[Experimental study of osseointegration of nHA/BG coating and Bio-Oss in implant defects].

PURPOSE: To evaluate bone regeneration in defects at titanium implants with nHA/BG coating in conjunction with Bio-Oss. METHODS: Four mandibular premolars were extracted in 6 Beagle dogs. After 3 months, buccal dehiscence-type defects (2.25 mm×3 mm×4 mm) were surgically created following implant site. The three treatment modalities were randomly allocated: nHA/BG implant/Bio-Oss, nHA/BG implant/blood clot, and mHA implant/Bio-Oss. After 8 and 16 weeks, the dogs were sacrificed respectively. A histomorphometric analysis was performed. The data was analyzed with SPSS 13.0 software package for Student's t test and ANOVA. RESULTS: At 8- and 16-week, nHA/BG implant group revealed comparable mean BIC (30% to 18% versus 61% to 53%). However, mHA implant/Bio-Oss group revealed significantly lower mean BIC (21% versus 46%) values than nHA/BG implant/Bio-Oss group.A significant difference was observed for the mean BIC and RA values at 8-week between nHA/BG implant/Bio-Oss group and mHA implant/Bio-Oss group. CONCLUSIONS: It is concluded that the application of Bio-Oss graft did not seem to interfere with the nHA/BG coating activity, but ensured a stabilization of the newly formed bone for defects.

Enhanced osteointegration of orthopaedic implant gradient coating composed of bioactive glass and nanohydroxyapatite.

We conducted histologic and histomorphometric studies to evaluate the osteointegration of gradient coatings composed of bioactive glass and nanohydroxyapatite (BG-nHA) on titanium-alloy orthopaedic implants and surrounding bone tissue in vivo. Titanium-alloy implants with a gradient coating (gradient coating group), uncoated implants (uncoated group), and implants with a conventional hydroxyapatite (HA) coating (HA coating group) were randomly implanted in bilateral femoral condyles of 36 male New Zealand rabbits. The bone-implant contact at 12 and 24 weeks and the new bone volume in the notch created for observing bone ingrowth at 4, 12, and 24 weeks were found greater in the gradient coating group than those in both the uncoated group and the HA coating group (p < 0.05). Fluorescence micrographs showed active osteogenesis in the gradient coating group at 4 weeks after implantation. These findings indicated that BG-nHA gradient coatings could enhance the osteointegration of orthopaedic implant.

[Experimental study on the osseointegration of nanophase hydroxyapatite biograde-coated implants].

OBJECTIVE: To study the osseointegration of the nanophase hydroxyapatite biograde-coated implants and host bone. METHODS: Nanophase hydroxyapatite biograde-coated implants, hydroxyapatite biograde-coated implants and noncoated Ti-6Al-4V implants were inserted into both femoral of Beagle canines the tissue response, dynamic osteogensis and SEM were studied at 4, 8 and 12 weeks. RESULTS: The degradation of nanophase hydroxyapatite was slower than hydroxyapatite, dynamic osteogensis and the form of osteoblast were better than the control groups. CONCLUSION: The biological reaction of Nanophase hydroxyapatite biograde-coated implants is better than hydroxyapatite coated implant.