Hypodontia Research Articles

Patterns of tooth agenesis in individuals with Down syndrome: A secondary analysis using the Tooth Agenesis Code.

Tooth agenesis (TA) is common in Down syndrome (DS). It is unknown whether this agenesis occurs in specific patterns, which is important regarding treatment planning and aetiological research. This study aimed to aggregate and analyze patterns of TA, excluding third molars, in individuals with DS using the tooth agenesis code (TAC). The study was designed as a secondary analysis, following STROSA guidelines. The search (MEDLINE-PubMed) and selection process resulted in six included studies encompassing 241 individuals with DS. TA data were systematically converted into TACs and analyzed per dentition, per jaw, and per tooth type. Symmetry was evaluated. The prediction was calculated for oligodontia. In the 155 cases with TA 86 distinct Overall-TAC patterns were identified. The most common patterns were bilateral maxillary lateral incisor agenesis (TAC002.002.000.000;10.3%), bilateral mandibular second premolar agenesis (TAC000.000.016.016;5.8%), and unilateral left maxillary lateral incisor agenesis (TAC000.002.000.000;5.2%). Symmetry in TA patterns was observed in 49.6% of TA cases in the maxilla and 52.3% in the mandible. The simultaneous absence of both mandibular central incisors had a large predictive value for oligodontia (OR12.44;95% CI:4.97-31.84; p<.001). Predominant TA patterns exist in DS. Observation of mandibular central incisor agenesis can promote early diagnosis of oligodontia in DS.

Etiology and clinical treatment strategies for second primary molars without permanent tooth germs

Congenital tooth agenesis is a type of craniofacial developmental anomaly with reduced number of teeth, which is caused by disturbances in tooth germ development. If the number of missing teeth is less than six (excluding the third molars), it is termed as hypodontia. The second premolars are most commonly affected. When the second premolars are missing, the second primary molars are more prone to suffer from retention, infraocclusion, caries, pulpitis, or periapical periodontitis. Without timely prevention and appropriate treatment, congenital loss of second premolars may cause adverse effects on the patients' tooth arrangement, occlusal function, craniofacial development, and even future prosthetic treatment. This review summarises the aetiological and diagnostic features of the agenesis of second premolars, and discusses the clinical considerations of retaining or extracting the second primary molars without permanent tooth germs, when the absence of permanent tooth germs is fully established or not, so as to provide references for dentists.

Next-generation sequencing applied to non-syndromic tooth agenesis: A systematic literature review

BackgroundTo explore the genetic profile of Non-Syndromic Tooth Agenesis (NSTA) detected by Next-Generation Sequencing (NGS). MethodsA systematic review exploring PubMed, ScienceDirect, BMC, LILACS, Scopus, Embase and Web of Science was conducted. Studies investigating the genetic alterations involved in NSTA detected by NGS were selected. Data were extracted and risks of biases were evaluated. ResultsAfter screening 191 articles, 4 articles were included in this study. The overall qualities of the studies were considered high for 3 papers and low for the other one. Among 636 permanent missing teeth, second premolars and lateral incisors were the most affected ones. Whole exome sequencing and gene panel sequencing focusing either on exons plus exon-intron boundaries, or only exons were focused. Mutations on MSX1, PAX9, EDA, EDAR, AXIN2, WNT10A, LAMA3, DKK1, COL17A1, IRF6, LRP6, CHD7, CREBBP, EVC, LEF1, ROR2, TBX22, FGFR1 and TP63 were identified. Allelic frequencies of some variants were reported only in polish and Turkish populations and showing both slight and important variations. Moreover, Functional analysis was performed only for LRP6 variant in Turkish population. The published in-silico analyses of the proteins corresponding to the mutated LAMA3, MSX1 and WNT10 genes revealed a truncated protein for MSX1 and disulfide bridges destabilization for LAMA3 and WNT10A. ConclusionsSeveral genes were associated with NSTA and the candidacy of novel genes was suggested. Further research focusing on the exon-intron boundaries and the impact of mutations on the antisense transcripts should be carried out to better puzzle out their impact on the protein translation and structure.

Agenesis of all premolars – the first reported case

Abstract The agenesis of teeth is the most common developmental anomaly in humans. Although third molars, mandibular second premolars, maxillary lateral incisors and maxillary second premolars are frequently found to be missing, the absence of all premolars has never been reported in the literature. This case report highlights the first-ever case of the complete agenesis of premolars in a 10-year-old male patient. It also discusses related definitions; commonly missing teeth and their prevalence; associated dental and skeletal features; genetic, drug-related and pathogenic etiological factors; and considerations for the future management of such cases.

Ectopic Activation of Fgf8 in Dental Mesenchyme Causes Incisor Agenesis and Molar Microdontia.

Putatively, tooth agenesis was attributed to the initiation failure of tooth germs, though little is known about the histological and molecular alterations. To address if constitutively active FGF signaling is associated with tooth agenesis, we activated Fgf8 in dental mesenchyme with Osr-cre knock-in allele in mice (Osr2-creKI; Rosa26R-Fgf8) and found incisor agenesis and molar microdontia. The cell survival assay showed tremendous apoptosis in both the Osr2-creKI; Rosa26R-Fgf8 incisor epithelium and mesenchyme, which initiated incisor regression from cap stage. In situ hybridization displayed vanished Shh transcription, and immunostaining exhibited reduced Runx2 expression and enlarged mesenchymal Lef1 domain in Osr2-creKI; Rosa26R-Fgf8 incisors, both of which were suggested to enhance apoptosis. In contrast, Osr2-creKI; Rosa26R-Fgf8 molar germs displayed mildly suppressed Shh transcription, and the increased expression of Ectodin, Runx2 and Lef1. Although mildly smaller than WT controls prenatally, the Osr2-creKI; Rosa26R-Fgf8 molar germs produced a miniature tooth with impaired mineralization after a 6-week sub-renal culture. Intriguingly, the implanted Osr2-creKI; Rosa26R-Fgf8 molar germs exhibited delayed odontoblast differentiation and accelerated ameloblast maturation. Collectively, the ectopically activated Fgf8 in dental mesenchyme caused incisor agenesis by triggering incisor regression and postnatal molar microdontia. Our findings reported tooth agenesis resulting from the regression from the early bell stage and implicated a correlation between tooth agenesis and microdontia.

A novel WNT10A variant impairs the homeostasis of alveolar bone mesenchymal stem cells

AbstractObjectivesTo explore the influence of a novel WNT10A variant on bone mineral density, proliferation, and osteogenic differentiation capacities of alveolar bone mesenchymal stem cells in humans.Subjects and MethodsWhole‐exome sequencing and Sanger sequencing were utilized to detect gene variants in a family with non‐syndromic tooth agenesis (NSTA). The panoramic mandibular index was calculated on the proband with WNT10A variant and normal controls to evaluate bone mineral density. Alveolar bone mesenchymal stem cells from the proband with a novel WNT10A variant and normal controls were isolated and cultured, then proliferation and osteogenic differentiation capacities were evaluated and compared.ResultsWe identified a novel WNT10A pathogenic missense variant (c.353A &gt; G/p. Tyr118Cys) in a family with NSTA. The panoramic mandibular index of the proband implied a reduction in bone mineral density. Moreover, the proliferation and osteogenic differentiation capacities of alveolar bone mesenchymal stem cells from the proband with WNT10A Tyr118Cys variant were significantly decreased.ConclusionsOur findings broaden the spectrum of WNT10A variants in patients with non‐syndromic oligodontia, suggest an association between WNT10A and the proliferation and osteogenic differentiation of alveolar bone mesenchymal stem cells, and demonstrate that WNT10A is involved in maintaining jaw bone homeostasis.

Non-syndromic tooth agenesis in Latvian adolescent dental patients: a retrospective study with relevant literature review

AimTo investigate the prevalence of tooth agenesis and associated dental anomalies in Latvian adolescent dental patients and compare it to other European countries.DesignCross-sectional study of 2692 11-to-14-year-old patients (39.9% males and 60.1% females) attending Riga Stradins University Institute of Stomatology with panoramic radiographs taken between August 2020 and September 2021. Patients with any genetic syndromes were excluded. Data on tooth agenesis (excluding third molars) and other dental anomalies were recorded.ResultsThe prevalence of tooth agenesis in Latvian adolescent dental patients was 9.3% with no statistically significant difference between genders (χ2 test, p = 0.472). The most commonly missing teeth were mandibular second premolars, followed by upper lateral incisors and upper second premolars. There was a statistically significant association with the presence of other dental anomalies in tooth agenesis patients (p < 0.001).ConclusionsThis study found that the prevalence of non-syndromic tooth agenesis in Latvian adolescent dental patients was 9.3% with no statistically significant differences between the genders. Patients with tooth agenesis have a statistically significant possibility of the presence of other dental anomalies (p < 0.001).

Genetic Variants in KCTD1 Are Associated with Isolated Dental Anomalies.

KCTD1 plays crucial roles in regulating both the SHH and WNT/β-catenin signaling pathways, which are essential for tooth development. The objective of this study was to investigate if genetic variants in KCTD1 might also be associated with isolated dental anomalies. We clinically and radiographically investigated 362 patients affected with isolated dental anomalies. Whole exome sequencing identified two unrelated families with rare (p.Arg241Gln) or novel (p.Pro243Ser) variants in KCTD1. The variants segregated with the dental anomalies in all nine patients from the two families. Clinical findings of the patients included taurodontism, unseparated roots, long roots, tooth agenesis, a supernumerary tooth, torus palatinus, and torus mandibularis. The role of Kctd1 in root development is supported by our immunohistochemical study showing high expression of Kctd1 in Hertwig epithelial root sheath. The KCTD1 variants in our patients are the first variants found to be located in the C-terminal domain, which might disrupt protein-protein interactions and/or SUMOylation and subsequently result in aberrant WNT-SHH-BMP signaling and isolated dental anomalies. Functional studies on the p.Arg241Gln variant are consistent with an impact on β-catenin levels and canonical WNT signaling. This is the first report of the association of KCTD1 variants and isolated dental anomalies.

Orodental malformations associated with human MSX1 sequence variants

BackgroundMSX1 sequence variants have been known to cause human tooth agenesis (TA) with or without orofacial clefts. However, their roles during the whole processes of tooth development are not fully understood. This study aimed to characterize a 4-membered family with TA carrying a novel MSX1 pathogenic variant and investigate the disease mechanism. MethodsThe authors conducted whole exome analysis to define the disease-causing sequence variant. They performed microcomputed tomography, morphometric analyses, transcriptome profiling, and molecular characterization to study the affected teeth and the gene variant. ResultsThe authors identified an MSX1 pathogenic variant, p.Glu232∗, in affected family members with TA and concomitant orodental anomalies, namely, prominent maxillary labial frenum, central incisor diastema, median maxillary anterior alveolar cleft, tooth fusion, mandibular molar dysmorphology, thin dentin layer, and slender dental roots. MSX1-defective teeth were not apparently microdontic but had thin dentin layers. The mandibular molars showed a homeotic transformation to maxillary counterparts. Genes involved in extracellular matrix organization and dentinogenesis, such as DMP1 and MMP20, were downregulated in dental pulp tissues of MSX1-defective teeth. The p.Glu232∗-truncated MSX1 properly localized to the nucleus but partially lost its transactivation ability. Analyzing reported cases indicated that truncation sequence variants within the homeobox domain of MSX1 caused a more severe TA phenotype than those outside of the homeobox domain, probably due to dominant negativity compared with haploinsufficiency. ConclusionsThis study provides in vivo evidence that MSX1 contributes to developmental processes of various orodental tissues in humans. Practical ImplicationsClinically, hypertrophic labial frenum, incisor diastema, and median maxillary anterior alveolar cleft might be considered diagnostic for MSX1-associated TA.

Investigation of the fungiform papillae number in children with tooth number anomalies

ObjectiveThis cross-sectional study investigated the association between fungiform papillae (FP) numbers and tooth number anomalies in children, considering variables related to hypodontia and hyperdontia. The aim was to explore this association while adjusting for age and sex differences.Materials and methodsA total of 144 children (aged 8–10) were categorized into hypodontia (n = 48), hyperdontia (n = 48), and control groups (n = 48). Clinical and radiographic diagnoses were used to classify tooth number anomalies. Hypodontia was categorized by number and location, while hyperdontia was categorized by number, shape, and location. FP were assessed using the Denver Papillae Protocol. Data analyses were performed using NCSS software, with p < 0.05 considered statistically significant.ResultsThe hypodontia group (22.5 ± 8.4) exhibited significantly lower FP than the control group (30.4 ± 9.2) and the hyperdontia group (27.9 ± 7.8) (p < 0.0005, p = 0.003, respectively). No significant difference existed between the hyperdontia and control groups. FP numbers in hypodontia subgroups showed no significant differences based on teeth agenesis numbers or locations. Similarly, hyperdontia subgroup analyses revealed no significant differences in FP numbers based on supernumerary teeth shapes (supplemental, conical, tuberculoid, paramolar) or the numbers of supernumerary teeth.ConclusionsThe lower FP numbers in children with hypodontia suggested an association between teeth and FP number. However, the non-significant difference in FP numbers with hyperdontia underscored the complexity of tooth development, warranting further investigations.Clinical relevanceChildren with hypodontia may exhibit distinct FP numbers compared to those without tooth number anomalies.

Assessment of prevalence and distribution of congenital missing teeth among patients visiting tertiary care hospital: A radiographic study

IntroductionDental Agenesis is the usual developmental dental anomaly involving both primary and permanent dentition but most commonly it affects the permanent teeth. Genetic mutations in genes like MSX, PAX9,TGFA and AXIN2 are the likely primary contributors to tooth agenesis. Identifying the prevalence and distribution of congenital missing teeth allows for early detection and intervention which is crucial for preventing or mitigating potential dental issues that may arise due to missing teeth. Aim & objectivesTo assess the prevalence and distribution of congenitally missing teeth across different quadrants of the jaw among patients visiting to the Dental out patient department at Tertiary Care Centre of Lucknow city. Material & methodA Questionnaire and orthopantomogram based cross-sectional study was conducted on both male and female patients aged between 15 and 30 years, coming for evaluation of their dental health problems to the hospital. Written informed consent was obtained. ResultsThe overall prevalence of CMT was found to be 33.3 %. The significant difference was observed in proportion of CMT between Maxilla and Mandible sites (p = 0.008). Higher prevalence was in females compared to males for both maxillary and mandibular congenital missing teeth. (p = 0.020). ConclusionThe most common CMT were third molars followed by lateral incisors. The insights derived from the study would aid dental professional in gaining a deeper comprehension of tooth agenesis.

Identification of a novel de novo mutation in SOX4 for syndromic tooth agenesis.

Coffin-Siris Syndrome (CSS) is a congenital disorder characterized by delayed growth, dysmorphic facial features, hypoplastic nails and phalanges of the fifth digit, and dental abnormalities. Tooth agenesis has been reported in CSS patients, but the mechanisms regulating this syndromic tooth agenesis remain largely unknown. This study aims to identify the pathogenic mutation of CSS presenting tooth genesis and explore potential regulatory mechanisms. We utilized whole-exome sequencing to identify variants in a CSS patient, followed by Sanger validation. In silico analysis including conservation analysis, pathogenicity predictions, and 3D structural assessments were carried out. Additionally, single-cell RNA sequencing and fluorescence in situ hybridization (FISH) were applied to explore the spatio-temporal expression of Sox4 expression during murine tooth development. Weighted Gene Co-expression Network Analysis (WGCNA) was employed to examine the functional role of SOX4. A novel de novo SOX4 missense mutation (c.1255C > G, p.Leu419Val) was identified in a Chinese CSS patient exhibiting tooth agenesis. Single-cell RNA sequencing and FISH further verified high expression of Sox4 during murine tooth development, and WGCNA confirmed its central role in tooth development pathways. Enriched functions included cell-substrate junctions, focal adhesion, and RNA splicing. Our findings link a novel SOX4 mutation to syndromic tooth agenesis in CSS. This is the first report of SOX4 missense mutation causing syndromic tooth agenesis. This study not only enhances our understanding of the pathogenic mutation for syndromic tooth agenesis but also provides genetic diagnosis and potential therapeutic insights for syndromic tooth agenesis.

“Examining the link between tooth agenesis and papillary thyroid cancer: is there a risk factor?” Observational study

BackgroundMutations in one or multiple genes can lead to hypodontia and its characteristic features. Numerous studies have shown a strong genetic influence on the occurrence of hypodontia, and identified several genes, including AXIN2, EDA, FGF3, FGFR2, FGFR10, WNT10A, MSX1, and PAX9, that are directly associated with dental agenesis and carcinogenesis. The objective of this study was to investigate the occurrence and pattern of tooth agenesis, microdontia, and palatally displaced canine (PDC) in women diagnosed with papillary thyroid cancer (PTC), compared to a control group of women without any malignancy or thyroid disease.Materials and methodsThis case–control study was carried at the Department of Orthodontics, School of Dental Medicine University of Zagreb, and Department of Oncology and Nuclear Medicine Sestre Milosrdnice University Hospital Centre. The study involved a clinical examination and evaluation of dental status, panoramic X-ray analysis, and assessment of medical and family history of 116 female patients aged 20–40 with PTC, as well as 424 females in the control group who were of similar age.ResultsThe prevalence of hypodontia, microdontia, and PDC was statistically higher in women with PTC than in the control group. The prevalence rate of hypodontia was 11.3% in the experimental group and 3.5% in the control group. The experimental group showed a higher occurrence of missing upper lateral incisors, lower left central incisors, and all the third molars (except the upper left) compared to the control group. Women with PTC showed the prevalence of PDC significantly higher than the control group (3.5%, 0.7%, p = 0.002). The probability of hypodontia as a clinical finding increases 2.6 times, and microdontia occurs 7.7 times more frequently in women with PTC.ConclusionOur study suggests a possible link between odontogenesis and PTC. The absence of permanent teeth may increase the likelihood of PTC in women. Leveraging the age-7 orthopantomogram to identify women at high risk for PTC within a critical early detection window could significantly improve oral health outcomes and PTC prognosis through proactive interventions.

Identification and functional study of a novel variant of PAX9 causing tooth agenesis.

To search for pathogenic gene of a family with non-syndromic tooth agenesis, and explore the possible pathogenesis. A Chinese family with non-syndromic tooth agenesis was recruited and screened for the pathogenic variants by whole exome sequencing technology and co-segregation analysis. The subcellular localization of wild-type and mutant protein was detected by immunofluorescence assay. Cycloheximide chase assay was performed to examine the difference in degradation rate between mutant protein and wild-type one. Dual-luciferase reporter assays were conducted to explore the alterations of mutant protein in the regulation of downstream target genes. A novel missense variant of PAX9 (c.296C>A:p.A99D) was found in this family. Bioinformatics software showed β-return and the random coil were shortened in the p.A99D. The variant did not affect the subcellular localization of PAX9, but the degradation rate of p.A99D was accelerated (p < 0.05). p.A99D inhibited the activation of downstream target gene BMP4 (p < 0.05). This novel variant expands the pathogenic gene spectrum. The variant impaired the protein structure, accelerated the degradation of protein, and inhibited the activation of the downstream target gene BMP4, an upstream molecule in the TGF-β/BMP pathway, which may contribute to tooth agenesis in this family.

Agenesis of the permanent teeth in sub-Saharan Africans: Prevalence, patterns, interpretations

ObjectiveDental agenesis data in modern and premodern sub-Saharan Africans are presented by region, West, Central, East, and South, and by sex. Beyond characterizing the anomaly, comparisons are made with other populations and future work is encouraged. The findings should be of use to dental clinicians and anthropologists. MethodsAgenesis of the UI2, LI1, UP2, LP2, UM3, and LM3 was recorded in 52 discrete samples of mainly skeletal dentitions (n = 2162) from across the subcontinent. After dividing into temporal categories, regional pooling was effected for adequate sample sizes across the vast geographic area. Only adults were included to record M3 status. Analyses included 95% confidence intervals and chi-square comparisons by region and sex. ResultsOf 1668 modern individuals 2.3% have UI2-LP2 agenesis (CI 1.6–3.1%). Regional and sex differences are non-significant, though females are most affected. For M3s it is 7.0% (5.7–8.4%), with the Central region sample differing significantly from the East and South. Females again have greater prevalence, with the difference in the West significant. UI2-LP2 agenesis affects 0.6% of 494 premodern individuals (0.1–1.8%), while M3 agenesis is 8.5% (6.1–11.5%). None of these differences are significant. ConclusionsRates are toward the low end of global ranges, including 0.0–12.6% for UI2-LP2 from case reports, and 5.3–56.0% for M3 agenesis. With exceptions, generally insignificant inter-region differences imply that rates reasonably represent sub-Saharan peoples overall. Results will be of interest to anthropologists, but those related to risk factors, patterning, and prevalence may assist clinicians in tailoring treatment, while informing patients how this anomaly differs by population ancestry.

Tooth agenesis related to a novel KDF1 variant: A case report and literature review.

To investigate the role of Keratinocyte Differentiation Factor 1 (KDF1) in ectodermal dysplasia (ED) and nonsyndromic tooth agenesis (NSTA) and perform a literature review. Genome sequencing was used to identify genetic variants in a Thai, NSTA proband and validated through Sanger sequencing. Pathogenicity was assessed using ACMG guidelines, MetaRNN and AlphaMissense. A comprehensive review of KDF1/NSTA cases informed genotype-phenotype analysis of the proband. The proband revealed multiple missing teeth, caries and extensive periodontal disease. Deep phenotyping showed no signs of ED beyond tooth agenesis. The identified novel KDF1 variant, p.Ile243Leu, was classified as 'likely pathogenic' by ACMG and predicted as 'detrimental' by MetaRNN and AlphaMissense analyses. Atotal of 14 reviewed KDF1 cases revealed ED-associated variants (3 variants in 8patients) clustering in the region of amino acids 251-275, within the DUF4656 domain, while NSTA-causing variants (4 variants in 6 patients) were typically found in amino- or carboxy-termini to this region. KDF1/NSTA cases exhibited an average of 15 missing teeth, with a higher prevalence in the mandible. This study identifies a novel KDF1 variant-related NSTA in Thai people. The genotype-phenotype correlates suggest a distinctive pattern and tooth agenesis of KDF1-related NSTA.

Congenital Tooth Agenesis and Risk of Early-Onset Cancer

There is some evidence that tooth agenesis (congenital absence of 1 or more teeth) is associated with cancer risk, especially carcinomas of the colon and ovaries, but results of previous studies are conflicting, and associations have not yet been evaluated in a population-based setting. To examine the association between tooth agenesis and specific cancer types before 40 years of age. This population-based cohort study used linking data from nationwide registries in Denmark to assess all Danish live-born singletons born from January 1, 1977, to December 31, 2018, and followed up for up to 40 years. Data were analyzed from January through June 2023. Tooth agenesis as documented by the Danish Central Registry of Odontology (Danish municipal pediatric dental care) from January 1, 1988, to December 31, 2018, and from hospital encounters in the Danish National Patient Registry within the entire study period. The primary outcome was first cancer diagnosis before 40 years of age obtained from the Danish Cancer Registry. Associations between tooth agenesis and specific cancers were estimated by Cox proportional hazards regression as hazard ratios (HRs) with 95% CIs. Analyses were split into age groups: younger than 1 year, 1 to younger than 3 years, 3 to younger than 10 years, 10 to younger than 20 years, 20 to younger than 30 years, and 30 to younger than 40 years. Associations with nonsyndromic tooth agenesis were evaluated after exclusion of individuals with known syndromes. Among 2 501 715 included individuals (1 284 292 [51.3%] male), 70 288 (2.8%) had a diagnosis of tooth agenesis (mean [SD] age at diagnosis, 13.2 [4.1] years) and 26 308 (1.1%) had a diagnosis of early-onset cancer within the study period; 778 individuals had co-occurrence of tooth agenesis and cancer. Overall, tooth agenesis was positively associated with several cancer types, including neuroblastoma (age 1 to <3 years; HR, 4.20; 95% CI, 2.24-7.88), nephroblastoma (age 1 to <3 years; HR, 4.59; 95% CI, 2.37-8.91), hepatoblastoma (age 1 to <3 years; HR, 7.10; 95% CI, 2.70-18.68), osteosarcoma (age 10 to <20 years; HR, 2.19; 95% CI, 1.11-4.32), colorectal carcinomas (age 30 to <40 years; HR, 2.81; 95% CI, 1.38-5.71), and carcinomas of bladder (age 20 to <30 years; HR, 3.35; 95% CI, 1.35-8.30). This cohort study found associations between congenital tooth agenesis and several cancer types, from childhood to early adulthood. Further evaluation of these associations is needed to assess possible clinical implications.

Occlusal characteristics in modern humans with tooth agenesis

Non-syndromic permanent tooth agenesis affects a significant proportion of the population, especially if third molars are considered. Although tooth agenesis has been linked to a smaller craniofacial size, reduced facial convexity and a shorter skeletal face, the occlusal characteristics of individuals with tooth agenesis remain largely unexplored. Therefore, this study investigated potential associations between tooth agenesis and metric occlusal traits in 806 individuals (491 with 4.1 missing teeth per subject, including third molars, and 315 without any tooth agenesis). Dentoskeletal morphology was defined through anatomical landmarks on pre-treatment cephalometric radiographs. Multivariate regression models, adjusted for sex and age, showed that tooth agenesis was significantly associated with a reduced overjet, an increased interincisal angle, and shorter upper and lower dental arch lengths, but not with overbite. Moreover, apart from reduced tooth length and dentoalveolar effects, as the number of missing teeth increased the upper front teeth were progressively retruded according to the craniofacial complex and to the face. Thus, tooth agenesis has a substantial influence on dental and occlusal characteristics, as well as on the sagittal position and inclination of anterior teeth. These findings emphasize the necessity for personalized, multidisciplinary approaches in individuals with multiple agenesis to successfully meet treatment goals.

Awareness Dental Specialists about Different Treatment Modalities to Replace Congenitally Missing Lateral Incisors

Aims. The purpose of this study is to ascertain the dentists' and dental experts' knowledge of orthodontic closure vs. replacement as treatment options for congenitally missing lateral incisors. Methods. A cross-sectional study involving 185 dentists from several areas was carried out between September and October of 2023. A set of twenty-four multiple-choice questions was developed. Microsoft Excel 2010 was used for data collection, while SPSS version 26 was used for analysis utilising descriptive statistics and Chi-square tests. Results. A study of 185 questionnaires found that the majority of participants were general practitioners, with 56.6% working in private and government-funded clinics. Most participants exhibited an elevated incidence of lateral incisor tooth absence, a trend frequently identified through routine diagnostic procedures. A dentist with over ten years of experience identified a growing occurrence of lateral incisor tooth absence, calling for a specialised treatment approach. Participants generally preferred dental implants over orthodontics, fixed prostheses, and removable prostheses. Most general practitioners, oral surgeons, prosthodontists, and orthodontists preferred implant replacement for long-term aesthetic and functional results. The study found significantly those general practitioners and oral surgeons mostly stay updated on missing lateral incisor treatment through continuing education courses, while orthodontists and prosthodontists prefer reading professional journals. Conclusion. It is evident that the prevalence of tooth agenesis has increased, leading to a heightened demand for specialised dental treatment. Management of this anomaly requires comprehensive planning, considering self-consciousness, aesthetics, and malocclusion. The study emphasises the need for a multidisciplinary approach in the treatment of missing lateral incisors to ensure optimal outcomes.

Small RNAs and tooth development: The role of microRNAs in tooth agenesis and impaction

Background/purposeTooth development, or odontogenesis, is a complex process in which several molecular pathways play a key role. Recently, microRNAs, a class of approximately 20-nucleotide small RNA molecules that regulate gene expression, have been implicated in the odontogenesis process. This study aimed to assess the role of miRNAs in odontogenesis anomalies, specifically agenesis and impaction. Materials and methodsWe analyzed a manually curated list of 82 miRNAs associated with human odontogenesis, sourced from literature data. Employing two different approaches to validate findings, we conducted functional enrichment analysis to evaluate the cell pathways, diseases, and phenotypes enriched for those miRNAs. ResultsOur findings indicate that the analyzed miRNAs regulate pathways linked to tooth anomalies, including the TGFꞵ and Wnt signaling pathways, and those governing the pluripotency of stem cells, known to mediate various cellular processes, and interconnected with odontogenesis-related pathways. Furthermore, the analysis disclosed several pathways associated with tumors, including small cell lung and gastric cancer. These results were confirmed also by diseases and phenotypes enrichment evaluation. Moreover, cell network analysis disclosed that miRNAs are embedded and interconnected in networks associated with dental diseases and cancer development, thus confirming the functional enrichment analyses. ConclusionIn summary, our results offer a quantitative measure of the potential involvement of miRNAs in regulating pathways crucial for developmental processes, notably odontogenesis, and provide results suggesting potential association with oncogenesis processes as well.