Retrospective study of concomitant hypodontia and hyperdontia in 145 subjects.

OBJECTIVES: This study aims to investigate the incidence and clinical characteristics of concomitant hypodontia and hyperdontia (CHH) by performing panoramic radiographs. METHODS: A total of 41 648 panoramic radiographs of pediatric patients who were admitted to the hospitals from January 2019 to May 2021 were reviewed, and 145 CHH patients were included in the study. The presence of CHH was recorded. SPSS 24.0 software was used for statistical analysis. RESULTS: The prevalence of CHH was 0.35% (145/41 648). Males (102 cases) were obviously more than females (43 cases), and the difference between genders was statistically significant (P<0.001). The features of congenital permanent tooth loss in this group were predominantly 1 and 2 teeth missing and preferably mandibular lateral incisors and mandibular second premolars missing. The incidence of congenital permanent teeth loss was higher in the mandible than in the maxilla (P<0.001), but no difference was found in the distribution between left and right (P=0.84). The features of supernumerary teeth in this group were 1 and 2 teeth, mostly in the maxillary anterior area, mostly conical, mostly vertical inversion and orthotopic growth. CONCLUSIONS: CHH is a rare mixed numeric dental anomaly characterized by congenital missing teeth and supernumerary teeth occurring in the same individual. CHH cases are higher in men than in women. The characteristics of their hypodontia and hyperdontia are similar to those of patients with congenital permanent tooth absence or supernumerary teeth. Early diagnosis of the condition and a multidisciplinary approach for management of such case is recommended.

Agenesis of maxillary lateral incisors: diagnosis and treatment options.

INTRODUCTION: There are different possibilities of orthodontic planning for cases with congenital absence of maxillary lateral incisors. This subject divides the opinion of orthodontists and oral rehabilitation clinicians, due to the advantages and disadvantages of each treatment option, which may involve opening spaces for future implants and/or prosthetic restorations, or closing the spaces by positioning the maxillary canines in the place of lateral incisors. The correct diagnosis and careful evaluation of each patient allow to determine the best therapeutic approach. This paper discusses the main topics to be considered when planning these cases. OBJECTIVES: To evaluate the main aspects related to orthodontic treatment planning in cases of congenital absence of maxillary lateral incisors, to aid the decision-making, with clinical and scientific basis.

Agenesias dentárias atípicas: relato de caso clínico / Atypical dental agenesis: clinical case report

A agenesia dentaria é uma anomalia de desenvolvimento caracterizada pela determinação congênita de menor numero de dentes, podendo estar associada a síndromes genéticas ou ocorrer isoladamente. Embora seja considerada uma das anomalias mais frequentes quando envolve terceiros molares, segundo pré-molares e incisivos laterais, sua ocorrência em dentes estáveis, tais como o canino e o primeiro molar permanente é rara. Desta forma, este relato apresentará o caso de uma paciente do sexo feminino, 8 anos idade, que iniciou tratamento de rotina na Clínica de Odontopediatria da UNIFENAS. Na anamnese não foi relatada pela responsável a ocorrência de alterações sistêmicas, nem queixa ou histórico odontológico relevante. No exame clínico odontológico, notou-se o não irrompimento do primeiro molar permanente superior direito (16). Diante dos exames de imagem, foi confirmada a agenesia do dente 16 e também do canino permanente superior direito (13). A agenesia, sobretudo de dentes estáveis e relevantes no arco dentário, pode comprometer o desenvolvimento adequado da oclusão, mastigação, fonação e estética. Desta maneira, é importante o diagnóstico precoce desta ocorrência com o objetivo de favorecer a elaboração de um adequado plano de tratamento e, minimizar as sequelas destas agenesias atípicas(AU)

Dental agenesis is a developmental anomaly characterized by the congenital determination of fewer teeth, may be associated with genetic syndromes or occur in an isolated form. Although it is considered one of the most frequent anomalies when it involves third molars, second lateral premolars and incisors, the occurrence in stable teeth, such as the permanent canine and the permanent first molar is rare. This report will present the case of an 8-year-old female patient who started routine treatment at the Pediatric Dentistry Clinic of UNIFENAS. In the anamnesis, the responsible person did not report the occurrence of systemic alterations, or a relevant dental complaint or history. On dental clinical examination, it was noticed the non-rupture of the permament maxillar right first molar (16). In view of the imaging tests, the agenesis of tooth 16 and also of the permanent maxillary right canine (13) was confirmed. Agenesis, especially of stable and relevant teeth in the dental arch, may compromise the proper development of occlusion, chewing, phonation and aesthetics. Thus, it is of paramount importance to early diagnosis of this occurrence in order to favor the development of an appropriate treatment plan in order to minimize the sequelae of these atypical agenesis(AU)

Targeted next-generation sequencing (NGS) analysis of mutations in nonsyndromic tooth agenesis candidate genes : Analysis of a Turkish cohort.

PURPOSE: The goal of this study was to assess genes known to be associated with tooth agenesis with next-generation sequencing (NGS) and analyze the relationship between these mutations and tooth agenesis phenotypes. METHODS: The study included 49 individuals aged between 6 and 13 years. A total of 14 genes related to nonsyndromic tooth agenesis were selected for targeted NGS. Mutations in Msh homeobox 1 (MSX1), Wnt family member 10A (WNT10A), axis inhibition protein 2 (AXIN2), keratin 17 (KRT17), lipoprotein receptor 6 (LRP6), and secreted protein, acidic and rich in cysteine (SPARC)-related modular calcium-binding protein 2 (SMOC2) genes were investigated. RESULTS: Mutations in six genes were detected in 12 of 49 subjects. Fifteen variants were identified, including the unknown variants c.657G > C in MSX1, c.2029C > T in AXIN2, and c.1603A > T in LRP6. Second premolar tooth agenesis was observed in 43.3% of all tooth agenesis cases with mutations, and it was the predominant phenotype observed for each mutated gene, followed by tooth agenesis of the lateral incisors (20%). CONCLUSIONS: Variations in MSX1, WNT10A, AXIN2, KRT17, LRP6, and SMOC2 may be a risk factor for hypodontia or oligodontia in the Turkish population.

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.

Single median maxillary central incisor syndrome and variant in SMO gene associated with SHH pathway.

Solitary median maxillary central incisor syndrome (SMMCI) is a rare congenital oronasal-dental midline anomaly. The aim of this paper is a presentation of a patient with SMMCI without other visible dentofacial anomalies, with a potentially new molecular etiology consisting of a gene-gene reaction and conservative therapeutic approach to nasal obstruction. Potentially pathogenic variants in the SMO gene (p.Gly422Glu) and in P2RY13 gene (p.Trp205*) inherited from the probant's father, and in the PLD2 gene (p.Gln319fs), inherited from the mother were found. A multidisciplinary approach is necessary for the management of patients with SMMCI, including a genetic consultation with genetic tests.

Autosomal dominant mutation of MSX1 gene causing tooth and nail syndrome.

Tooth and Nail Syndrome or Nail Dysplasias with Hypodontiaor Witkop´s Syndrome is an autosomal dominant condition present at birth and improves by age. An early diagnosis is essential to avoid future functional, aesthetic, and psychological problems. Here we report two classic cases with brief clinical, radiological and genetic investigation along with a brief review of literature.

A novel mutation (c.1010G>T; p.R337L) in TP63 as a cause of split-hand/foot malformation with hypodontia.

BACKGROUND: Tumor protein p63 (TP63)-related disorders can be divided into at least six categories, including ectrodactyly-ectodermal dysplasia-cleft lip/palate syndrome 3 (EEC syndrome 3), ankyloblepharon-ectodermal defects-cleft lip/palate syndrome (AEC syndrome), acro-dermo-ungual-lacrimal-tooth syndrome (ADULT syndrome), limb-mammary syndrome (LMS), Rapp-Hodgkin syndrome (RHS) and split-hand/foot malformation 4 (SHFM4), and are all a result of heterozygous mutations of TP63. The phenotypes of TP63-related disorders broadly involve ectodermal dysplasias, acromelic malformation and orofacial cleft. SHFM and hypodontia are prominent clinical manifestations of TP63-related disorders. METHODS: The present study investigated a family with SHFM and hypodontia; determined the sequences of DLX5, WNT8B, WNT10B, BHLHA9, CDH3, DYNC1I1 and FGFR1; and performed single nucleotide polymorphism-array analysis. We detected the mutation by multiple sequence alignments and a bioinformatic prediction. RESULTS: We identified a novel missense mutation of TP63 (c.1010G>T; R337L) in the family without mutations of DLX5, WNT8B, WNT10B, BHLHA9, CDH3, DYNC1I1, FGFR1 and copy number variants causing SHFM. CONCLUSIONS: A mutation of TP63 (c.1010G>T; R337L) leads to SHFM with hypodontia. The identification of this mutation expands the spectrum of known TP63 mutations and also may contribute to novel approaches for the genetic diagnosis and counseling of families with TP63-related disorders.

The solitary median maxillary central incisor (SMMCI) syndrome: Associations, prenatal diagnosis, and outcomes.

Solitary median maxillary central incisor (SMMCI) syndrome is a complex disorder consisting of multiple, developmental defects involving midline structures of the head, which includes the cranial bones, the maxilla, and its container dentition (specifically the central incisor tooth germ), together with other midline structures of the body. SMMCI may appear as an isolated trait or in association with other midline developmental anomalies. We describe the case of a patient with SMMCI. He presented with a solitary median maxillary incisor, short stature, corpus callosum anomalies and a microform of holoprosencephaly (HPE), diabetes insipidus, and neurodevelopmental delay. The diagnosis was performed postnatally based on clinical features, radiological imaging, and a comprehensive genetic study. SMMCI can be diagnosed during the prenatal or neonatal periods or during infancy. Evaluation of the superior maxillary bone is important for prenatal diagnosis. Direct evaluation through bidimensional ultrasound or the use of multiplanar ultrasound or tridimensional reconstruction should be performed in cases of brain or face malformations. Early diagnosis can contribute to improved prenatal assessment and postnatal management.

A biallelic ANTXR1 variant expands the anthrax toxin receptor associated phenotype to tooth agenesis.

Tooth development is regulated by multiple genetic pathways, which ultimately drive the complex interactions between the oral epithelium and mesenchyme. Disruptions at any time point during this process may lead to failure of tooth development, also known as tooth agenesis (TA). TA is a common craniofacial abnormality in humans and represents the failure to develop one or more permanent teeth. Many genes and potentially subtle variants in these genes contribute to the TA phenotype. We report the clinical and genetic impact of a rare homozygous ANTXR1 variant (c.1312C>T), identified by whole exome sequencing (WES), in a consanguineous Turkish family with TA. Mutations in ANTXR1 have been associated with GAPO (growth retardation, alopecia, pseudoanodontia, and optic atrophy) syndrome and infantile hemangioma, however no clinical characteristics associated with these conditions were observed in our study family. We detected the expression of Antxr1 in oral and dental tissues of developing mouse embryos, further supporting a role for this gene in tooth development. Our findings implicate ANTXR1 as a candidate gene for isolated TA, suggest the involvement of specific hypomorphic alleles, and expand the previously known ANTXR1-associated phenotypes.

Pre-maxillary hypohyperdontia: a report of two cases.

BACKGROUND: Hypodontia and hyperdontia are considered to be at opposite ends of the dental development spectrum. Nevertheless, these anomalies may occur concomitantly (hypohyperdontia). CASE REPORT: This clinical report describes two case of hypohyperdontia occurring exclusively in the premaxillary region, and the difficulties associated with its diagnosis and management. Following 24 months of follow-up examinations, Case 1 developed a sequential supernumerary tooth in the tooth 35 region. CONCLUSION: Cases of hypohyperdontia can occur exclusively in the premaxillary region and may be difficult to diagnose. Multidisciplinary treatment planning is essential to facilitate appropriate management, and long-term follow-up is necessary as sequential supernumerary teeth may develop.