[Corrosion behavior of different screws and posts in the root canal]

A series of extracted teeth with failures in their restoration by root canal posts or screws was examined for corrosive processes on these posts and screws. The teeth were ground who make metallographic specimens. By structural analysis, measurements of hardness and by roentgenfluorescence analysis the fabricates were identified and grouped into known metal groups for such posts and screws. Corrosion was examined morphologically and discussed in connection with the type of material and the specific circumstances of its surrounding. Metal impregnation of the root was studied by microprobe. The material investigated could be classified into four groups and a characteristic behaviour of each material to corrosion could be identified. In conclusion, certain minimal properties were proposed as a guide to the use of root posts and screws.