الفهرس 
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Abstract
The aim of this in vitro study was to compare the color
stability and surface roughness of interim restorative materials
fabricated using two techniques: milled and additive. Using two
surface treatments: polishing and glazing.
Two provisional resin restorative materials were used in the
study, divided into two groups according to the method of
construction: 3D Printing and Milling by CAD/CAM using two
surface finishing Protocols. A total of 42 samples were fabricated;
disc-shaped specimens of 10 mm in diameter and 2 mm in thickness
were fabricated. Samples of each material were divided into two
groups according to the technique of fabrication; (group M): milled
(n = 21) and (group A): additive (n = 21) samples. Each group was
divided into 3 subgroups according to the type of surface finishing:1-
(Subgroup C) control subgroup: no surface finishing was done to the
samples (n=7).2: (Subgroup P) polished subgroup: samples were
polished using polishing paste (n = 7).3: (Subgroup G) glazed
subgroup: samples were glazed using glaze material (n = 7).
Specimens in (subgroup P) were polished using the Enhance
finishing and polishing kit, finishing with carry out using aluminium
oxide discs along with Prisma Gloss polishing paste. Specimens in
(subgroup G) were finished using aluminium oxide discs and
prepared with additional clear light-polymerizing protective coatings
(Opti glaze). All samples were subjected to thermocycling for 5000
cycles between 5 ±2⁰ C and 55 ± 2⁰ C with a dwell time of 30
seconds in each bath and 20sec interval between baths at ambient air.
Color measurements were obtained using a digital spectrophotometer
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in conjunction with The CIE L*a*b* system before and after
thyrmocycling. Surface roughness (Ra) was measured after
thyrmocycling with USB digital surface profile gauge (Elcometer
Instruments, Great Britain) and data were recorded using computer
software of roughness tester supplier (Elcomaster 2, Elcometer
Instruments). Three-way mixed model ANOVA was used for surface
roughness analysis and two-way ANOVA was used for color change
analysis. Comparison of main and simple effects were done utilizing
one-way ANOVA followed by Tukey‘s post hoc test for independent
samples and repeated measures ANOVA followed by Bonferroni post
hoc test for paired samples.
The results of surface roughness reveled that, regardless of
surface finishing protocol, 3D printed samples had a significantly
higher value than milled samples. Moreover, results of surface
roughness showed that regardless of the fabrication method, the
highest value was found in polished samples, followed by control
group , while the lowest value was found in glazed samples .
The results of color stability showed that, regardless of
surface finishing protocol,3D printed samples had a significantly
higher value than milled samples. Furthermore, results of color
stability showed that regardless of the fabrication method, The
highest value was found in the control group, followed by polished
samples, while the lowest value was found in glazed samples .