title: The osseointegration behavior of titanium-zirconium implants in ovariectomized rabbits.
abstract: OBJECTIVE
  The aim of this study is to compare the osseointegration behavior of titanium (Ti) and titanium-zirconium (TiZr) implants in ovariectomized (OVX) rabbits.
  
  
  METHODS
  Twelve ovariectomized New Zealand rabbits submitted to a hypocalcic diet and 12 sham-aged rabbits were used. After the bone mass loss induction period, TiZr or Ti implants both benefiting from a SLActive surface treatment were randomly inserted in the tibia and femur of each animal. The total of 24 rabbits were divided in four groups (n = 6): SHAM + Ti, OVX + Ti, SHAM + TiZr,OVX + TiZr. The animals were respectively sacrificed 3 and 6 weeks after dental implant placement. Six implants in each group at each time point were subjected to removal torque testing, and the remaining implants were prepared for histomorphometric analysis.
  
  
  RESULTS
  At the end of the healing period, all implants were osseointegrated. The removal torque value of the SHAM-TiZr group was significantly higher than those of the SHAM-Ti group (P < 0.001). The removal torque of the OVX-Ti group was significantly lower than those of the OVX-TiZr group. All groups demonstrated an increase in the peak torque value after 6 weeks: 46.0 and 50.8 Ncm for the OVX and the SHAM animals, respectively, in the case where Ti implants were used. When TiZr implants were inserted, the values reached 60.7 and 76.2 Ncm with a similar group configuration. The BIC and the BA/TA analysis showed an increase between week 3 and 6 in the case of nonovariectomized animals. From week 3 to 6, the BIC went from 37.1 ± 14.3 to 47.7 ± 8.7 for the SHAM + Ti group and from 37.6 ± 10.9 to 50.4 ± 11 for the SHAM + TiZr group. The BIC values were not significantly different between groups.
  
  
  CONCLUSIONS
  The parameters intended to be representative of the bone morphology (BIC & BATA) did not help to discriminate between Ti and TiZr which appeared to behave similarly in this experimental model. However, the removal torque values for the TiZr group were statistically higher than those of the Ti group in both the SHAM and the ovariectomized animals. That likely reflected an increased quality of bone around the TiZr implants.
authors: Division of Implant Dentistry, Department of Oral & Maxillofacial Surgery, Affiliated Stomatological Hospital of Medical School, Nanjing University, Nanjing, China.
authors: Bo
authors: B
authors: Wen
authors: Feng
authors: F
authors: Zhu
authors: Zhen
authors: Z
authors: Li
authors: Peng
authors: P
authors: Zhang
authors: Xingnan
authors: X
authors: Lin
authors: Michel
authors: M
authors: Dard
mesh_terms: D000818:Animals; D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants; D020878:Device Removal; D005260:Female; D005269:Femur / Q000601:surgery; D016348:Osseointegration / Q000502:physiology*; D010052:Ovariectomy; D011817:Rabbits; D013977:Tibia / Q000601:surgery; D014025:Titanium; D019415:Torque; D015040:Zirconium
chemical_list: D015921:Dental Implants; D015040:Zirconium; D014025:Titanium
keywords: SLActive implants; osseointegration; osteoporosis; ovariectomized rabbits; titanium-zirconium implants