Coefficient of Friction Characterization of Surface‐Modified Polycrystalline Alumina

Applications in dental medicine sometimes require efficient and reproducible sliding, while maintaining biocompatibility and aesthetics. Several techniques of surface modification are explored for polycrystalline alumina materials: ion implantation, diamond‐like carbon coating, and plasma deposition. Using a light‐load, low‐velocity, single‐pass device, the frictional coefficients of orthodontic appliances are simulated. Materials that were investigated include couples of polycrystalline alumina (PCA) against stainless steel (SS) or β‐titanium (β‐Ti). Although all techniques of surface modification reduced the frictional coefficients below those values for the control couples, plasma deposition and diamond‐like carbon coating proved best for the PCA/SS and PCA/β‐Ti couples, respectively. In these cases, values decreased below those of conventional SS against SS and β‐Ti against SS, respectively.