The effect of different beverages on the surface characteristics of PEEK and PEKK polymers.

To evaluate the effects of various beverages on surface roughness and microhardness of PEEK and PEKK polymers. Rectangular-shaped PEEK and PEKK polymers were fabricated and examined in the study. The specimens were immersed for 28 days at 37°C in red wine, coffee, and distilled water. The surface microhardness (Vickers microhardness tester) and roughness (profilometry) measurements of the polymers were performed before and after immersion. The Kolmogorov test was used to evaluate the normal distribution of the variables. Kruskal Wallis test was used to compare independent groups and Wilcoxon Signed Rank test was used to compare two dependent groups (P< 0.05). Acidic beverages adversely affected the properties of the tested materials. The microhardness of tested materials was significantly decreased after immersion in the various beverages, whereas surface roughness was increased except for distilled water. Removable partial dentures can be exposed to chemical agents found in acidic beverages either intermittently or continuously, and this may lead to chemical degradation and changes in surface properties of the denture framework. With the developments in dentistry, framework materials are also developing and diversifying. The clinical performance of PEEK and PEKK polymer-based frameworks is still uncertain.