Second premolar agenesis as a subclinical phenotype of isolated cleft palate

Association between molar incisor hypomineralisation and tooth agenesis: a cross-sectional study in Brazilian children and adolescents

PURPOSE

The aim of the present was to assess the association between MIH and tooth agenesis (TA) in orthodontic patients from the Federal University of Rio Grande do Norte, Natal, Brazil.

METHODS

A cross-sectional study was performed to evaluate the presence of MIH and TA in a sample of 371 pretreatment orthodontic records from patients aged 9-18 years. Statistical analyses were performed using the Chi-square and Fisher's exact tests, and logistic regressions.

RESULTS

There was a statistically significant association between the prevalence of tooth agenesis and MIH. A higher percentage of third molar agenesis, maxillary premolar agenesis, and mandibular second premolar agenesis was observed among children with MIH-affected teeth. Patients with MIH had a 2.43 times greater chance of third molar agenesis, and a 5.88 times higher likelihood of mandibular premolar agenesis.

CONCLUSION

There is a weak association between MIH and TA. Furthermore, the presence of hypomineralised molars increases the risk of tooth agenesis.

A Genome-wide association study of premolar agenesis in a chinese population

OBJECTIVE

Premolar agenesis is a common subtype of tooth agenesis. Although a genome-wide study (GWAS) has identified some variants involved in tooth agenesis in Europeans, the genetic mutation related to premolar agenesis in the Chinese population remains unclear.

MATERIALS AND METHODS

We present a GWAS in 218 premolar agenesis cases and 1,222 controls using the Illumina Infinium^® Global Screening Array. 5,585,618 single nucleotide polymorphisms (SNPs) were used for tests of associations with premolar agenesis.

RESULTS

Four independent SNPs on chromosome 2 were identified as susceptibility loci, including rs147680216, rs79743039, rs60540881, and rs6738629. The genome-wide significant SNP rs147680216 (p = 6.09 × 10^-9 ) was predicted to change the structure of the WNT10A protein and interact with hedgehog signaling pathway components. Meta-analysis showed that the rs147680216 A allele significantly increased the risk of tooth agenesis (p = 0.000). The other three SNPs with nominal significance are novel susceptibility loci. Of them, rs6738629 (p = 5.40 × 10^-6 ) acts as a potential transcriptional regulator of GCC2, a gene playing a putative role in dental and craniofacial development.

CONCLUSION

Our GWAS indicates that rs147680216 and additional three novel susceptibility loci on chromosome 2 are associated with the risk of premolar agenesis in the Chinese population.

Dental anomalies frequency in submucous cleft palate versus complete cleft palate

BACKGROUND/OBJECTIVES

This retrospective study evaluated the prevalence of dental anomalies of number in different subphenotypes of isolated cleft palate.

MATERIALS/METHODS

The sample comprised 26 individuals with submucous cleft palate (group S) and 68 individuals with complete cleft palate (group C) aged between 9 and 12 years from a single centre. Panoramic radiographs were evaluated regarding the presence of dental anomalies of number in permanent teeth. Intergroup comparison was performed using chi-square tests (P < 0.05).

RESULTS

Tooth agenesis was found in 34.61 and 36.76 per cent of group S and group C, respectively. The most commonly missing teeth were the maxillary second premolar, maxillary lateral incisor, and mandibular second premolar. Supernumerary teeth were found in none and 1.47 per cent of the individuals with submucous and complete cleft palate, respectively. No statistically significant difference was found between groups for the frequency of tooth agenesis and supernumerary teeth.

LIMITATIONS

Only dental anomalies of number were evaluated.

CONCLUSIONS/IMPLICATIONS

Individuals with submucous and complete cleft palate showed similar prevalence for tooth agenesis and supernumerary teeth. Dental anomalies frequency seems not to be a discriminator for subphenotypes of cleft palate.

Patterns of dental anomalies in patients with nonsyndromic oral cleft

Aim: To characterize the patterns of dental anomalies (DA) in the mixed and permanent dentitions of patients with nonsyndromic oral cleft (NSOC). Methods: This cross-sectional, observational, case-control study included 173 patients, 61 with mixed dentition (NSOC=29 and control=32) and 112 with permanent dentition (NSOC=57 and control=55). All subjected were submitted to clinical and radiographic examination. Dental anomalies of eruption, number, size and shape outside the cleft area were considered. Results: Although there was no statistical significance among patients with mixed dentition, dental agenesis was the anomaly more common in this group. In patients with permanent dentition, a higher prevalence of DA in NSOC group compared to control group was observed (p=0.02). Gyroversion and dental agenesis were the DA more frequently observed in the permanent dentition and the second premolar was the tooth more affected (p=0.003). Mandible and the left side were more involved, and dental agenesis was more frequently found in patients with unilateral cleft lip with or without cleft palate (NSCL±P). Conclusion: Our findings show a higher frequency of DA in NSOCs than in the control group in patients with permanent dentition, mainly due to a higher occurrence of agenesis of second premolars in patients with unilateral NSCL±P.