Studying the effect of surface conditioning on the corrosion performance of titanium dental implants

Abstract

Abstract The biocompatibility of dental implants is dependent on good interaction between implant-human body tissue and a good osseointegration. The surface roughness plays an important role enhancing bone healing and promoting biomechanical properties at the bone/implant interface. The increase in surface roughness can simultaneously improve cell migration and attachment of an implant, and enhance the osseointegration process. However surface roughness has shown to be detrimental to corrosion, raising the need to achieve a balance between good osseointegration and corrosion performance. This study characterised the corrosion performance of commercially pure titanium grade 4 with different surface conditionings. Implants in the form of 15 mm discs and implant screws were tested in basic Ringers lactate solution of pH 5.5 at 37°C and in modified Ringers of pH 2. Corrosion tests included open circuit potential (OCP), potentiodynamic polarization test (PDP) and mass loss corrosion tests. Metallurgical characterisation showed that titanium Grade 4 consisted of equiaxed alpha (α-Ti) grains. The OCP test showed that the machined implants were nobler than the roughened implants. The corrosion rates obtained were very low, below 0.13 mm/y which is an acceptable corrosion rate for biomaterial design and application. Mass-loss tests showed that the alloys passivated regardless of the surface conditioning. The machined surface had a corrosion resistance higher than that of the roughened surface finish in all conditions.