Surface roughness and color measurements of glazed or polished hybrid, feldspathic, and Zirconia CAD/CAM restorative materials after hot and cold coffee immersion

Background

The purpose of this study evaluates and compares the effect of surface roughness (Ra) and color stability on computer-aided design/computer-aided manufacturing (CAD/CAM) hybrid resin (Vita Enamic), feldspathic (Vitablocs® Mark II), and lithium disilicate Zirconia (Vita Suprinity) glazed or polished ceramics immersed in hot Arabic Qahwa and cold coffee.

Methods

A total of 96 standardized samples were prepared from CAD/CAM restorative materials. Half of the samples were polished as per the manufacturer’s instructions using a porcelain polishing kit, and the other half were glazed. Samples were distributed and immersed in hot Arabian Qahwa and cold coffee followed by thermocycling. Ra measurements and color changes were conducted before and after immersion. SEM images were captured from each type of glazed or polished ceramic. One-way ANOVA paired Student’s t-test, and Bonferroni test were conducted to detect significant difference between the groups. P > 0.05 was a significant level.

Results

Of all the tested samples, Ra increased without any significant difference; however, mean color changes (ΔE*) showed significant differences. An increase in Ra was noted for all the glazed and polished samples after immersion and thermocycling. However, differences were significant only in VM II. In addition, ΔE* was significant only in Vita Suprinity (VS) samples. For immersion groups, significant Ra changes were noticed in glazed samples, only in Vita Enamic (VE) with no ΔE*. In polished samples, mean Ra changes were observed in VM II and VS samples. Significant differences were also noticed in polished VE and VS subgroups of ΔE*.

Conclusions

Ra affects all the tested samples, providing higher values on the polished specimens. The ΔE* caused by hot Arabic Qahwa and cold coffee on glazed or polished CAD/CAM restorative materials were clinically acceptable.

Gender Comparison of Students’ Perception of Educational Environment using DREEM Inventory, College of Dentistry, Jazan University

Background:

The Educational Environment (EE) has an extremely important role in effective student learning. The Dundee Ready Education Environment Measure (DREEM) is a validated and widely tool to assess the EE in health and particularly in dental professional education programs.

Objective:

This study aimed to compare male and female dental students' perception regarding DREEM inventory of EE in Jazan University. A cross-sectional questionnaire included questions on demographic information and the DREEM of EEs.

Methods:

DREEM was used to gather information from our BDS students’ program about the environment in our institution. The data were selected from 3rd, 4th, 5th, 6th year students. Data from 330 participants were distributed manually. Other factors such as type of graduated school, level of education, student’s GPA, and monthly income of family were assessed. All the data were analyzed.

Results:

286 (86%) of the students completed and returned the DREEM questionnaires. There was no statistically significant difference between genders with respect to mean scores of perceptions of learning. Also, there was a significant difference in terms of educational level, but no significant differences were observed in the DREEM subscales. The average overall DREEM score of the study subjects indicated a positive learning perception of 130.8 for males and 130.2 for females. The subscale for both genders involved students’ perception of learning as 32.1, the students’ perception of teaching as 29.1, while the students’ academic self-perception was 21.7. The students’ self-perception of atmosphere was 30.0 while students’ social self-perception accounted for 17.5.

Conclusion:

Both gender students recorded positive values of the learning environment. Further, a qualitative investigation is recommended to be done on every single course to evaluate the changes and make necessary alterations.

Effects of Khat on Surface Roughness and Color of Feldspathic and Zirconia Porcelain Materials under Simulated Oral Cavity Conditions

Background and Objectives: Khat chewing is considered as a daily habit that is practiced by more than five million people globally. The effect of khat chewing on the surface roughness and the color stability of natural teeth and the material used in the fabrication of dental prosthesis remains unknown. This study was conducted to explore and compare the effect of khat homogenate (KH) on the surface roughness (Ra) and the average color changes (ΔE*) amongst natural teeth and selected shades from different porcelain types, namely, feldspathic metal ceramic (MC) VM13, computer-aided design/computer assisted manufacture (CAD/CAM) feldspathic (Vitablocs Mark II), and multilayer zirconia (Ceramill Zolid PS) porcelains. Materials and Methods: Seventy samples were prepared from natural teeth, feldspathic MC, CAD/CAM Vitablocs Mark II, and zirconia porcelain. The Ra values were measured using a profilometer and expressed in micrometers, whereas the ΔE* values were measured using VITA Easyshade^® V spectrophotometer for all samples before and after frequent immersion and thermocycling in KH for 30 days. The surface topography was used to assess the materials surfaces (glazed or polished) after KH immersion by using a white light interferometry machine. Results: Results revealed that the Ra and the ΔE* values of the different types of tested porcelain were influenced by KH. The order of surface roughness values was glazed or polished MC > polished Zircon > polished Vitablocs Mark II > natural teeth. The lowest ΔE* values were recorded for glazed Vitablocs Mark II and MC, and the values could be arranged as polished zircon > natural teeth > glazed zircon > polished MC > polished Vitablocs Mark II. P values were significantly varied (<0.001) among all the tested groups, except the zircon group (>0.05) for both Ra and ΔE*. Conclusions: KH significantly affected both surface parameter and color of glazed or polished porcelain materials and natural teeth.