BMP2 rs1005464 is associated with mandibular condyle size variation.

This study aimed to evaluate the association between single nucleotide polymorphisms (SNPs) in endochondral development-related genes and mandibular condyle shape, size, volume, and symmetry traits. Cone-beam Computed Tomographies and genomic DNA from 118 individuals were evaluated (age range: 15-66 years). Data from twelve 3D landmarks on mandibular condyles were submitted to morphometric analyses including Procrustes fit, principal component analysis, and estimation of centroid sizes and fluctuating asymmetry scores. Condylar volumes were additionally measured. Seven SNPs across BMP2, BMP4, RUNX2 and SMAD6 were genotyped. Linear models were fit to evaluate the effect of the SNPs on the mandibular condyles' quantitative traits. Only the association between BMP2 rs1005464 and centroid size remained significant after adjusting to account for the false discovery rate due to multiple testing. Individuals carrying at least one A allele for this SNP showed larger condylar size than common homozygotes GG (ß = 0.043; 95% CI: 0.014-0.071; P value = 0.028). The model including BMP2 rs1005464, age and sex of the participants explained 17% of the variation in condylar size. Shape, volume, and symmetry were not associated with the evaluated SNPs. These results suggest that BMP2 rs1005464 might be associated with variation in the mandibular condyles size.

Deformation of the circummaxillary sutures during acute micro-implant assisted rapid palatal expansion and tooth-supported expansion: An ex vivo study.

INTRODUCTION: This study aimed to assess and compare the deformation that develops in the circummaxillary sutures during activation of micro-implant assisted rapid palatal expander (MARPE) and tooth-supported expander (Hyrax) s, in the rapid maxillary expansion. SETTINGS AND SAMPLE: 7 pigs Sus Scrofa received custom-made MARPE (n = 3) and Hyrax (n = 4) appliances. MATERIAL AND METHODS: The devices were activated 25 times with strain readings captured by strain gauges attached to the following regions: posterior midpalatal suture (MPS), maxilla-premaxilla suture (MPM), maxilla-zygomatic suture (MZ) and maxilla pterygoid-process suture (MPP). The intermolar distance and suture width were measured immediately before activation and at the 20th and 25th activation. ANOVA and Kruskal-Wallis test was applied. RESULTS: The MARPE group presented greater MPS displacement in all measured regions, and one of the devices produced a significant opening (1.7 mm) in the posterior region. The accumulated tension in the MPS was higher compared to the other sutures (P < .05). A MARPE animal presented higher median tension in the MPS region (294.77µÎµ) compared to all other animals except one Hyrax animal (P < .05). Regarding the median tensions of the different activation intervals, the median tension measured during the 16th to 25th activation interval in the Hyrax group was lower than that measured during the first 8 activations, in both the MPS and MZ (P < .05). CONCLUSIONS: MARPE expanders developed more constant tensions during all activations (MPS and MZ), while Hyrax showed lower tension in the 16th to 25th activation.

Association between craniofacial morphological patterns and tooth agenesis-related genes.

BACKGROUND: The aim of the present study was to assess if genetic polymorphisms in tooth agenesis (TA)-related genes are associated with craniofacial morphological patterns. METHODS: This cross-sectional, multi-center, genetic study evaluated 594 orthodontic Brazilians patients. The presence or absence of TA was determined by analysis of panoramic radiography. The patients were classified according to their skeletal malocclusion and facial growth pattern by means of digital cephalometric analysis. Genomic DNA was extracted from squamous epithelial cells of buccal mucosa and genetic polymorphisms in MSX1 (rs1042484), PAX9 (rs8004560), TGF-α (rs2902345), FGF3 (rs1893047), FGF10 (rs900379), and FGF13 (rs12838463, rs5931572, and rs5974804) were genotyped by polymerase chain reaction using TaqMan chemistry and end-point analysis. RESULTS: Genotypes (p = 0.038) and allele (p = 0.037) distributions for the FGF3 rs1893047 were significantly different according to the skeletal malocclusion. Carrying at least one G allele increased in more than two times the chance of presenting skeletal class III malocclusion (OR = 2.21, CI 95% = 1.14-4.32; p = 0.017). There was no association between another skeletal craniofacial pattern and some polymorphism assessed in the present study. CONCLUSION: Our results suggest that the genetic polymorphism rs1893047 in FGF3 might contribute to variations in the craniofacial sagittal pattern.

Combined maxillary and mandibular distraction osteogenesis in patients with hemifacial microsomia.

INTRODUCTION: Hemifacial microsomia is a deformity of variable expressivity with unilateral hypoplasia of the mandible and the ear. In this study, we evaluated skeletal soft tissue changes after bimaxillary unilateral vertical distraction. METHODS: Eight patients (4 preadolescents 4 adolescents) each with a grade II mandibular deformity underwent a LeFort I osteotomy and an ipsilateral horizontal mandibular ramus osteotomy. A semiburied distraction device was placed over the ramus, and intermaxillary fixation was applied. Anteroposterior cephalometric and frontal photographic analyses were conducted before and after distraction. Statistics were used to analyze the preoperative and postoperative changes. RESULTS: Cephalometrically, the nasal floor and the occlusal and gonial plane angles decreased. The ratios of affected-unaffected ramus and gonial angle heights improved by 15% and 20%, respectively. The position of menton moved toward the midline. The photographic analysis showed a decrease of the nasal and commissure plane angles, and the chin moved to the unaffected side. The parallelism between the horizontal skeletal and soft tissue planes improved, with an increase in the affected side ramus height and correction of the chin point toward the midline. CONCLUSIONS: Simultaneous maxillary and mandibular distraction improved facial balance and symmetry. Patients in the permanent dentition with fixed orthodontic appliances and well-aligned dental arches responded well to this intervention.

Does rapid maxillary expansion have long-term effects on airway dimensions and breathing?

INTRODUCTION: In this systematic review, we identified and qualified the evidence of long-term reports on the effects of rapid maxillary expansion (RME) on airway dimensions and functions. METHODS: Electronic databases (Ovid, Scirus, Scopus, Virtual Health Library, and Cochrane Library) were searched from 1900 to September 2010. Clinical trials that assessed airway changes at least 6 months after RME in growing children with rhinomanometry, acoustic rhinometry, computed tomography, or posteroanterior and lateral radiographs were selected. Studies that used surgically assisted RME and evaluated other simultaneous treatments during expansion, systemically compromised subjects, or cleft patients were excluded. A methodologic-quality scoring process was used to identify which studies would be most valuable. RESULTS: Fifteen articles fulfilled the inclusion criteria, and full texts were assessed. Three were excluded, and 12 were assessed for eligibility. Four articles with low methodologic quality were not considered. The remaining 8 were qualified as moderate. The posteroanterior radiographs showed that nasal cavity width increases; in the lateral radiographs, decreased craniocervical angulation was associated with increases of posterior nasal space. Cone-beam computed tomography did not show significant increases of nasal cavity volume. Rhinomanometry showed reduction of nasal airway resistance and increase of total nasal flow, and acoustic rhinometry detected increases of minimal cross-sectional area and nasal cavity volume. CONCLUSIONS: There is moderate evidence that changes after RME in growing children improve the conditions for nasal breathing and the results can be expected to be stable for at least 11 months after therapy.

Mechanical testing and finite element analysis of orthodontic teardrop loop.

INTRODUCTION: Understanding how teeth move in response to mechanical loads is an important aspect of orthodontic treatment. Treatment planning should include consideration of the appliances that will meet the desired loading of the teeth to result in optimized treatment outcomes. The purpose of this study was to evaluate the use of computer simulation to predict the force and the torsion obtained after the activation of tear drop loops of 3 heights. METHODS: Seventy-five retraction loops were divided into 3 groups according to height (6, 7, and 8 mm). The loops were subjected to tensile load through displacements of 0.5, 1.0, 1.5, and 2.0 mm, and the resulting forces and torques were recorded. The loops were designed in AutoCAD software(2005; Autodesk Systems, Alpharetta, GA), and finite element analysis was performed with Ansys software(version 7.0; Swanson Analysis System, Canonsburg, PA). Statistical analysis of the mechanical experiment results was obtained by ANOVA and the Tukey post-hoc test (P < .01). The correlation test and the paired t test (P < .05) were used to compare the computer simulation with the mechanical experiment. RESULTS AND CONCLUSIONS: The computer simulation accurately predicted the experimentally determined mechanical behavior of tear drop loops of different heights and should be considered an alternative for designing orthodontic appliances before treatment.