Interface shear strength of titanium implants with a sandblasted and acid-etched surface: A biomechanical study in the maxilla of miniature pigs

The purpose of the present study was to evaluate the interface shear strength of unloaded titanium implants with a sandblasted and acid-etched (SLA) surface in the maxilla of miniature pigs. The two best documented surfaces in implant dentistry, the machined and the titanium plasma-sprayed (TPS) surfaces served as controls. After 4, 8, and 12 weeks of healing, removal torque testing was performed to evaluate the interface shear strength of each implant type. The results revealed statistically significant differences between the machined and the two rough titanium surfaces (p < .00001). The machined surface demonstrated mean removal torque values (RTV) between 0.13 and 0.26 Nm, whereas the RTV of the two rough surfaces ranged between 1.14 and 1.56 Nm. At 4 weeks of healing, the SLA implants yielded a higher mean RTV than the TPS implants (1.39 vs. 1.14 Nm) without reaching statistical significance. At 8 and 12 weeks of healing, the two rough surfaces showed similar mean RTVs. The implant position also had a significant influence on removal torques for each implant type primarily owing to differences in density in the peri-implant bone structure. It can be concluded that the interface shear strength of titanium implants is significantly influenced by their surface characteristics, since the machined titanium surface demonstrated significantly lower RTV in the maxilla of miniature pigs compared with the TPS and SLA surfaces.