Comparison of the intrusive effects of miniscrews and utility arches.

INTRODUCTION: The aim of this prospective study was to compare the effects of incisor intrusion obtained with the aid of miniscrews and utility arches.

METHODS: Twenty-four patients (10 male, 14 female) with a deepbite of at least 4 mm were divided to 2 groups. In group 1, 13 patients (3 male, 10 female; mean age, 20.90 ± 7.12 years) in the postpubertal growth period were treated by using miniscrews; in group 2, 11 patients (7 male, 4 female; mean age, 15.25 ± 3.93 years) were treated with utility arches. Lateral cephalometric headfilms were taken at the beginning of treatment and after intrusion for the evaluation of the treatment changes. Statistical analyses of the data were performed with a significance level of P <0.05.

RESULTS: Intrusion lasted 6.61 ± 2.95 months for group 1 and 6.61 ± 2.46 months for group 2. The changes in the center of resistance of the incisors were 1.75 ± 0.4 mm (P <0.05) for group 1 and 0.86 ± 0.5 mm (P >0.05) for group 2; the difference between the groups was significant (P <0.05). In the miniscrew group, the incisors were protruded 0.79 ± 1.4 mm (P >0.05) relative to pterygoid vertical and 3.85° ± 2.4° (P >0.05) relative to the palatal plane. In group 2, the incisors showed 3.91 ± 0.7 mm (P <0.05) of protrusion relative to pterygoid vertical and 13.55° ± 2.4° (P <0.05) relative to the palatal plane. The maxillary first molars showed significant distal tipping in group 2 (P <0.05).

CONCLUSIONS: Unlike with utility arches, true maxillary incisor intrusion can be achieved by application of intrusive forces close to the center of resistance by using miniscrews with no counteractive movements in the molars.