title: Biomechanical and histomorphometric analyses of the osseointegration of microscrews with different surgical techniques in beagle dogs.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the difference between the drill-free method and the drilling method regarding their effects on microscrew stability after 2, 4 and 8 weeks of implantation.
  
  
  METHODS
  Thirty-six screw-type microscrews were inserted into the buccal region of the maxilla in 6 beagle dogs. The microscrews were divided into 2 groups of 18 each: the drill-free group and the drilling group. Microscrews in the drill-free group were inserted without drilling, and those in the drilling group were inserted into the site that had been drilled with a pilot drilling bur. After 2, 4, and 8 weeks of healing, the dogs were killed and all bone-screw specimens were prepared for biomechanical testing, histologic observation, and histomorphometric evaluation.
  
  
  RESULTS
  Histologic observations revealed a continuing bone remodeling with new bone formation in the periscrew region in both groups. The pullout force and the bone-implant contact were significantly higher in the drill-free groups compared with the drilling groups for the 2 and 4 weeks (P < .05), but there was no significant difference after 8 weeks' healing period (P > .05).
  
  
  CONCLUSIONS
  The present study demonstrated that drill-free microscrews could provide stronger stability in the maxilla than the drilling microscrews in the early phase of healing.
authors.affiliation: Department of Orthodontics, West China College of Stomatology, Sichuan University, Chengdu, China.
authors.forename: Xiuping
authors.initials: X
authors.lastname: Wu
authors.forename: Feng
authors.initials: F
authors.lastname: Deng
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Wang
authors.forename: Zhihe
authors.initials: Z
authors.lastname: Zhao
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
mesh_terms: D000539:Alveolar Process / Q000601:surgery; D000818:Animals; D001696:Biomechanical Phenomena; D001863:Bone Screws; D003755:Dental High-Speed Technique; D003758:Dental Implantation, Endosseous / Q000379:methods*; D003799:Dental Stress Analysis; D004285:Dogs; D005260:Female; D020007:Implants, Experimental; D008904:Miniaturization; D052280:Orthodontic Anchorage Procedures / Q000379:methods; D016348:Osseointegration