Comparison of Corrosion Products from Implant and Various Gold-based Abutment Couplings: The Effect of Gold Plating.

ABSTRACTThis study compared Ti, Pd, Pt, Au ion release following induced accelerated tribocorrosion from 3 gold alloy abutment groups coupled to titanium implants over time; investigated contacting surface structural changes; and explored the effect of gold plating. Three abutment groups: G (n=8, GoldAdaptTM, Nobel Biocare®), N (n=8, cast UCLA, Biomet3i™), P (n=8, cast UCLA, Biomet3i™, gold plated), coupled to implants (Nobel Biocare®), immersed in 1% lactic acid were cyclically loaded. Ions released (ppb) at T 1 , T 2 , T 3 , simulating 3, 5 and 12 months function were quantified by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and compared. Surface degradation and fretted particle composition after T 3 were evaluated with Scanning Electron Microscopy and Energy-dispersive X-ray Spectroscopy (SEM/EDX). ICP-MS data was non-parametric, expressed as medians and interquartile ranges. SEM/EDX showed pitting, crevice corrosion and fretted particles on the components. Released ion concentrations in all groups across time significantly decreased for Pd (p<0.001, medians ranged 1.70 to 0.09), Pt (p=0.021, 0.55 to 0.00) and Au (p<0.001, 1.01 to 0.00); and increased for Ti (p=0.018, 2.49 to 5.84). Total Ti release was greater than other ions combined for G (p=0.012, 9.86 vs 2.30) and N (p<0.001, 13.59 vs 5.70), but not P (p=0.141, 8.21 vs 3.53). Total Ti release did not differ between groups (p=0.36), but was less variable across Group P. On average, total ion release was 13.77 (8.91 to 26.03 IQR) ppb across the 12-month simulation. Tribocorrosion of titanium implants coupled with gold abutments in a simulated environment was evidenced by fretted particles, pitting and crevice corrosion of the coupling surfaces and release of ions. More Ti was released compared with Pd, Pt and Au; and continued to increase with time. Abutment composition influenced ion release. Gold plated abutments appeared to subdue variation in and minimize high concentration spikes of titanium.