Short-term postorthodontic changes in the absence of retention.

OBJECTIVE: To evaluate short-term postorthodontic tooth movement without retention.
MATERIALS AND METHODS: Thirty consenting patients participated in the study. At the end of active treatment (T(1)), final archwires were removed while leaving the fixed appliances on, and alginate impressions were taken. Four weeks later (T(2)) a second set of impressions was taken. A clinical examination performed at T(2) determined if the fixed appliances could be removed or if additional treatment was required. Based on the examination, patients were divided into two groups. Patients in group I (n = 13) had their fixed appliances removed, while those in group II (n = 17) required additional treatment. The American Board of Orthodontics' Objective Grading System scores and the following six variables were measured on plaster casts at T(1) and T(2): maxillary and mandibular crowding or spacing, overbite, overjet, and mandibular intercanine and intermolar widths. Data were analyzed to detect potential changes from T(1) to T(2) and to evaluate differences between the groups.
RESULTS: Mandibular crowding, overjet, and interproximal contacts worsened for the entire sample, while marginal ridges, occlusal contacts, and total American Board of Orthodontics scores improved. No statistically significant changes were found within group I from T(1) to T(2). Mandibular crowding, overbite, overjet, alignment/rotations, and interproximal contacts worsened within group II from T(1) to T(2), while marginal ridges and occlusal contacts improved. Significant differences were noted between the groups in terms of alignment/rotations, interproximal contacts, and mandibular intercanine width.
CONCLUSION: Short-term postorthodontic tooth movement without retainers demonstrated improvement in specific characteristics of the occlusion but negatively affected alignment and interproximal contacts in the sample.