title: The centered T-loop--a new way of preactivation.
abstract: The force system of a prefabricated and preactivated T-loop used for reciprocal space closure was determined by simultaneously measuring the horizontal and vertical forces, as well as the moments using a computer controlled measuring apparatus. Interbracket distances of 21, 24, 27, and 30 mm were used to mimic typical clinical situations. At a loop activation of 7 mm, the anterior and posterior segments first underwent controlled tipping, then translation, and finally, root uprighting as the moment-to-force ratio increased with deactivation. After the loop has been deactivated to 4 mm, however, it should be exchanged to avoid root abutment.
authors.affiliation: Department of Orthodontics, School of Dental Medicine, University of Vienna, Austria.
authors.forename: K D
authors.initials: KD
authors.lastname: Hoenigl
authors.forename: J
authors.initials: J
authors.lastname: Freudenthaler
authors.forename: M R
authors.initials: MR
authors.lastname: Marcotte
authors.forename: H P
authors.initials: HP
authors.lastname: Bantleon
mesh_terms: D000704:Analysis of Variance; D003799:Dental Stress Analysis; D003970:Diastema / Q000209:etiology / Q000628:therapy; D004548:Elasticity; D006801:Humans; D008961:Models, Structural; D016382:Orthodontic Appliance Design; D009967:Orthodontic Appliances; D009971:Orthodontics, Corrective / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012399:Rotation; D013314:Stress, Mechanical; D014081:Tooth Extraction / Q000009:adverse effects; D016388:Tooth Loss / Q000209:etiology / Q000628:therapy*