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This study aimed to evaluate changes in palatal shape after orthodontic treatment from a borderline sample of extraction and nonextraction patients with a Class I relationship. A borderline sample regarding premolar extractions was obtained through discriminant analysis and comprised 30 nonextraction and 23 extraction patients. The digital dental casts of these patients were digitized with 3 curves and 239 landmarks placed on the hard palate. Procrustes superimposition and principal component analysis were implemented to assess group shape variability patterns. The success of the discriminant analysis in identifying a borderline sample regarding the extraction modality was validated using geometric morphometrics. Concerning palatal shape, no sexual dimorphism was found (P = 0.78). The first 6 principal components that were statistically significant accounted for 79.2% of the total shape variance. Palatal changes were 61% more pronounced in the extraction group, which exhibited a decrease in palatal length (P = 0.02; 10,000 permutations). In contrast, the nonextraction group showed an increase in the palatal width (P <0.001; 10,000 permutations). Intergroup comparisons indicated that the nonextraction group exhibited longer palates, whereas the extraction group exhibited higher palates (P = 0.02; 10,000 permutations). Considerable changes in palatal shape were seen for the nonextraction and extraction treatment group, with the latter exhibiting more pronounced changes, mainly in terms of palatal length. Further investigations are needed to clarify the clinical significance of the palatal shape changes in borderline patients after extraction and nonextraction treatment. • Borderline extraction patients were evaluated for palatal shape changes. • No sexual dimorphism existed in palatal shape. • The extraction group exhibited a decrease in palatal length. • The nonextraction group showed an increase in palatal width. • Comparisons showed longer palates in the nonextraction and higher palates in the extraction group. [ABSTRACT FROM AUTHOR]

Spacing between the maxillary anterior teeth is a common concern for young patients and their parents. Patients often consider a diastema to be an annoying but minor problem; they might consult their general dentists for help, or try to address the issue themselves by applying elastic "gap bands." Moreover, parents, without any informed consent, sometimes accept this erroneous method as an easy and inexpensive treatment approach. A 9-year-old boy had severe acute periodontitis involving the maxillary central incisors caused by the placement of an elastic band and its apical migration. Despite periodontal and surgical interventions, the maxillary central incisors were finally extracted, and the patient started orthodontic treatment. The orthodontic treatment plan included maxillary lateral incisor substitution to replace the lost central incisors and mesialization of the maxillary posterior dentition. An interdisciplinary approach with excellent cooperation among the orthodontist, general dentist, and other dental specialists obtained an esthetically pleasing and optimized functional result. Treating the diastema between the anterior teeth with elastic gap bands and without fixed orthodontic appliances should be avoided. Patients should seek proper orthodontic advice for even small-scale orthodontic problems to prevent catastrophic outcomes, as exhibited in this case report. [ABSTRACT FROM AUTHOR]

Introduction: The aims of this study were to identify a sample of borderline Class I extraction and nonextraction patients and to investigate posttreatment changes in arch-width and perimeter measurements.Methods: A parent sample of 580 Class I patients was subjected to discriminant analysis, and a borderline subsample of 62 patients, 31 treated with extraction of 4 first premolars and 31 treated without extractions, was obtained. The patients' plaster casts were digitally scanned, and the maxillary and mandibular intercanine and intermolar widths and perimeters were assessed.Results: The extraction group showed increases in maxillary and mandibular intercanine widths (P <0.001) and decreases in mandibular intermolar width and in maxillary and mandibular perimeters (P <0.001). The nonextraction group showed increases in all 4 arch-width measurements (P ≤0.003), whereas the maxillary and mandibular perimeters were maintained. The posttreatment differences between the 2 groups showed significant differences in the maxillary (P <0.001) and mandibular intermolar widths (P <0.001). Also, the comparison of the arch perimeters between the 2 treatment groups showed adjusted differences of -8.51 mm (P <0.001) and -8.44 mm (P <0.001) for the maxillary and mandibular arches, respectively. The intercanine widths showed no changes between the 2 treatment groups.Conclusions: Borderline Class I patients treated with extraction of 4 first premolars had decreased maxillary and mandibular intermolar and perimeter measurements compared with nonextraction patients. The maxillary and mandibular intercanine widths showed no significant difference between the 2 treatment groups. [ABSTRACT FROM AUTHOR]

Introduction: The aim of this study was to compare treatment outcomes in university vs private practice settings with Class I patients using the American Board of Orthodontics Objective Grading System.Methods: A parent sample of 580 Class I patients treated with and without extractions of 4 first premolars was subjected to discriminant analysis to identify a borderline spectrum of 66 patients regarding the extraction modality. Of these patients, 34 were treated in private orthodontic practices, and 32 were treated in a university graduate orthodontic clinic. The treatment outcomes were evaluated using the 8 variables of the American Board of Orthodontics Objective Grading System.Results: The total scores ranged from 10 to 47 (mean, 25.44; SD, 9.8) for the university group and from 14 to 45 (mean, 25.94; SD, 7.7) for the private practice group. The university group achieved better scores for the variables of buccolingual inclination (mean difference, 2.28; 95% confidence interval [CI], 0.59, 3.98; P = 0.01) and marginal ridges (mean difference, 1.32; 95% CI, 0.28, 2.36; P = 0.01), and the private practice group achieved a better score for the variable of root angulation (mean difference, -0.65; 95% CI, -1.26, -0.03; P = 0.04). However, no statistically intergroup differences were found between the total American Board of Orthodontics Objective Grading System scores (mean difference, -0.5; 95% CI, -3.82, 4.82; P = 0.82).Conclusions: Patients can receive similar quality of orthodontic treatment in a private practice and a university clinic. The orthodontists in the private practices were more successful in angulating the roots properly, whereas the orthodontic residents accomplished better torque control of the posterior segments and better marginal ridges. [ABSTRACT FROM AUTHOR]

Introduction A controversy exists regarding better treatment outcomes when patients treated with extractions and without extractions are evaluated. The aims of this study were to use the American Board of Orthodontics objective grading system (ABO-OGS) to evaluate and compare treatment outcomes in extraction vs nonextraction Class I patients and to determine whether the treatment choice was a significant predictor of success according to the ABO examination. Methods Discriminant analysis was applied to a sample of 542 patients, and a borderline sample of 55 patients was obtained. Of these patients, 25 were treated with extractions and 30 without extraction of the 4 first premolars. Treatment results were then assessed using the 8 variables of the ABO-OGS. Results The total scores ranged from 11 to 41 (mean, 27.04; SD, 6.3) for the extraction group and from 16 to 44 (mean, 29.07; SD, 7.1) for the nonextraction group. The variable of buccolingual inclination had the highest scores in both groups (8.44 [SD, 3.3] for the extraction group; 8.90 [SD, 3.8] for the nonextraction group; mean difference, 0.46; 95% CI, −1.44, 2.37; P = 0.63). However, no statistically significant intergroup differences were found, either between the scores of the 8 ABO-OGS variables or between the total ABO-OGS scores. Regarding the success rates of the ABO examination, no significant difference was found between the 2 treatment groups (odds ratio, 2.55; 95% CI, 0.74, 0.85; P = 0.14). Conclusions For a patient with a borderline Class I malocclusion, extraction and nonextraction treatment can achieve the same quality of results as assessed by the ABO-OGS. Additionally, in these Class I patients, the treatment modality (extraction or nonextraction) is not a significant predictor of passing the ABO examination. [ABSTRACT FROM AUTHOR]

Mechanical loading is considered to be a major parameter of the periodontal ligament (PDL) remodeling and differentiation. However, the molecular mechanisms that translate these forces to cellular responses are not fully elucidated. Especially, although aging affects PDL homeostasis, the role of cellular senescence on the activation of signaling pathways in periodontal ligament fibroblasts (PDLF) in response to mechanical stimulation has not been studied yet. Here, we present evidence showing that cyclic mechanical stimulation activates ERK, JNK and p38 MAPK in young (early-passage) human PDLF, in a RhoK-dependent manner. This response was found to be independent of the substratum (i.e. fibronectin or collagen) on which these cells grow. Stretching up-regulates also c-fos , a classical cellular response to mechanical deformation. Inhibition of ERK and JNK reduces, while that of p38 enhances stress-mediated c-fos expression. In addition, cyclic stretching stimulates the expression and activity of alkaline phosphatase ( ALP ), an early marker of osteoblastic differentiation. We have recently shown that senescent human PDLF have a significantly decreased expression of ALP , linked to an inability towards osteoblastic differentiation. Here, we found that senescent PDLF are able to respond to cyclic mechanical stretching by activating ERK, JNK and p38 MAPK, with similar kinetics compared to young cells, and by up-regulating c-fos and ALP expression and activity. However, even after stimulation, ALP levels in senescent cells are still much lower compared to the basal levels of their young counterparts, suggesting that senescence impairs the differentiation of human PDLF when subjected to cyclic mechanical deformation. [ABSTRACT FROM AUTHOR]