Comparison of the outcomes of the lower incisor extraction, premolar extraction and non-extraction treatments

Department of Orthodontics, Faculty of Dentistry, Selcuk University, Konya, Turkey.
The European Journal of Orthodontics (Impact Factor: 1.48). 07/2011; 34(6). DOI: 10.1093/ejo/cjr064
Source: PubMed


The aim of this retrospective study was to evaluate the treatment outcome of lower incisor extraction and to compare it with premolar extraction and non-extraction treatment. The sample consisted of 60 subjects with Class I malocclusion and moderate crowding. The sample was separated into three groups: extraction of a lower incisor group, extraction of a four first premolar group and a non-extraction group. All groups involved 13 girls and 7 boys with a total of 20 patients. The Peer assessment rating (PAR) index was applied to a patient's pre-treatment (T1) and post-treatment (T2) dental casts. T1 dental casts were also used for determining Bolton discrepancy. One-way analysis of variance and post hoc Tukey HSD tests were used for statistical analysis. For the mean percentage PAR score reduction for each group, there was one significant difference seen between the lower incisor extraction group and the non-extraction group (P = 0.047). For the mean anterior ratios, there were significant differences among premolar extraction group versus non-extraction group (P = 0.042) and non-extraction group versus lower incisor extraction group (P = 0.000). For the mean overall ratios, there were significant differences among the premolar extraction group versus lower incisor extraction group (P = 0.048) and the non-extraction group versus lower incisor extraction group (P = 0.001). Orthodontic treatment without extraction has a better treatment outcome than the four-first premolar extraction and single lower incisor extraction protocols in Class I cases with moderate to severe mandibular anterior crowding.

Full-text preview

Available from:
  • Source
    • "The main difference between these three studies was the extraction/non-extraction protocol. In a previous study, Ileri et al.29 reported that, using the PAR as an index to assess treatment outcome, non-extraction treatment with CBs had a better treatment result than that with the four first premolar extraction and single lower incisor extraction protocol in Class I cases with moderate to severe mandibular anterior crowding. Machibya et al.27 reported a mean percentage PAR reduction of 86.33% and no significant differences between SLBs and CBs. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Objective To evaluate the long-term effects of self-ligating brackets (SLBs) on transverse dimensions of arches and skeletal and soft tissues and to quantitatively evaluate the treatment outcome after non-extraction treatment with SLBs. Methods The sample consisted of 24 (18 female and six male) subjects, with a mean age of 14.23 ± 2.19 years, who received treatment with the Damon®3 appliances. Complete records including cephalometric radiographs and plaster models were obtained before treatment (T1), immediately after treatment (T2), six months after treatment (T3), and two years (T4) after treatment. Digital study models were generated. Twenty lateral cephalometric, six frontal cephalometric, and eight dental cast measurements were examined. The Peer Assessment Rating index was used to measure the treatment outcome. The Wilcoxon test was applied for statistical analysis of the changes. Results There were significant increases in all transverse dental cast measurements with active treatment. There was some significant relapse in the long term, particularly in maxillary width (p < 0.05). Statistically significant increases were found in nasal (p < 0.001), maxillary base, upper molar, lower intercanine, and antigonial (p < 0.05) widths in T1-T2. Lower incisors were proclined and protruded in T1-T2. Conclusions SLBs correct crowding by mechanisms involving incisor proclination and protrusion and expansion of the dental arches, without induction of clinically significant changes in hard and soft tissues of the face.
    Full-text · Article · May 2014 · Korean Journal of Orthodontics
  • Source
    • "Narrow upper lateral incisors do not guaranty perfect finishing (Fig 2). Reduction of the mesiodistal widths of upper incisors improve the finishing specially in cases with very mild or no crowding in the upper arch [10, 16]. Mandibular incisor extraction is also indicated in mild Cl III patients with an open bite tendency who do not require sagittal alterations in the posterior occlusion [7]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Mandibular incisor extraction in carefully selected cases as an alternative option to four bicuspid extraction or non extraction treatment has been advocated. The purpose of this study was to determine the degree of improvement in occlusion in patients with Bolton discrepancy treated by one lower incisor extraction using Peer Assessment Rating Index (PAR indexes). Pre and post treatment dental casts of 14 patients treated with one lower incisor extraction were included in the study. Pre and post treatment dental casts were scored with PAR index. 70% reduction in PAR index was considered as high standard improvement. To test the hypothesis that the mean improvement in dental occlusion after one mandibular incisor extraction is at least 70%, one-tail one-sample student t-test was used. The mean improvement in dental occlusion in this group of patients was 78%. Fifty percent of the cases finished with a post treatment PAR score of 2. Spearman correlation coefficient was 0.763 (p<0.01), showing that more severe cases had greater post treatment PAR scores. Mandibular incisor extraction treatment may provide a high standard treatment outcome.
    Full-text · Article · Mar 2012
  • [Show abstract] [Hide abstract]
    ABSTRACT: The purpose of the present study was to examine the efficiency of correcting a Class II, Division 2 malocclusion using a completely customized lingual appliance. In 18 consecutively completed, Class II, Division 2 malocclusion patients, the correction of the upper incisor inclination, deep and distal bite were assessed by means of plaster casts, digital lateral cephalograms, and intraoral photographs taken at the time of debond. Furthermore, two independent calibrated examiners determined the weighted Peer Assessment Rating index (PAR Index) of the initial and end models. All Class II, Division 2 patients were treated successfully: upper incisor inclination using the palatal plane as a reference improved on average from 95.4° to 111.2°. The deep bite was reduced on average from 3.6 mm to 1.7 mm. Neutral occlusion was achieved in all patients who had undergone correction of an initially pronounced distal occlusion (4.5 mm on average). An 86.2% marked improvement was observed in the weighted PAR index score from an average of 24.7 at the beginning of treatment to 2.9 at the end of treatment, with no patient classified as "worse or no different." Class II, Division 2 malocclusions can be efficiently and reliably treated by a combination of a completely customized lingual appliance and the Herbst device.
    No preview · Article · May 2012 · Fortschritte der Kieferorthopädie
Show more