Prevalence of Dentinogenesis Imperfecta in a French Population

Morphological and Ultrastructural Collagen Defects: Impact and Implications in Dentinogenesis Imperfecta

Collagen is the building block for the extracellular matrix in bone, teeth and other fibrous tissues. Osteogenesis imperfecta (OI), or brittle bone disease, is a heritable disorder that results from defective collagen synthesis or metabolism, resulting in bone fragility. The dental manifestation of OI is dentinogenesis imperfecta (DI), a genetic disorder that affects dentin structure and clinical appearance, with a characteristic feature of greyish-brown discolouration. The aim of this study was to conduct a systematic review to identify and/or define any ultrastructural changes in dentinal collagen in DI. Established databases were searched: Cochrane Library, OVID Embase, OVID Medline and PubMed/Medline. Search strategies included: Collagen Ultrastructure, DI and OI. Inclusion criteria were studies written in English, published after 1990, that examined human dental collagen of teeth affected by DI. A Cochrane data extraction form was modified and used for data collection. The final dataset included seventeen studies published from 1993 to 2021. The most prevalent findings on collagen in DI teeth were increased coarse collagen fibres and decreased fibre quantity. Additional findings included changes to fibre orientation (i.e., random to parallel) and differences to the fibre organisation (i.e., regular to irregular). Ultrastructural defects and anomalies included uncoiled collagen fibres and increased D-banding periodicity. Studies in collagen structure in DI reported changes to the surface topography, quantity, organisation and orientation of the fibres. Moreover, ultrastructural defects such as the packing/coiling and D-banding of the fibrils, as well as differences in the presence of other collagens are also noted. Taken together, this study provides an understanding of the changes in collagen and its impact on clinical translation, paving the way for innovative treatments in dental treatment.

Dental Anomalies in a Sample of Lebanese Children: a Retrospective Study

BACKGROUND

Dental anomalies (DAs) represent a significant chapter in pediatric dentistry with a lot of practical relevance. Both primary and permanent dentitions may be affected.

OBJECTIVE

The main objective of our study was to evaluate, using digital panoramic radiographs, the prevalence, distribution, and patterns of DAs in a sample of Lebanese children aged between 8 and 15 years old.

METHODS

112 digital panoramic radiographs of patients aged between 8 and 15 years (60 males and 52 females) from the year 2017 till 2022 attending the department of Pediatric Dentistry and Dental Public Health at the Faculty of Dental Medicine at the Lebanese University were assessed for DAs of number (hypodontia, oligodontia, hyperdontia), of size (microdontia, macrodontia), of shape (fusion, gemination, dilaceration, taurodontism), of position (transposition, ectopia, impaction), and of structure (dentin dysplasia, amelogenesis imperfecta, dentinogenesis imperfecta). The data were analyzed statistically using Chi-square and Fisher's exact tests.

RESULTS

Out of 112 patient radiographs, 84 showed at least one DA, which suggests a very high prevalence (75%). Among them, 36.9% exhibited multiple types of anomalies. These 84 patients showed a total of 274 DAs, distributed equally among males and females.

CONCLUSION

Dentists should be alerted to the presence of DAs. Their high prevalence requires careful clinical and radiological examinations for early detection. Regular monitoring is mandatory and could guide preventive approaches to minimize associated dental complications.

A Review of Dentinogenesis Imperfecta and Primary Dentin Disorders in Dogs

This review describes the clinical, radiographic and histologic characteristics of dentinogenesis imperfecta diagnosed in two unrelated young dogs without evidence of concurrent osteogenesis imperfecta. The dentition was noted to have generalized coronal discoloration ranging from grey-blue to golden brown. Clinical pulp exposure, coronal wear and fractures were observed as was radiographic evidence of endodontic disease, thin dentin walls or dystrophic obliteration of the pulp canal. The enamel was severely affected by attrition and abrasion despite histologically normal areas; loss was most likely due to poor adherence or support by the underlying abnormal dentin. Histologically, permanent and deciduous teeth examined showed thin, amorphous dentin without organized dentin tubules and odontoblasts had dysplastic cell morphology. Primary dentin disorders, including dentinogenesis imperfecta and dentin dysplasia, have been extensively studied and genetically characterized in humans but infrequently reported in dogs. Treatment in human patients is aimed at early recognition and multi-disciplinary intervention to restore and maintain normal occlusion, aesthetics, mastication and speech. Treatment in both humans and canine patients is discussed as is the documented genetic heritability of primary dentin disorders in humans.

Clear Aligners in Patients with Amelogenesis and Dentinogenesis Imperfecta

Dentinogenesis imperfecta (DI) and amelogenesis imperfecta (AI) are hereditary abnormalities of dental hard tissues. Dental abnormalities may also be accompanied by symptoms of disorders such as osteogenesis imperfecta. AI and DI have a significant burden on socializing, function, and comfort; therefore, frequent screening and accurate diagnosis is the cornerstone of managing such conditions. Both AI and DI could be treated with many strategies, including restorative, prosthetic, periodontal, surgical, and orthodontics treatment. The interdisciplinary combination of orthodontic, prosthodontic, and periodontic treatment has been proven to improve the prognosis of AI and DI. Regarding orthodontic treatment, the most difficult element of orthodontic therapy may be maintaining a high level of motivation for what might be a prolonged form of treatment spanning several years. There are many forms of orthodontic management for AI and DI, including removable appliances, functional appliances, and fixed appliances. Clear aligner therapy (CAT) contains a broad range of equipment that works in different ways, has different construction processes, and is compatible with different malocclusion procedures. The application of CAT in patients with AI and DI is favorable over the fixed applicants. However, the available evidence regarding the application of CAT in AI is weak and heterogeneous. In this review, we discussed the current evidence regarding the application of clear CAT in patients with AI and DI.

Oral lichen planus: a microbiologist point of view

Oral lichen planus (OLP) is a chronic disease of uncertain etiology, although it is generally considered as an immune-mediated disease that affects the mucous membranes and even the skin and nails. Over the years, this disease was attributed to a variety of causes, including different types of microorganisms. This review analyzes the present state of the art of the disease, from a microbiological point of view, while considering whether or not the possibility of a microbial origin for the disease can be supported. From the evidence presented here, OLP should be considered an immunological disease, as it was initially proposed, as opposed to an illness of microbiological origin. The different microorganisms so far described as putative disease-causing agents do not fulfill Koch’s postulates; they are, actually, not the cause, but a result of the disease that provides the right circumstances for microbial colonization. This means that, at this stage, and unless new data becomes available, no microorganism can be envisaged as the causative agent of lichen planus.

[Role of bone morphogenetic protein 1/tolloid proteinase family in the development of teeth and bone]

The bone morphogenetic protein (BMP) 1/tolloid (TLD) proteinase family is a group of important metalloproteinases, which play key roles in the growth and development of tissues and organs via regulating the biosynthetic processing of the extracellular matrix. Clinical reports have revealed that mutations in the genes encoding BMP1/TLD proteinases lead to dentinogenesis imperfecta type Ⅰ, accompanied with osteogenesis imperfecta. Therefore, this proteinase family is essential for the development of hard tissues. In this study, we review the research progress in the function and mechanism of the BMP1/TLD proteinase family in the development of teeth and bone.

Dentinogenesis and Tooth-Alveolar Bone Complex Defects in BMP9/GDF2 Knockout Mice

Tooth development is regulated by sequential and reciprocal epithelium-mesenchymal interactions and their related molecular signaling pathways, such as bone morphogenetic proteins (BMPs). Among the 14 types of BMPs, BMP9 (also known as growth differentiation factor 2) is one of the most potent BMPs to induce osteogenic differentiation of mesenchymal stem cells. The purpose of this study was to examine potential roles of BMP9 signaling in tooth development. First, we detected the expression pattern of BMP9 in tooth germ during postnatal tooth development, and we found that BMP9 was widely expressed in odontoblasts, ameloblasts, dental pulp cells, and osteoblasts in alveolar bones. Then, we established a BMP9-KO mouse model. Gross morphological examination revealed that the tooth cusps of BMP9-KO mice were significantly abraded with shorter roots. Micro-computed tomography and three-dimensional reconstruction analysis indicated that the first molars of the BMP9-KO mice exhibited a reduced thickness dentin, enlarged pulp canals, and shortened roots, resembling the phenotypes of the common hereditary dental disease dentinogenesis imperfecta. Further, the alveolar bone of the BMP9-KO mutants was found to be shorter and had a decreased mineral density and trabecular thickness and bone volume fraction compared with that of the wild-type control. Mechanistically, we demonstrated that both dentin sialophosphoprotein and dentin matrix protein 1 were induced in dental stem cells by BMP9, whereas their expression was reduced when BMP9 was silenced. Further studies are required to determine whether loss of or decreased BMP9 expression is clinically associated with dentinogenesis imperfecta. Collectively, our results strongly suggest that BMP9 may play an important role in regulating dentinogenesis and tooth development. Further research is recommended into the therapeutic uses of BMP9 to regenerate traumatized and diseased tissues and for the bioengineering of replacement teeth.

Dentinogenesis imperfecta type II in Swedish children and adolescents

Background

Dentinogenesis imperfecta (DGI) is a heritable disorder of dentin. Genetic analyses have found two subgroups in this disorder: DGI type I, a syndromic form associated with osteogenesis imperfecta (OI), and DGI type II, a non-syndromic form. The differential diagnosis between types I and II is often challenging. Thus, the present cross-sectional study had two aims: to (i) investigate the prevalence and incidence of DGI type II among Swedish children and adolescents and (ii) search out undiagnosed cases of DGI type I by documenting the prevalence of clinical symptoms of OI in these individuals. We invited all public and private specialist pediatric dental clinics (n = 47) in 21 counties of Sweden to participate in the study. We then continuously followed up all reported cases during 2014−2017 in order to identify all children and adolescents presenting with DGI type II. Using a structured questionnaire and an examination protocol, pediatric dentists interviewed and examined patients regarding medical aspects such as bruising, prolonged bleeding, spraining, fractures, hearing impairment, and family history of osteoporosis and OI. Joint hypermobility and sclerae were assessed. The clinical oral examination, which included a radiographic examination when indicated, emphasized dental variables associated with OI.

Results

The prevalence of DGI type II was estimated to be 0.0022% (95% CI, 0.0016–0.0029%) or 1 in 45,455 individuals. Dental agenesis occurred in 9% of our group. Other findings included tooth retention (17%), pulpal obliteration (100%), and generalized joint hypermobility (30%). Clinical and radiographic findings raised a suspicion of undiagnosed OI in one individual, a 2-year-old boy; he was later diagnosed with OI type IV.

Conclusions

These results show a significantly lower prevalence of DGI type II than previously reported and point to the importance of excluding OI in children with DGI.

Electronic supplementary material

The online version of this article (10.1186/s13023-018-0887-2) contains supplementary material, which is available to authorized users.