The effect of thermocycling on the bonding of different restorative materials to access opening through porcelain fused to metal restorations

Influence of Surface Type with Coffee Immersion on Surface Topography and Optical and Mechanical Properties of Selected Ceramic Materials

BACKGROUND The aim of this study was to assess and compare the effect of surface type (glazed or polished) with coffee immersion and aging on surface topography (Ra), optical properties (TP, OP), and mechanical properties (fracture forces and modes) of zirconia-reinforced lithium silicate (Vita Suprinity), hybrid polymer-infiltrated-feldspathic ceramic network material (Vita Enamic), and leucite-containing feldspathic glass (Vitablocs® Mark II) made by computer-aided design and computer-aided manufactured (CAD/CAM) ceramic materials. MATERIAL AND METHODS Fifty-four specimens were assembled out of the above 3 CAD/CAMs ceramic materials. Each group was divided into glazed or polished surfaces, having 9 specimens of every type and stained in coffee for 15 days. Ra and color of specimens in the form of TP and OP were recorded before and after immersion in staining material. Fracture forces and modes were analyzed after the 90-day aging. Data were analyzed using ANOVA, then post hoc analysis and Bonferroni tests. RESULTS Our study found significant differences in Ra, TP, and Op before and after coffee immersion between glazed and polished specimens, with higher values in the polished surfaces among the 3 ceramic materials. The highest values of fracture resistance were noted in Vita Suprinity, and Vita Enamic had the lowest values, without significant differences among groups. CONCLUSIONS Most of the TP and OP values were in acceptable clinical range, and Vita Suprinity had superior TP than the other groups. Reparable fracture types were observed in Vita Suprinity, whereas semi-reparable and non-reparable were predominant in other groups.

Assessment of Color Stainability of Computer-Aided Design and Computer-Aided Manufacturing (CAD/CAM) Ceramic Materials After Hot and Cold Coffee Immersion at Different Time Intervals

BACKGROUND This spectrophotometric study assessed the color stability of CAD/CAM restorative materials with different exposed surfaces following staining by hot Arabic Qahwa and cold coffee. MATERIAL AND METHODS Ninety-six specimens were fabricated from 3 different CAD/CAM ceramic materials: Vita Suprinity (Vita-S), Vita Enamic (Vita-E), and Vitablocs Mark II (Vitablocs-MII). We divided 32 specimens for each group into glazed or polished surfaces, with 16 specimens in each group, then subdivided them according to staining materials: Arabic Qahwa and Frappuccino Cold Coffee. Color of specimens was measured during immersion in staining materials (BEFORE) as baseline with (Vita classic) and (L, a, b), for average color changes (ΔE₀₀), then remeasured after 2, 4, and 12 weeks, and described as 1st, 2nd, and 3rd measurements for VITAPAN Classic shade and T1, T2, and T3 for ΔE00 values using the CIE L*a*b* equation. We performed ANOVA and then post hoc testing. RESULTS We found significant differences in ΔE₀₀ values during immersing in hot Arabic Qahwa and cold coffee for tested materials in glazed or polished specimens. Polished specimens of Vita-S and Vita-E had the highest color changing and staining compared to glazed surfaces. Vitablocs-MII had the best color stability through immersion periods. Moreover, there were changes in relation to VITAPAN Classic shade guide for both Vita-S and Vita-E specimens during different immersion periods. CONCLUSIONS Coffee caused staining and contamination of ceramic material. Values of ΔE₀₀ for tested ceramic materials were significantly different but were within the clinically acceptable range. Polished specimens showed higher staining; therefore, we highly recommend re-glazing of ceramic restorations to maintain color stability.

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.

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*. Conclusion: KH significantly affected both surface parameter and color of glazed or polished porcelain materials and natural teeth.