title: The effect of varying healing times on orthodontic mini-implant stability: a microscopic computerized tomographic and biomechanical analysis.
abstract: OBJECTIVE
  The aim of this study was to evaluate the effect of different healing times on the stability of titanium mini-implants used for orthodontic anchorage.
  
  
  METHODS
  Eight male beagles were used and randomized into 4 groups according to different healing times (1, 3, 5, and 7 weeks); each group had 2 beagles. Sixty-four mini-implants were inserted bilaterally in the maxilla and mandible of the beagles. Microscopic computerized tomography (μCT) and pull-out test were used for morphometric and biomechanical analysis, respectively.
  
  
  RESULTS
  All μCT parameters and F(max) (maximum pull-out force) increased with the prolongation of healing time. One week after insertion, all 4 measurements, namely osseointegration, trabecular bone volume density, intersection surface, and F(max), were lower in the maxilla group than in the mandible group (P < .05). Between the span of 1 and 3 weeks after insertion, a more obvious rising tendency of the 4 values was observed in the maxilla group than in the mandible group. Five and 7 weeks after insertion, the maxilla group expressed higher values of the 4 measurements than the mandible group (P < .05).
  
  
  CONCLUSIONS
  Although insertion in the mandible could provide higher primary stability for mini-implants, with the prolongation of healing time, insertion in the maxilla achieves higher osseointegration. The results indicated that insertion in maxilla has a more positive effect on the stability of mini-implants than insertion in the mandible.
authors.affiliation: State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhang
authors.forename: Lixing
authors.initials: L
authors.lastname: Zhao
authors.forename: Yeke
authors.initials: Y
authors.lastname: Wu
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.forename: Zhihe
authors.initials: Z
authors.lastname: Zhao
authors.forename: Zhenrui
authors.initials: Z
authors.lastname: Xu
authors.forename: Xing
authors.initials: X
authors.lastname: Wei
authors.forename: Tian
authors.initials: T
authors.lastname: Tang
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D015519:Bone Density / Q000502:physiology; D015921:Dental Implants; D004285:Dogs; D021621:Imaging, Three-Dimensional / Q000379:methods; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging / Q000503:physiopathology; D008437:Maxilla / Q000000981:diagnostic imaging / Q000503:physiopathology; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation*; D016348:Osseointegration / Q000502:physiology; D011897:Random Allocation; D013314:Stress, Mechanical; D013997:Time Factors; D014945:Wound Healing / Q000502:physiology; D055114:X-Ray Microtomography / Q000379:methods*
chemical_list: D015921:Dental Implants