Search

Background: In the long-lasting debate of extraction versus non-extraction treatment, the impact of extractions on the skeletal vertical dimension remains rather unclear. The aim of this retrospective research study was to obtain a bias-free sample of morphologically similar borderline patients treated with or without extraction of the four first premolars and to retrospectively evaluate the vertical changes that occurred., Methods: A borderline sample of 83 patients, 41 treated with four first premolar extractions and 42 treated without, was obtained by means of discriminant analysis applied to a previously investigated parent sample of 542 class I patients. The pretreatment and posttreatment cephalometric radiographs were analyzed digitally, and seven measurements were assessed for vertical skeletal changes. Also, average tracings between the two treatment groups were evaluated using the Procrustes superimposition method., Results: The variables of SN to Go-Gn and Y-axis showed adjusted intergroup differences of - 0.91° and - 1.11° (P = 0.04). Comparing the mean intra-group differences of all the variables simultaneously, a significant difference was found between the two treatment groups (overall P value = 0.04). In the extraction group, only the gonial angle showed a significant decrease (P = 0.01) while the overall P value evaluating the intra-group differences between pre- and posttreatment was significant (overall P value < 0.01). In the non-extraction group, the variable of N-ANS/N-Me showed a significant decrease (P = 0.02) and the overall P value evaluating the intra-group differences between pre- and posttreatment was also significant (overall P value < 0.01). Differences in treatment duration were assessed using a log-normal model and showed that extraction treatment lasted significantly longer than non-extraction treatment (P < 0.01)., Conclusions: The borderline group of patients identified by the discriminant analysis exhibited similar morphological characteristics at treatment's onset; therefore, the posttreatment changes could safely be attributed to the choice of extraction or non-extraction treatment and not to pre-existing differences. Treatment choice had an impact on the patients' vertical skeletal dimensions. Patients treated with four first premolar extractions showed a slight decrease in the vertical skeletal measurements, whereas non-extraction patient treatment showed a slight increase. The treatment time was also significantly higher in the extraction group.

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., (Copyright © 2016 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.)

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., (Copyright © 2016 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.)

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., (Copyright © 2014 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.)

Background: The extraction rate in orthodontics varies throughout the years. While the extraction decision is easily made or excluded in clear-cut cases, it still remains controversial what makes an orthodontist decide to extract in borderline cases. The aim of this retrospective study was to identify the percentage of extraction cases in a large group of Class I malocclusions and to clarify which variables contributed most to the extraction decision., Methods: The sample consisted of 542 randomly selected records of Class I patients treated in a university graduate program and in five private orthodontic offices. Of these patients, 331 were female and 211 male. The mean age was 14.55 (standard deviation (SD) 5.36) for the non-extraction group and 14.52 (SD 4.86) for the extraction group. The extensive series of 32 linear and angular measurements derived from the cephalometric analysis and the dental casts, along with the variables of age and gender, fueled a stepwise discriminant analysis., Results: The percentage of the patients treated with four first premolar extractions was 26.8%. The results showed that the variables of lower crowding, lower lip to E-plane, upper crowding, and overjet accounted most for the decision to extract at a very significant level (Sig. 0.000). The discriminant analysis assigned a classification power of 83.9% to the predictive model (p<0.0001). Fisher's linear discriminant functions provided a mathematical model, according to which any case can be classified into the adequate treatment group., Conclusions: In a large contemporary sample of 542 Class I patients, the extraction rate was 26.8%. The most important measurements when the orthodontist decides extractions in Class I cases are lower crowding, lower lip to E-plane, upper crowding, and overjet. In clinical orthodontic practice, the findings facilitate treatment by providing evidence-based treatment predictors for Class I malocclusions.

Objective: To obtain through the use of discriminant analysis a relatively bias-free sample of extraction and nonextraction, Class I, equally susceptible to both treatments' malocclusions and to analyze retrospectively the soft tissue changes between the two different treatment groups., Materials and Methods: The cephalometric, model, and demographic data of 215 patients (females and males) fueled a stepwise discriminant analysis that provided the borderline homogenous subsample (30 extraction and 32 nonextraction cases). The pretreatment and postreatment cephalograms of the borderline sample were then subjected to a thorough soft tissue cephalometric analysis., Results: The results indicated that the three variables that played the most important role in the clinician's treatment decision were indicators of lower crowding, soft tissue convexity, and lower incisor protrusion. Significant differences (P < .001) regarding upper and lower lip protrusion, upper lip thickness (P < .05), and the nasiolabial angle (P < .05) occurred., Conclusion: Extraction treatment of Class I borderline malocclusions led to significant soft tissue changes regarding the upper and lower lip position and thickness as well as the nasiolabial angle, whereas the nonextraction treatment resulted in significant upper lip retraction and lower lip protraction.