title: Treatment effects and anchorage potential of sliding mechanics with titanium screws compared with the Tweed-Merrifield technique.
abstract: The purposes of this study were to quantify the treatment effects of titanium screws on en-masse retraction of 6 anterior teeth and to compare the anchorage potential of treatment with titanium screws with the Tweed-Merrifield technique, which requires patient compliance with a high-pull J-hook. Sixteen nongrowing patients (14 women, 2 men; ages, 22.5 +/- 4.8 years) who had been treated orthodontically for bialveolar protrusion were selected. All patients had 2 maxillary first premolars extracted, 13 had mandibular first premolars extracted, and 3 had second premolars extracted. Maxillary titanium screws were placed in all patients to provide anchorage for retraction of 6 anterior teeth. Screws were placed in 8 patients to apply intrusive force to the mandibular posterior teeth. To compare the anchorage potential with a high-pull J-hook, 14 nongrowing patients (11 women, 3 men; ages, 22.9 +/- 4.0 years) who were treated with the Tweed-Merrifield technique and had an excellent compliance with a high-pull J-hook were used. There was more anchorage loss of the maxillary posterior teeth in the Tweed-Merrifield group than in the titanium screw group. Both groups had excellent vertical control of the maxillary posterior teeth. There was a skeletal effect on the maxilla--reduction of A-point in the titanium screw group; this contributed to improvement of the facial profile. Treatment time in the titanium screw group was less compared with the Tweed-Merrifield technique. The success rate for the titanium screws was 87% in 25.6 +/- 5.5 months. These results suggest that titanium screws can provide acceptable and reliable anchorage and might produce skeletal effects on the maxilla.
authors.affiliation: Department of Orthodontics, School of Dentistry, Kyungpook National University, Daegu, Korea. parkhs@knu.ac.kr
authors.forename: Hyo-Sang
authors.initials: HS
authors.lastname: Park
authors.forename: Duk-Young
authors.initials: DY
authors.lastname: Yoon
authors.forename: Chang-Suk
authors.initials: CS
authors.lastname: Park
authors.forename: Seong-Hwa
authors.initials: SH
authors.lastname: Jeoung
mesh_terms: D000328:Adult; D001863:Bone Screws; D002508:Cephalometry; D005115:Extraoral Traction Appliances; D005260:Female; D006801:Humans; D007180:Incisor / Q000503:physiopathology; D008297:Male; D008310:Malocclusion / Q000628:therapy*; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation / Q000379:methods*; D016910:Orthodontic Brackets; D009971:Orthodontics, Corrective / Q000379:methods; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome