title: The effect of latency on bone lengthening force and bone mineralization: an investigation using strain gauge mounted on internal distractor device.
abstract: BACKGROUND
  The purpose of this study was to investigate the effect of latency on the development of bone lengthening force and bone mineralization during mandible distraction osteogenesis.
  
  
  METHODS
  Distraction tensions were investigated at different latency period in 36 rabbits using internal unilateral distractor. Strain gauges were prepared and attached to the distractor to directly assess the level of distraction tension during mandible lengthening. The tensile force environment of the mandible of rabbit during distraction was evaluated through in vivo experiments using two gauges. The animals were divided into 3 groups each containing 12 rabbits. Latency periods of 0, 4 and 7 days respectively were observed prior to beginning distraction. The distraction protocol consisted of a lengthening rate of 1 mm once daily for 8 days, followed by a consolidation phase of 2 weeks after which the animals were killed. Biopsies specimens were taken from the distracted area at the end of the distraction period. A non-distracted area of the mandible bone served as control. The specimens were analyzed by scanning electron microscopy to assess the ultrastructural pattern, and the bone mineralization.
  
  
  RESULTS
  The resting tension acting on the distraction gap increases through distraction. The 7-day latency groups exhibit higher tension then those of 0-day and 4-days latency groups. Quantitative energy dispersive spectral analysis confirmed that immediate distractions were associated with lower calcium and phosphate atomic weight ratio.
  
  
  CONCLUSIONS
  the latency periods could affect the bone lengthening tension and the bone mineralization process.
authors.affiliation: The key Laboratory of Biomedical Information Engineering of Ministry of Education, Institute of Biomedical Engineering, Xi'an Jiaotong University, Xi'an, 710049, China. sekou2d@yahoo.com
authors.forename: Sekou
authors.initials: S
authors.lastname: Singare
authors.forename: Dichen
authors.initials: D
authors.lastname: Li
authors.forename: Yaxiong
authors.initials: Y
authors.lastname: Liu
authors.forename: Zhongying
authors.initials: Z
authors.lastname: Wu
authors.forename: Jue
authors.initials: J
authors.lastname: Wang
mesh_terms: D000818:Animals; D002113:Calcification, Physiologic / Q000502:physiology*; D008334:Mandible / Q000502:physiology* / Q000601:surgery*; D019857:Osteogenesis, Distraction / Q000295:instrumentation / Q000379:methods*; D011817:Rabbits; D013314:Stress, Mechanical; D013997:Time Factors; D014159:Transducers; D016896:Treatment Outcome