Abstract
The effects of khat chewing habits on the stainability of feldspathic metal ceramic (MC) materials used in the fabrication of dental restorations remain unexplored. This study investigated the effect of khat extract (KE) on mean color changes (Delta E*) and surface topography among different feldspathic MC materials, namely, VMK VM13, VMK MASTER, and VMK 95). Sixty feldspathic MC specimens were prepared from nickel chromium alloy with the above-mentioned ceramic materials. The Delta E* of the specimens were measured using a spectrophotometer before and after immersion in KE and thermocycling for 10 days. The surface topography was captured to examine the surface of specimens after KE staining with a white light interferometric microscope. Results showed that the Delta E* values of the different types of tested feldspathic MC were influenced by KE. The lowest values of Delta E* were recorded from glazed VMK VM13, VMK MASSTER, and VMK 95 with acceptable color changes, whereas the highest and unacceptable values of Delta E* were observed from polished VMK MASTER and VMK 95. All the tested groups and subgroups obtained significant differences with p values > 0.05 in Student's t-test and ANOVA test. All the tested feldspathic MC materials had showed significant differences in the parameter of average color changes for all tested groups in form of glazed or polished specimens. Clinical significance: Re-glazing step is an essential step before final cementation and after chair-side adjustment of any feldspathic MC prosthesis for patients who chew khat..