Elements of morphology: Standard terminology for the teeth and classifying genetic dental disorders

i-Dent: A virtual assistant to diagnose rare genetic dental diseases

Rare genetic diseases are difficult to diagnose and this translates in patient's diagnostic odyssey! This is particularly true for more than 900 rare diseases including orodental developmental anomalies such as missing teeth. However, if left untreated, their symptoms can become significant and disabling for the patient. Early detection and rapid management are therefore essential in this context. The i-Dent project aims to supply a pre-diagnostic tool to detect rare diseases with tooth agenesis of varying severity and pattern. To identify missing teeth, image segmentation models (Mask R-CNN, U-Net) have been trained for the automatic detection of teeth on patients' panoramic dental X-rays. Teeth segmentation enables the identification of teeth which are present or missing within the mouth. Furthermore, a dental age assessment is conducted to verify whether the absence of teeth is an anomaly or a characteristic of the patient's age. Due to the small size of our dataset, we developed a new dental age assessment technique based on the tooth eruption rate. Information about missing teeth is then used by a final algorithm based on the agenesis probabilities to propose a pre-diagnosis of a rare disease. The results obtained in detecting three types of genes (PAX9, WNT10A and EDA) by our system are very promising, providing a pre-diagnosis with an average accuracy of 72 %.

Pycnodysostosis: Characteristics of teeth, mouth and jaws

OBJECTIVES

To describe the clinical and radiographic oro-dental characteristics of patients with pycnodysostosis (PDO).

MATERIALS & METHODS

A short interview and clinical examination of seven patients with PDO were performed as well as assessment of the temporomandibular joints and masticatory muscles using the diagnostic criteria for temporomandibular disorders, DC-TMD form. A full set of records were taken including photos and intraoral scan. Finally, existing cone beam computed tomography (CBCT) images and radiographs were also studied.

RESULTS

All patients presented with bimaxillary micrognathia, five had a convex profile, and two had a straight profile. In addition, posterior open bite, Angle Class III molar relation with accompanying anterior crossbite and a grooved median palate were common findings. No patient showed symptoms of temporomandibular disorder (TMD) apart from some clicking. Finally, the main radiographic findings were the obtuse mandibular angle, the frontal bossing, the elongation of the coronoid/condylar process and the presence of hypercementosis with obliterated pulp chambers.

CONCLUSION

The examined patients with PDO were characterized by dental crowding, malocclusion (anterior crossbite, posterior open bite), hypercementosis, obliterated pulp chambers and deviations in mandibular morphology. In conclusion, patients with PDO have a specific need for dental and orthodontic monitoring with focus on crowding and posterior open bite. The patients will benefit from a long-term orthodontic plan including extractions.

Advances in clinical diagnosis and management of amelogenesis imperfecta in children and adolescents

OBJECTIVE

To summarize studies published between 2017 and 2023 examining the clinical diagnosis and restorative management of amelogenesis imperfecta (AI) in children and adolescents.

DATA

The review incorporated publications on clinical diagnosis, patient-reported outcomes, clinical trials, cohort studies, and case reports that included individuals below 19 years of age with non-syndromic AI.

SOURCES

A literature search was conducted across electronic databases, PubMed, Web of Science, and CINAHL, including papers published between 2017 and 2023. The search yielded 335 unique results, of which 38 were eligible for inclusion.

RESULTS

New evidence on the genetic background of AI makes it now advisable to recommend genetic testing to supplement a clinical AI diagnosis. The discussions of the dental profession and the public on social media do not always incorporate recent scientific evidence. Interview studies are finding that the impact of AI on quality of life is more severe than previously appreciated. New evidence suggests that single-tooth ceramic crowns should be the first choice of treatment. Due to incomplete reporting, case reports have been of limited value.

CONCLUSION

In young patients with AI symptoms of pain and hypersensitivity decreased, and aesthetics were improved following all types of restorative therapy. Resin composite restorations were mainly performed in cases with hypoplastic AI and mild symptoms. Single tooth ceramic crown restorations have a high success rate in all types of AI and can be used in young individuals with AI.

CLINICAL SIGNIFICANCE

Prosthetic rehabilitation in adolescents with severe AI is cost effective, improves esthetics, reduces tooth sensitivity, and improves oral health-related quality of life.

Translation and validation of the French version of the child perceptions questionnaire for children aged 11 to 14 years old (CPQ11-14) short-form

OBJECTIVES

The COHQoL is a set of questionnaires used to evaluate the impact of oral health on children's quality of life. Although the CPQ8-10 and the P-CPQ have been translated and validated in French, the CPQ11-14 14 has not yet been validated. The aim was to develop a French version of the CPQ11-14 16-items.

MATERIALS AND METHODS

The French version of CPQ11-14 was obtained by a forward-backward translation process and pretested. The final version was tested on children aged 11-14 and divided into three groups: children with orofacial clefts, children with rare dental diseases other than clefts, and children without anomalies. We conducted a cross-sectional study and evaluated the reliability with test-retest and internal consistency, and the questionnaire validity with construct validity and discriminant validity. We performed an Exploratory Factory Analysis (EFA).

RESULTS

187 children tested the questionnaire. The ICC of the test-retest was 0.76 and the Cronbach's alpha was 0.77. The correlation between the CPQ11-14 and self-assessment of oral health and general well-being was > 0.2. Patients with orofacial clefts and rare diseases had significantly higher scores for overall short-form CPQ11-14. The EFA revealed six factors.

CONCLUSION

The French CPQ11-14 is valid to assess the impact of oral health on children's quality of life.

CLINICAL RELEVANCE

The translation of this questionnaire into French will enable us to assess the impact of oral health on the quality of life of adolescents. This questionnaire complements the 8-10 years version of the CPQ, as well as the parental version that can be used in conjunction with the questionnaire.

Dental anomalies in craniofacial microsomia and condylo-mandibular dysplasia: A retrospective study of 103 patients

INTRODUCTION

Craniofacial microsomia (CFM) and camel-hump condylo-mandibular dysplasia (CMD) are developmental disorders affecting the mandible that share common clinical features. This study aimed to investigate and compare the dental anomalies (DA) between the two entities for differential diagnosis and to propose appropriate treatment.

METHODS

This retrospective cross-sectional study was based on panoramic radiographs of patients diagnosed with CFM or CMD. DA were evaluated using the classification reported by Bilge. Delayed tooth eruption on the affected side was noted based on a comparison with the contralateral side. Nolla's stages of tooth calcification were used to assess dental development.

RESULTS

A total of 103 patients were included, 80 subjects (77.7 %) in CFM group and 23 patients (22.3 %) in CMD group. The prevalence of DA among CFM and CMD-affected patients were 80.0 % and 95.7 %, respectively. Tooth ectopia, tooth impaction, dental development delay, and delayed tooth eruption on the affected side exhibited a significant association with the two craniofacial malformations. The overall affected teeth (molars, premolars, canines) differed between the two craniofacial malformations. Dental abnormalities such as oligodontia, hyperdontia, dentin dysplasia, and anomalies of shape were seen only in subjects affected by CFM.

CONCLUSION

DA were widely observed in patients with CFM and CMD. The global distribution of affected teeth differed between the two conditions and some DA were detected only in CFM patients. When clinical diagnosis remains uncertain, some specific radiological characteristics of DA can be used to differentiate CFM from CMD.

Dental and jawbone abnormalities linked to amelogenesis imperfecta: A retrospective and analytic study comparing panoramic radiographs

BACKGROUND

Amelogenesis Imperfecta (AI) is a disorder of tooth development characterized by abnormal enamel formation. In order to detect other dental and jawbone abnormalities that could be associated with AI, a retrospective and analytic study was conducted comparing panoramic radiographs of AI and non-AI patients.

MATERIAL AND METHODS

Digital panoramic radiographs of 60 AI and 60 non-AI patients were examined. Abnormalities in dental number, size, shape, eruption, and in the shape of the dental arches were checked and blindly recorded by two experimented observers. Descriptive statistics using percentages and chi-square test with .05 level of significance value was used.

RESULTS

Prevalence of supernumerary teeth, dental agenesis, microdontia, taurodontism, radicular dilacerations, dental inclusions, temporary teeth persistence, and pulp calcifications was significantly higher in AI patients compared to control patients. Prevalence of periapical images, cysts, and hypercementosis was lower in AI patients compared to control patients, with no statistically significant difference. A significant prevalence of mandibular hypoplasia was also noted in AI patients.

CONCLUSION

In addition to enamel defect, panoramic radiography was useful in detecting other dental abnormalities and mandibular hypoplasia associated with AI and should therefore be systematically indicated for AI patients' care.

Comprehensive Oral Diagnosis and Management for Women with Turner Syndrome

Turner Syndrome (TS) is a rare genetic disorder that affects females when one of the X chromosomes is partially or completely missing. Due to high genetic and phenotypic variability, TS diagnosis is challenging and is often delayed until adolescence, resulting in poor clinical management. Numerous oral, dental and craniofacial anomalies have been associated with TS, yet a comprehensive description is still lacking. This study addresses this gap through a detailed analysis of oral health and craniofacial characteristics in a cohort of 15 females with TS and their first-degree relatives. Subjects with TS ranged from 3 to 48 years old, none showed evidence of periodontal disease and only the youngest was in mixed dentition. Using the Multifunction System, we identified an aggregation of multiple signs and symptoms in each TS subject, including tooth anomalies (supernumerary molars, agenesis, microdontia, enamel defects, alterations in eruption patterns -advanced and delayed for chronological age-, crowding, rotations and transpositions), malocclusion (class II/1 and II/2) and Class II facial profile, while relatives exhibited fewer manifestations. The early detection of these signs and symptoms is crucial for appropriate referral and the optimal clinical management of TS, especially during the critical period of 9 to 10 years when congenital dental anomalies appear. The use of an established taxonomy to describe these phenotypic features is essential for early detection. Multidisciplinary teams are required to ensure holistic care management in rare diseases like TS.

Root resorptions induced by genetic disorders: A systematic review

OBJECTIVES

Root resorption in permanent teeth is a common pathological process that often follows dental trauma or orthodontic treatment. More rarely, root resorption is a feature of genetic disorders and can help with diagnosis. Thus, the present review aims to determine which genetic disorders could induce pathological root resorptions and thus which mutated genes could be associated with them.

METHODS

We conducted a systematic review following the PRISMA guidelines. Articles describing root resorptions in patients with genetic disorders were included from PubMed, Embase, Web of Science, and Google Scholar. We synthesized the genetic disorder, the type, severity, and extent of the resorptions, as well as the other systemic and oral symptoms and histological features.

RESULTS

The synthetic analysis included 25 studies among 937 identified records. We analyzed 21 case reports, three case series, and one cohort study. Overall, we highlighted 14 different pathologies with described root resorptions. Depending on the pathology, the sites of resorption, their extent, and their severity showed differences.

CONCLUSION

With 14 genetic pathologies suspected to induce root resorptions, our findings are significant and enrich a previous classification. Among them, three metabolic disorders, three calcium-phosphorus metabolism disorders, and osteolysis disorders were identified.

[Oral mesenchymal cells, a specific niche, from development to regeneration]

Oral buccal tissues, including bone and mucosa, have unique properties. Oral mucosal fibroblasts and jaw osteoblasts, both derived from Cranial Neural Crest cells, play a key role in healing and repair. These cells express a specific repertoire of genes with their regenerative properties, but also craniofacial diseases. Understanding these tissues holds clinical promise for tissue regeneration and repair of bone and mucosal defects. These multidisciplinary advances also offer potential for better management of periodontal-related conditions and improved oral health.

[The tooth: A marker of developmental abnormalities]

Tooth formation results from specific epithelial-mesenchymal interactions, which summarize a number of developmental processes. Tooth anomalies may thus reflect subclinical diseases of the kidney, bone and more broadly of the mineral metabolism, skin or nervous system. Odontogenesis starts from the 3rd week of intrauterine life by the odontogenic orientation of epithelial cells by a first PITX2 signal. The second phase is the acquisition of the number, shape, and position of teeth. It depends on multiple transcription and growth factors (BMP, FGF, SHH, WNT). These ecto-mesenchymal interactions guide cell migration, proliferation, apoptosis and differentiation ending in the formation of the specific dental mineralized tissues. Thus, any alteration will have consequences on the tooth structure or shape. Resulting manifestations will have to be considered in the patient phenotype and the multidisciplinary care, but also may contribute to identify the altered genetic circuity.

Oligodontia in the Clinical Spectrum of Syndromes: A Systematic Review

The aim of this systematic review was to describe the clinical and genetic features of syndromes showing oligodontia as a sign. The review was performed according to the PRISMA 2020 checklist guidelines, and the search was conducted using PubMed, Scopus, Lilacs, Web of science, Livivo, and EMBASE and supplemented by a gray literature search on Google Scholar and ProQuest, applying key terms relevant to the research questions. The systematic review identified 47 types of syndromes in 83 studies, and the most common was hypohidrotic ectodermal dysplasia, which was reported in 24 patients in 22 studies. Other common syndromes that reported oligodontia included Axenfeld-Rieger syndrome, Witkop's syndrome, Ellis-van Creveld syndrome, blepharocheilodontic syndrome, and oculofaciocardiodental syndrome. The X-linked mode of inheritance was the most reported (n = 13 studies), followed by the autosomal dominant (n = 13 studies). The review describes the main syndromes that may have oligodontia as a clinical sign and reinforces the need for orodental-facial examining for adequate diagnosis and treatment of the affected patients. Molecular analysis in order to better understand the occurrence of oligodontia is imperative.

Reduced bone dimension in patients affected by oligodontia: A retrospective study on maxillary and mandibular CBCT

AIM

Oligodontia (OD) is a rare developmental condition characterized by the absence of six or more teeth. Dental implant placement may be challenging due to anatomical factors. This study aims to evaluate the alveolar bone dimensions in OD patients compared with controls.

MATERIALS AND METHODS

On maxillary and mandibular cone-beam computed tomography (CBCT), bone height and width were measured at every tooth and edentulous site. The distance to the inferior alveolar nerve was also measured. Fifty-three OD patients (40 maxillary and 32 mandibular CBCT) and 82 controls (51 maxillary and 31 mandibular CBCT) were compared using mixed models.

RESULTS

Compared with those in OD patients, maxillary permanent teeth and edentulous sites showed significantly higher mean height in control patients (incisive-canine site height: +2.12 mm; edentulous incisive-canine site height: +4.46 mm [p > .001]). For the mandibular permanent teeth, mean height was higher in controls than in OD patients at the incisive-canine (+3.82 mm [p > .001]) and premolar areas (+2.06 mm [p > .001]). Only edentulous incisive-canine sites were significantly different between controls and OD patients (mean: +0.52 mm [p > .001]). Changes in alveolar nerve position were observed in case of molar agenesis.

CONCLUSION

Maxillary and mandibular bone dimensions are reduced in OD patients compared with controls both in sites with permanent teeth and in edentulous areas.

Oro-dental phenotyping and report of three families with RELT-associated amelogenesis imperfecta

Amelogenesis imperfecta (AI) is a group of rare genetic conditions characterized by quantitative and/or qualitative tooth enamel alterations. AI can manifest as an isolated trait or as part of a syndrome. Recently, five biallelic disease-causing variants in the RELT gene were identified in 7 families with autosomal recessive amelogenesis imperfecta (ARAI). RELT encodes an orphan receptor in the tumor necrosis factor (TNFR) superfamily expressed during tooth development, with unknown function. Here, we report one Brazilian and two French families with ARAI and a distinctive hypomineralized phenotype with hypoplastic enamel, post-eruptive enamel loss, and occlusal attrition. Using Next Generation Sequencing (NGS), four novel RELT variants were identified (c.120+1G>A, p.(?); c.120+1G>T, p.(?); c.193T>C, p.(Cys65Arg) and c.1260_1263dup, p.(Arg422Glyfs*5)). Our findings extend the knowledge of ARAI dental phenotypes and expand the disease-causing variants spectrum of the RELT gene.

Association between Dentofacial Features and Bullying from Childhood to Adulthood: A Systematic Review

Bullying occurs when an individual is repeatedly victimised by negative actions performed by peers. As oral features, like malocclusion and dental structural defects, can promote psychological distress, which is also found in those who are bullied, we aimed to study the association between orofacial conditions and bullying. A systematic review (PROSPERO CRD42022331693), including articles dealing with bullying and dentofacial traits, was performed following the PRISMA chart. The iterative search of eligible publications was carried out on 27 March 2023 on four databases (PubMed, PubPsych, Web of Science and Cochrane Reviews) and in the grey literature. Among the 25 articles included, 4 referred to qualitative studies, which analysed 632 interviews with children, 8 interviews with parents, 292 letters, and 321 Twitter posts. The other 21 were cross-sectional studies, which included 10,026 patients from 7 to 61 years old. Two of the qualitative studies and seven of the cross-sectional studies rated a low risk of bias, according to Joanna Briggs Institute's Critical Appraisal Tools. The majority of studies (88%) reported a relationship between malocclusion or structural defects and exposure to bullying among young adolescents. Structural dental abnormalities and severe malocclusion should be managed, among others, for psychological questions because they crystallise the loss of self-confidence and increase the risk of bullying.

Nance-Horan Syndrome: characterization of dental, clinical and molecular features in three new families

BACKGROUND

Nance-Horan syndrome (NHS; MIM 302,350) is an extremely rare X-linked dominant disease characterized by ocular and dental anomalies, intellectual disability, and facial dysmorphic features.

CASE PRESENTATION

We report on five affected males and three carrier females from three unrelated NHS families. In Family 1, index (P1) showing bilateral cataracts, iris heterochromia, microcornea, mild intellectual disability, and dental findings including Hutchinson incisors, supernumerary teeth, bud-shaped molars received clinical diagnosis of NHS and targeted NHS gene sequencing revealed a novel pathogenic variant, c.2416 C > T; p.(Gln806*). In Family 2, index (P2) presenting with global developmental delay, microphthalmia, cataracts, and ventricular septal defect underwent SNP array testing and a novel deletion encompassing 22 genes including the NHS gene was detected. In Family 3, two half-brothers (P3 and P4) and maternal uncle (P5) had congenital cataracts and mild to moderate intellectual deficiency. P3 also had autistic and psychobehavioral features. Dental findings included notched incisors, bud-shaped permanent molars, and supernumerary molars. Duo-WES analysis on half-brothers showed a hemizygous novel deletion, c.1867delC; p.(Gln623ArgfsTer26).

CONCLUSIONS

Dental professionals can be the first-line specialists involved in the diagnosis of NHS due to its distinct dental findings. Our findings broaden the spectrum of genetic etiopathogenesis associated with NHS and aim to raise awareness among dental professionals.

Amelogenesis imperfecta: Next-generation sequencing sheds light on Witkop's classification

Amelogenesis imperfecta (AI) is a heterogeneous group of genetic rare diseases disrupting enamel development (Smith et al., Front Physiol, 2017a, 8, 333). The clinical enamel phenotypes can be described as hypoplastic, hypomineralized or hypomature and serve as a basis, together with the mode of inheritance, to Witkop's classification (Witkop, J Oral Pathol, 1988, 17, 547-553). AI can be described in isolation or associated with others symptoms in syndromes. Its occurrence was estimated to range from 1/700 to 1/14,000. More than 70 genes have currently been identified as causative. Objectives: We analyzed using next-generation sequencing (NGS) a heterogeneous cohort of AI patients in order to determine the molecular etiology of AI and to improve diagnosis and disease management. Methods: Individuals presenting with so called "isolated" or syndromic AI were enrolled and examined at the Reference Centre for Rare Oral and Dental Diseases (O-Rares) using D4/phenodent protocol (www.phenodent.org). Families gave written informed consents for both phenotyping and molecular analysis and diagnosis using a dedicated NGS panel named GenoDENT. This panel explores currently simultaneously 567 genes. The study is registered under NCT01746121 and NCT02397824 (https://clinicaltrials.gov/). Results: GenoDENT obtained a 60% diagnostic rate. We reported genetics results for 221 persons divided between 115 AI index cases and their 106 associated relatives from a total of 111 families. From this index cohort, 73% were diagnosed with non-syndromic amelogenesis imperfecta and 27% with syndromic amelogenesis imperfecta. Each individual was classified according to the AI phenotype. Type I hypoplastic AI represented 61 individuals (53%), Type II hypomature AI affected 31 individuals (27%), Type III hypomineralized AI was diagnosed in 18 individuals (16%) and Type IV hypoplastic-hypomature AI with taurodontism concerned 5 individuals (4%). We validated the genetic diagnosis, with class 4 (likely pathogenic) or class 5 (pathogenic) variants, for 81% of the cohort, and identified candidate variants (variant of uncertain significance or VUS) for 19% of index cases. Among the 151 sequenced variants, 47 are newly reported and classified as class 4 or 5. The most frequently discovered genotypes were associated with MMP20 and FAM83H for isolated AI. FAM20A and LTBP3 genes were the most frequent genes identified for syndromic AI. Patients negative to the panel were resolved with exome sequencing elucidating for example the gene involved ie ACP4 or digenic inheritance. Conclusion: NGS GenoDENT panel is a validated and cost-efficient technique offering new perspectives to understand underlying molecular mechanisms of AI. Discovering variants in genes involved in syndromic AI (CNNM4, WDR72, FAM20A … ) transformed patient overall care. Unravelling the genetic basis of AI sheds light on Witkop's AI classification.

Palatal Rugae Patterns in Fars, Turkmen, and Sistani Ethnicities in the Eastern Part of the Caspian Littoral of Iran

In forensic medicine, it is important to identify whole or fragmented bodies. This aim can be particularly challenging in mass disasters. Palatal rugae patterns can be used as a surrogate parameter in forensic medicine. This stems from the difficulty in falsifying these patterns, their resistance to trauma, to decomposition for several days postmortem, and to combustion under high-temperatures, as well as being distinguishable among different races. The present study aimed to analyze the differences in the palatal rugae patterns among three Iranian ethnicities (Fars, Turkmen, and Sistani). This retrospective study involved the use of archived materials. The study casts were selected from the database of patients who visited a private orthodontics clinic. A total of 309 dental casts (103 Fars, 103 Turkmen, and 103 Sistani) were assessed, which belonged to 181 females and 128 males aged between 12 and 30 years (mean: 16.86 ± 3.18 years). The difference in the mean number of palatal rugae in women between the three ethnicities was statistically significant. Also, the differences in the total number of straight rugae were significant between the three ethnic groups. The most common rugae shapes in the three ethnic groups were the straight and wavy shapes. The length of the palatal rugae in the primary and secondary rugae among the study subjects younger than 18-years-old was significantly different between the three ethnic groups. Thus, the present research highlighted the differences in palatal rugae patterns among three Iranian ethnicities. Therefore, palatal rugae can be used in forensic medicine as a complementary approach to human identification.

Dental anomalies in syndromes displaying hypertrichosis in the clinical spectrum

Hypertrichosis and dental anomalies may occur alone or in combination in the spectrum of many syndromes. To identify genetic entities characterized by hypertrichosis and dental anomalies, a search was performed in the Mendelian Inheritance in Man database with the terms "hypertrichosis" or "hirsutism" and "tooth" or "dental abnormalities." Nondependent androgen metabolism disturbances were classified as hypertrichosis. Genetic entities with hypertrichosis and dental anomalies were included in the study. Additional searches were performed in the PubMed and Orphanet databases, when necessary, in order to include data from scientific articles. An integrative analysis of the genes associated with the identified syndromes was conducted using STRING to characterize biological processes, pathways, and interactive networks. The p-values were subjected to the false discovery rate for the correction of multiple tests. Thirty-nine syndromes were identified, and dental agenesis was the most frequent dental anomaly present in 41.02% (n = 16) of the syndromes. Causative genes were identified in 33 out of 39 genetic syndromes. Among them, 39 genes were identified, and 38 were analyzed by STRING, which showed 148 biological processes and three pathways that were statistically significant. The most significant biological processes were the disassembly of the nucleosome (GO:0006337, p = 1.09e-06), chromosomal organization (GO:0051276, p = 1.09e-06) and remodeling of the chromatin (GO: 0006338, p = 7.86e-06), and the pathways were hepatocellular carcinoma (hsa05225, p = 5.77e-05), thermogenesis (hsa04714, p = 0.00019), and cell cycle (hsa04110, p = 0.0433). Our results showed that the identification of hypertrichosis and dental anomalies may raise the suspicion of one of the thirty-nine syndromes with both phenotypes.

A paleoepidemiological approach to the challenging differential diagnosis of an isolated 1500-year-old anomalous molar from Panamá

OBJECTIVE

This study seeks to quantify the presence and prevalence of specific genetic and infectious diseases in the pre-Colombian Panamanian population and uses these data to consider the plausibility of these diseases as causative factors in the development of an abnormal supernumerary cusp morphology in a 1500-year-old isolated molar recovered from Cerro Juan Díaz (Los Santos, Panama).

MATERIALS

267 individuals from pre-Columbian sites throughout Panama.

METHODS

The anomalous tooth was analyzed through macroscopic, odontometric, and radiographic means. Tentative differential diagnosis was performed using inferences from paleopathological features of the broader regional population.

RESULTS

The regional sample showed evidence of treponemal infection and developmental anomalies in 10.1% and 10.9% of individuals, respectively.

CONCLUSIONS

While not able to rule out three potential genetic conditions, more evidence was found to support the differential diagnosis of congenital syphilis as the causative agent leading to the development of abnormal supernumerary cusps in the isolated molar.

SIGNIFICANCE

This study demonstrates how characterizing disease experience in the population can assist in differential diagnoses at the individual level and cautions against the assumption that any one lesion in isolation is unique to only one specific pathological condition.

LIMITATIONS

The timing discrepancy between clinical descriptions of congenital syphilis and genetic disorders, lack of knowledge on pathophysiological mechanisms of the former, poor preservation of Treponema pathogen ancient DNA, and deficiencies in modern public health data from Panama limit the differential diagnosis.

SUGGESTIONS FOR FURTHER RESEARCH

Inclusion and serious contemplation of genetic diseases in paleopathological differential diagnoses is necessary.

Elements of morphology: Standard terminology for the trunk and limbs

An international group of clinicians working in the field of dysmorphology has initiated the standardization of terms used to describe human morphology. The goals are to standardize these terms and reach consensus regarding their definitions. In this way, we will increase the utility of descriptions of the human phenotype and facilitate reliable comparisons of findings among patients. Additional discussions with other workers in dysmorphology and related fields, such as developmental biology and molecular genetics, will become more precise. Here we introduce the anatomy of the trunk and limbs and define and illustrate the terms that describe the major characteristics of these body regions.

Impact of claudin-10 deficiency on amelogenesis: Lesson from a HELIX tooth

In epithelia, claudin proteins are important components of the tight junctions as they determine the permeability and specificity to ions of the paracellular pathway. Mutations in CLDN10 cause the rare autosomal recessive HELIX syndrome (Hypohidrosis, Electrolyte imbalance, Lacrimal gland dysfunction, Ichthyosis, and Xerostomia), in which patients display severe enamel wear. Here, we assess whether this enamel wear is caused by an innate fragility directly related to claudin-10 deficiency in addition to xerostomia. A third molar collected from a female HELIX patient was analyzed by a combination of microanatomical and physicochemical approaches (i.e., electron microscopy, elemental mapping, Raman microspectroscopy, and synchrotron-based X-ray fluorescence). The enamel morphology, formation time, organization, and microstructure appeared to be within the natural variability. However, we identified accentuated strontium variations within the HELIX enamel, with alternating enrichments and depletions following the direction of the periodical striae of Retzius. These markings were also present in dentin. These data suggest that the enamel wear associated with HELIX may not be related to a disruption of enamel microstructure but rather to xerostomia. However, the occurrence of events of strontium variations within dental tissues might indicate repeated episodes of worsening of the renal dysfunction that may require further investigations.

Consideration of oral health in rare disease expertise centres: a retrospective study on 39 rare diseases using text mining extraction method

Background

Around 8000 rare diseases are currently defined. In the context of individual vulnerability and more specifically the one induced by rare diseases, ensuring oral health is a particularly important issue. The objective of the study is to evaluate the pattern of oral health care course for patients with any rare genetic disease. Description of oral phenotypic signs—which predict a theoretical dental health care course—and effective orientation into an oral healthcare were evaluated.

Materials and methods

We set up a retrospective cohort study to describe the consideration of patient oral health and potential orientation to an oral health care course who have at least been seen once between 1 January 2017 and 1 January 2020 in Necker Enfants Malades Hospital. We recruited patients from this study using the data warehouse, Dr Warehouse® (DrWH), from Necker-Enfants Malades Hospital.

Results

The study sample included 39 rare diseases, 2712 patients, with 54.7% girls and 45.3% boys. In the sample studied, 27.9% of patients had an acquisition delay or a pervasive developmental disorder. Among the patient files studied, oral and dental phenotypic signs were described for 18.40% of the patients, and an orientation in an oral healthcare was made in 15.60% of patients. The overall "network" effect was significantly associated with description of phenotypic signs (corrected p = 1.44e−77) and orientation to an oral healthcare (corrected p = 23.58e−44). Taking the Defiscience network (rare diseases of cerebral development and intellectual disability) as a reference for the odd ratio analysis, OSCAR, TETECOU, FILNEMUS, FIMARAD, MHEMO networks stand out from the other networks for their significantly higher consideration of oral phenotypic signs and orientation in an oral healthcare.

Conclusion

To our knowledge, no study has explored the management of oral health in so many rare diseases. The expected benefits of this study are, among others, a better understanding, and a better knowledge of the oral care, or at least of the consideration of oral care, in patients with rare diseases. Moreover, with the will to improve the knowledge on genetic diseases, oral heath must have a major place in the deep patient phenotyping. Therefore, interdisciplinary consultations with health professionals from different fields are crucial.

Assessing the prevalence of S-shaped root canal and associated genes in humans

BACKGROUND

Multiple signaling molecules have been shown to play crucial roles in dental root development. Therefore, we aimed to investigate the prevalence of S-shaped roots and also to investigate, if single nucleotide polymorphisms (SNPs) in BMP2, BMP4 and SMAD6 are associated with this phenotype in humans.

METHODS

This is a cross-sectional phenotype-genotype association study that used radiographs to determine the phenotypes and DNA to investigate SNPs in candidate genes. During the radiographic exam, teeth presenting root canal(s) doubly curved were considered S-shaped roots. SNPs in BMP2 (rs1005464 and rs235768), BMP4 (rs17563) and SMAD6 (rs2119261 and rs3934908) were blindly genotyped by real-time PCR using TaqMan assay. The relative and absolute frequency of S-shaped roots were calculated. Chi-square test was used to compare the genotype distributions between control and S-shaped groups.

RESULTS

Among the 578 subjects, 61 (10.6%) presented at least one tooth with an S-shaped root. The most commonly affected type of tooth was the premolar. rs1005464 in BMP2 was statistically associated with an S-shaped root (p=0.036). rs235768 in BMP2 was associated with an S-shaped root also in mandibular teeth (p=0.017). A statistical significance was observed for the rs3934908 in SMAD6 (p=0.049) for S-shaped root in the mandible. In the analysis stratified according to the type of tooth, rs235768 in BMP2 was associated with S-shaped roots in premolars (p=0.029).

CONCLUSION

The prevalence of S-shaped roots is 10.6% in permanent teeth. SNPs in BMP2 and SMAD6 could be involved in a higher chance to present S-shaped roots.

Oral Phenotype of Singleton-Merten Syndrome: A Systematic Review Illustrated With a Case Report

Background: Singleton-Merten syndrome type 1 (SGMRT1) is a rare autosomal dominant disorder caused by IFIH1 variations with blood vessel calcifications, teeth anomalies, and bone defects. Aim: We aimed to summarize the oral findings in SGMRT1 through a systematic review of the literature and to describe the phenotype of a 10-year-old patient with SGMRT1 diagnosis. Results: A total of 20 patients were described in the literature, in nine articles. Eight IFIH1 mutations were described in 11 families. Delayed eruption, short roots, and premature loss of permanent teeth were the most described features (100%). Impacted teeth (89%) and carious lesions (67%) were also described. Our patient, a 10-year-old male with Singleton-Merten syndrome, presented numerous carious lesions, severe teeth malposition, especially in the anterior arch, and an oral hygiene deficiency with a 100% plaque index. The panoramic X-ray did not show any dental agenesis but revealed very short roots and a decrease in the jaw alveolar bone height. The whole-genome sequencing analysis revealed a heterozygous de novo variant in IFIH1 (NM_022168.4) c.2465G > A (p.Arg822Gln). Conclusion: Confused descriptions of oral features occurred in the literature between congenital findings and "acquired" pathology, especially carious lesions. The dental phenotype of these patients encompasses eruption anomalies (delayed eruption and impacted teeth) and lack of root edification, leading to premature loss of permanent teeth, and it may contribute to the diagnosis. An early diagnosis is essential to prevent teeth loss and to improve the quality of life of these patients. Systematic Review Registration: [https://www.crd.york.ac.uk/prospero/], identifier [CRD42022300025].

Confirmation of a Phenotypic Entity for TSPEAR Variants in Egyptian Ectodermal Dysplasia Patients and Role of Ethnicity

Ectodermal dysplasia (ED) are hereditary disorders characterized by the disturbance of the ectodermal development of at least two of four ectodermal tissues: teeth, hair, nails and sweat glands. Clinical classification of ED is challenged by overlapping features, variable expressivity, and low number of patients, hindering full phenotypic spectrum identification. Disease-causing variants in elements of major developmental pathways, e.g., Ectodysplasin/NFκB, Wnt, and Tp63 pathways, have been identified in fewer than half of ED phenotypes. Whole-exome sequencing (WES) was performed for ten Egyptian ED patients presenting with tooth agenesis, normal sweating, scalp hypotrichosis, and sharing characteristic facial features. WES was followed by in silico analysis of the effects of novel detected genetic variants on mRNA and protein structure. The study identified four novel rare pathogenic and likely pathogenic TSPEAR variants, a gene which was recently found to be involved in ectodermal organogenesis. A novel in-frame deletion recurred in eight patients from six unrelated families. Comparing our cohort to previously reported TSPEAR cohorts highlighted the influence of ethnicity on TSPEAR phenotypic affection. Our study expands the clinical and mutational spectrum of the growing TSPEAR associated phenotypes, and pinpoints the influence of WES and in silico tools on identification of rare disease-causing variants.

The Human Genetics of Dental Anomalies

The development of tooth is a highly complex procedure and mastered by specific genetic programs. Genetic alterations, environmental factors, and developmental timing can disturb the execution of these programs, and result in various dental anomalies like hypodontia/oligodontia, and supernumerary teeth, which are commonly seen in our clinical practice. Advances in molecular research enabled the identification of various genes involved in the pathogenesis of dental anomalies. In the near future, it will help provide a more accurate diagnosis and biological-based treatment for these anomalies. In this article, we present the molecular phenomenon of tooth development and the genetics of various dental anomalies.

Transcriptional Regulation of Jaw Osteoblasts: Development to Pathology

Craniofacial and jaw bones have unique physiological specificities when compared to axial and appendicular bones. However, the molecular profile of the jaw osteoblast (OB) remains incomplete. The present study aimed to decipher the bone site-specific profiles of transcription factors (TFs) expressed in OBs in vivo. Using RNA sequencing analysis, we mapped the transcriptome of confirmed OBs from 2 different skeletal sites: mandible (Md) and tibia (Tb). The OB transcriptome contains 709 TF genes: 608 are similarly expressed in Md-OB and Tb-OB, referred to as "OB-core"; 54 TF genes are upregulated in Md-OB, referred to as "Md-set"; and 18 TF genes are upregulated in Tb-OB, referred to as "Tb-set." Notably, the expression of 29 additional TF genes depends on their RNA transcript variants. TF genes with no previously known role in OBs and bone were identified. Bioinformatics analysis combined with review of genetic disease databases and a comprehensive literature search showed a significant contribution of anatomical origin to the OB signatures. Md-set and Tb-set are enriched with site-specific TF genes associated with development and morphogenesis (neural crest vs. mesoderm), and this developmental imprint persists during growth and homeostasis. Jaw and tibia site-specific OB signatures are associated with craniofacial and appendicular skeletal disorders as well as neurocristopathies, dental disorders, and digit malformations. The present study demonstrates the feasibility of a new method to isolate pure OB populations and map their gene expression signature in the context of OB physiological environment, avoiding in vitro culture and its associated biases. Our results provide insights into the site-specific developmental pathways governing OBs and identify new major OB regulators of bone physiology. We also established the importance of the OB transcriptome as a prognostic tool for human rare bone diseases to explore the hidden pathophysiology of craniofacial malformations, among the most prevalent congenital defects in humans.

Oral health-related quality of life in patients with X-linked hypophosphatemia: a qualitative exploration

INTRODUCTION

X-linked hypophosphatemia (XLH) is a rare, hereditary, and lifelong phosphate-wasting disorder characterized by rickets in childhood and impaired teeth mineralization. In the oral cavity, spontaneous abscesses can often occur without any clinical signs of alteration of the causal tooth. The objective of our study was to evaluate the oral care pathway and the oral health-related quality of life (OHRQoL) of patients following in an expert oral medicine department located within a Parisian hospital and working in close collaboration with an endocrinology department expert in this pathology.

METHODS

This study employed a qualitative descriptive design including semi-structured interviews using guiding themes.

RESULTS

Twenty-one patients were included in the study. The topics brought up exceeded the initial objectives as the patients mostly addressed the alteration of their oral health-related and general quality of life; a very chaotic oral health care pathway with oral health professionals not aware of their pathology; consequences on their social, professional, and school integration. Patients declared the importance of having a multidisciplinary team around them, including medical and dental professionals.

CONCLUSIONS

The variety of manifestations in patients with XLH necessitates high coordination of multidisciplinary patient care to optimize quality of life and reduce disease burden. Oral health care pathways are very chaotic for patients who have difficulty in finding professionals with sufficient knowledge of the disease. OHRQoL is therefore diminished. This situation improves when patients enter a coordinated care network.

Factors and Mechanisms Involved in Acquired Developmental Defects of Enamel: A Scoping Review

BACKGROUND

Developmental Defects of Enamel (DDE) is a pathology of the teeth that can greatly alter the quality of life of patients (hypersensitivity, esthetic issues, loss of function, etc.). The acquired DDE may occur as a result of a wide range of acquired etiological factors and his prevalence of this pathology may reach up to 89.9%. The main objective of this research was to identify and analyze, in current literature, the factors related to acquired DDE, in order to propose a general theory about the mechanisms involved.

METHODS

The search of the primary literature was conducted until [December 31, 2021]. Our search strategy uses the Pubmed/MEDLINE database and was structured around 3 terms ["Development," "Defect," and "Enamel"]. To be included, references had to be primary studies, written in English. Exclusion criteria were reviews, in vitro, animal, genetic or archeology studies, and studies focused on clinical management of DDE. One hundred and twenty three articles were included in this scoping review: 4 Randomized clinical trials, 1 letter, 5 cases reports, 2 fundamentals studies, and 111 observational studies (33 Cross-sectional studies, 68 Cohort study and 10 Case-control study). The quality of evidence was assessed using the PEDro scale for clinical trials, the Newcastle-Ottawa scale for observational studies, and a published tool to assess the quality of case reports and case series.

RESULTS

A scoping review of the literature identified 114 factors potentially involved in acquired DDE. The most frequently encountered pathologies are those causing a disorder of calcium homeostasis or a perturbation of the ARNT pathway in mother or child. The link between the ARNT pathway and metabolism deficiency in uncertain and needs to be defined. Also, the implication of this mechanism in tissue impairment is still unclear and needs to be explored.

CONCLUSIONS

By identifying and grouping the risk factors cited in the literature, this taxonomy and the hypotheses related to the mechanism allow health practitioners to adopt behaviors that limit the risk of developing aDDE and to set up a prevention of dental pathology. In addition, by reviewing the current literature, this work provides guidance for basic research, clinical studies, and literature searches.

Oro-dental features in Egyptian patients with familial mediterranean fever

INTRODUCTION

Familial Mediterranean fever (FMF) is an episodic inflammatory disease that is inherited as an autosomal recessive trait. It is primarily featured by fever, pain in joints, chest, and abdomen due to Serositis.

AIM

This study delineated the oro-facial structures presented associated with FMF, as well as, the determination of the potential influences of the long-term inflammatory process of FMF on several oral structures.

METHODS

Fifty eight Egyptian FMF patients were examined to define different oro-facial structures. Serum amyloid A (SAA) was requested for the selected patients, MEFV gene mutation was also investigated.

RESULTS

The clinical examination revealed peritonitis in 79%, fever in 63.7%, and arthritis in 55% of FMF patients examined, while, oral features as high arched palate, enamel defect, dental malocclusion, and macroglossia in 32%, 27.5%. 26%, and 13.5%, respectively. The previous symptoms might be attributed to the pathology of the disease. Macroglossia when tested versus SAA levels, a highly significant difference was detected. The ROC curve when examining the SAA value to assess macroglossia, displayed reasonable sensitivity and specificity values of, 87.5% and 77.8%, respectively.

CONCLUSION

The noticed oro-dental in FMF patients might be influenced by the chronic inflammatory process.

TSPEAR variants are primarily associated with ectodermal dysplasia and tooth agenesis but not hearing loss: A novel cohort study

Biallelic loss‐of‐function variants in the thrombospondin‐type laminin G domain and epilepsy‐associated repeats (TSPEAR) gene have recently been associated with ectodermal dysplasia and hearing loss. The first reports describing a TSPEAR disease association identified this gene is a cause of nonsyndromic hearing loss, but subsequent reports involving additional affected families have questioned this evidence and suggested a stronger association with ectodermal dysplasia. To clarify genotype–phenotype associations for TSPEAR variants, we characterized 13 individuals with biallelic TSPEAR variants. Individuals underwent either exome sequencing or panel‐based genetic testing. Nearly all of these newly reported individuals (11/13) have phenotypes that include tooth agenesis or ectodermal dysplasia, while three newly reported individuals have hearing loss. Of the individuals displaying hearing loss, all have additional variants in other hearing‐loss‐associated genes, specifically TMPRSS3, GJB2, and GJB6, that present competing candidates for their hearing loss phenotype. When presented alongside previous reports, the overall evidence supports the association of TSPEAR variants with ectodermal dysplasia and tooth agenesis features but creates significant doubt as to whether TSPEAR variants are a monogenic cause of hearing loss. Further functional evidence is needed to evaluate this phenotypic association.

Nestin and dental pulp stones - a case report-driven hypothesis

The dental pulp stem cells (DPSCs) are mesenchymal stem/stromal cells (MSCs) with multilineage potential of differentiation. Different studies investigated dental pulp stones (PS), the calcified masses in the dental pulp, in regard to their prevalence, topography and structure. The etiology of PS is still unclear and, to our knowledge, the DPSCs were not attributed yet specific roles in PS formation. We report here an immunohistochemical study of a PS-embedding dental pulp from an impacted third mandibular molar of an adult patient, in which we used antibodies against CD34, Ki67, glial fibrillary acidic protein (GFAP), α-smooth muscle actin (α-SMA) and nestin. While endothelial cells expressed CD34 and pericytes or vascular smooth muscle cells expressed α-SMA, DPSCs and the osteoblasts coating the PS were exclusively labeled with nestin antibody. Stromal networks of nestin-expressing DPSCs were regarded as in situ providers of osteogenic progenitors involved in PS formation. Further experimental studies, with larger lots of tissue samples, as well as extended panels of markers, are needed in order to elucidate the DPSC hypothesis in the PS etiology.

The external phenotype of aging

Aging is widely studied as a physiological process. Segmental aging can also occur prematurely in Mendelian disorders, and these can act this way as excellent sources of information, specifically for the underlying mechanisms. Adequate recognition of such aging characteristics in Mendelian disorders needs a well-defined phenotype of aging. Here the external phenotype of aging is described that can be recognized in the consulting room without major additional studies. Existing definitions of the signs and symptoms in Elements of Morphology or Human Phenotype Ontology are added or a new definition is suggested if none is available.

Primary Immunodeficiencies With Defects in Innate Immunity: Focus on Orofacial Manifestations

The field of primary immunodeficiencies (PIDs) is rapidly evolving. Indeed, the number of described diseases is constantly increasing thanks to the rapid identification of novel genetic defects by next-generation sequencing. PIDs are now rather referred to as “inborn errors of immunity” due to the association between a wide range of immune dysregulation-related clinical features and the “prototypic” increased infection susceptibility. The phenotypic spectrum of PIDs is therefore very large and includes several orofacial features. However, the latter are often overshadowed by severe systemic manifestations and remain underdiagnosed. Patients with impaired innate immunity are predisposed to a variety of oral manifestations including oral infections (e.g., candidiasis, herpes gingivostomatitis), aphthous ulcers, and severe periodontal diseases. Although less frequently, they can also show orofacial developmental abnormalities. Oral lesions can even represent the main clinical manifestation of some PIDs or be inaugural, being therefore one of the first features indicating the existence of an underlying immune defect. The aim of this review is to describe the orofacial features associated with the different PIDs of innate immunity based on the new 2019 classification from the International Union of Immunological Societies (IUIS) expert committee. This review highlights the important role played by the dentist, in close collaboration with the multidisciplinary medical team, in the management and the diagnostic of these conditions.

Heimler Syndrome

Heimler syndrome is a rare syndrome associating sensorineural hearing loss with retinal dystrophy and amelogenesis imperfecta due to PEX1 or PEX6 biallelic pathogenic variations. This syndrome is one of the less severe forms of peroxisome biogenesis disorders. In this chapter, we will review clinical, biological, and genetic knowledges about the Heimler syndrome.

Dental anomalies and orthodontic characteristics in patients with pseudohypoparathyroidism

Background

Pseudohypoparathyroidism (PHP) is a rare and inherited disease caused by mutations in the GNAS-gene or upstream of the GNAS complex locus. It is characterized by end-organ resistance to PTH, resulting in hypocalcemia and hyperphosphatemia. We aimed to investigate the dental anomalies according to tooth types and the orthodontic characteristics of patients with PHP.

Methods

Using a cross-sectional design, 29 patients (23 females) with PHP, living in Denmark, were included, and their clinical intraoral photos and radiographs were examined.

Results

Pulp calcification was found in 76% of the patients. Blunting of root apex was present in 55% and shortening of root in 48% of the examined patients. Blunting and shortening of roots were seen more often in premolars than in other tooth types (p_both < 0.01). Crowding of lower anterior teeth was frequently observed (36%) as well as diastema in the upper arch (25%), midline diastema (18%), and Class III malocclusion (11%).

Conclusion

In the present study population, the teeth were frequently affected by pulp calcification and/or deviation of the root morphology. Blunting and shortening of root(s) were more often seen in premolars than in other tooth types. Class III malocclusion was relatively prevalent. It is important to pay attention to dental anomalies and occlusion in order to provide adequate care for patients with PHP.