• Journal of Dental Rehabilitation and Applied Science
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• v.30 no.3
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• pp.223-230
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• 2014

Purpose: The purpose of this study was to evaluate the improvement and posttreatment stability of patients treated with extraction of lower incisors. Materials and Methods: The total of 20 patients with extracted lower incisors were analyzed by means of diagnostic models and panoramic x-rays at the time of initial, final and after 2 years of retention period of the treatment. Irregularity index, overjet, overbite, tooth size-arch length discrepancy (TSALD), intercanine width, intermolar width and American Board of Orthodontics cast/radiographic evaluation (ABO-CRE) were analyzed. Statistical analysis was performed using Wilcoxon signed-rank test. Results: After treatment, irregularity index showed significant decrease (P = 0.000). TSALD showed significant increase (P = 0.028). During retention period, irregularity index showed significant increase (P = 0.001). For ABO-CRE, total score showed significant decrease after treatment (P = 0.000) and showed average decreased which was not significant result (P = 0.053). Conclusion: Through evaluation of stability of extraction of lower incisors by means of diagnostic models and panoramic x-rays, it can be concluded that lower incisor extraction treatment had been stable for 2 years after treatment.

• The korean journal of orthodontics
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• v.51 no.6
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• pp.397-406
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• 2021

Objective: The purpose of this study was to evaluate the effects of self-ligating brackets (SBs) and other factors that influence orthodontic treatment outcomes. Methods: This two-armed cohort study included consecutively treated patients in a private practice. The patients were asked to choose between SBs and conventional brackets (CBs); if any patient did not have a preference, he or she was randomly allocated to the CB or SB group. All patients were treated using an identical archwire sequence. Evaluated parameters were as follows: treatment duration, number of bracket failures, poor oral hygiene, poor elastic wear, extraction, use of orthodontic mini-implants (OMI), OMI failure, American Board of Orthodontics (ABO) Discrepancy Index (DI), arch length discrepancy, and ABO Cast-Radiograph Evaluation (CRE) score. Stepwise regression analysis was performed to generate the equation for prediction of the CRE. Results: The final sample comprised 134 patients with an average age of 22.73 years. The average DI, CRE, and treatment duration were 21.81, 14.25, and 28.63 months, respectively. Analysis of covariance showed a significant difference in CRE between the CB and SB groups after adjusting for the effects of confounding variables. Stepwise regression analysis using four variables, namely extraction, SB use, poor elastic wear, and additional appliance use, could explain only 25.2% of the variance in the CRE. Conclusions: Although the CRE was significantly better for CBs than for SBs, the clinical significance of this result seems to be limited. Extraction, SB use, poor elastic wear, and additional appliance use may have significant effects on treatment outcomes.