Correlation between the Rotation of the First Molars and the Severity of Class II Division 1 Malocclusion.
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ABSTRACT:
SUBMITTER: Lima BP
PROVIDER: S-EPMC4488541 | biostudies-other | 2015
REPOSITORIES: biostudies-other
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Project description:ObjectivesTo determine factors that could predict Class II/1 malocclusion patient compliance during functional treatment.Materials and methodsThe sample consisted of 77 subjects (aged 11-13 years; 47% girls) presenting with Class II/1 malocclusion. Inclusion criteria were distal molar relationship, overjet greater than 5 mm, and confirmed pubertal growth spurt. Removable functional appliances (62% Twin Block [TB], 38% Sander Bite Jumping [BJ]) with built-in maxillary expansion screws were used. Follow-up period was 1 year. Patients and parents independently filled out the Child Perception Questionnaire, Parental/Caregiver Perception Questionnaire, and Family Impact Scale to assess emotional and social well-being, oral symptoms, functional limitations, parental emotions, family activities, conflicts, and financial burden as possible predictors of compliance during treatment. Sex, overjet, and appliance type were also analyzed.ResultsThere were more noncompliant than compliant patients (55% vs 45%). Parental perception of altered emotional well-being of their children was the strongest predictor, increasing compliance odds 3.4 times (95% confidence interval [CI], 1.2-9.4; P = .017). Patients were 3.2 times (95% CI, 1.1-9.3; P = .033) more likely to cooperate with TB compared with BJ appliance. OJ ≥ 8 mm increased compliance odds 3.1 times (95% CI, 1.0-9.4; P = .044).ConclusionsParental perception of child's emotional well-being alteration, severity of malocclusion, and type of appliance are major predictors of compliance. Psychosocial issues and oral function limitations reported by children and family impact are of negligible influence.
| S-EPMC8259759 | biostudies-literature
Project description:OBJECTIVES:Malocclusion features differ across various populations and ethnicities. At this time, no data are available regarding the dentofacial differences between Syrian and European adolescents with Class II division 1 malocclusion, which is one of the most frequently treated pathologies in orthodontic practice. The present combined cephalometric and tooth-size study aimed to compare the dentoskeletal and tooth-size characteristics of Syrian and Hungarian adolescents with Class II division 1 malocclusion. RESULTS:Class II division 1 malocclusion in Hungarian adolescents was a sagittal discrepancy, while in Syrian adolescents, it was a result of excessive vertical development. Syrian adolescents had a significantly excessive vertical development when compared with Hungarian adolescents, regardless of sex (p?<?0.01). Hungarian boys had significantly more protruded maxillae (p?<?0.001) and less retruded mandibles (p?<?0.01) when compared with Syrian boys, while Hungarian girls had significantly shorter mandibles relative to those of Syrian girls (p?<?0.01). Syrian girls had significantly more protrusive lower incisors (p?<?0.001), accompanied by significantly larger anterior tooth-size ratios when compared to Hungarian girls (p?<?0.001). In conclusion, these findings underscore the importance of considering ethnic differences during orthodontic diagnosis and may have implications for optimizing orthodontic treatments in Syrian and Hungarian adolescents with Class II division 1 malocclusion.
| S-EPMC7268623 | biostudies-literature
Project description:This study aimed to evaluate and compare the dentoalveolar effects of the myofunctional trainer T4KTM versus twin block in children with class II division I malocclusion. Two parallel arm randomized comparative clinical trial was conducted, including twenty healthy children, 9-12 years old, showing Angle's class II division I malocclusion due to mandibular retrusion. Children were randomly assigned into two groups according to the appliance used; Group 1: T4k, and Group II: twin block. Follow-up was done every 4 weeks for 9 months. Postoperative cephalometric X ray, study casts and photographs were taken for measurements and comparison. T4K showed a statistically significant reduction in the overjet (-2.50 ± 1.00 mm) (p < 0.0001), and a significant increase in the lower arch perimeter (LAP) (1.19 ± 0.96 mm) (p = 0.01). The twin block showed a statistically significant reduction in the overjet (-3.75 ± 1.10 mm) (p < 0.0001), a significant reduction in the overbite (-16.22 ± 17.02 %) (p = 0.03), and a significant increase in the LAP (1.69 ± 0.70 mm) (p < 0.0001). The overjet showed a higher significant decrease in the twin block group than in T4K (p = 0.03). The mean values of the overbite were significantly decreased in twin block than in T4k (p < 0.0001). Both groups showed significant dentoalveolar improvements toward class I occlusion; however, the twin block showed significantly better results than T4K appliance.
| S-EPMC7345969 | biostudies-literature
Project description:Background:An innovative caries treatment protocol for primary teeth, termed Ultra-Conservative Treatment (UCT), restores small cavities through the Atraumatic Restorative Treatment (ART) protocol and cleans medium to large open cavities with toothbrush and fluoride toothpaste. However, UCT-treated primary molars were found to exfoliate earlier than amalgam (CRT) and ART-restored cavities, which may lead to unacceptable loss of space for normal eruption of permanent successors. The null-hypothesis tested was that there is no difference between the three treatment protocols and the intra-arch distances, and index of orthodontic treatment need (IOTN) after 4 years. Methods:Dental casts were taken at baseline (T0) and four (T4) years. The space of the premolars (D + E space), arch perimeter, anterior and total arch depth were measured using a morphometric computer programme. The presence and level of malocclusion were assessed according to the IOTN index. Dependent variables were all intra-arch distances and the IOTN while the independent variable was treatment protocol (CRT, ART and UCT). Data were analysed using linear and logistic regression. Results:The sample consisted of 867 pairs of casts of 272 initial 6-7-year-olds. No difference was observed between the UCT protocol and the two restorative protocols for the intra-arch variables in both maxilla and mandible over the 4 year period. There was no difference between the UCT and the CRT and ART protocols regarding the occurrence of orthodontic treatment need (malocclusion). In conclusion, the UCT treatment protocol does not differ significantly from the traditional amalgam (CRT) and ART restorative protocols with respect to intra-arch distances and malocclusion. The earlier exfoliation of UCT-treated primary molars does not lead to a worsening of the eruption pattern of permanent successors.
| S-EPMC7008815 | biostudies-literature
Project description:IntroductionClass II malocclusion affects about 15% of the population in the United States and is characterized by a convex profile and occlusal disharmonies. The specific etiologic mechanisms resulting in the range of Class II dentoskeletal combinations observed are not yet understood. Most studies describing Class II phenotypic diversity have used moderate sample sizes or focused on younger patients who later in life might outgrow their Class II discrepancies; such a focus might also preclude the visualization of adult Class II features. The majority have used simple correlation methods resulting in phenotypes that might not be generalizable to different samples and thus might not be suitable for studies of malocclusion etiology. The purpose of this study was to address these knowledge gaps by capturing the maximum phenotypic variations in a large sample of white Class II subjects selected with strict eligibility criteria and rigorously standardized multivariate reduction analyses.MethodsSixty-three lateral cephalometric variables were measured from the pretreatment records of 309 white Class II adults (82 male, 227 female; ages, 16-60 years). Principal component analysis and cluster analysis were used to generate comprehensive phenotypes to identify the most homogeneous groups of subjects, reducing heterogeneity and improving the power of future malocclusion etiology studies.ResultsPrincipal component analysis resulted in 7 principal components that accounted for 81% of the variation. The first 3 components represented variation on mandibular rotation, maxillary incisor angulation, and mandibular length. The cluster analysis identified 5 distinct Class II phenotypes.ConclusionsA comprehensive spectrum of Class II phenotypic definitions was obtained that can be generalized to other samples to advance our efforts for identifying the etiologic factors underlying Class II malocclusion.
| S-EPMC4007218 | biostudies-literature
Project description:To characterize soft-tissue facial height and width variation in Class II malocclusion and test for correlations with genes HMGA2, AJUBA, and ADK.Nine facial proportions were estimated from 2D frontal repose photographs of 330 Caucasian adults with Class II malocclusion.After adjustments for age and gender, the facial proportions were submitted to a principal component analyses (PCA). The most meaningful phenotypic variations were correlated with SNPs rs7924176 (ADK), rs17101923 (HMGA2), and rs997154 (AJUBA) genotyped in 106 individuals.Principal component analyses resulted in four principal components (PCs), which explained 75% of total variation. PC1 captured variation in the intercanthus distance and explained 28% of total variation. PC2 explained 21% of the variations in facial taper and facial index. PC3 explained 14% and reflected variations in the vertical dimension of the lower face. PC4 explained 12% and captured variations in distance between the eyes, width of the commissures, and the length of the superior aspect of the lower face height corresponding to the vertical dimension of the philtrum of the upper lip. A suggestive association (p<0.05) was observed between PC4 and rs997154 corroborating the role of AJUBA in variation of facial dimensions.2D frontal photographs can be used to derive quantitative measures of soft-tissue phenotypes that are of clinical relevance. The methods described are suitable for discovery and replication of associations between genotypes and malocclusion phenotypes.
| S-EPMC4396710 | biostudies-literature
Project description:PurposeThis study evaluated dentoalveolar skeletal changes promoted by the Forsus appliance, associated to fixed orthodontic appliance, in the correction of Class II, division 1 malocclusion, from Computed Tomography (CT).Methodssample consisted of 10 youngsters (7 males and 3 females), with a mean age of 13.86 years. Two Forsus® models were installed after the alignment and leveling phase of the teeth. Two tomographic images of each patient, T1 and T2 (initial and immediately after removal of Forsus® appliance) were done to perform the anatomical tracings and obtain the variables of interest. The data were described by means and standard deviations. For the comparison between the initial and final phases, the paired "t" test was used and a significance level of 5% was considered (p < 0.05).Resultssmall skeletal changes were observed, such as posterior maxillary displacement and a slight mandibular growth. Larger dentoalveolar changes occurred as extrusion, retrusion and lingualization of upper incisors; Intrusion, protrusion and vestibularization of the lower incisors; Mesialization and extrusion of lower molars.ConclusionConsidering the patients evaluated in this study, Forsus® presented similar results to other mandibular propulsion appliances, with dentoalveolar effects that favored Class II correction, however, with very slight skeletal modifications.
| S-EPMC6593311 | biostudies-literature
Project description:Background:The prevalence of malocclusion cases in the orthodontic specialist clinic in Airlangga University's Dental Hospital in Surabaya, Indonesia, in 2014-2016 is fairly high, as 55.34% of the occurrences were identified as class II skeletal malocclusion. This type of skeletal malocclusion, which is usually recognized in adults, occurs as a result of variation during growth and development. Lately, there have been many reports on gene polymorphisms of COL1A1 and COL11A1, which are assumed to be associated with class II skeletal malocclusion in Caucasians. Purpose:This study aims to analyze the relationship between single nucleotide polymorphisms (SNPs) of COL1A1 and COL11A1 with class II skeletal malocclusion in Javanese ethnic group patients with mandibular micrognathism. Materials and Methods:The diagnosis of class II skeletal malocclusion was established using the lateral cephalometric radiographs (ANB angle ?4°) (n=50). DNA was extracted from the patient's peripheral blood. After that, PCR, electrophoresis, and DNA sequencing were conducted on the extracted DNA based on COL1A1 and COL11A1 primers. Results:The SNPs in COL1A1 are c.20980G/A in 27 patients and c.20980G>A in 8 patients, whereas SNPs in COL11A1 are both c.134373C/A and c.134555C/T in 8 patients and both c.[134373A>C] and c.134582G>A in 10 patients. All samples show the deletion (c.[134227delA]) in COL11A1. Conclusion:SNPs in COL1A1 and COL11A1 have been found in class II skeletal malocclusion of Javanese ethnic group patients. Seventy percent of SNPs in COL1A1 occur in rs.2249492, whereas 36% of newly discovered SNPs appear in COL11A1. All samples also have deletion in COL11A1.
| S-EPMC7187937 | biostudies-literature
Project description:Structures of peptide-loaded major histocompatibility complex class I (pMHC-I) and class II (pMHC-II) complexes are similar. However, whereas pMHC-II complexes include similar-sized IIα and IIβ chains, pMHC-I complexes include a heavy chain (HC) and a single domain molecule β2-microglobulin (β2-m). Recently, we elucidated several pMHC-I and pMHC-II structures of primitive vertebrate species. In the present study, a comprehensive comparison of pMHC-I and pMHC-II structures helps to understand pMHC structural evolution and supports the earlier proposed-though debated-direction of MHC evolution from class II-type to class I. Extant pMHC-II structures share major functional characteristics with a deduced MHC-II-type homodimer ancestor. Evolutionary establishment of pMHC-I presumably involved important new functions such as (i) increased peptide selectivity by binding the peptides in a closed groove (ii), structural amplification of peptide ligand sequence differences by binding in a non-relaxed fashion, and (iii) increased peptide selectivity by syngeneic heterotrimer complex formation between peptide, HC, and β2-m. These new functions were associated with structures that since their establishment in early pMHC-I have been very well conserved, including a shifted and reorganized P1 pocket (aka A pocket), and insertion of a β2-m hydrophobic knob into the peptide binding domain β-sheet floor. A comparison between divergent species indicates better sequence conservation of peptide binding domains among MHC-I than among MHC-II, agreeing with more demanding interactions within pMHC-I complexes. In lungfishes, genes encoding fusions of all MHC-IIα and MHC-IIβ extracellular domains were identified, and although these lungfish genes presumably derived from classical MHC-II, they provide an alternative mechanistic hypothesis for how evolution from class II-type to class I may have occurred.
| S-EPMC8236899 | biostudies-literature
Project description:The role played by genetic components in the etiology of the Class III phenotype, a class of dental malocclusion, is not yet understood. Regions that may be related to the development of Class III malocclusion have been suggested previously. The aim of this study was to search for genetic linkage with 6 microsatellite markers (D1S234, D4S3038, D6S1689, D7S503, D10S1483, and D19S566), near previously proposed candidate regions for Class III. We performed a two-point parametric linkage analysis for 42 affected individuals from 10 Brazilian families with a positive Class III malocclusion segregation. Analysis of our data indicated that there was no evidence for linkage of any of the 6 microsatellite markers to a Class III locus at = zero, with data supporting exclusion for 5 of the 6 markers evaluated. The present work reinforces that Class III is likely to demonstrate locus heterogeneity, and there is a dependency of the genetic background of the population in linkage studies.
| S-EPMC6761732 | biostudies-literature