Extraction space reopening in different orthodontic retention protocols in 4 premolar extraction cases

The aim of this study is to compare the success of fixed lingual retainers, and additionally used essix retainers and duran retainers, in preventing the reopening of extraction spaces and relapse. Our study included a total of 66 patients treated at the Department of Orthodontics, Trakya University, with the extraction of four first premolar teeth. Of these, 22 patients were treated with a 0.0215-inch, 6-strand stainless steel wire (G&H Orthodontics, Franklin, USA) between the canines in both the maxillary and mandibular arches, 22 patients received an essix retainer (Pro-form, Keystone Industries, PA, USA) in addition to the stainless steel wire, and 22 patients were treated with a duran retainer (Duran, Scheu-dental, Iserlohn, Germany) alongside the stainless steel wire. Alginate impressions were taken from the upper and lower arches of the patients at different time points: pre-treatment, at the end of treatment, 3 months, 6 months, and 12 months post-treatment. These impressions were used to create plaster models, which were then scanned to produce digital models. Using a software program capable of making measurements on digital models (Orthomodel, Istanbul, Turkey), the intercanine distance, intermolar distance, Little's irregularity index, and the amount of space reopening were measured. Additionally, during control appointments, the integrity of the wires (e.g., breakage, loosening) and the essix retainers (e.g., wear, tearing) was evaluated. Results showed that after a 12-month follow-up period, no significant differences were found between the fixed retainer, the fixed retainer combined with the essix retainer, and the fixed retainer combined with the duran retainer in terms of intercanine distance, intermolar distance, Little's irregularity index, or the amount of space reopening. No instances of wire breakage or wear and tear of the clear aligners were observed in any of the groups. It was concluded that all three methods could be suitable as retention strategies in cases involving premolar extractions. Keywords: premolar extraction, retention, relapse, space reopening