Effects of extraction and nonextraction therapy with air-rotor stripping on facial esthetics in postadolescent borderline patients.Am J Orthod Dentofacial Orthop. 2008 Apr; 133(4):539-49.AJ
A prospective randomized study was designed to compare the skeletal, dental, and soft-tissue profile changes in Class I borderline patients treated with extraction and nonextraction by means of the air-rotor stripping (ARS) technique and to compare the treatment times.
Twenty-six borderline patients with balanced and orthognathic facial profiles were randomly divided into 2 groups. In the first group, 13 subjects with a mean age of 18.1 +/- 3.7 years and mean maxillary and mandibular crowding of 5.7 +/- 1.5 and 5.9 +/- 1.4 mm, respectively, were treated by removal of 4 premolars with minimum anchorage. In the second group, 13 subjects with a mean age of 17.8 +/- 2.4 years and mean maxillary and mandibular crowding of 5.0 +/- 1.3 and 5.9 +/- 1.3 mm, respectively, were treated with ARS. Lateral cephalometric radiographs and dental models taken before and after treatment were evaluated.
The initial skeletal, dental, and profile characteristics of both groups were similar. In the first group, the maxillary and mandibular incisors were slightly retracted, whereas lip positions did not change. In the nonextraction group, maintenance of maxillary incisor position, slight protrusion of the mandibular incisors and the upper and lower lips were observed at the end of treatment. The nasolabial angle decreased significantly. Because of postpubertal growth of the nose and the chin, the lips appeared slightly retrusive after extraction therapy, whereas lip protrusion was compensated in the nonextraction group. The main soft-tissue profile differences between the 2 groups were 1 to 1.5 mm more retruded upper and lower lip positions in the extraction patients, but both groups had well-balanced and desirable facial esthetics with all profile measurements within normal limits. Nonextraction therapy with ARS reduced treatment time by 8 months.
Both extraction and ARS combined with nonextraction therapies are effective treatment alternatives for Class I borderline patients with good facial profile and moderate dental crowding.