title: Effect of force on alveolar bone surrounding miniscrew implants: a 3-dimensional microcomputed tomography study.
abstract: BACKGROUND
  The primary aim of this study was to better understand how bone adapts to forces applied to miniscrew implants. A secondary aim was to determine whether the direction of force applied to miniscrew implants has an effect on bone surrounding the miniscrew implants.
  
  
  METHODS
  A randomized split-mouth design, applied to 6 skeletally mature male foxhound dogs, was used to compare miniscrew implants loaded for 9 weeks with 200 or 600 g to unloaded control miniscrew implants. By using microcomputed tomography, with an isotropic resolution of 6 μm, bone volume fractions (bone volume/total volume) were calculated for bone around the entire miniscrew implant surface. Bone volume fractions were calculated for bone 6 to 24, 24 to 42, and 42 to 60 μm from the miniscrew implant surface. For each loaded miniscrew implant, the bone volume fraction was also calculated for 2 compression and 2 noncompression zones.
  
  
  RESULTS
  The 6 to 24-μm layer showed a significantly lower (P <0.05) bone volume fraction than did the 24 to 42-μm and the 42 to 60-μm layers, which were not significantly different. The bone volume fractions of cortical bone surrounding the apical aspects of the unloaded miniscrew implants were significantly greater (P <0.05) than the bone volume fractions of cortical bone surrounding the loaded miniscrew implants. In contrast, the bone volume fractions of noncortical bone surrounding loaded miniscrew implants were significantly greater (P <0.05) than the bone volume fractions of bone surrounding the unloaded miniscrew implants. Miniscrew implants loaded with 200 g showed significantly greater (P <0.05) amounts of noncortical bone volume fractions than did miniscrew implants loaded with 600 g. With both 200 and 600 g, zones under compression had significantly greater bone volume fractions than did the noncompression zones.
  
  
  CONCLUSIONS
  The application of force, the amount of force applied, and the direction of force all have significant effects on the amounts of bone produced around miniscrew implants.
authors: Restorative Sciences, Baylor College of Dentistry, Texas A&M Health Science Center, Dallas, TX 75246, USA.
authors: Christopher C
authors: CC
authors: Massey
authors: Elias
authors: E
authors: Kontogiorgos
authors: Reginald
authors: R
authors: Taylor
authors: Lynne
authors: L
authors: Opperman
authors: Paul
authors: P
authors: Dechow
authors: Peter H
authors: PH
authors: Buschang
mesh_terms: D000539:Alveolar Process / Q000000981:diagnostic imaging / Q000473:pathology*; D000818:Animals; D015519:Bone Density / Q000502:physiology; D001863:Bone Screws; D003722:Dental Alloys / Q000737:chemistry; D015921:Dental Implants; D004285:Dogs; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging / Q000473:pathology*; D009532:Nickel / Q000737:chemistry; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation*; D016382:Orthodontic Appliance Design; D009969:Orthodontic Wires; D011897:Random Allocation; D013193:Stainless Steel / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors; D014025:Titanium / Q000737:chemistry; D055114:X-Ray Microtomography / Q000379:methods*
chemical_list: D003722:Dental Alloys; D015921:Dental Implants; C040654:titanium nickelide; D013193:Stainless Steel; D009532:Nickel; D014025:Titanium