IN-VITRO CORROSION OF TITANIUM

Titanium is used in dentistry for implants and frame work because of i ts sufficient chemical, physical and biological properties. The corros ion behaviour is from high interest to value biocompatibility. A stati c immersion test was undertaken with a titanium test specimen (30 mm x 10 mm x 1 mm, immersion time = 4 x 1 w, n = 3 for each series). The f ollowing parameters were investigated: specimen preparation, grinding, pH-value, different casting systems, comparison with CAD/CAM, influen ce of chloride, thiocyanate, fluoride, lactate, citrate, oxalate, acet ate. Atomic absorption spectroscopy was used to analyse the solutions weekly. The course of corrosion was investigated photometrically. Tita nium reveals ion releases [(0.01-0.1) mu g/(cm(2) x d)] in the magnitu de of gold alloys. There is little influence of grinding and casting s ystems in comparison with organic acids or pH value. The ion release i ncreases extreme (up to 500 mu g/(cm(2) x d)) in the presence of fluor ide. Low pH values accelerate this effect even more. Clinically, no co rrosion effects were observed. Nevertheless it is recommended that it is best to avoid the presence of fluoride or to reduce contact time. I n prophylactic fluoridation of teeth, a varnish should be used. (C) 19 98 Published by Elsevier Science Ltd. All rights reserved.