RESUMEN
The maxilla is formed by the medial nasal and maxillary processes fusion. The dental lamina develops from 2 origins connecting in the lateral incisor. The maxillary lateral incisor region is often affected by dental anomalies and clefting. It is possible that genes involved in oral cleft could also be associated with a variety of phenotypic variations in the maxillary lateral incisor. In this phenotype-genotype study, we explored the association between polymorphisms in the oral-cleft-related genes BMP2 and BMP4 and root curvature of maxillary lateral incisors.Cross-sectional study.Universities and private clinics.Panoramic radiographs and DNA from 231 patients were analyzed.Schneider method (1971) was applied to estimate the degree of root curvature of the maxillary lateral incisors and to classify the root as straight (5° or less) or curved (higher than 5°). Genetic polymorphisms in BMP2 (rs235768 and rs1005464) and BMP4 (rs17563) were genotyped. Statistical analysis was performed.A total of 401 teeth (199 left and 202 right) were evaluated. Genetic analysis demonstrated trends toward association for the rs1005464 in BMP2 (P = .025) in co-dominant model and in dominant model (P = .026) for left incisors. The rs235768 in BMP2 showed trends toward association with the degree of root curvature in left incisors in the recessive model (P = .031). rs17563 in BMP4 also showed trends toward association with the degree of the root curvature in left incisors (P = .019).BMP2 (rs235768 and rs1005464) and BMP4 (rs17563) might be involved in maxillary lateral incisor root curvature.
RESUMEN
BACKGROUND: Multiple signaling molecules have been shown to play crucial roles in dental root development. Therefore, we aimed to investigate the prevalence of S-shaped roots and also to investigate, if single nucleotide polymorphisms (SNPs) in BMP2, BMP4 and SMAD6 are associated with this phenotype in humans. METHODS: This is a cross-sectional phenotype-genotype association study that used radiographs to determine the phenotypes and DNA to investigate SNPs in candidate genes. During the radiographic exam, teeth presenting root canal(s) doubly curved were considered S-shaped roots. SNPs in BMP2 (rs1005464 and rs235768), BMP4 (rs17563) and SMAD6 (rs2119261 and rs3934908) were blindly genotyped by real-time PCR using TaqMan assay. The relative and absolute frequency of S-shaped roots were calculated. Chi-square test was used to compare the genotype distributions between control and S-shaped groups. RESULTS: Among the 578 subjects, 61 (10.6 %) presented at least one tooth with an S-shaped root. The most commonly affected type of tooth was the premolar. rs1005464 in BMP2 was statistically associated with an S-shaped root (p = 0.036). rs235768 in BMP2 was associated with an S-shaped root also in mandibular teeth (p = 0.017). A statistical significance was observed for the rs3934908 in SMAD6 (p = 0.049) for S-shaped root in the mandible. In the analysis stratified according to the type of tooth, rs235768 in BMP2 was associated with S-shaped roots in premolars (p = 0.029). CONCLUSION: The prevalence of S-shaped roots is 10.6 % in permanent teeth. SNPs in BMP2 and SMAD6 could be involved in a higher chance to present S-shaped roots.