Surface degradation of dental ceramics as a function of environmental pH

We tested the hypotheses that glass-ceramic veneers and overglazes degrade by ion exchange in an acidic environment,and that they degrade by breakdown of the silica network in a basic environment. disk specimens of glass-ceramic veneer and glaze were fabricated and immersed in ph 2,7,or 10 buffer solutions,for 1,3,5,10,15,and 30 days. each specimen was placed in a shaker bath containing de-ionized distilled water at 80 °c. concentrations of al3+,ca2+,zn2+,li2+,and si4+ were analyzed by means of inductively coupled plasma atomic emission spectrometry (icp/aes). statistical analyses were performed by factorial anova. significant differences occurred among leached ion concentrations as a function of material type,solution ph,and exposure time. a substantial release of si occurred at ph 10 over time,leading to a breakdown of the glass phase. at ph 2,dissolution was controlled by an ionic exchange mechanism. we conclude that ceramic veneers and glazes may be susceptible to considerable degradation in low- and high-ph buffer solutions. © 2013 international & american associations for dental research.