title: Comparison of two preoperative protocols for mandibular symphyseal distraction osteogenesis to reduce the risk of tooth damage.
abstract: Two techniques to separate the lower incisors prior to mandibular symphyseal distraction osteogenesis (MSDO) were evaluated with respect to avoiding tooth damage.
  
  
  METHODS
  Fifty patients (20.2 ± 7.0 years) requiring MSDO were treated with a tooth-borne appliance by utilizing two preoperative protocols to separate the central incisors: i) brackets and a V-bent wire with an open coil spring (two-step; TS; n = 24) and ii) a wire attached from the appliance to the central incisors with subsequent dento-alveolar expansion prior to surgery (one-step; OS; n = 26). The distance between the lower incisors was measured preoperatively on radiographs and measurements at the cast models were performed. Complications and radiographs were analyzed.
  
  
  RESULTS
  The mean distance (±SD) between the lower central incisors for OS and TS prior to surgery was 3.44 ± 1.05 and 3.18 ± 1.13 mm, respectively. The mean expansion for OS and TS was 4.3 ± 2.9 and 4.3 ± 2.7 mm at the dental level and 3.8 ± 3.2 and 4.0 ± 2.1 mm at the bone level, respectively. Four patients undergoing the TS and one patient undergoing the OS showed transient dental complications.
  
  
  CONCLUSIONS
  Pre-surgical dento-alveolar expansion by utilizing a one-step technique to separate the lower central incisors reduces the risk of permanent tooth damage and weakens the mandibular bone in the midline.
authors.affiliation: Dental School, University of Graz, Austria.
authors.forename: Heinz
authors.initials: H
authors.lastname: Winsauer
authors.affiliation: Department of Oral and Maxillofacial Surgery, Academic Teaching Hospital, Feldkirch, Austria. Electronic address: oliver.ploder@lkhf.at.
authors.forename: Oliver
authors.initials: O
authors.lastname: Ploder
authors.affiliation: Department of Oral- and Cranio-Maxillofacial Surgery, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Juengling
authors.affiliation: Department of Orthodontics and Dentofacial Orthopaedics, School of Dentistry, Universitat Internacional de Catalunya, Barcelona, Spain.
authors.forename: Andre
authors.initials: A
authors.lastname: Walter
authors.affiliation: Department of Oral- and Cranio-Maxillofacial Surgery, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Kolk
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002985:Clinical Protocols; D005260:Female; D006801:Humans; D007180:Incisor / Q000601:surgery*; D007431:Intraoperative Complications / Q000517:prevention & control*; D008297:Male; D008334:Mandible / Q000601:surgery*; D019857:Osteogenesis, Distraction / Q000379:methods*; D011300:Preoperative Care / Q000379:methods*; D012307:Risk Factors; D018677:Tooth Injuries / Q000517:prevention & control*; D055815:Young Adult
keywords: Complication; Mandibular symphyseal distraction osteogenesis; Relapse; Tooth damage; Tooth-borne appliance