Response to Yang et al

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Cervical vertebrae anomalies in subjects with Class II malocclusion assessed by lateral cephalogram and cone beam computed tomography

A high prevalence of cervical vertebrae anomalies (CVA) has been recently associated with various malocclusions. Our aim was to study the prevalence of CVA on lateral cephalograms in Class II subjects and to compare the findings with those obtained from cone beam computed tomography (CBCT). Standardized cephalograms of 238 Class II patients were analysed for CVA. Cephalogram and CBCT were available for an additional 21 subjects. Cephalometric values were correlated with vertebrae morphology; logistic regressions and intraobserver agreement were evaluated. Inspection of lateral cephalograms could exclude CVA in 90.3 per cent of the subjects, while 9.7 per cent showed potential fusions. No correlations were found between the cephalometric values and potential vertebrae anomalies. In the 21 patients with a CBCT and a lateral cephalogram, the visual assessment of the cephalogram yielded a potential fusion in nine cases. None could be confirmed by CBCT. A low number of potentially fused cervical vertebrae could be detected on lateral cephalograms. The possible fusions did not correlate to any cephalometric values nor could they be confirmed by CBCT, the gold standard for assessing CVA. Visual examination of a cephalogram may result in a false-positive finding and does not allow reliable diagnosis of CV

Long-term changes in pharyngeal airway dimensions following activator-headgear and fixed appliance treatment

The aim of this study was to evaluate changes in the pharyngeal airway in growing children and adolescents and to compare these with a group of children who received activator-headgear Class II treatment. The sample consisted of 64 children (32 males and 32 females), 32 had a combined activator-headgear appliance for at least 9 months (study group) followed by fixed appliance therapy in most patients, while the other half received only minor orthodontic treatment (control group). Lateral cephalograms before treatment (T1, mean age 10.4 years), at the end of active treatment (T2, mean age 14.5 years), and at the long-term follow-up (T3, mean age 22.1 years) were traced and digitized. To reveal the influence of somatic growth, body height measurements were also taken into consideration. A two-sample t-test was applied in order to determine differences between the groups. At T1, the study group had a smaller pharynx length (P = 0.030) and a greater ANB angle (P < 0.001) than the controls. The pharyngeal area and the smallest distance between the tongue and the posterior pharyngeal wall also tended to be smaller in the study group. During treatment (T1-T2), significant growth differences between the two groups were present: the study group had a greater reduction in ANB (P < 0.001) and showed a greater increase in pharyngeal area (P = 0.007), pharyngeal length (P < 0.001) and the smallest distance between the tongue and the posterior pharyngeal wall (P = 0.038). At T2, the values for the study group were similar to those of the control group and remained stable throughout the post-treatment interval (T2-T3). Activator-headgear therapy has the potential to increase pharyngeal airway dimensions, such as the smallest distance between the tongue and the posterior pharyngeal wall or the pharyngeal area. Importantly, this increase seems to be maintained long term, up to 22 years on average in the present study. This benefit may result in a reduced risk of developing long-term impaired respiratory functio

Pharyngeal airway dimensions: a cephalometric, growth-study-based analysis of physiological variations in children aged 6-17

SummaryOBJECTIVE: The aim was to assess pharyngeal airway dimensions and physiological changes based on lateral cephalometric radiographs from healthy untreated children aged 6-17 years. MATERIALS/METHODS: The sample consisted of 880 lateral cephalograms (412 females and 468 males) of the Zurich Craniofacial Growth Study. Statistical analyses on cephalometric measurements of airway dimensions (distances ‘p': shortest distance between soft palate and posterior pharyngeal wall and ‘t': shortest distance between tongue and posterior pharyngeal wall) and craniofacial parameters were performed. To disclose differences between different age groups, a Kruskal-Wallis test was applied. The influence of gender on ‘p' and ‘t' was analysed by a Mann-Whitney U-test for each age group separately. The Spearman correlation was computed in order to investigate associations between craniofacial parameters. Variables associated with ‘p' and ‘t' were chosen for multiple regression model investigation. RESULTS: The results demonstrated high interindividual variations. A slight influence of age on ‘p' (P = 0.034) could be attested (+1.03mm) but not on ‘t' (P = 0.208). With the exception of the 9-year age group, no significant differences between the genders were found. Correlation analysis revealed several statistically significant correlations between ‘t' or ‘p' and antero-posterior cephalometric variables. All correlation coefficients were, however, very low and the adjusted coefficient of determination also revealed the regression model to be very weak. CONCLUSIONS: The high interindividual variations of ‘p' and ‘t' render the use of reference values problematic. Contrary to other craniofacial structures, neither age-related changes nor sexual dimorphism were found for ‘p' and ‘t'. Any associations to antero-posterior cephalometric characteristics seem lo

Dentofacial and upper airway characteristics of mild and severe class II division 1 subjects

The aim of this retrospective, cross-sectional study was to assess whether mild and severe Class II division 1 subjects have craniofacial and upper airway characteristics, which relate to the severity of Class II as judged by overjet or ANB angle. The sample consisted of pre-treatment lateral cephalograms and dental casts of 131 males and 115 females (mean age 10.4 ± 1.6). Inclusion criteria were: healthy Caucasian subjects, at least ¾ Class II first molar relationship on both sides and overjet ≥ 4 mm. The cephalograms were traced and digitized. Distances and angular values were computed. Mild and severe Class II was defined by overjet (<10 mm/≥ 10 mm) or by ANB angle (<7 degrees/≥7 degrees). Statistics were performed with two-sample t-test and Pearson's correlation analysis. In the two overjet groups, significant differences were mainly found for incisor inclination while the two ANB groups differed significantly in SNA, WITS, Go-Pg, SpaSpp/MGo, SN/MGo, and Ar-Gn. The shortest airway distance between the soft palate and the posterior pharyngeal wall was significantly correlated to the NS/Ar angle. Statistical analysis revealed several significant correlations. Patients with a large overjet or ANB angle differed significantly from patients with a small overjet or ANB angle mainly in their incisor inclination. In the present sample, the overjet and to some extent also the ANB angle is determined by soft tissue or individual tooth position rather than by skeletal background. In retrognathic patients, a tendency towards smaller airway dimensions was found. However, statistical analysis did not reveal a strong connection between upper airway and dentoskeletal parameters, but a large interindividual variatio

Academic experience satisfaction of pharmacy and dentistry students

Objective: To assess the psychometric properties of the Academic Experience Satisfaction Scale (ESEA) applied to Pharmacy and Dentistry students and investigate the effect of demographic and course-related characteristics on the ESEA factors. Methods: This was a cross-sectional study. Academic satisfaction was assessed by the ESEA. Construct validity was measured by confirmatory factor analysis (CFI, TLI, RMSEA). The composite reliability (CR) and the ordinal α were estimated. Structural model was elaborated considering demographic and course-related characteristics as the independent variable and ESEA factors as the dependent variables. The model fit and path estimates significance (β) were evaluated (z test; α = 5%). Results: 544 students participated in the study (70.0% female; mean age: 21.4 ± 2.4 years; 52.4% dental students). ESEA showed adequate fit to the data (CFI = 0.90; TLI = 0.90; RMSEA = 0.064, CR and α ≥ 0.88). In general, students reported being satisfied with their academic experience. Dental students and those from the first and second years of the course showed greater satisfaction with the academic experience. Sex did not have a significant impact on any of the scale's factors. Conclusion: ESEA produced valid and reliable data. Course-related characteristics, but not demographic characteristics, significantly affected the academic experience of students.info:eu-repo/semantics/publishedVersio

Impact of body and orofacial appearance on life satisfaction among Brazilian adults

Aims 1. to elaborate a general model of physical appearance taking into account body image (BI) and orofacial appearance (OA) components; and 2. to evaluate the impact of BI and OA on life satisfaction among Brazilian adults. Methods This is a cross-sectional observational study. The cognitive, behavioral, affective, and satisfaction/ dissatisfaction aspects of BI, the satisfaction and psychosocial impact of OA, and life satisfaction were evaluated by self-reported psychometric scales. Principal Component Analysis and Parallel Analysis were performed. Structural equation models were elaborated to estimate the impact of BI and OA on life satisfaction. The fit of the models was verified and the significance of the path estimates (β) was evaluated using z-tests (α = 5%). Results A total of 1,940 individuals participated in the study (age: mean = 24.8, standard deviation = 5.7 years; females = 70.1%). In the male sample, three physical appearance factors were retained (OA, cognitive and behavioral components of BI, and affective and satisfaction/dissatisfaction components of BI). In the female sample, two factors were retained (OA and all components of BI). All factors had significant impact on life satisfaction (β = |0.26|-|0.48|, p<0.001) in both samples. Individuals dissatisfied with BI and OA had lower levels of life satisfaction. For men, the affective and satisfaction components of BI had a greater impact on life satisfaction (β = 0.48, p<0.001) than the other factors (β =] -0.30;-0.25[, p<0.001). For women, both BI and OA had a similar impact (BI: β = -0.30, p<0.001; OA: β = -0.32, p<0.001). Conclusion BI and OA formed distinct clusters in the physical appearance evaluation. Physical appearance was perceived differently by men and women, fostering discussion about the sociocultural construction of the body. BI and OA had a significant impact on life satisfaction and should be considered in assessment and treatment protocols.info:eu-repo/semantics/publishedVersio

No self-similar aggregates with sedimentation

Two-dimensional cluster-cluster aggregation is studied when clusters move both diffusively and sediment with a size dependent velocity. Sedimentation breaks the rotational symmetry and the ensuing clusters are not self-similar fractals: the mean cluster width perpendicular to the field direction grows faster than the height. The mean width exhibits power-law scaling with respect to the cluster size, ~ s^{l_x}, l_x = 0.61 +- 0.01, but the mean height does not. The clusters tend to become elongated in the sedimentation direction and the ratio of the single particle sedimentation velocity to single particle diffusivity controls the degree of orientation. These results are obtained using a simulation method, which becomes the more efficient the larger the moving clusters are.Comment: 10 pages, 10 figure