RESUMO
BACKGROUND: Non-syndromic orofacial cleft (NSOC) is a complex phenotype, involving multiple genetic and environmental factors. Association studies exploring the genetic susceptibility to this prevalent oral malformation show variability of results in different populations. Using a candidate gene approach, we aimed to verify the role of four single-nucleotide polymorphisms (SNPs) in the susceptibility to NSOC in Portuguese patients. METHODS: A total of 254 non-consanguineous individuals of Portuguese were recruited, including 120 patients with NSOC and 134 controls. About 92% of these patients had non-syndromic cleft lip with or without cleft palate (NSCL/P) and 8% had only non-syndromic cleft palate (NSCP). SNPs in the MTHFR (rs1801133), IRF6 (rs642961), PAX7 (rs742071) and TP63 (rs9332461) genes were studied, using a real-time approach with TaqMan probes. Allelic, genotypic, dominant, recessive and over-dominant models were explored using a chi-squared test. Adjusted p-value was calculated for multiple comparisons using the Benjamini-Hochberg false discovery rate (FDR). RESULTS: All SNPs were in Hardy-Weinberg equilibrium. For MTHFR, IRF6, and PAX7 SNPs, no statistically significant difference was highlighted for any of the evaluated models. For TP63 SNP, data fitted an over-dominant model, with a protective effect for heterozygotes (OR 1.897; CI 95% [1.144-3.147]; p < .016, when comparing controls vs. cases), but significance was lost when applying adjusted p-value for multiple comparisons (4 × 5 tests). CONCLUSION: In this Portuguese population, there was no evidence of an association between the evaluated SNPs and NSOC. For TP63 SNP, the possibility of a protective effect of heterozygotes should be further investigated.
RESUMO
BACKGROUND: The use of CBCT exam in the study of IMC is not new. However, it's still not known in what specific aspects CBCT exam shows a better result than then conventional exams. The aim of this study was to compare and conclude in what way the opinion regarding upper canine impaction differed when observing a panoramic image compared to the observation of a set of CBCT reconstructions. MATERIAL AND METHODS: Twenty patients (10 males and 10 females) with a total of 28 impacted maxillary canines were identified from the database of the Department of Dentistry, Faculty of Medicine, University of Coimbra. For each canine, two different images were available: a panoramic image and a set of CBCT reconstructions. After a random distribution of both groups images, nine orthodontists completed a questionnaire where they were asked to evaluate ten different questions regarding canine impaction. Statistic analysis was performed using Cronbach's alpha statistics, Kappa statistics and McNemar test, considering p<0,05 statistically significant. RESULTS: This study showed differences between the two images regarding tooth position. A statistical significant poor agreement was found between the two methods for the mesio-distal position of the apex (k=0,388, p<0,001) and for the labio-palatal tip cusp position (k=0,035, p=0,114). The adjacent root resorption showed a poor and very poor agreement between the two methods. Every other items were scored with an agreement between modalities ranging from moderate to strong. CONCLUSIONS: The analyses of panoramic images versus CBCT images reconstructions provided different information regarding tooth position (especially concerning the mesio-distal apex position and the labio-palatal cusp position) but also in the assessment of root resorption. Further investigation should be done to determine in what cases CBCT exam has a clear advantage over conventional 2D exams, justifying its use. Key words:Cone-Beam Computed Tomography, Orthodontics, Impacted Tooth, Root resorption.