Failure of eruption of permanent molars: a diagnostic dilemma

Etiological Mechanisms and Genetic/Biological Modulation Related to PTH1R in Primary Failure of Tooth Eruption

Primary failure of eruption (PFE) is a rare disorder that is characterized by the inability of a molar tooth/teeth to erupt to the occlusal plane or to normally react to orthodontic force. This condition is related to hereditary factors and has been extensively researched over many years. However, the etiological mechanisms of pathogenesis are still not fully understood. Evidence from studies on PFE cases has shown that PFE patients may carry parathyroid hormone 1 receptor (PTH1R) gene mutations, and genetic detection can be used to diagnose PFE at an early stage. PTH1R variants can lead to altered protein structure, impaired protein function, and abnormal biological activities of the cells, which may ultimately impact the behavior of teeth, as observed in PFE. Dental follicle cells play a critical role in tooth eruption and root development and are regulated by parathyroid hormone-related peptide (PTHrP)-PTH1R signaling in their differentiation and other activities. PTHrP-PTH1R signaling also regulates the activity of osteoblasts, osteoclasts and odontoclasts during tooth development and eruption. When interference occurs in the PTHrP-PTH1R signaling pathway, the normal function of dental follicles and bone remodeling are impaired. This review provides an overview of PTH1R variants and their correlation with PFE, and highlights that a disruption of PTHrP-PTH1R signaling impairs the normal process of tooth development and eruption, thus providing insight into the underlying mechanisms related to PTH1R and its role in driving PFE.

Metabolic Bone Diseases Affecting Tooth Eruption: A Narrative Review

Tooth eruption is an essential process for the development of the oral and maxillofacial system. Several inherited and acquired diseases might affect this tightly regulated process, resulting in premature, delayed, or even failed tooth eruption. The purpose of this article is to review the literature and the clinical parameters of metabolic bone diseases that affect tooth eruption. It examines the physiological aspects of tooth eruption and the pathophysiological changes induced by metabolic bone diseases, including changes in bone metabolism, density, and structure. The search strategy for this review included an electronic search in PubMed, Google Scholar, Medline, Scopus, and the Cochrane Library using the following keywords: "metabolic bone diseases", "tooth eruption", "delayed tooth eruption", and each reported disease in combination with "tooth eruption disorders", covering publications up to March 2024 and limited to English-language sources. Understanding the influence of metabolic bone diseases on tooth eruption is crucial for managing both dental and skeletal manifestations associated with these disorders. This review suggests that a multidisciplinary approach to treatment may significantly improve oral outcomes for patients suffering from such conditions. Clinicians should be aware of the specific dental abnormalities that may arise and consider comprehensive evaluations and individualized treatment plans. These findings underscore the need for further research into targeted therapies that address these abnormalities.

TMEM119 (c.G143A, p.S48L) Mutation Is Involved in Primary Failure of Eruption by Attenuating Glycolysis-Mediated Osteogenesis

Primary failure of eruption (PFE) is a rare oral disease with an incidence rate of 0.06%. It is characterized by abnormal eruption mechanisms that disrupt tooth eruption. The underlying pathogenic genetic variant and mechanism of PFE remain largely unknown. The purpose of this study was to explore the role of a novel transmembrane protein 119 (TMEM119) mutation in two PFE patients in a Chinese family. Information collection was performed on the family with a diagnosis of PFE, and blood samples from patients and healthy family members were extracted. Whole-exome sequencing was performed. Bioinformatics analysis revealed that a heterozygous variant in the TMEM119 gene (c.G143A, p.S48L) was a disease-associated mutation in this family. Recombinant pcDNA3.1 plasmid-containing wild-type and mutant TMEM119 expression cassettes were successfully constructed and transfected into MC3T3-E1 cells, respectively. The results of in vitro analysis suggested that the subcellular distribution of the TMEM119 protein was transferred from the cell cytoplasm to the nucleus, and the ability of cells to proliferate and migrate as well as glycolytic and mineralized capacities were reduced after mutation. Furthermore, rescue assays showed that activating transcription factor 4 (ATF4) overexpression rescued the attenuated glycolysis and mineralization ability of cells. Results of in vivo analysis demonstrated that TMEM119 was mainly expressed in the alveolar bone around the mouse molar germs, and the expression level increased with tooth eruption, demonstrated using immunohistochemistry and immunofluorescence. Collectively, the novel TMEM119 mutation is potentially pathogenic in the PFE family by affecting the glucose metabolism and mineralized function of osteoblasts, including interaction with ATF4. Our findings broaden the gene mutation spectrum of PFE and further elucidate the pathogenic mechanism of PFE.

Primary Failure Eruption: Genetic Investigation, Diagnosis and Treatment: A Systematic Review

AIM

The aim of this systematic review is to explore the pathology, diagnosis, treatment, and genetic basis of Primary Failure of Eruption (PFE) in the field of pediatric dentistry and orthodontics.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed for this review. The databases PubMed, Science Direct, Scopus, and Web of Science were searched from 1 July 2013 to 1 July 2023, using keywords "primary failure of tooth eruption" OR "primary failure of eruption" OR "tooth eruption failure" OR "PFE" AND "orthodontics". The study selection process involved screening articles based on the inclusion and exclusion criteria.

RESULTS

A total of 1151 results were obtained from the database search, with 14 papers meeting the inclusion criteria. The review covers various aspects of PFE, including its clinical features, diagnosis, treatment options, and genetic associations with mutations in the PTH1R gene. Differentiation between PFE and Mechanical Failure of Eruption (MFE) is crucial for accurate treatment planning. Orthodontic and surgical interventions, along with multidisciplinary approaches, have been employed to manage PFE cases. Genetic testing for PTH1R mutations plays a significant role in confirming the diagnosis and guiding treatment decisions, although some cases may not be linked to this mutation.

CONCLUSIONS

This systematic review provides valuable insights into the diagnosis, treatment, and genetic basis of PFE. Early diagnosis and personalized treatment planning are crucial for successful management. Genetic testing for PTH1R mutations aids in accurate diagnosis and may influence treatment decisions. However, further research is needed to explore the complex genetic basis of PFE fully and improve treatment outcomes for affected individuals.

Identification of a novel PTH1R variant in a family with primary failure of eruption

BACKGROUND

Primary failure of tooth eruption (PFE) is a rare autosome genetic disorder that causes open bite. This work aimed to report a small family of PFE(OMIM: # 125,350) with a novel PTH1R variant. One of the patients has a rare clinical phenotype of the anterior tooth involved only.

CASE PRESENTATION

The proband was a 13-year-old young man with an incomplete eruption of the right upper anterior teeth, resulting in a significant open-bite. His left first molar partially erupted. Family history revealed that the proband's 12-year-old brother and father also had teeth eruption disorders. Genetic testing found a novel PTH1R variant (NM_000316.3 c.1325-1336del), which has never been reported before. The diagnosis of PFE was based on clinical and radiographic characteristics and the result of genetic testing. Bioinformatic analysis predicted this variant would result in the truncation of the G protein-coupled receptor encoded by the PTH1R, affecting its structure and function.

CONCLUSION

A novel PTH1R variant identified through whole-exome sequencing further expands the mutation spectrum of PFE. Patients in this family have different phenotypes, which reflects the characteristics of variable phenotypic expression of PFE.

Primary failure of tooth eruption: Etiology and management

Primary failure of eruption (PFE) is a rare disorder defined as incomplete tooth eruption despite the presence of a clear eruption pathway. PFE is known to be caused by rare variants in the parathyroid hormone 1 receptor gene (PTH1R). Although several PTH1R variants have been reported, the etiology of PFE remains unclear. However, important studies that help elucidate the pathology of PFE have recently been published. The purpose of this review is to summarize current treatment options, clinical symptoms or phenotypes for diagnosis, genetic information including solid evidence in mouse disease models and disease-specific induced pluripotent stem cells, thus approaching the etiology of PFE from the perspective of the latest research.

Eruption disturbances in the mixed dentition: orthodontic considerations for primary dental care

The primary dental care clinician is in a prime position to identify deviations from normal dental development. Disturbances can affect any new erupting tooth. The objective of this narrative review is to describe several situations in which eruption disturbances can arise during the mixed dentition. It will provide an overview of the orthodontic considerations of these disturbances in addition to key summary points on interceptive management, based on the best available evidence.

Review and case report of the treatment in a young girl with primary failure of eruption

Any localized non-eruption of teeth can be attributed to myriad of factors. A failure of a permanent tooth to erupt or cessation of initial eruption with no obvious local/systemic causative factor is said to be primary failure of eruption (PFE). The etio-pathogenesis of PFE is due to the mutation of PTH1R gene. Clinical features such as infra-occluded teeth, posterior open bite, lack of any cause or habit are usually attributed to diagnosing the condition, and a confirmatory diagnosis is done by the gene analysis of PTH1R gene. Treatment of such a condition is tricky as any application of orthodontic traction to teeth affected by PFE will not be successful and may cause ankylosis. This correspondence reviews and demonstrates the treatment of a case of PFE to restore function and esthetics to the best possible outcome.

Revisiting the human dental follicle: From tooth development to its association with unerupted or impacted teeth and pathological changes

Dental follicles are involved in odontogenesis, periodontogenesis, and tooth eruption. Dental follicles are unique structures, considering that their remnants can persist within the jawbones after odontogenesis throughout life if the tooth does not erupt. Pathological changes may occur in these tissues as individuals age. The changes range from benign to life threatening. Thus, the assessment of age-related changes in dental follicles associated with unerupted teeth is of paramount importance. In this review, we summarize the physiological roles and changes in dental follicles in odontogenesis, tooth eruption, and aging, in addition to the pathological changes associated with these structures. We encourage investigators to consider this peculiar tissue as a unique model and explore its potential to clarify its importance from the viewpoints of developmental biology, tissue physiology, and pathology.

Primary Retention of Molars and RANKL Signaling Alteration during Craniofacial Growth

The primary retention of molars observed in clinic corresponds to a still-unexplained absence of molar eruption despite the presence of an eruption pathway, resembling the experimental transient inhibition of RANKL signaling in mice. The aim of the present study was to confront the hypothesis according to which the primary retention of molars is associated with transitory perturbations to RANKL signaling during growth as part of a wider craniofacial skeleton pattern. The experimental strategy was based on combining a clinical study and an animal study corresponding to the characterization of the craniofacial phenotypes of patients with primary retention of molars and analyses in mice of the consequences of transient inhibition of RANKL signaling on molar eruption and craniofacial growth. The clinical study validated the existence of a particular craniofacial phenotype in patients with primary retention of molars: a retromandibular skeletal class II typology with reduced mandibular dimensions which manifests itself at the dental level by a class II/2 with palatoversion of the upper incisors and anterior overbite. The animal study demonstrated that transient invalidation of RANKL signaling had an impact on the molar eruption process, the severity of which was dependent on the period of inhibition and was associated with a reduction in two craniofacial morphometric parameters: total skull length and craniofacial vault length. In conclusion, primary retention of molars may be proposed as part of the craniofacial skeleton phenotype associated with a transitory alteration in RANKL signaling during growth.

Failure of eruption of first permanent molar teeth: a diagnostic challenge

Ankylosis, mechanical and primary failure of eruption of molar teeth are rare and often difficult to distinguish between. All may have significant repercussions on the occlusion and successful management may involve invasive procedures. We present a case where an initial presentation characteristic of mechanical failure of eruption (ankylosis) of a first permanent molar tooth was excluded following a period of monitoring. Subsequent relief of crowding using a removable and then sectional fixed orthodontic appliance allowed spontaneous eruption of the tooth obviating the need for surgical intervention. This case highlights the utilisation of conservative treatment options until a diagnosis was confirmed to minimise the risk of iatrogenic damage and unnecessary treatment.

Primary failure of eruption (PFE): a systematic review

BACKGROUND

Primary failure of eruption (PFE) is a rare disease defined as incomplete tooth eruption despite the presence of a clear eruption pathway. Orthodontic extrusion is not feasible in this case because it results in ankylosis of teeth. To the best of our knowledge, besides the study of Ahmad et al. (Eur J Orthod 28:535-540, 2006), no study has systematically analysed the clinical features of and factors associated with PFE. Therefore, the aim of this study was to systematically evaluate the current literature (from 2006 to 2017) for new insights and developments on the aetiology, diagnosis, genetics, and treatment options of PFE.

METHODS

Following the PRISMA guidelines, a systematic search was performed using the PubMed/Medline database for studies reporting on PFE. The following terms were used: "primary failure of tooth eruption", "primary failure of eruption", "tooth eruption failure", and "PFE".

RESULTS

Overall, 17 articles reporting clinical data of 314 patients were identified. In all patients, the molars were affected. In 81 reported cases, both the molars and the premolars were affected by PFE. Further, 38 patients' primary teeth were also affected. In 27 patients, no family members were affected. Additional dental anomalies were observed in 39 patients. A total of 51 different variants of the PTH1R gene associated with PFE were recorded.

CONCLUSIONS

Infraocclusion of the posterior teeth, especially if both sides are affected, is the hallmark of PFE. If a patient is affected by PFE, all teeth distal to the most mesial tooth are also affected by PFE. Primary teeth can also be impacted; however, this may not necessarily occur. If a patient is suspected of having PFE, a genetic test for mutation in the PTH1R gene should be recommended prior to any orthodontic treatment to avoid ankylosis. Treatment options depend on the patient's age and the clinical situation, and they must be evaluated individually.

The first permanent molar: spontaneous eruption after a five-year failure

BACKGROUND

It is rare for a first permanent molar (FPM) to temporarily exhibit clinical features of failure of eruption, followed by regeneration of full eruptive capacity 5 years later. Indeterminate failure of eruption (IFE) is a diagnosis of exclusion where the distinction between primary failure of eruption (PFE) and mechanical failure of eruption (MFE) is unclear, including patients too young to specify.

CASE REPORT

An 11-year-old girl attended the orthodontic clinic at Mid Yorkshire Hospitals NHS Trust regarding an unerupted lower right FPM. Her medical and dental trauma history was unremarkable. She presented with a Class II division 2 malocclusion in the mixed dentition, with all other FPMs fully erupted.

CONCLUSION

This report documents that an unerupted FPM in an 11-year-old patient may still have the eruptive potential to become functional within the dentition. The period spent monitoring the FPM's outcome prior to surgical intervention has avoided an operation under general anaesthetic and potentially unnecessary orthodontic treatment, as the tooth subsequently erupted without treatment.