Associations between tooth agenesis and displaced maxillary canines: a cross-sectional radiographic study

Association between agenesis of permanent teeth and other dental anomalies in nonsyndromic patients: Systematic review

BACKGROUND

Most cases of tooth agenesis are presented in the form of hypodontia with different patterns of missing teeth. In addition, there is a frequent clinical association between tooth agenesis and other anomalies.

OBJECTIVE

To systematically analyze the literature on the prevalence of agenesis of permanent teeth associated with other dental anomalies in nonsyndromic patients.

MATERIAL AND METHODS

An electronic search was performed in seven primary databases (Embase, LILACS, BBO, MedLine via PubMed, SciELO, Scopus, and Web of Science) and two additional ones (OATD, and ProQuest) to partially capture the "gray literature." The PECO strategy was used to identify observational studies evaluating the prevalence of agenesis of permanent teeth associated with other dental anomalies in nonsyndromic patients, without restrictions on publication language or year. Two reviewers extracted the data and assessed the individual risk of bias of the eligible studies using the JBI Critical Appraisal Tools for use in JBI Systematic Reviews - Checklist for Cross-sectional, Case-Control, and Cohort Studies.

RESULTS

The electronic search revealed 8659 records, seven of which met the eligibility criteria, and were included in the qualitative synthesis. The studies were published from 1961 to 2024. Patients with agenesis were more likely to present taurodontism, microdontia, enamel hypoplasia and distoangulation of the second premolar. Ectopic eruption, infraocclusion of the first deciduous molar and impacted tooth showed mixed results among the eligible studies.

CONCLUSION

Based on limited evidence, tooth agenesis was positively associated with the prevalence of other concomitant tooth agenesis.

Does Current Evidence Support the Discussion Around the Guidance Theory? A Systematic Review and Meta-Analysis on the Association Between Maxillary Lateral Incisor Agenesis and Displacement or Impaction of the Permanent Canine

Palatal impaction of the maxillary canine is commonly considered as a genetic condition, while the lateral incisor root has been suggested to guide maxillary permanent canine eruption. This review assessed whether agenesis of the maxillary lateral incisor is associated with eruption disturbances of the maxillary canine (displacement or impaction). Unrestricted searches in six databases for observational case-control human studies until May 2024 assessing eruption disturbances of the permanent maxillary canine in conjunction with permanent maxillary lateral incisor agenesis were performed. Study selection, data extraction and risk-of-bias assessment with the Joanna Briggs Institute's tool were performed in duplicate. Random-effects meta-analyses of odds ratios (ORs) with their 95% confidence intervals (CIs) were performed, followed by meta-regressions and sensitivity analyses. Seventeen reports pertaining to 17 case-control studies were included covering 10,155 patients (11.6 year-old/46% male on average). Maxillary lateral incisor agenesis was associated with eruption disturbance of the maxillary canine (17 studies; OR = 3.88; 95% CI = 2.05-7.34; p < 0.001; I 2 = 58). Lateral incisor agenesis was more associated with canine displacement (7 studies; OR = 7.56; 95% CI = 2.10-27.18; p = 0.008; I 2 = 57) and to a lesser degree with canine impaction (10 studies; OR = 2.39; 95% CI = 1.28-4.48; p = 0.01). No significant effects of patient age or sex were seen, and the results were robust to study design and precision. The quality of evidence was low due to the inclusion of observational case-control studies with methodological issues and residual confounding. Evidence indicates that permanent maxillary lateral incisor agenesis is associated with eruption disturbances of the permanent maxillary canine, including mainly displacement, but also impaction. Trial Registration: PROSPERO database number: CRD42024549898.

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

BACKGROUND

Mutations 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 METHODS

This 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.

RESULTS

The 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.

CONCLUSION

Our 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.

Prescription of panoramic radiographs in children using age-based prevalence of dental anomalies and pathologies

BACKGROUND

Panoramic radiographs (PRs) are used in the detection and diagnosis of developmental dental anomalies and pathologies (DDAPs) in children.

AIM

The primary objective of this observational cohort study was to evaluate the age-based prevalence of DDAP on PRs, whereas the secondary objective was to determine a threshold age for the detection of DDAP to provide supportive evidence for the prescription of PR in paediatric dental practice.

DESIGN

The study examined diagnostic PRs from 581 subjects aged 6 to 19 years. All PRs were reviewed by experienced, calibrated, masked examiners for the identification or presence of anomalies in size, shape, position, structure, and other developmental anomalies and pathologies (ODAP) of the face-neck region in a standardized condition. The data were statistically analyzed for interpretation.

RESULTS

Overall, 74% (n = 411) of the cohort had at least one anomaly (shape anomaly: 12%, number anomaly: 17%, positional anomaly: 28%, structural anomaly: 0%, and ODAP: 63%). The optimal Youden index cutoff for any anomaly was 9 years. Twelve and 15 years also showed predictive ability.

CONCLUSION

The results suggest that PRs should be prescribed at ages 9, 12, and 15 years for the diagnosis of DDAP.

Dental anomalies in an Albanian orthodontic sample: a retrospective study

BACKGROUND

To evaluate the prevalence and the distribution of dental anomalies in an Albanian orthodontic sample.

METHODS

For this retrospective study, a sample of panoramic radiographs (PR) of n. 779 (456 F and 323 M, mean age of 15.1 ± 5.5 years) Albanian subjects with no genetic syndromes or craniofacial malformations (e.g., cleft lip/palate), history of extraction, trauma or previous orthodontic treatment drawn from the archives of the University Dental Clinic Our Lady of Good Counsel, was examined. The inclusion criteria were: subjects from 8 to 30 years of age, good quality of PRs in order to allow the assessment of crown and root development. For different dental anomalies, both the prevalence and the association were evaluated by using Chi-square test (p < 0.05).

RESULTS

24.4% of the sample had at least one dental anomaly and 4.6% had more than one. The following dental anomalies were most prevalent: hypodontia (9.8%), dental impaction (7.6%), and ectopic eruption (5.3%). No statistically significant correlation was found between males and females (p > 0.05).

CONCLUSIONS

The most common anomalies in this group are found to be those of number and position, and only radiological investigations can reveal either of these anomalies. Early diagnosis of dental anomalies can contribute to prevent their complications and to establish the most suitable therapy to achieve a functional occlusion.

Family-based association study of genetic analysis of paired box gene 9 polymorphisms in the peg-shaped teeth in the Jordanian Arab population

OBJECTIVE

The aim of this study is to genotype thirteen Single Nucleotide Polymorphisms (SNPs) within the paired box gene 9 (PAX9) in 36 Jordanian Arab families with peg-shaped teeth, and also to investigate the association between the PAX9 gene and peg-shaped teeth disorder.

METHODS

Genomic DNA samples were extracted from families according to distinguished processes. Then, DNA was amplified by polymerase chain reaction technique (PCR) using specified primers for the exons of the PAX9 gene. In addition, single nucleotide polymorphisms analysis was conducted using the DNA sequencing genotyping method to identify specific single nucleotide polymorphisms in the PAX9 gene associated with peg-shaped teeth.

RESULTS

Thirteen single nucleotide polymorphisms in the PAX9 gene (Chromosome 14q13.3) were used; seven of them (rs104894467, rs104894469, rs28933373, rs28933970, rs28933971, rs28933972, and rs7143727) were non-polymorphic, and the other six were polymorphic (rs2073244, rs2073246, rs2295222, rs4904155, rs4904210, and rs12881240). Both rs12881240 and rs2295222 SNPs showed significant association with peg-shaped teeth disorder (P < 0.05). Moreover, the haplotype genetic analysis revealed that there is a genetic association with peg-shaped teeth disorder susceptibility (P < 0.05) in the Jordanian families of Arab descent.

CONCLUSION

Our findings exhibited significant variations compared to the data recorded from other countries.

Study of rs12532, rs8670 Polymorphism of Msh Homeobox 1 (MSX1), rs61754301, rs4904155 Polymorphism of Paired Box Gene 9 (PAX9), and rs2240308 Polymorphism of Axis Inhibitor Protein 2 (AXIN2) Genes in Nonsyndromic Hypodontia

The etiology of hypodontia is complex, in which both genetic and environmental factors can be related. The main objective of our study was to contribute to elucidating the genetic background of nonsyndromic hypodontia (NSH). In this order, we selected 97 NSH subjects (70 females and 27 males) from patients referred to orthodontic treatment, and we matched to each NSH subject a control by age and sex. DNA was obtained from epithelial cells from the oral mucosa. Genotyping of the PAX9 (rs4904155 and rs61754301), MSX1 (rs8670 and rs12532), and AXIN2 (rs2240308) SNPs was performed by using TaqMan SNP Genotyping Assays on a real-time PCR system. Single-nucleotide polymorphisms (SNPs) were studied for the whole NSH group and for frontal and lateral agenesis NSH subjects separately. Our results showed that the variant genotype (p=0.0008, OR = 2.9, 95% CI = 1.58–5.3) and variant T allele (p=0.0002, OR = 2.65, 95% CI = 1.6–4.39) of the MSX1 rs8670 SNP increased the risk of hypodontia in the studied population when the whole NSH group was compared with controls. The variant genotype of the MSX1 rs8670 SNP was the most frequent in frontal agenesis; meanwhile in the lateral agenesis NSH group, the AXIN2 rs2240308 SNP showed a higher frequency of the variant genotype, with a trend towards statistical significance. In conclusion, the results of the present study showed that the variant genotype and variant T allele of the MSX1 rs8670 SNP increased the risk of hypodontia in the studied population. The presence of the variant A allele of AXIN2 rs2240308 is associated with frontal agenesis but not with lateral agenesis.