since both can affect deciduous and permanent dentures. Clinical treatment has changed over the years, and the protocol indicated the need for extraction for a less invasive treat ment, using methods that consist of maintaining oral hygiene, the age of the patient, the severity of the disease, the extent of symptoms and regular dental care. This paper aims to present the clinical case of an 8-year-old boy, diagnosed with type I dentin dysplasia and with the presence of unsatisfactory restorations in the mixed dentition. Thus, adequate planning is significant, in favor of improvements in prophylactic maintenance... (AU)

VPS4B deficiency causes early embryonic lethality and induces signal transduction disorders of cell endocytosis.

VPS4B (vacuolar protein sorting 4B), a member of the ATPase associated with diverse cellular activities (AAA) protein family, is a component of the endosomal sorting complexes required for transport machinery which regulates the internalization and lysosomal degradation of membrane proteins. We previously reported that VPS4B is one of the pathogenic genes related to dentin dysplasia type I, although its function was largely unknown. To investigate the role of VPS4B in tooth development, we deleted the Vps4b gene in mice. We found that heterozygous knockout mice (Vps4b+/- ) developed normally and were fertile. However, homozygous deletion of the Vps4b gene resulted in early embryonic lethality of Vps4b-/- mice at approximately embryonic day 9.5 (E9.5). To investigate the underlying molecular mechanisms, we examined the molecular functions of VPS4B in vivo and in vitro. Cell experiments showed that VPS4B influenced the proliferation, apoptosis, and cell cycle of transfected human neuroblastoma cells (IMR-32 cells) with over-expression or knockdown of VPS4B. Moreover, qRT-PCR detection showed that the mRNA expression levels of apoptosis-, cell cycle-, and endocytosis-related genes was significantly down or up-regulated in RNA interference-mediated knockdown of VPS4B in IMR-32 cells and Vps4b+/- E12.5 embryos. We accordingly speculated that signal transduction disorders of cell endocytosis are a contributing factor to the prenatal lethality of Vps4b-/- mice.

Endodontic treatment of dentin dysplasia type I D.

Dentin dysplasia (DD) Type I is a developmental condition affecting dentin, inherited in an autosomal-dominant pattern or occurring due to a new mutation. Whilst the crowns of DD Type I affected teeth appear clinically normal, the roots are blunt and shortened. Pulp necrosis and periapical pathoses may be seen in the absence of obvious causes. Pulp stones and calcifications are frequently encountered. Endodontic management of DD may be challenging. A case of DD Type I, sub-classification d, in which spontaneous irreversible pulpitis developed on three mandibular incisors is documented. The case was managed by conventional endodontic treatment. Knowledge of this uncommon dental condition may assist dentists to adequately diagnose and manage these cases. Extraction should not be considered the first-line treatment option when sufficient root length is available to attempt endodontic treatment. Referral for medical evaluation is recommended to rule out systemic diseases which may mimic this condition.

Guided endodontic treatment of multiple teeth with dentin dysplasia: a case report.

BACKGROUND: To report the outcome of guided endodontic treatment (GET) of a case of dentin dysplasia with pulp canal calcification (PCC) and apical periodontitis based on the use of a 3D-printed template designed by merging cone-beam computed tomography (CBCT) and surface scan data. CASE PRESENTATION: A 12-year old female with radicular dentin dysplasia type I (DD-1) presented for endodontic treatment. Radiography revealed PCC in all teeth and apical radiolucency in seven teeth (12, 15, 26, 31, 32, 36 and 46). Tooth 36 had the most acute symptoms and was thus treated first by conventional access cavity preparation and root canal detection. Despite meticulous technique, the distal and mesiolingual canals were perforated. The perforations were immediately repaired with mineral trioxide aggregate, and the decision was made to switch to guided endodontic treatment for the remaining 6 teeth. CBCT and intraoral surface scans were acquired and matched using coDiagnostix planning software (Dental Wings Inc.), the respective drill positions for root canal location were determined, and templates were virtually designed and 3D-printed. The template was positioned on the respective tooth, and a customized drill was used to penetrate the calcified part of the root canal and perform minimally invasive access cavity preparation up to the apical region. All root canals were rapidly and successfully located with the templates. At 1-year follow-up, clear signs of apical healing were present in all treated teeth. CONCLUSIONS: In patients with dentin dysplasia, conventional endodontic therapy is challenging. GET considerably facilitates the root canal treatment of teeth affected by dentin dysplasia.

VPS4B mutation impairs the osteogenic differentiation of dental follicle cells derived from a patient with dentin dysplasia type I.

A splicing mutation in VPS4B can cause dentin dysplasia type I (DD-I), a hereditary autosomal-dominant disorder characterized by rootless teeth, the etiology of which is genetically heterogeneous. In our study, dental follicle cells (DFCs) were isolated and cultured from a patient with DD-I and compared with those from an age-matched, healthy control. In a previous study, this DD-I patient was confirmed to have a loss-of-function splicing mutation in VPS4B (IVS7 + 46C > G). The results from this study showed that the isolated DFCs were vimentin-positive and CK14-negative, indicating that the isolated cells were derived from the mesenchyme. DFCs harboring the VPS4B mutation had a significantly higher proliferation rate from day 3 to day 8 than control DFCs, indicating that VPS4B is involved in cell proliferation. The cells were then replenished with osteogenic medium to investigate how the VPS4B mutation affected osteogenic differentiation. Induction of osteogenesis, detected by alizarin red and alkaline phosphatase staining in vitro, was decreased in the DFCs from the DD-I patient compared to the control DFCs. Furthermore, we also found that the VPS4B mutation in the DD-I patient downregulated the expression of osteoblast-related genes, such as ALP, BSP, OCN, RUNX2, and their encoded proteins. These outcomes confirmed that the DD-I-associated VPS4B mutation could decrease the capacity of DFCs to differentiate during the mineralization process and may also impair physiological root formation and bone remodeling. This might provide valuable insights and implications for exploring the pathological mechanisms underlying DD-I root development.

An unusual variation of radicular dentin dysplasia: A rare case report with review of literature.

Dentin dysplasia (DD) is a rare autosomal dominant disorder of dentin development, which is generally divided into two types based on the clinical and radiographic appearance of the affected dentinal tissues: Type-I (Radicular DD) and Type-II (Coronal DD). This paper reports the case of a 17-year-old female patient with both classical and atypical features of radicular DD in the permanent dentition. The present case shows clinically normal appearing crowns, localised mobility in the maxillary teeth, completely obliterated pulp chambers, widened root canals without any obliterations and the presence of multiple periapical radiolucencies. The clinical and radiographic findings observed in this present case report are different from those reported in the past literature, which suggests that the present case could be a variation of radicular DD.

VPS4B mutation impairs the osteogenic differentiation of dental follicle cells derived from a patient with dentin dysplasia type I / 国际口腔科学杂志·英文版

A splicing mutation in VPS4B can cause dentin dysplasia type I (DD-I), a hereditary autosomal-dominant disorder characterized by rootless teeth, the etiology of which is genetically heterogeneous. In our study, dental follicle cells (DFCs) were isolated and cultured from a patient with DD-I and compared with those from an age-matched, healthy control. In a previous study, this DD-I patient was confirmed to have a loss-of-function splicing mutation in VPS4B (IVS7 + 46C > G). The results from this study showed that the isolated DFCs were vimentin-positive and CK14-negative, indicating that the isolated cells were derived from the mesenchyme. DFCs harboring the VPS4B mutation had a significantly higher proliferation rate from day 3 to day 8 than control DFCs, indicating that VPS4B is involved in cell proliferation. The cells were then replenished with osteogenic medium to investigate how the VPS4B mutation affected osteogenic differentiation. Induction of osteogenesis, detected by alizarin red and alkaline phosphatase staining in vitro, was decreased in the DFCs from the DD-I patient compared to the control DFCs. Furthermore, we also found that the VPS4B mutation in the DD-I patient downregulated the expression of osteoblast-related genes, such as ALP, BSP, OCN, RUNX2, and their encoded proteins. These outcomes confirmed that the DD-I-associated VPS4B mutation could decrease the capacity of DFCs to differentiate during the mineralization process and may also impair physiological root formation and bone remodeling. This might provide valuable insights and implications for exploring the pathological mechanisms underlying DD-I root development.

A histological continuum between dentinogenesis imperfecta and dentin dysplasia: A case report with literature review.

Dentinogenesis Imperfecta and dentin dysplasia are genetic oral diseases inherited in a simple autosomal dominant mode, with high penetrance and a low mutation rate. Both of them are present with bulbous crowns, marked cervical constrictions, severe attritions, few periapical radiolucencies, and premature tooth loss. The diagnosis is based on family history, and detailed clinical examination, while genetic diagnosis may become useful in the future once sufficient disease-causing mutations have been discovered. Here, we present a case with overlapping features of both dentinogenesis imperfecta and dentin dysplasia asserting both the anomalies to be part of the same continuum of the genetic event.

Spontaneous Development of Dental Dysplasia in Aged Parp-1 Knockout Mice.

Poly(ADP-ribose) polymerase (Parp)-1 catalyzes polyADP-ribosylation using NAD+ and is involved in the DNA damage response, genome stability, and transcription. In this study, we demonstrated that aged Parp-1-/- mouse incisors showed more frequent dental dysplasia in both ICR/129Sv mixed background and C57BL/6 strain compared to aged Parp-1+/+ incisors, suggesting that Parp-1 deficiency could be involved in development of dental dysplasia at an advanced age. Computed tomography images confirmed that dental dysplasia was observed at significantly higher incidences in Parp-1-/- mice. The relative calcification levels of Parp-1-/- incisors were higher in both enamel and dentin (p < 0.05). Immunohistochemical analysis revealed (1) Parp-1 positivity in ameloblasts and odontoblasts in Parp-1+/+ incisor, (2) weaker dentin sialoprotein positivity in dentin of Parp-1-/- incisor, and (3) bone sialoprotein positivity in dentin of Parp-1-/- incisor, suggesting ectopic osteogenic formation in dentin of Parp-1-/- incisor. These results indicate that Parp-1 deficiency promotes odontogenic failure in incisors at an advanced age. Parp-1 deficiency did not affect dentinogenesis during the development of mice, suggesting that Parp-1 is not essential in dentinogenesis during development but is possibly involved in the regulation of continuous dentinogenesis in the incisors at an advanced age.