title: Treatment options in distraction osteogenesis therapy using a new bidirectional distractor system.
abstract: OBJECTIVE
  The purpose of this retrospective study was to compare a bidirectional distraction system with a unidirectional system with regard to bone height attained and the need for secondary graft procedures.
  
  
  METHODS
  Unidirectional and bidirectional distractor devices were used for vertical augmentation of the maxilla and mandible in 2 separate groups of patients (n = 10 and n = 11, respectively). Clinical and radiographic outcome data were collected at postoperative follow-up examinations for up to 2.5 years. The height of the augmented alveolar ridge and the sagittal location of the bone fragment were measured on panoramic radiographs or lateral cephalograms. These data were analyzed with 1-way analysis of variance. Nonparametric data, such as treatment complications, were analyzed with the Fisher exact test. The dental implant survival data were evaluated with a Kaplan-Meier survival analysis.
  
  
  RESULTS
  The difference in vertical bone gain observed between unidirectional and bidirectional groups (5.3 +/- 1.8 mm vs 6.1 +/- 2.3 mm) was not statistically significant. In the unidirectional group, additional autogenous bone grafting was required in 6 cases, while grafting was required in only 2 cases in the bidirectional group. This difference was due to the more precise control of the distraction process associated with the bidirectional distractor; however, it was not a statistically significant difference. Postaugmentation, 59 implants were placed in the augmented sites. These implants exhibited primary stability and were restored with good functional and esthetic results.
  
  
  CONCLUSIONS
  The need for additional grafting procedures may be reduced in cases where the distraction vector is optimized, as generally seen with bidirectional distractor use.
authors.affiliation: Clinic of Maxillofacial Surgery/Plastic Surgery, Friedrich Schiller University, Jena, Germany. schleier@online.no
authors.forename: Peter
authors.initials: P
authors.lastname: Schleier
authors.forename: Christina
authors.initials: C
authors.lastname: Wolf
authors.forename: Hansgeorg
authors.initials: H
authors.lastname: Siebert
authors.forename: David
authors.initials: D
authors.lastname: Shafer
authors.forename: Martin
authors.initials: M
authors.lastname: Freilich
authors.forename: Alexander
authors.initials: A
authors.lastname: Berndt
authors.forename: Dieter
authors.initials: D
authors.lastname: Schumann
mesh_terms: D000328:Adult; D000368:Aged; D000539:Alveolar Process / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D000540:Alveolar Ridge Augmentation / Q000295:instrumentation* / Q000379:methods; D000704:Analysis of Variance; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019857:Osteogenesis, Distraction / Q000295:instrumentation* / Q000379:methods; D011859:Radiography; D012189:Retrospective Studies; D018709:Statistics, Nonparametric