Wetting Behavior of Dental Implants

Purpose: Hydrophilicity is gaining increasing interest as a factor that might influence the osseointegration of dental implants. Therefore, in this study the dynamic wetting behavior of currently marketed dental titanium implants was analyzed by tensiometry, and its relationship to surface topography was examined. Materials and Methods: Nine screw-type implant systems from eight manufacturers were evaluated. Dynamic water contact angles were analyzed by tensiometric multiloop Wilhelmy experiments (10 loops, 10 mm/min immersion speed). The wetted length (perimeter) of the immersed samples was estimated by three-dimensional picture profile measurement of the thread height of the respective implant screws. Wettability was quantified by first advancing contact angles. Additionally, static contact angles were determined using the sessile drop technique. All implant surfaces were characterized by scanning electron microscopy (SEM). Contact angle data were subjected to one-way analysis of variance followed by the Student t test. Results: SEM revealed different types of surface morphology resulting from the different manufacturing processes. The first advancing mean contact angles of all implants ranged from 0 degrees (SLActive) to 138 degrees (OsseoSpeed), demonstrating statistically significant differences between implants. Because of kinetic hysteresis, initially hydrophobic implants became hydrophilic during following immersion loops. Conclusions: The tensiometric method was used to compare wettability of dental implants. A range from fully wettable/superhydrophilic to virtually unwettable/hydrophobic was observed on the implant surfaces examined. Keywords: dental implant, dynamic contact angle, hydrophilicity, surface topography, tensiometry, wettability