A biomechanical comparison between original and used titanium miniplates

Effect of human organism on the oxide layer formed on titanium osteosynthesis plates: a surface analytical study

The question of whether or not to remove the titanium osteosynthesis plates used in maxillofacial surgery is not yet answered. These plates can be left a long time in the organism if there is no harmful interaction between the plates and the organism. The authors examined the properties of the surface oxide layers formed on osteosynthesis titanium plates by subsequent thermal and anodic oxidation, together with the properties of plates removed from patients after three years. Surface analytical method Secondary Ion Mass Spectroscopy (SIMS) was chosen. It was found that inside of the about 200-mum thick oxide on the original plates the concentration of impurities is much lower than near the oxide/titanium interface. On the surface of plates removed from the human body, a C (carbon), Ca (calcium) and P (phosphorus) enrichment was detected, suggesting a biological interaction between the organism and the plate. The passivating layer formed with thermal and anodic oxidation has not changed significantly in three years; it resisted to the corrosive effect of the human organism.

Surface analysis of titanium maxillofacial plates and screws retrieved from patients

This investigation is a controlled human plate-retrieval study. The surface appearances and elemental composition of 50 titanium maxillofacial plates and associated screws retrieved from 39 patients were compared with a control sample of unused plates and screws using stereomicroscopy, scanning electron microscopy and energy dispersive X-ray analysis. There were two surface finishes, either anodized or non-anodized. Surface contamination was detected on both retrieved and control plates consisting of aluminium and silica and was more commonly present on non-anodized specimens. Manufacturing defects comprising rough metal edges and protuberances were identified on the unused controls and surgical damage was evident on the retrieved specimens. There were no signs of corrosion or surface deterioration on the retrieved plates and screws which had been in the tissues for between 1 month and 13 years. There was no evidence from this study to support the routine removal of titanium maxillofacial miniplates plates due to corrosion up to a period of 13 years.