Primary failure of tooth eruption: Etiology and management

Abnormal dental follicle cells: A crucial determinant in tooth eruption disorders (Review)

The dental follicle (DF) plays an indispensable role in tooth eruption by regulating bone remodeling through their influence on osteoblast and osteoclast activity. The process of tooth eruption involves a series of intricate regulatory mechanisms and signaling pathways. Disruption of the parathyroid hormone‑related protein (PTHrP) in the PTHrP‑PTHrP receptor signaling pathway inhibits osteoclast differentiation by DF cells (DFCs), thus resulting in obstructed tooth eruption. Furthermore, parathyroid hormone receptor‑1 mutations are linked to primary tooth eruption failure. Additionally, the Wnt/β‑catenin, TGF‑β, bone morphogenetic protein and Hedgehog signaling pathways have crucial roles in DFC involvement in tooth eruption. DFC signal loss or alteration inhibits osteoclast differentiation, affects osteoblast and cementoblast differentiation, and suppresses DFC proliferation, thus resulting in failed tooth eruptions. Abnormal tooth eruption is also associated with a range of systemic syndromes and genetic diseases, predominantly resulting from pathogenic gene mutations. Among these conditions, the following disorders arise due to genetic mutations that disrupt DFCs and impede proper tooth eruption: Cleidocranial dysplasia associated with Runt‑related gene 2 gene mutations; osteosclerosis caused by CLCN7 gene mutations; mucopolysaccharidosis type VI resulting from arylsulfatase B gene mutations; enamel renal syndrome due to FAM20A gene mutations; and dentin dysplasia caused by mutations in the VPS4B gene. In addition, regional odontodysplasia and multiple calcific hyperplastic DFs are involved in tooth eruption failure; however, they are not related to gene mutations. The specific mechanism for this effect requires further investigation. To the best of our knowledge, previous reviews have not comprehensively summarized the syndromes associated with DF abnormalities manifesting as abnormal tooth eruption. Therefore, the present review aims to consolidate the current knowledge on DFC signaling pathways implicated in abnormal tooth eruption, and their association with disorders of tooth eruption in genetic diseases and syndromes, thereby providing a valuable reference for future related research.

Abnormal dental phenotypes in GAPO syndrome: A descriptive study with a new ANTXR1 variant & insights on teeth eruption

Objective

GAPO syndrome is usually diagnosed clinically owing to its characteristic features of growth retardation, alopecia, pseudoanodontia, and ophthalmic anomalies. Pseudoanodontia describes the failure of eruption of the two sets of teeth in these patients. Thus, the abnormal dental phenotype is the emergence of a set or part of a set of dentitions.

Purpose

This study reports the physical, oro-dental, and molecular findings of two new sibs with GAPO syndrome and provides a description of the dental phenotype of one of the patients reported before.

Materials & Methods

The patients were subjected to full medical history taking and three generations-pedigree construction. They were phenotyped according to the elements of morphology: Standard terminology series. After parental consents were acquired, molecular analysis was carried out for the two sibs (Patient 1 & 2).

Results

These included a new gene variant associated with erupted teeth in GAPO syndrome and new clinical features. A new classification for the terminologies of eruption disturbances was suggested.

Conclusion

The study asserts the importance of oro-dental examination and follow-ups as dental updates may occur in these cases.

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 of Dental Eruption Due to Variants Parathyroid Hormone Receptor 1: Retrospective Study and Proposal of Guidelines Treatment

OBJECTIVE

Primary failure of eruption is characterized by a nonsyndromic defect in tooth eruption in the absence of mechanical obstruction. It is correlated to rare heterozygous variants in the parathyroid hormone receptor 1 gene. The management of primary failure of eruption is complex because many therapies are ineffective. The present study aimed to compare the clinical outcomes of our patients with the findings reported in the literature, and to propose a treatment guideline based on the literature and our experience.

METHODS

Retrospective study of patients affected by primary dental eruption failure in the department and analyse of the results and compare with those of the litterature.

RESULTS

Twelve patients belonging to 5 families (9 males, 3 females; 13-52 y old) diagnosed and treated in the maxillofacial surgery and stomatology department of the Lille University Hospital were included. All patients showed posterior tooth involvement, and most patients showed bilateral defects. None of the affected teeth had coronal alveolar bone, whereas 6 patients showed root resorption in the affected teeth. Genetic analyses, performed on 11 patients, identified a parathyroid hormone receptor 1 disease-causing variant in 7 of them (63%). Multidisciplinary treatment was required to rehabilitate these patients. Orthodontic interventions, even at an early age, are difficult in affected teeth, which are often blocked or have internal resorption. Moreover, retention of these affected teeth during growth leads to dentoskeletal malocclusions, requiring difficult surgical management in the long term. Therefore, early extraction of these teeth is frequently recommended once the diagnosis has been confirmed. An implant-borne prosthetic rehabilitation can then be achieved at the end of growth after correction of the jaw discrepancy. In case of a late diagnosis, other surgical or noninvasive techniques may be used depending on the clinical situation. Distraction osteogenesis or segmental osteotomy could be discussed for patients with mild phenotypes.

CONCLUSIONS

Early diagnosis of primary eruption defects is crucial to offer appropriate management as early as possible, and so to avoid late complicated treatments.

Rare Case of First Permanent Molar Primary Failure of Eruption with Agenesis of Premolars

Primary failure of eruption (PFE) is a rare non-syndromic condition involving total or partial non-eruption of posterior teeth in the absence of mechanical obstruction. This paper presents the case of a healthy girl referred at age 4 for asymmetry of the upper arch. Clinical examination confirmed a slight shift of the upper midline to the left, with no erupted teeth distal to the upper left canine and a left posterior open bite. Panoramic X-rays showed delayed intraosseous development of the lateral left upper teeth compared to the right side. Clinic and radiographic follow-up during the next 9 years showed that 26 had not erupted by almost 13 years of age, 27 had delayed development and an unusual shape, and there was an agenesis in 24 and 25. Genetic analysis using the PTH1R single-gene sequencing method did not detect any known disease-causing or rare pathogenic variants that could explain the patient's phenotype. Even when detected early, PFE raises difficult problems with regard to diagnosis and ortho-surgical treatment planning due to the impossibility of accurately predicting its evolution. Tooth agenesis on the same arch worsens the prognosis and adds challenges to planning the treatment. Close long-term follow-up and timely adjustment of the treatment plan in accordance with the evolution of the case are needed.

Identification of a novel heterozygous PTH1R variant in a Chinese family with incomplete penetrance

BACKGROUND

Mutations in PTH1R are associated with Jansen-type metaphyseal chondrodysplasia (JMC), Blomstrand osteochondrodysplasia (BOCD), Eiken syndrome, enchondroma, and primary failure of tooth eruption (PFE). Inheritance of the PTH1R gene can be either autosomal dominant or autosomal recessive, indicating the complexity of the gene. Our objective was to identify the phenotypic differences in members of a family with a novel PTH1R mutation.

METHODS

The proband was a 13-year, 6-month-old girl presenting with short stature, abnormal tooth eruption, skeletal dysplasia, and midface hypoplasia. The brother and father of the proband presented with short stature and abnormal tooth eruption. High-throughput sequencing was performed on the proband, and the variant was confirmed in the proband and other family members by Sanger sequencing. Amino acid sequence alignment was performed using ClustalX software. Three-dimensional structures were analyzed and displayed using the I-TASSER website and PyMOL software.

RESULTS

High-throughput genome sequencing and Sanger sequencing validation showed that the proband, her father, and her brother all carried the PTH1R (NM_000316) c.1393G>A (p.E465K) mutation. The c.1393G>A (p.E465K) mutation was novel, as it has not been reported in the literature database. According to the American College of Medical Genetics and Genomics (ACMG) guidelines, the p.E465K variant was considered to have uncertain significance. Biological information analysis demonstrated that this identified variant was highly conserved and highly likely pathogenic.

CONCLUSIONS

We identified a novel heterozygous mutation in the PTH1R gene leading to clinical manifestations with incomplete penetrance that expands the spectrum of known PTH1R mutations.

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.

Genotype-phenotype analysis of selective failure of tooth eruption-A systematic review

Tooth eruption is an important and unique biological process during craniofacial development. Both the genetic and environmental factors can interfere with this process. Here we aimed to find the failure pattern of tooth eruption among five genetic diseases. Both systematic review and meta-analysis were used to identify the genotype-phenotype associations of unerupted teeth. The meta-analysis was based on the characteristics of abnormal tooth eruption in 223 patients with the mutations in PTH1R, RUNX2, COL1A1/2, CLCN7, and FAM20A respectively. We found all the patients presented selective failure of tooth eruption (SFTE). Primary failure of eruption patients with PTH1R mutations showed primary or isolated SFTE1 in the first and second molars (59.3% and 52% respectively). RUNX2 related cleidocranial dysplasia usually had SFTE2 in canines and premolars, while COL1A1/2 related osteogenesis imperfecta mostly caused SFTE3 in the maxillary second molars (22.9%). In CLCN7 related osteopetrosis, the second molars and mandibular first molars were the most affected. While FAM20A related enamel renal syndrome most caused SFTE5 in the second molars (86.2%) and maxillary canines. In conclusion, the SFTE was the common characteristics of most genetic diseases with abnormal isolated or syndromic tooth eruption. The selective pattern of unerupted teeth was gene-dependent. Here we recommend SFTE to classify those genetic unerupted teeth and guide for precise molecular diagnosis and treatment.