Comparison of Cephalometric and Dental Cast Measurements of Patients Treated with Single Lower Incisor Extraction and Non-extraction Orthodontic Treatment

Abstract

Objective: The aim of this retrospective study was to compare the treatment results of patients treated with non-extraction (NE) and single lower incisor extraction (SLIE) using cephalometric and dental cast analysis. Methods: The lateral cephalometric radiographs and dental casts of 40 patients (20 patients of treated with Single Lower Incisor Extraction (SLIE), and 20 patients of treated with non-extraction (NE) were examined. The positions of the upper and lower incisors were examined cephalometrically; dental arch widths, arch lengths, Little Irregularity Index and Bolton Analysis were measured on the dental casts. Results: In the SLIE and NE group, the amounts of maxillary irregularity were 2.67 ± 0.30 (mm) and 3.07 ± 0.36 (mm), the amounts of mandibular irregularity were 7.11±0.27 (mm) and 3.29±0.46 (mm) respectively. Lower intercanine (3-3) width was significantly decreased in the SLIE group and the changes between the groups were statistically significant as well. In SLIE group, no statistically significant change was observed in the parameters of the upper and lower incisor measurements, while in the NE group, the upper incisor angle (1-NA˚) and the distance of the upper incisors to the N-A plane (1-NA (mm)) increased significantly (p<0.05). Conclusion: Successful dentoalveolar outcomes may be achieved by performing SLIE therapy as an alternative to NE applied to treat Class I patients with mandibular irregularity. Lower incisor extraction can be applied to avoid lower incisor protrusion.

Keywords

• single lower incisor extraction
• Non-extraction orthodontic treatment
• Bolton’s analysis.

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