title: Evaluation of fixation of expandable implants in the mandibles of ovariectomized sheep.
abstract: OBJECTIVE
  This study aimed to investigate the effects of an expandable implant (EI) in ovariectomized sheep.
  
  
  METHODS
  The EI and taper implant (control group) were produced and placed in mandibles of ovariectomized sheep. Twelve weeks after implantation, resonance frequency analysis, biomechanical tests, histomorphometry, and micro-computed tomography were applied to detect the osseointegration in the 2 groups.
  
  
  RESULTS
  The implant stability quotient values, maximal pullout forces, and bone-implant contact (BIC) were 60.3 ± 7.9, 511.0 ± 18.7 N, and 53.14% ± 4.56%, respectively, in the EI group and 58.3 ± 8.9, 394.5 ± 54.5 N, and 46.85% ± 5.04%, respectively, in the control group. There was no significant difference between the 2 groups in implant stability quotient values (P > .05); however, in the EI group the maximal pullout force and BIC were increased significantly (P < .05 and P < .01, respectively). Micro-computed tomography analysis showed that the bone volume/total volume ratio and trabecular number increased significantly (P < .01) and trabecular separation decreased significantly (P < .05) in the EI group.
  
  
  CONCLUSIONS
  EI could improve osseointegration in osteoporosis after 12 weeks of implantation by increasing BIC around the implant and by supplying an extra osseointegration surface.
authors.affiliation: Department of Stomatology, PLA 252 Hospital, Baoding, China.
authors.forename: Jian-Rui
authors.initials: JR
authors.lastname: Xiao
authors.forename: De-Hua
authors.initials: DH
authors.lastname: Li
authors.forename: Yu-Xuan
authors.initials: YX
authors.lastname: Chen
authors.forename: Shu-Jun
authors.initials: SJ
authors.lastname: Chen
authors.forename: Su-Min
authors.initials: SM
authors.lastname: Guan
authors.forename: Liang
authors.initials: L
authors.lastname: Kong
mesh_terms: D000818:Animals; D015519:Bone Density; D017076:Computer-Aided Design; D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention; D003799:Dental Stress Analysis; D005260:Female; D008334:Mandible / Q000601:surgery; D016348:Osseointegration; D010024:Osteoporosis / Q000534:rehabilitation; D010052:Ovariectomy; D034561:Sheep, Domestic; D055114:X-Ray Microtomography
chemical_list: D015921:Dental Implants