A Comparative Study of the Effect of tow Polishing Agents on Color Stability of Provisional Crowns Manufactured from PMMA Material Method by CAD/CAM (In-Vitro Study)

Abstract

Background and Aim of study: The most important factor affecting the aesthetic aspect is the color, whether the restoration is final or provisional Therefore, the discoloration of the provisional restoration can cause aesthetic problems that are critical for both the patient and the dentist. , this research aimed to compare the effect of two polishing materials on the color stability of provisional crowns Manufactured from PMMA material method by CAD/CAM designed.

Materials and Research Methods: The research sample consisted of 40 provisional crowns of PMMA material method by CAD/CAM designed for an upper premolar that was prepared to receive a full ceramic crown. After obtaining the sample, the sample was divided into two main groups according to the type of polishing material used (aluminum oxide paste or diamond paste), after polishing, the color measurements of the research sample were made using a measuring device. Spectrophotometer Vita Easyshade®. After that, the crowns were immersed in a solution of tea,

distilled water, and stored in an incubator at a temperature (37+-1 °C) for 8  weeks, then colorimetric measurements were repeated and the color change ΔE was calculated for each of the research samples.

The data were analyzed using Student's T-test for independent samples to study the significance of the differences in the mean amount of color change ∆E between the group of PMMA crowns were polished with diamond paste and the group of PMMA crowns, which were polished, with alumina paste in the research sample.

Results: At the 95% confidence level, there were no statistically significant differences between aluminum oxide and diamond in the chromatic stability of the studied provisional restoration.

Conclusions: Within the limitations of this study, there is no clear difference between the effect of the two materials of aluminum oxide paste and diamond paste in terms of the color stability of the provisional restoration material.