Surgical Management of External Cervical Resorption Using Different Materials in Relation to the Bone Crest: A Case Report.

External cervical resorption is a condition that leads to the loss of hard dental tissues, including enamel, cementum, and dentin. Although it is an aggressive condition, its causes are not yet fully understood. The treatment of resorptions depends on their extent, location and the material used. When managing these lesions, the position of the bone crest and the ability of the periodontal tissue to adhere to the material after setting must be considered. This case report aims to demonstrate a clinical case of external cervical resorption which was treated by a proposed protocol that uses different dentin substitute restorative materials depending on the location of the resorptive area in relation to the bone crest. The success of this treatment depended on the correct use of materials and adequate tissue management. The combination of different materials has shown promising results in treating resorptions in both supra- and infra-osseous areas.

Treatment of Invasive Cervical Resorption in a Central Incisor by Intentional Replantation: A Case Report.

Invasive cervical resorption (ICR) is an aggressive pathological condition that can affect any permanent tooth. This process is characterized by replacement of the tooth structure with granulomatous fibrovascular or fibro-osseous tissue. Despite its asymptomatic nature, ICR can lead to tooth loss. This study reports a case of ICR in a 15-year-old boy with a history of dental trauma. The patient had a diagnosis of ICR in tooth #21. After considering the risks of an external surgical approach and exclusive endodontic treatment, intentional re-implantation combined with extraoral composite resin restoration and endodontic treatment was proposed. The procedure consisted of atraumatic tooth extraction, removal of granulomatous tissue, restoration of the cavity with composite resin, re-implantation of the tooth in the alveolus, and endodontic treatment. This approach resulted in satisfactory repair of the resorptive lesion observed in over 3 years of follow-up. This case highlights intentional re-implantation combined with appropriate endodontic treatment as a viable treatment option for ICR.

Genetic Testing as a Source of Information Driving Diagnosis and Therapeutic Plan in a Multidisciplinary Case.

In many cases, the etiopathogenesis of oral cavity diseases depends on the presence of variants in some genes. Being able to identify these variants defines the possibilities and limits of therapies. This multidisciplinary case describes several pathologies of the oral cavity in a young patient affected by type 1 diabetes. The patient presented with an impacted palatal canine. Further investigation revealed cervical root resorption of the upper right central incisor. Genetic testing was performed for interleukin, VDR receptor genes, and the evaluation of periodontopathogenic bacteria. The mutational analysis carried out for the VDR polymorphisms and the IL1A, IL1B, IL6, and IL10 polymorphisms showed the presence of pathogenetic variants. The results for bacterial load showed the presence of periodontal pathogenes. The first intervention was the intentional replantation of the incisor. The second intervention was the orthodontic recovery of the impacted canine, using light forces and a hybrid anchorage with a miniscrew. At the end of orthodontic treatment, a crack was found in the upper left first premolar, which was extracted. Throughout treatment, non-invasive periodontal interventions were performed periodically to control periodontal inflammation. This case is an example of the integration of genetic analyses into the multidisciplinary diagnostic pathway.

Resilience of the replacing dentition in adult reptiles.

The dentition is critical to animal survival and teeth are present in modern vertebrates including teleost fish, sharks, amphibians, mammals and reptiles. The developmental processes that give rise to teeth are not just preserved through evolution but also share high level of similarity with the embryogenesis of other ectodermal organs. In this review we go beyond the embryonic phase of tooth development to life-long tooth replacement. We will address the origins of successional teeth, the location of putative tissue-resident stem cells, how de novo tooth formation continues throughout life and how teeth are shed in a spatially and temporally controlled manner. We review the evidence that the dental epithelium, which is the earliest recognizable dental structure in the reptilian dentition, serves as a putative niche for tissue-resident epithelial stem cells and recent molecular findings from transcriptomics carried out in reptilian dentitions. We discuss how odontoclasts resorb the primary tooth allowing eruption of the successional tooth. The reptiles, particularly lizards, are emerging as some of the most accessible animals to study tooth replacement which has relevance to evolution of the dentition and human dental disorders.

Three-dimensional assessment of root changes after Le Fort I osteotomy.

The study aim was to assess the volumetric, linear, and morphological changes of the maxillary incisor, canine, and premolar roots following Le Fort I osteotomy. Sixty patients (585 teeth) were included retrospectively from among individuals who underwent combined orthodontics and orthognathic surgery. The study group comprised 30 patients who underwent orthodontics and one-piece Le Fort I osteotomy, while the control group consisted of 30 patients who underwent orthodontics and bilateral sagittal split osteotomy but no maxillary surgery. CBCT scans were obtained at four time points: preoperative, 6 months, 1 year, and 2 years postoperative. A fully automated three-dimensional evaluation protocol was utilized to assess root changes of the maxillary teeth. Significant differences in the apical and middle parts of the teeth were observed between the study and control groups at 1 and 2 years postoperative, with greater percentage changes in the study group (all P < 0.05). Greater root remodelling in the canines, first and second premolars was observed in the study group (all P < 0.005). Spearman correlation analysis indicated a positive relationship between root remodelling and maxillary advancement, with larger advancements contributing to increased root remodelling in the apical and middle root parts (both P < 0.05). These findings can be valuable for surgeons and orthodontists in evaluating root changes.

A large case-control study indicates a breed-specific predisposition to feline tooth resorption.

Tooth resorption (TR) is one of the most common dental diseases of cats. It is a painful condition leading to tooth loss. The etiology of TR remains unclear, but old age, breed, other oral and dental diseases, and environmental factors are suspected predisposing factors. In our study, we used part of the data from the extensive feline health online survey of 8115 Finnish cats. As TR is difficult to detect and as the feline health survey included diagnoses defined by both veterinarians and the owners, we limited our study to a subpopulation of cats diagnosed with oral or dental disease by a veterinarian and had dental examination or surgery under sedation (n=944). We utilized case-control study analysed by multivariable logistic regression to determine the risk factors and breed variation of feline TR. The 202 cats diagnosed with TR were defined as TR cases and the remaining 742 cats as controls. The frequency of veterinarian-diagnosed TR was 3.9% in the health survey data (316/8115) and 21% in the subpopulation (202/944). The risk of TR increased with age (14.7% in youngest and 25.3% in oldest age group). Our finding that TR was significantly associated with gingivitis or periodontitis in cats that had also calculus (OR: 2.49 and 3.70, respectively) suggests that inflammatory changes caused by calculus increase the risk of TR. We found that Cornish Rex, European, and Ragdoll are at higher risk for TR (OR: 2.44, 2.98 and 2.90, respectively). Exotic-Persians breed group had lower risk (OR: 0.28). TR was not observed in Turkish van or Devon Rex. The differences between breeds highlight a genetic contribution. In addition, female cats that had food available constantly had significantly less TR than female cats that had feeding times (OR: 0.44). The underlying reasons for this remain unexplained in our study.

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.

Pre-eruptive intramural resorption in unerupted teeth: a cone-beam computed tomography evaluation of prevalence and related factors.

OBJECTIVE: Pre-eruptive intramural resorption (PEIR) is defined as an abnormal, well-circumscribed radiolucency within the coronal dentin of the tooth, which is often overlooked in plain radiographs. This study aimed to investigate the prevalence of PEIR and its related factors using cone-beam computed tomography (CBCT). METHODS: CBCT images of 590 unerupted teeth were evaluated for the presence of PEIR, location of PEIR, number of lesions in the affected tooth, PEIR score, tooth angulation, tooth position, and pericoronal space. Binary logistic tests were used to analyze the association between the characteristics of PEIR and the patient's demographic data and related factors. RESULTS: The tooth prevalence of PEIR was 13.6% among unerupted teeth. However, it was noteworthy that 19.2% of the unerupted teeth with PEIR were planned to be kept. PEIR was significantly associated with transverse (p = 0.020), inverted-angulated (p = 0.035), and centrally-positioned teeth (p = 0.043). The severity of PEIR was more pronounced in teeth with distal (p = 0.019), lingual (p = 0.023), or inverted-angulated (p = 0.040) positions, and in the absence of pericoronal space (p = 0.036). CONCLUSION: PEIR should be suspected in transverse, inverted-angulated, centrally positioned unerupted teeth, particularly in molars, with no pericoronal space. Further monitoring through CBCT is recommended in such cases. CLINICAL RELEVANCE: The management of unerupted teeth does not always involve surgical removal. Instead, they could be utilized for artificial eruption or tooth transplantation. The present study emphasizes the significance of early detection of PEIR. Clinical recommendations for screening PEIR in unerupted teeth are also proposed, which can be applied to routine plain radiographs.

Prevalence of Tooth Resorptive Lesions in 120 Feline Dental Patients in Israel.

Tooth resorption (TR) is a common dental condition seen in domestic cats, with a reported prevalence of 29-37.5% in clinically healthy cats and 60.8-67% in cats presenting for dental problems. Radiological and medical records of 120 cats that underwent dental treatment at a private veterinary clinic in Israel between October 2015 and February 2023 were reviewed. Records in which full-mouth radiographs had been obtained were included in the study. Radiographs were screened for TR according to the AVDC classification. Teeth affected by TR were identified in 79/120 (66%) cats. The mean age of cats with TR and non-TR was 8.3 and 6.2 years, respectively. The median age of the TR and non-TR cat populations was 8 and 7 years, respectively. A correlation was found between the number of teeth affected per cat and the age in TR cats. Cats 10 years of age and older, had a TR prevalence of 83.3%. The teeth most commonly affected by TR (82.3%) were the mandibular fourth premolar teeth (308,408).

Cone-beam computed tomography-based investigation of pre-eruptive intracoronal resorption prevalence.

This retrospective study aimed to investigate the prevalence of pre-eruptive intracoronal resorption (PEIR) using cone-beam computed tomography (CBCT) and to explore the mechanism and characteristics of PEIR development. CBCT images of patients aged ≤ 20 years with unerupted teeth at Hiroshima University Hospital were collected. We examined 1530 patients with 10,576 unerupted teeth. Teeth with PEIR were identified for the detailed location and size of the PEIR in the crown using multiplanar reconstruction. The subject and tooth prevalence rates of PEIR were 1.96% and 0.31%, respectively. The teeth that were the most commonly affected by PEIR were mandibular third molars (3.09%). The prevalence of PEIR was significantly higher in females than in males, and higher in the mandible than in the maxilla. No significant difference between in the position of PEIR within the crown was observed. Moreover, CBCT imaging revealed the onset of PEIR in one case. This study demonstrated the prevalence of PEIR and identified statistically significant sex- and location-based differences. Furthermore, one case of CBCT imaging supports the hypothesis that the onset of PEIR was due to resorption after completion of the crown.

The Oral Microbiome across Oral Sites in Cats with Chronic Gingivostomatitis, Periodontal Disease, and Tooth Resorption Compared with Healthy Cats.

Feline chronic gingivostomatitis (FCGS) is a chronic mucosal and gingival inflammatory disease in which pathogenesis remains unclear. Interactions between the host inflammatory process, the host immune response, and the oral microbiome are implicated in this pathogenesis. To begin to understand this disease and the impact of the microbiome to host inflammatory disease states, we collected sterile noninvasive plaque biofilm samples from ten distinct sites within the oral cavity in cats with stomatitis (n = 12), healthy cats (n = 9), and cats with tooth resorption or periodontitis (n = 11). Analysis of full-length 16S rRNA gene sequences indicated that the microbiomes of cats with FCGS presented marked dysbiosis at multiple oral sites. Additionally, microbiome beta diversity varied with oral condition, indicating that stomatitis, periodontitis, and/or tooth resorption influence the microbiome differently. Lastly, we found that the microbiomes of swabs taken from the oral cavity were comparable to those taken from plaque using endodontic paper points, validating this as another sampling method. Collectively, our work furthers our understanding of the dysbiosis and composition of bacteria in the oral microbiome in FCGS, with hopes of contributing to the prevention, diagnosis, and treatment of this challenging condition in felines.

Dental health in Roman dogs: A pilot study using standardized examination methods.

OBJECTIVE: To utilize standardized clinical veterinary methods to analyze dental health in a series of Roman dog maxillae and mandibles and to compare results to modern clinical data. MATERIALS: 28 skulls of juvenile and adult dogs from three archaeological sites in Switzerland and Germany dating to the Roman period. METHODS: Standardized examination was carried out, which included metric radiographic assessment to diagnose oral pathology and estimate age at death. In one case, CT analysis was undertaken. RESULTS: The estimated average age at death was between three and four years old. Tooth fracture, periodontal disease, the presence of non-vital teeth, and brachycephalic skull form were found in the sample. Tooth resorption was unexpectedly noted. CONCLUSION: The study provides valuable insights into the dental health of dogs in the Roman era. Compared to modern dogs, Roman dogs examined in this study appear to have a shorter lifespan but display a high rate of pathological dental disease, while disease patterns were very similar to those of modern dogs. Dogs with pronounced brachycephalic features were found. SIGNIFICANCE: This pilot study is the first to use standardized clinical examination and recording techniques to assess dental health in dogs from archaeological contexts. It provides insight into the dental health of Roman era dogs and offers data upon which cross-populational studies can be initiated. LIMITATIONS: The sample size and geographic location of the archaeological sites were limited. SUGGESTIONS FOR FURTHER RESEARCH: Subsequent standardized studies, preferably in as many different Roman Empire regions as possible, are recommended.

Capillary gingival hemangioma in a cat.

A 12-year-old spayed female American short-haired cat presented with a palatal gingival mass located between the right maxillary third incisor and the canine teeth. The mass was dark red and had a narrow attachment to the gingival margin of the canine tooth. The mass was completely removed by marginal excision and the histopathological diagnosis was a capillary hemangioma. The mass did not relapse until 1 year later; however, the tooth was extracted because of cervical resorption of the right maxillary canine immediately adjacent to the mass resection site. This report presents a rare case of the gingival hemangioma in a cat and the possibility of a causal relationship between the occurrence of external cervical tooth resorption and hemangioma resection.

Widespread prevalence of Equine Odontoclastic Tooth Resorption and Hypercementosis detected in German Icelandic horse population: impact of anamnestic factors on etiology.

OBJECTIVE: To compare anamnestic factors in Equine Odontoclastic Tooth Resorption and Hypercementosis (EOTRH) in affected and nonaffected horses to detect risk factors for horses developing EOTRH. ANIMALS: A total of 154 Icelandic horses, aged 15 years and older, examined at 22 locations in Lower Saxony, Germany. The investigations took place from October 2020 to December 2021. METHODS: Anamnestic data were collected using an owner-completed questionnaire. Horses underwent a thorough physical examination and CBC. The rostral oral cavity was clinically examined, and intraoral radiographs of the incisors were taken. Clinical and radiographic findings were scored. Based on the results, the study population was separated into "EOTRH-affected" and "EOTRH-healthy" horses. Both groups were compared to identify differences within the anamnestic factors. In case of inconclusive findings, some horses were classified as "suspicious". RESULTS: The diagnosis of EOTRH was made in 72.2% (109/151) of horses. The risk of contracting the disease increased with the age of the horse (P = .004). In addition, there was a predisposition for male animals (P = .032). Feeding, keeping, and dental treatments showed no significant influence, while place of birth seemed to influence horses developing EOTRH (P = .017). CLINICAL RELEVANCE: The results highlight how widespread EOTRH is among the German Icelandic horse population and the need for raising awareness of EOTRH, as many horses were not suspected of having EOTRH beforehand. Moreover, numerous etiological propositions exist, but, to date, no studies have investigated their relevance.

Effect of applying intermittent force with and without vibration on orthodontic tooth movement.

PURPOSE: This study aimed to determine whether orthodontic tooth movement could be accelerated by applying an intermittent force protocol. It also examined the effect of applying additional vibrational forces on orthodontic tooth movement and root resorption rates. METHODS: This study included 24 patients (16 males and 8 females) who underwent orthodontic treatment involving first premolar extraction and distal movement of the canines in the maxilla. A Hycon device (Adenta GmbH, Gilching, Germany) was used for canine distalization in all patients. The patients were randomly divided into two groups: one group received 20 min of vibration per day using the AcceleDent device (OrthoAccel Technologies, Inc., Bellaire, TX, USA), while the other group received no vibration. In addition, a split-mouth design was used: an activation-only force protocol was applied on one side, and an intermittent activation-deactivation-activation (ADA) protocol was applied on the other. The duration required for complete canine tooth distalization on each side was calculated. In addition, the effect of vibration on the orthodontically induced root resorption was examined. RESULTS: The intermittent ADA protocol significantly accelerated orthodontic tooth movement compared to the activation-only protocol (p < 0.05). The application of additional vibration did not affect the orthodontic tooth movement rate (p > 0.05). CONCLUSIONS: Using a Hycon device and following an ADA protocol provided significantly faster canine distalization than the activation-only protocol (p < 0.05). This intermittent force method proved very effective in closing the spaces. However, vibration did not significantly affect the orthodontic tooth movement rate (p > 0.05).

Feline Tooth Resorption: A Description of the Severity of the Disease in Regard to Animal's Age, Sex, Breed and Clinical Presentation.

Feline tooth resorption (odontoclastic resorptive lesion) is a common and important issue in veterinary dentistry. This study aimed to analyse the disease's severity and correlation with clinical information in the population of feline patients in Poland in the area of Lower Silesia. An analysis of the clinical charts of 174 cats with dental problems, which were diagnosed as tooth resorption, was conducted. The gender and breed had no influence on the disease severity, but the disease progressed with age. The lesions were mostly encountered within the third and fourth maxillary premolars (107, 108, 207, 208) and mandibular molars (309, 409). No direct correlation was found between the presence or severity of the disease and the clinical signs of affected cats. The study shows that feline tooth resorption is a common issue in feline dentistry and should be taken into account in all cases of animals with any signs of oral disease, including gingivitis and/or dental plaque with preserved appetite. A careful intraoral radiographic examination is essential to avoid false negative results in ambiguous cases.

The prevalence of equine odontoclastic tooth resorption and hypercementosis and the role of interincisal angulation in disease severity in a representative cohort of horses in Switzerland.

INTRODUCTION: Equine odontoclastic tooth resorption and hypercementosis (EOTRH) is an increasingly diagnosed degenerative dental disease in aged horses. The primary aim of this retrospective study was to determine the prevalence of EOTRH in horses admitted to the Equine Hospital, University of Zurich, for dental procedures from 2004 to 2017. A secondary goal was to measure and compare interincisal angles on two-dimensional radiographs of horses with EOTRH to determine whether the interincisal angle is associated with age and severity of the disease. Radiographs were assessed for the presence of lysis and/or hypercementosis, and the number and position of the teeth affected were determined. Each tooth was also evaluated using the modified classification system introduced by Rehrl et al. (2018), in which stage 0 indicates no radiographic abnormalities and stage 3 denotes severe abnormalities. The overall stage was defined by the tooth with the most severe lesions. The interincisal angle was determined in horses that had suitable radiographs. The medical records of 838 horses admitted for dental procedures were evaluated, and 85 (10,1 %) had clinical evidence of EOTRH. The mean interincisal angle was 136,06 ° in horses with mild to moderate EOTRH and 135,10 ° (SD = 11,90 °) in severely affected patients. In conclusion, the angle measurements on lateral radiographs were highly reproducible. However, the interincisal angle was not associated with age or the severity of EOTRH. The interincisal angle and the disease pattern were not correlated.

INTRODUCTION: La résorption et l'hypercémentose odontoclastique des dents chez le cheval (EOTRH) est une maladie dentaire dégénérative de plus en plus diagnostiquée chez les animaux âgés. L'objectif principal de cette étude rétrospective était de déterminer la prévalence de l'EOTRH chez les chevaux admis à l'Hôpital équin de l'Université de Zurich pour des interventions dentaires entre 2014 et 2017. Un objectif secondaire était de mesurer et de comparer les angles inter-incisifs sur des radiographies bidimensionnelles de chevaux atteints d'EOTRH afin de déterminer si cet angle est associé à l'âge et à la gravité de la maladie. Les radiographies ont été évaluées pour la présence de lyse et/ou d'hypercémentose, et le nombre et la position des dents affectées ont été déterminés. Chaque dent a également été évaluée à l'aide du système de classification modifié introduit par Rehrl et al. (2018), dans lequel le stade 0 indique l'absence d'anomalies radiographiques et le stade 3 indique des anomalies graves. Le stade global a été défini par la dent présentant les lésions les plus sévères. L'angle inter-incisif a été déterminé chez les chevaux qui avaient des radiographies appropriées. Les dossiers médicaux de 838 chevaux admis pour des interventions dentaires ont été évalués et 85 (10,1 %) présentaient des signes cliniques d'EOTRH. L'angle inter-incisif moyen était de 136,06° chez les chevaux présentant une EOTRH légère à modérée et de 135,10° (écart-type = 11,90°) chez les patients gravement atteints. En conclusion, les mesures d'angle sur les radiographies latérales étaient très reproductibles. Cependant, l'angle inter-incisif n'était pas associé à l'âge ou à la sévérité de l'EOTRH. L'angle inter-incisif et le profil de la maladie n'étaient pas corrélés.

Lesões reabsortivas múltiplas em cão: relato de caso / Multiple resorptive lesions in dogs: case report

A lesão de reabsorção dentária consiste em um processo patológico que acomete elementos dentários permanentes, principalmente de animais adultos e idosos, e sua expressão na espécie canina vem aumentando. Etiologias diversas e não esclarecidas, associada ao subdiagnóstico por falta da realização de exames radiográficos na rotina e profissionais não especializados na área odontológica, tem permitido que injúrias na estrutura externa e interna do dente sofram processo reabsortivo por células clásticas. Frequentemente se confunde com a doença periodontal ou a ela está associada. O diagnóstico baseia-se nos achados clínicos e na radiografia intraoral. O tratamento depende do estágio da doença, sendo a exodontia a opção que devolve a qualidade de vida natural ao animal no longo prazo. O presente relato tem como objetivo descrever o caso de um cão da raça Dachshund, com seis anos de idade, inteiro, com queixa de halitose, disfagia, ptialismo, anorexia, desidratação, perda de peso, letargia, meneios de cabeça e espirros, e ao exame de imagem apresentava diversas lesões de reabsortivas, cujo tratamento periodontal promoveu remissão de todos os sinais clínicos e bem-estar ao paciente.

Tooth resorption injury consists of a pathological process that affects permanent dental elements, especially in adult and elderly animals, and its expression in the canine species has been increasing. Several and unclear etiologies, associated with underdiagnosis due to lack of routine radiographic examinations and professionals not specialized in the dental area, have allowed injuries to the external and internal structure of the tooth to undergo a resorptive process by cells clastic. It is often confused with or associated with periodontal disease. Diagnosis is based on clinical findings and intraoral radiography. The treatment depends on the stage of the disease, and tooth extraction is the option that returns the natural quality of life to the animal in the long term. The present report aims to describe the case of a six-year-old Dachshund dog, whole, complaining of halitosis, dysphagia, ptyalism, anorexia, dehydration, weight loss, lethargy, head sneezing and sneezing, and the imaging exam presented several resorptive lesions, whose periodontal treatment promoted remission of all clinical signs and well-being to the patient.

Early identification of a 12-bp tandem duplication in TNFRSF11A encoding receptor activator of nuclear factor-kappa B (RANK): Clinical characterization and response to bisphosphonate therapy.

INTRODUCTION: Ultra-rare mendelian osteolytic disorders caused by different length in-frame activating duplications within exon 1 of TNFRSF11A encoding receptor activator of nuclear factor-kappa B (RANK) comprise familial expansile osteolysis (FEO), expansile skeletal hyperphosphatasia (ESH), early-onset familial Paget's disease of bone (PDB2), juvenile Paget's disease 2 (JPD2), and panostotic expansile bone disease (PEBD). FEO typically presents with childhood-onset deafness followed by resorption of permanent dentition, and then appendicular bone pain, fractures, and deformities from progressive focal expansile osteolytic lesions emerging from a background of generalized high bone turnover. An 18-bp duplication in TNFRSF11A has been reported in all kindreds with FEO, whereas a 12-bp duplication was found in the young man with PEBD complicated by a massive jaw tumor. We report the clinical course and successful treatment with bisphosphonates of a girl with the 12-bp duplication yet a skeletal phenotype seemingly milder than PEBD. CASE PRESENTATION AND DISCUSSION: This 10-year-old girl presented for dental and orthodontic treatment and was found to have progressive external tooth root resorption. Speech delay was identified at age 18 months, and audiological evaluation showed both conductive and sensorineural hearing loss subsequently treated with a cochlear implant at age 3 years. Biochemical studies indicated increased bone turnover with elevated urinary N-telopeptide levels and serum alkaline phosphatase in the upper normal range. Low lumbar spine bone mineral density (BMD) was revealed by dual-energy X-ray absorptiometry, but whole-body Technetium-99 m bone scintigraphy was normal. Genetic testing identified the identical de novo 12-bp duplication within exon 1 of TNFRSF11A harbored by the young man with PEBD and massive jaw tumor. Bisphosphonate treatment, initiated with one dose of intravenous zoledronic acid that caused prolonged hypocalcemia, then comprised weekly oral alendronate that decreased bone turnover markers and normalized her BMD. CONCLUSION: Constitutive activation of RANK signaling should be considered a possible cause in any young person with rapid bone turnover, particularly in the context of early-onset deafness and/or root resorption of permanent teeth. Early diagnosis and anti-resorptive treatment, given judiciously to avoid sudden and prolonged hypocalcemia, may prevent further skeletal disease.

Primary failure of eruption: From molecular diagnosis to therapeutic management.

Introduction: Primary Failure of Eruption (PFE) is a rare condition affecting posterior teeth eruption resulting in a posterior open bite malocclusion. Differential diagnosis like ankylosis or mechanical eruption failure should be considered. For non-syndromic forms, mutations in PTH1R, and recently in KMT2C genes are the known etiologies. The aim of this work was to describe the variability of clinical presentations of PFE associated with pathogenic variants of PTHR1. Material and methods: Diagnosis of non-syndromic PFE has been suggested for three members of a single family. Clinical and radiological features were collected, and genetic analyses were performed. Results: The clinical phenotype (type and number of involved teeth, depth of bone inclusions, functional consequences) is variable within the family. Severe tooth resorptions were detected. A heterozygous substitution in PTH1R (NM_000316.3): c.899T > C was identified as a class 4 likely pathogenic variant. The multidisciplinary management is described involving oral biology, pediatric dentistry, orthodontics, oral surgery, and prosthodontics. Conclusion: In this study, we report a new PTH1R variant involved in a familial form of PFE with variable expressivity. Therapeutic care is complex and difficult to systematize, hence the lack of evidence-based recommendations and clinical guidelines.