الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 123 |  |  |
| | | from | 123 | | |
Abstract
Several ceramic systems, including lithium desilicated, lithium desilicated derivatives, and zirconium oxide ceramics, have been brought to the dental market. The distinctive microstructure of lithium desilicated ceramics is crucial in determining its mechanical and optical qualities.
The color qualities and color stability of ceramic restorations are equally crucial as their mechanical properties. Tooth color analysis was conducted to get a quantitative record of the studied color, which can be characterized using color systems such as the Munsell color system and the CIELAB color system.
Typically, this is not feasible, leading to a substantial quantity of residual material. Hence, the concept of repurposing residual material through suppressing was proposed and endorsed by numerous scholars. Presentation was made regarding concerns regarding the mechanical qualities of the reutilized material for therapeutic purposes. Researchers conducted limited investigations to examine the mechanical and microstructural characteristics of compressed ceramics, specifically assessing their biaxial flexural strength.
The hypothesis was that repeatedly compressing ceramics with varying weight percentages may impact the color and translucency of two types of pressable ceramic materials.
This study aimed to assess the inhibitory impact of Celtra and GC, with varying weight percentages, on color and translucency using a spectrophotometer. Additionally, it examined the effect of immersing ceramic discs in different types of medium (acidic and alkaline).
Acidic Solution Lemon juice, with a pH ranging from 2 to 3, and alkaline solutions of green tea, with a pH ranging from 8 to 10, were utilized.
We employed two commercially available glass ceramic materials: GC Initial® LiSi Press, which is a lithium desilicated ingot with high strength and incorporates proprietary HDM (High Density Micronization) technology. This technology ensures that micro-crystals are evenly distributed throughout the glass matrix, as opposed to larger crystals typically used. As a result, the material exhibits outstanding physical properties and aesthetics. The material exhibits a biaxial flexural strength above 500 megapascals and shows minimal formation of a reaction layer upon removal. Celtra is a modern type of glass ceramics known as zirconia reinforced lithium silicate (ZLS), which possesses exceptional strength. It is primarily used for its great strength in pressable glass ceramics applications.
A total of sixty ceramic disc-shaped samples were fabricated using the heat pressing process. Each sample had a diameter of 10 mm and a thickness of 1.5 mm. The samples were categorized into two categories based on the type of ceramic material.
group G consists of 30 participants who used the GC lisi press, while group C consists of 30 participants who used the Celtra press. The categories were divided into five subgroups each. The sample size was 6, and it was divided into subgroup 1 based on the weight percentage. The composition of the subgroups is as follows: sub group 1 consists of 100% new ceramic, sub group 2 consists of 75% new ceramic and 25% repressed ceramic, sub group 3 consists of 50% new ceramic and 50% repressed pottery, sub group 4 consists of 25% new ceramic and 75% repressed ceramic, and sub group 5 consists of 100% repressed ceramic. In addition, the samples from each subgroup were picked in a random manner and divided into two categories based on the immersion solution: Class L, which represents lemon juice, and Class T, which represents green tea.
The color shift and translucency of all samples were measured both before and after immersion. The data were carefully chosen, organized into tables, and subjected to rigorous statistical analysis.
Based on the constraints of this study, the findings indicate that the variables that influenced ΔE were the variation in ceramic type and immersion medium. However, the varying weight percentages of the freshly ceramic ingot and repressed ceramic did not have any impact on the average ΔE. The green tea, which is a medium with alkaline properties, had a greater impact on the change in average ΔE compared to the lemon juice, which is an acidic medium. This effect was observed for both the Celtra and GC ceramic types.
Regarding the translucency parameter (TP), our findings indicate that all the elements we examined - ceramic type, weight percentage during repressing, immersion, and immersion medium - had a significant impact on TP. Raising the percentage of novel ceramic material resulted in enhanced translucency.
The average total phenolic (TP) content decreases when immersed, particularly in an alkaline environment. This is because green tea has a substantially lower average TP content compared to lemon juice. The translucency of G.C ceramic types was more significantly impacted compared to Celtra ceramic type, particularly following immersion in both green tea and lemon juice.
Among both types of used ceramics, those that were completely new exhibited the highest average TP, with statistical significance. The group with 75% new/25% repressed had a much lower average TP. This was followed by the group with 50% new/50% repressed, and then the group with 25% new/75% repressed. The group with 100% repression exhibited the lowest mean TP, which was statistically significant.