Osseotite vs. machined surface in poor bone quality. A study in dogs

Implant sites with low bone content have exhibited lower implant survival rates than dense bone areas. Alterations of the implant surface seem to influence the bone-to-implant contact rate and may have an impact on implant failure rates in such sites. It was the objective of this animal study to histomorphometrically compare two different implant surfaces in so-called poor bone quality sites. All premolars on one side of the mandible were extracted in five fox hounds. After a healing time of 8 months, four screw-type implants (two with a machined surface (ICE group) and two with a double acid-etched (Osseotite) surface (OSS group)) were inserted into the mandible. Upon insertion, the implant apex was located in the 'hollow' part of the dog mandible, where the bone content is low. After 4 months healing, histomorphometric evaluations were performed. All implants osseointegrated clinically and histologically. Periapical density measurements revealed similar bone contents in both groups (ICE 49.9+/-16.7%, OSS 52.2+/-8.4%; P>0.05). Despite these similar amounts of bone content in the apical area around the implant, the Osseotite implant surface had a significantly higher bone-to-implant contact rate than the machined surface (OSS 62.9+/-12.4%, ICE 39.5+/-13.0%; P<0.01). It is concluded from this animal experiment that, in poor bone quality sites, an implant with an Osseotite surface can achieve a significantly higher bone-to-implant contact compared to a machined surface.