Surface roughness and translucency of glazed lithium disilicate (IPS E.Max) vs. glazed and polished "zirconia-reinforced lithium silicate" (Celtra duo) (in vitro study)

Abstract

This article investigates the tribological performances of modified refined, bleached and deodorized palm kernel oil as a potential vegetable-based lubricant under the trans-esterification process at 3, 4.5 and 6 h reaction time. By using calcium oxide as the catalyst, this investigation was validated using a four-ball tribotester machine under increasing loads (40, 60, 80 and 100 kg). From the analysis of the chemical compounds, coefficient of friction, wear scar and wear worn tests as well as the surface roughness, which was performed through the use of gas chromatography–mass spectrometry, optical microscope and surface profilometer, the 4.5 h newly refined lubricants were found to have not only exhibited a favourable tribology performance and superior friction reduction, but also a lower worn surface area and showed better surface finished improvement than those of neat base oils. Apart from the 4.5 h newly refined lubricants, the detailed aspects of the 3-h and 6-h performances were also discussed in this study.