Evaluation of Different pH Solutions on the Mechanical Behaviour of Two Hot Pressed Dental Ceramics

From all the materials that are used in modern dentistry to restore the natural dentition, ceramics have the best features to mimic the tooth structure. Although they are aesthetically superior, their main disadvantages are brittleness and low fracture resistance. Some processes used in manufacturing the ceramic, as well as the environment, can affect it's structure and it's mechanical properties. The aim of this study is to illustrate how the surface roughness and hardness, of one feldspathic glass ceramic and a lithium disilicate glass ceramic, are influenced by the surface processing (glazing and polishing) and after immersion in solutions with different pH and temperatures (tea, carbonated acidic beverage and distilled water) for a given amount of time. The research goals are calculating the Ra parameter and the Vickers microhardness of the tested ceramic disc-shaped samples. This study results showed that the surface treatments (glazing and polishing) affected the Ra parameter and the Vickers microhardness. The glazed samples from both types of ceramic proved to have better hardness .From the selected immersion solutions, the tea affected the most the roughness and especially affected the polished surfaces of the tested ceramics. (paper)