Cervical vertebral column morphology related to craniofacial morphology and head posture in preorthodontic children with Class II malocclusion and horizontal maxillary overjet
Torill Arntsen, and Liselotte Sonnesen. Am J Orthod Dentofacial Orthop 2011;140:e1-e7
I ntroduction: In preorthodontic children with Class II malocclusion and horizontal maxillary overjet, cervical column morphology was examined and related to craniofacial morphology and head posture for the first time. Methods: Two hundred thirteen children (aged 7-15 years) with a horizontal maxillary overjet of more than 6 mm were divided into 2 groups of skeletal and dentoalveolar overjets. The skeletal overjet group comprised 99 patients (43 girls, 56 boys). The dentoalveolar overjet group comprised 114 subjects (58 girls, 56 boys). Visual assessments of the cervical column and measurements of craniofacial morphology and head posture were made on profile radiographs. Results: Deviations in the cervical vertebral column morphology occurred significantly more often in the skeletal overjet group (28%) compared with the dentoalveolar overjet group (17%) ( P <0.05). Fusion anomalies were associated with a large sagittal jaw relationship, retrognathia of the jaws, large inclination of the jaws, and extended head posture ( P <0.05 and 0.01, respectively). Furthermore, a partial cleft was significantly associated with a large cranial base angle ( P <0.01). Conclusions: New associations were found between cervical column morphology, craniofacial morphology, and head posture in preorthodontic children with horizontal maxillary overjet. These findings are considered important for diagnostics and thus for a more accurate treatment plan of these patients.
Analysis of genetic polymorphisms in skeletal Class I crowding
Tung Yuen Ting, Ricky Wing Kit Wong, and A. Bakr M. Rabie. Am J Orthod Dentofacial Orthop 2011;140:e9-e15
I ntroduction: Dental crowding is a problem for both adolescents and adults in modern society. The purpose of this research was to identify single nucleotide polymorphisms (SNPs) responsible for crowding in subjects with skeletal Class I relationships. Methods: The case subjects consisted of healthy Chinese people living in Hong Kong with skeletal Class I relationships and at least 5 mm of crowding in either arch. The control subjects met the same requirements but lacked crowding or spacing. SNP genotyping was performed on the MassARRAY platform. The chi-square test was used to compare genotype and allele type distributions between the case and the control groups. Logistic regression was used to calculate odds ratios with 95% confidence intervals, and the effects of age and sex for each SNP. Analyses of linkage disequilibrium and haplotype associations between SNPs were performed with software. Results: Five SNPs were found to be significantly different in genotype or allele type distributions. SNP rs372024 was significantly associated with crowding ( P = 0.004). Two SNPs, rs3764746 and rs3795170, on the EDA gene were found to be associated marginally. SNPs rs1005464 and rs15705 also exhibited marginal association with crowding. The effects of associated SNPs remained significant after adjustments for age and sex factors. Conclusions: This study suggests an association for the genes EDA and XEDAR in dental crowding in the Hong Kong Chinese population.
Analysis of genetic polymorphisms in skeletal Class I crowding
Tung Yuen Ting, Ricky Wing Kit Wong, and A. Bakr M. Rabie. Am J Orthod Dentofacial Orthop 2011;140:e9-e15
I ntroduction: Dental crowding is a problem for both adolescents and adults in modern society. The purpose of this research was to identify single nucleotide polymorphisms (SNPs) responsible for crowding in subjects with skeletal Class I relationships. Methods: The case subjects consisted of healthy Chinese people living in Hong Kong with skeletal Class I relationships and at least 5 mm of crowding in either arch. The control subjects met the same requirements but lacked crowding or spacing. SNP genotyping was performed on the MassARRAY platform. The chi-square test was used to compare genotype and allele type distributions between the case and the control groups. Logistic regression was used to calculate odds ratios with 95% confidence intervals, and the effects of age and sex for each SNP. Analyses of linkage disequilibrium and haplotype associations between SNPs were performed with software. Results: Five SNPs were found to be significantly different in genotype or allele type distributions. SNP rs372024 was significantly associated with crowding ( P = 0.004). Two SNPs, rs3764746 and rs3795170, on the EDA gene were found to be associated marginally. SNPs rs1005464 and rs15705 also exhibited marginal association with crowding. The effects of associated SNPs remained significant after adjustments for age and sex factors. Conclusions: This study suggests an association for the genes EDA and XEDAR in dental crowding in the Hong Kong Chinese population.
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