The aim of this study was to compare dental arch-width and perimeter changes in patients with borderline Class I occlusion, treated with extractions or without extractions with air-rotor stripping (ARS).
The study was conducted with 26 sets of pretreatment and posttreatment dental models of patients with borderline Class I occlusion. Thirteen patients (mean age, 18.1 ± 3.7 years) were treated with 4 premolar extractions, and 13 (mean age, 17.8 ± 2.4 years) were treated without extractions but with the ARS technique. Mean maxillary and mandibular crowding values were 5.7 ± 1.5 and 5.9 ± 1.4 mm in the extraction group, and 5.0 ± 1.3 and 5.9 ± 1.3 mm in the nonextraction group, respectively. A digital caliper was used to measure maxillary and mandibular intercanine and intermolar arch widths and arch perimeters. The Wilcoxon test was used to evaluate treatment changes in each group. The Mann-Whitney U test was used to compare the pretreatment and posttreatment values and the treatment changes between the 2 groups.
At the start of treatment, the maxillary and mandibular intercanine and intermolar widths and the arch perimeters of both groups did not differ statistically. The maxillary intercanine widths were maintained in both groups. The maxillary and mandibular intermolar widths and arch perimeters decreased in the extraction group. In the nonextraction group, intermolar widths decreased, but arch perimeters did not change significantly. After treatment, the maxillary and mandibular intercanine widths were not different between the groups.
In Class I borderline patients with moderate crowding, extraction therapy with minimum anchorage did not result in narrower dental arches, and nonextraction treatment with ARS preserved the intercanine arch widths and arch perimeters.
Even experienced clinicians occasionally have difficulty deciding whether to extract teeth in a patient with a Class I malocclusion and moderate crowding. They might ask themselves, “Should I extract or not? Does it make any difference?” The literature is not definitive, and even veterans wonder whether there are other options. The aim of this clinical study was to assess arch-width and perimeter changes in Class I borderline patients treated with extractions or treated nonextraction but with ARS.
The sample included 26 borderline Angle Class I patients with moderate dental crowding who could have been treated either with or without extractions to achieve balanced facial profiles and dentoskeletal relationships. Patients who met the inclusion criteria were randomly divided into 2 groups prospectively. In the first group, 13 subjects were treated with the extraction of 4 premolars; in the second group, the patients were treated nonextraction, and ARS was used to gain space for alignment. All subjects were treated successfully, resulting in good occlusions, Class I dental relationships, and coordinated arches. With the small sample size, the results should be carefully evaluated, but they are encouraging.
ARS might be a useful treatment alternative when anteroposterior and lateral expansion of the dental arches must be avoided.
In Class I borderline patients with moderate crowding, nonextraction treatment with ARS preserved the maxillary and mandibular intercanine widths and arch perimeters.
There was no difference between intercanine widths after treatment with extraction or nonextraction combined with ARS.