title: Development of a novel spike-like auxiliary skeletal anchorage device to enhance miniscrew stability.
abstract: BACKGROUND
  Miniscrews are frequently used for skeletal anchorage during edgewise treatment, and their clinical use has been verified. However, their disadvantage is an approximately 15% failure rate, which is primarily attributed to the low mechanical stability between the miniscrew and cortical bone and to the miniscrew's close proximity to the dental root. To solve these problems, we developed a novel spike-like auxiliary skeletal anchorage device for use with a miniscrew to increase its stability.
  
  
  METHODS
  The retention force was compared between miniscrews with and without the auxiliary skeletal anchorage device at each displacement of the miniscrew. The combined unit was also implanted into the bones of 2 rabbits in vivo, and implantation was visually assessed at 4 weeks postoperatively while the compression force was applied.
  
  
  RESULTS
  The retention force of the combined unit was significantly and approximately 3 to 5 times stronger on average than that of the miniscrew alone at each displacement. The spiked portion of the auxiliary anchorage device embedded into the cortical bone of the hind limb at approximately a 0.3-mm depth at 4 weeks postimplantation in both rabbits.
  
  
  CONCLUSIONS
  The auxiliary skeletal anchorage device may increase miniscrew stability, allow a shortened miniscrew, and enable 3-dimensional absolute anchorage. Further evaluation of its clinical application is necessary.
authors.affiliation: Professor and chair, Department of Orthodontics, Field of Developmental Medicine, Health Research Course, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan. Electronic address: miyawaki@dent.kagoshima-u.ac.jp.
authors.forename: Shouichi
authors.initials: S
authors.lastname: Miyawaki
authors.affiliation: Assistant professor, Department of Orthodontics, Field of Developmental Medicine, Health Research Course, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tomonari
authors.affiliation: Lecturer, Department of Orthodontics, Field of Developmental Medicine, Health Research Course, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan.
authors.forename: Takakazu
authors.initials: T
authors.lastname: Yagi
authors.affiliation: Assistant professor, Department of Orthodontics, Field of Developmental Medicine, Health Research Course, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan.
authors.forename: Takaharu
authors.initials: T
authors.lastname: Kuninori
authors.affiliation: Postgraduate student, Department of Orthodontics, Field of Developmental Medicine, Health Research Course, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan.
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Oga
authors.affiliation: Professor and chair, Department of Biomaterials Science, Field of Oral and Maxillofacial Rehabilitation, Advanced Therapeutic Course, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Kikuchi
mesh_terms: D000497:Alloys; D000818:Animals; D001863:Bone Screws; D003722:Dental Alloys / Q000737:chemistry; D055119:Elastic Modulus; D005260:Female; D006614:Hindlimb / Q000601:surgery; D008297:Male; D008422:Materials Testing; D008904:Miniaturization; D008953:Models, Anatomic; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation*; D016382:Orthodontic Appliance Design; D011140:Polyurethanes / Q000737:chemistry; D011817:Rabbits; D012828:Silicones / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength; D014025:Titanium / Q000737:chemistry
chemical_list: D000497:Alloys; D003722:Dental Alloys; D011140:Polyurethanes; D012828:Silicones; C031462:titanium alloy (TiAl6V4); D014025:Titanium