Is galvanic corrosion between implant abutments and roots a possible scenario? An experimental study under simulated healthy and inflammatory peri-implant conditions and F anions.

Abstract

Purpose: To assess the effect of healthy and inflammatory conditions and the presence of F anions on the galvanic coupling between the root surface and titanium abutments of commercially available titanium implants MATERIALS AND METHODS: Eight pairs of three dental root-abutment couples (BEGO, MIS, NOBEL) were exposed to a neutral (pH=7.4) (HE) and an acidic (pH=4.0) (IN) phosphate buffer solution (PBS) simulating healthy and inflammatory conditions respectively. In order to simulate the presence of F anions, which is commonly used in toothpastes, 3.12 gr of NaF was added in both solutions simulating healthy conditions (HEF) and inflammatoy conditions (INF) with the presence of F anions respectively. The galvanic potential difference was recorded for 48 h and averaged. Physical appearance of abutment and roots were tested under a stereomicroscope. Scanning electron microscopy and X-ray energy dispersive spectroscopy (SEM/EDX) was used to characterize the materials under reseach and compare the surfaces before and after galvanic testing.

Results: All abutments are composed of Ti-6Al-4V alloy along with root of MIS system, while BEG and NOB are made of Ti according to the SEM/EDX analysis. No differences were identified in surface morphology before and after galvanic testing, while EDX analysis revealed only the presence of Na and F on the surface of MIS abutments after testing in INF conditions. All groups tested showed negligible potential difference and below the nominal threshold for triggering galvanic corrosion under HE, IN and HEF conditions. The same applies for BEG and MIS under INF conditions, while NOB presented an average potential difference value of -273 mV, which is above nominal thresshold for galvanic action. Only MIS abutment showed a color change from yellow to blue under INF conditions.

Conclusions and clinical implications: BEG and MIS implant systems are not prone to galvanic corrosion in all conditions tested. NOB was found vulnerable to galvanic corrosion under inflammatory peri-implant conditions in the presence of F anions. Galvanic reactions is a possible scenario even between Ti base implant components.