The aim of the present study was to evaluate the gingival connective tissue response to screw-type titanium implants coated with Type I collagen nanofibers, which were prepared using the electrospray deposition method. Implants were immediately inserted into the socket of maxillary first molars after the extraction. Undecalcified sections after 4 weeks implantation were histologically observed. Better contact of the gingival connective tissue was generally observed around the collagen nanofiber-coated implants than titanium and non-fibrous collagen-immobilized implants. Gingival connective tissue to implant contact was significantly greater with the collagen nanofiber-coated implants than with the titanium and collagen-immobilized implants at the distal side, but not at the mesial side. Polarized light microscopy revealed that some birefringent collagen fiber bundles are oriented perpendicularly to the implant surfaces in the gingival connective tissue adjacent to the collagen nanofiber-coated implants. Collagen nanofiber-coating may have a possibility for improving gingival connective tissue response to titanium implants.

The aim of this study was to evaluate the effects of alendronate immobilization on bone formation following the implantation of apatite-coated titanium implants in rats. Thin carbonate-containing apatite coatings were deposited onto titanium implants (Ti implants) using a molecular precursor method. Alendronate was then immobilized on apatite-coated titanium implants (HA implants) by immersing the HA implants in alendronate solution (Ald implants). The rat molars were extracted, and the implants were immediately placed in the tooth sockets. Bone labeling was performed 14 and 7 days before sacrifice. At 3 and 9 weeks after implantation, undecalcified sections were prepared and bone histomorphometry was performed. Greater bone mass was found around the Ald implants than around either the Ti or HA implants at both 3 weeks and 9 weeks. At 3 weeks, fluorochrome bone labeling was greater around the Ald implants than around the Ti implants, and the values of bone to implant contact (BIC) and bone mass (BM) were significantly greater around the Ald implants than around the HA and Ti implants. At 9 weeks, bone labeling decreased and the values of BIC and BM increased compared with those at 3 weeks for all types of implant. In conclusion, we found that immobilized alendronate triggered pronounced bone formation around the implants at an early stage of bone healing. These results suggest that alendronate immobilization accelerates implant fixation early in the healing phase.