title: Single versus triple daily activation of the distractor: no significant effects of frequency of distraction on bone regenerate quantity and architecture.
abstract: OBJECTIVE
  To study the effect of two different frequencies of distraction on the quantity and architecture of bone regenerate using micro-computed tomography, and to determine whether radiographic and ultrasonographic bone-fill scores provide reliable predictive value for the amount of new bone in the distraction area.
  
  
  METHODS
  Twenty-six skeletally mature rabbits underwent three full days of latency, after which midface distraction was started. Low-frequency group (n=12): a distraction rate of 0.9 mm/d achieved by one daily activation for 11 days to create a 10mm distraction gap. High-frequency group (n=12): idem, but three daily activations were used instead of one. Control group (n=2) underwent no distraction. After 21 days of consolidation, bone-fill in the distraction area was assessed by means of ultrasonography and radiography. Micro-computed tomography was used to quantify new bone formation and bone architecture.
  
  
  RESULTS
  Relative bone volume (BV/TV) showed a tendency towards a difference (P=0.09) between the low and high-frequency groups. No significant differences were found for bone architecture. No significant correlation between BV/TV values and bone-fill scores was found.
  
  
  CONCLUSIONS
  An increase in rhythm from one to three activations daily does not create significantly more bone. Bone-fill score values provided no reliable predictive value for the amount of new bone formation.
authors: Department of Oral and Maxillofacial Surgery, Erasmus MC, University Medical Center, Rotterdam, The Netherlands (Chair: Prof. K.G.H. van der Wal, DDS, MD, PhD). Electronic address: u.djasim@erasmusmc.nl.
authors: Urville Mardijanto
authors: UM
authors: Djasim
authors: Department of Oral and Maxillofacial Surgery, Erasmus MC, University Medical Center, Rotterdam, The Netherlands (Chair: Prof. K.G.H. van der Wal, DDS, MD, PhD).
authors: Eppo Bonne
authors: EB
authors: Wolvius
authors: Department of Plastic and Reconstructive Surgery, Erasmus MC, University Medical Center, Rotterdam, The Netherlands (Chair: Prof. S.E.R. Hovius, MD, PhD).
authors: Johan Wilhelm
authors: JW
authors: Van Neck
authors: Department of Biomedical Engineering, Erasmus MC, University Medical Center, Rotterdam, The Netherlands (Chair: Prof. A.F.W. van der Steen, PhD).
authors: Annemieke
authors: A
authors: Van Wamel
authors: Orthopaedic Research Laboratory of the Department of Orthopaedics, Erasmus MC, University Medical Center, Rotterdam, The Netherlands (Chair: Prof. H. Weinans, PhD).
authors: Harrie
authors: H
authors: Weinans
authors: Department of Oral and Maxillofacial Surgery, Erasmus MC, University Medical Center, Rotterdam, The Netherlands (Chair: Prof. K.G.H. van der Wal, DDS, MD, PhD).
authors: Karel George Hendrik
authors: KGH
authors: Van Der Wal
mesh_terms: D000818:Animals; D015519:Bone Density / Q000502:physiology; D001861:Bone Regeneration / Q000502:physiology*; D016267:External Fixators; D005260:Female; D007091:Image Processing, Computer-Assisted; D023421:Models, Animal; D009295:Nasal Bone / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D010012:Osteogenesis / Q000502:physiology; D019857:Osteogenesis, Distraction / Q000295:instrumentation / Q000379:methods*; D011237:Predictive Value of Tests; D011817:Rabbits; D011897:Random Allocation; D015203:Reproducibility of Results; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography