Dental implant surfaces after insertion in bone: an in vitro study in four commercial implant systems

Primary healing of dental implants is influenced by their surface morphology. However, little is known about any alterations in morphology during their insertion. Therefore, the aim of this study was to evaluate the surface morphology of four different implant systems, following their insertion in porcine jaw bones. Four fresh porcine mandible specimens were used. Six new implants of four systems (AnkylosA (R) 4.5 x 14 mm, Frialit SynchroA (R) 4.5 x 15 mm, NobelReplace A (R) Tapered Groovy RP 4.3 x 13 mm, Straumann SLAA (R) Bone Level 3.3 x 14 mm) were inserted, whereas one implant of each system served as a control. After their removal, implants were cleaned in an ultrasonic bath. All 28 implants were examined quantitatively by 3D confocal microscopy for surface characteristics. In the evaluated zones, implants of the Ankylos, Frialit, and Straumann systems showed mostly a reduction of the mean surface roughness Sa, the maximal surface roughness Sz, and the developed surface area ratio Sdr; Nobel implants showed an increase in these parameters. With respect to all three parameters Sa, Sz, and Sdr, statistical analysis revealed that differences between the four systems were highly significant in the apical region of implants. Controls showed no morphologic alterations. The insertion process had an impact on the surface of all four implant systems. Anodized implant surface modification seems to result in more alterations compared with subtractive surface modifications. Therefore, surgical planning should take into consideration the choice of surface treatment because the characteristics of the implants may be modified during the installation process. The given information is of value for daily implantation practice and the course of osseointegration.