Microstructural and mechanical analysis of two CAD-CAM lithium disilicate glass-reinforced ceramics

Tavares, Lucas do Nascimento; Zancopé, Karla; Silva, Anielle Christine Almeida; Raposo, L.; Soares, Carlos José; Neves, Flávio Domingues das

doi:10.1590/1807-3107bor-2020.vol34.0004

Cited by 10 publications

(7 citation statements)

References 18 publications

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“…Tavares et al reported a similar void analysis of commercially available sintered glass-reinforced ceramic blanks of IPS e.max and Rosetta SM CAD-CAM systems. They reported a porosity value of 0.05-0.1% for IPS e. max and 0.07-0.13% for Rosetta SM, with uniform pore distribution by MicroCT evaluation (17). The voids in this study could have formed during kneading or sintering and indicated the regions where powder distribution and packing were not homogeneous.…”

Section: Resultsmentioning

confidence: 60%

Monolith Dental Bridge by Soft Machining of Dried Ceramic Dough

et al. 2021

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All-ceramic fixed restorations are gaining popularity because of increased esthetic consciousness in the younger population. Monolith ceramic crowns and bridges are preferred to withstand masticatory loads where the availability of occlusal height is limited. Machining green blanks of ceramic with organic binders have been studied to reduce loss of final strength, cost, and wastage associated with milling partial sintered and sintered blanks. Notches on the surface/edge associated with green milling will disappear after sintering in contrast to sintered state machining where diamond polishing is essential. In this study, we explored a novel ceramic dough process to form a green body of alumina or 3 Mol% yttria-stabilized zirconium oxide (YSZ), and computer numerical control (CNC) machining was performed on the dried dough. Micro Computer Tomography analysis of the bridges after sintering revealed a negligible void volume, 0.06–0.08% of the total volume, with randomly dispersed voids. Precision analysis of the sintered bridges with respect to the reference file resulted in a deviation range of +0.56 to −0.79 mm, with negligible deviation on the cementation surface. The green machined surface had a roughness profile of 1.2–1.7 μm after machining and 2.2–2.4 μm after sintering, as revealed by 3D profilometry.

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Section: Resultsmentioning

confidence: 60%

Monolith Dental Bridge by Soft Machining of Dried Ceramic Dough

et al. 2021

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“…Thus reinforcement of lithium disilicate produces glass-ceramics having a flexural strength approximately 2-3 foldgreatercompared withthenon-reinforced restorations. 15 Translucency parameter significantly decreased on increasing thickness. Repeated firings significantly affected the translucency of lithium disilicate glass-ceramic as a result the translucency increased with decreasing thickness.…”

Section: Ahmed Sheirmentioning

confidence: 89%

Effect of veneering thickness and repeated firing on the flexural strength and translucency of lithium disilicate glass ceramic

2021

Mansoura Journal of Dentistry

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Objective: To evaluate effect of veneering thickness and repeated firing on the flexural strength and translucency of lithium disilicate glass ceramic. Materials and methods: Sixty-three-disc specimens were divided; each group have 21 discs specimens. First group was lithium disilicate core 1 mm with no veneering coverage, second group the lithium disilicate core was veneered by 0.5 mm nano flouroapatite glass ceramic. Third group was lithium disilicate core veneered by 1 mm nano flouroapatite glass ceramic. Each group was subjected to repeated firing cycles (3, 5, 7). Seven-disc specimens for each firing cycle were used to measure translucency then flexural strength. The degree of color difference between the compared colors was expressed in ∆E units. The total color difference, according to L*, H*, C* coordinates, was calculated. Then change in TP (∆TP) which is the difference between first and second sample regarding thickness and firing cycles was measured to determine the acceptability threshold. Then fracture load was applied to all specimens fixed on 3 balls fixture under static compressive loading using universal testing machine to determine the flexural strength. The results were tabulated and statistical analysis was performedusing repeated way ANOVA method. Results: Regarding value, chroma and hue, in 3 firing cycles value means revealed a significant difference in the comparison between 1 mm, 1.5 mm (P=0.001) thickness and between 1 mm, 2 mm (P=0.001) but non-significant difference was shown between 1.5 mm and 2 mm (P=0.325). While chroma and hue showed significant difference in comparison between 1 mm, 1.5 mm and 2 mm (P=0.001). However, in 5 firing cycles, value showed significant difference between 1 mm, 1.5 mm and 1 mm, 2 mm (P=0.001) and also between 1.5 mm, 2 mm (P=0.016), and chroma also showed significant difference between 1 mm, 1.5 mm, 2 mm (P=0.001), and hue showed significant difference between 1 mm, 1.5 mm (P=0.027), and also between 1 mm, 2 mm and 1.5 mm, 2 mm. However, in 7 firing cycles, value showed significant difference in comparison between 1 mm, 1.5 mm (P=0.001) and 1 mm, 2 mm (P=0.001) but non-significant difference was revealed between 1.5 mm, 2 mm (P=0.053). While chroma showed significant difference between 1 mm, 1.5 mm and 2 mm (P=0.001), while hue showed significant difference in comparison between 1 mm, 1.5 mm (P=0.001) but non-significant difference was found between 1 mm, 2 mm (P=0.11) and 1.5 mm, 2 mm (P=0.148). Translucency parameters revealed a significant difference (P=0.001) between different firing cycles with different thickness. Flexural strength showed no significant decrease with increasing firing cycles from 3 to 5 firing cycles in the same 1 mm thickness (P=0.153) and showed significant decrease on increasing firing cycles from 3 to 7 cycles (P=0.001) and 5 to 7 cycles (P=0.005). While in 1.5 mm thickness showed significant decrease in flexural strength on increasing firing cycles from 3 to 5 cycles (P=0.013) and from 3 to 7 cycles (P=0.001) and showed no sign...

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“…The XRD results are shown in Figures 8 and 9. Results showed that both the Amber Mill and e.max groups mainly exhibited diffraction peaks of lithium disilicate (ICCD 040-0376) [37,49]. At the same time, in all samples, Li 2 SiO 3 before sintering was transformed to Li 2 Si 2 O 3 .…”

Section: Xrd Analysismentioning

confidence: 92%

In Vivo Evaluation of the Effects of Sintering Temperature on the Optical Properties of Dental Glass-Ceramics

Fan

Lin

Tsao³

et al. 2022

Nanomaterials

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In prosthodontics, the ability of glass-ceramics to express the optical properties of natural teeth is an important goal of esthetic restorations. Dental restorations do not merely need to be similar in color to natural teeth; proper optical properties, such as opalescence, transparency, etc., must be combined in order to achieve excellent esthetic effects. The optical properties of ceramic materials are mainly distinguished by different hues (e.g., A, B, C, and D) combined with translucency (e.g., high translucency (HT), medium translucency (MT), low translucency (LT), and medium opacity (MO)). However, there are many varieties of tooth color. Therefore, it is expected that glass-ceramics can change their nanocrystal size and porosity through different heat-treatment temperatures and times and, thereby, present different transparency effects. This study mainly analyzed the influence of changes in sintering temperature on the optical properties of glass-ceramics. The optical properties of glass-ceramics in the oral cavity were evaluated with human trials. We hypothesized that (1) the transparency of glass-ceramics can be changed by controlling the sintering temperature and (2) glass-ceramics modified by the sintering temperature can be suitable for clinical applications. Results showed that the transparency decreased, the nanoparticle size increased, the crystallinity increased, and the surface hardness decreased as the sintering temperature increased. High-brightness glass-ceramics have more-sensitive optical properties. Results of clinical trials showed that glass-ceramics whose transparency was changed by controlling the sintering temperature can be candidates for clinical applications. Based on the above results, the hypotheses of this study were supported. In the future, we will continue to explore the esthetic field of dental restorations.

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Microstructural and mechanical analysis of two CAD-CAM lithium disilicate glass-reinforced ceramics

Abstract: Lucas do Nascimento TAVARES (a) Karla ZANCOPÉ (a) Anielle Christine Almeida SILVA (b) Luís Henrique Araújo RAPOSO (a) Carlos José SOARES (c) Flávio Domingues das NEVES (a)

Cited by 10 publications

References 18 publications

Monolith Dental Bridge by Soft Machining of Dried Ceramic Dough

Monolith Dental Bridge by Soft Machining of Dried Ceramic Dough

Effect of veneering thickness and repeated firing on the flexural strength and translucency of lithium disilicate glass ceramic

In Vivo Evaluation of the Effects of Sintering Temperature on the Optical Properties of Dental Glass-Ceramics

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