Comparison Of Orthodontic Treatment With Different Premolar Extraction Modalities In Terms Of Soft Tissue Profile

Abstract

Objectives: To evaluate the differences in changes in the soft tissue profile and dentoskeletal parameters between different premolar extraction and non-extraction treatment modalities. Materials and Methods: Fifty patients with skeletal Class I malocclusion were divided into three groups. Group 1 consisted of 17 patients (mean age:16.76± 1.68 years) treated with maxillary and mandibular first premolar extractions; Group 2 consisted of 16 patients (mean age:15.81± 1.19 years) treated with maxillary and mandibular second premolar extractions, and Group 3 consisted of 17 patients (mean age:16.29± 1.15 years) treated with non-extraction protocol. From the pre-treatment (T0) and post-treatment (T1) cephalometric radiographs, 13 measurements for dentoskeletal and 15 for soft tissue parameters were assessed. To determine changes due to treatment, and to compare differences among the groups, the Wilcoxon Signed-Rank and Kruskal-Wallis tests were performed, respectively. Results: Mx1-SN, Mx1-FH, Mx1-NA, IMPA and Md1-NB values decreased significantly in Groups 1 and 2 compared to Group 3 (p<0.001). According to the vertical reference line (VRL-li) and E-plane (E-LL), the lower lip showed a statistically significant change (retraction) in Group 1 and 2, compared to the non-extraction group (p<0.05). The mean change value for the upper and lower lip thicknesses in Groups 1 and 2 was greater than in Group 3 (p<0.05). Groups 1 and 2 did not show a significant difference in any dentoskeletal or soft tissue measurements. Conclusions: Soft tissue profile change following extraction treatment was similar regardless of the extracted teeth. However, extraction treatment modalities resulted in significant profile changes especially in the lower lip compared to the non-extraction control group. © 2019 Cumhuriyet University Faculty of Dentistry.