The influence of roughness on the resistance to impact of different CAD/CAM dental ceramics

2021 ◽  
Vol 32 (6) ◽  
pp. 54-65
Author(s):  
Luis Felipe Guilardi ◽  
Arie Werner ◽  
Niek de Jager ◽  
Gabriel Kalil Rocha Pereira ◽  
Cornelis Johannes Kleverlaan ◽  
...  
Keyword(s):  
Impact Strength ◽  
Glass Ceramic ◽  
Pearson Correlation ◽  
Tetragonal Zirconia ◽  
Lithium Silicate ◽  
Dental Ceramics ◽  
Strength Data ◽  
Milling Simulation ◽  
Cad Cam ◽  
The Impact

Abstract This study aimed to investigate the effect of surface roughness (polished vs. CAD/CAM milling simulation) on impact strength of five dental ceramics for manufacturing CAD/CAM monolithic restorations. Specimens of five ceramics (FC- feldspathic glass-ceramic; PICN- polymer-infiltrated ceramic-network; ZLS- zirconia-reinforced lithium silicate glass-ceramic; LD- lithium disilicate glass-ceramic; YZ- yttria-stabilized tetragonal zirconia polycrystal ceramic) to be tested under impact (15×10×2mm3; n= 15) were divided into two groups, according to surface treatment: polishing (pol) and grinding (gri) as CAD/CAM milling simulation. Impact strength was tested using the Dynstat method. Roughness, topographic, fractographic and finite element analyses were performed. The impact strength data were analyzed by Weibull, and Pearson correlation was used to correlate roughness and impact strength data. The CAD/CAM milling simulation led to significantly (p<0.05) greater roughness (Ra and Rz) and statistically reduced the impact strength for PICN (polPICN= 4.59 to griPICN= 1.09; ±76% decrease), for LD (polLD= 17.69 to griLD= 10.09; ±43% decrease) and for YZ (polYZ= 74.99 to griYZ= 20.67; ±72% decrease) ceramics; and also promoted a more irregular topography with scratches and grooves. Fractographic and FEA analyses depicted the origin of failure at the higher stress concentration side during the impact test, where the pendulum impacted. The CAD/CAM milling simulation significantly decreased the impact strength of the evaluated ceramic materials.

A Comparative Study of Light Transmission by Various Dental Restorative Materials and the Tooth Structure

2019 ◽  
Vol 45 (4) ◽  
pp. 442-452 ◽  
Author(s):  
N Ilie ◽  
G Furtos
Keyword(s):  
Optical Properties ◽  
Glass Ceramic ◽  
Light Transmission ◽  
Lithium Disilicate ◽  
Lithium Silicate ◽  
Restorative Process ◽  
Tooth Structure ◽  
Computer Aided ◽  
Restorative Materials ◽  
Cad Cam

Clinical Relevance Light transmission through dental materials and tooth structure has direct clinical implication on such factors as selecting an appropriate curing technique during a restorative process. SUMMARY Introduction: This study aims to quantify and compare the amount of light that passes through seven different types of direct and indirect restorative materials comprising light-cured resin based composites (regular and bulk-fill), computer-aided design/computer-aided manufacturing (CAD/CAM) restoratives such as resin based composites, poly(methyl methacrylate) (PMMA) resin, leucite glass-ceramic, lithium silicate glass-ceramic, feldspar ceramic, and the natural tooth structure. Methods and Materials: Individual sets (n=6) of plane-parallel test specimens (2 mm) of 32 restorative materials belonging to the aforementioned seven material types and the tooth structure were prepared. Within the analyzed materials, one leucite glass-ceramic and one lithium disilicate glass-ceramic were considered in two different translucencies. In addition, two light-cured resin composites, one CAD/CAM resin composite, and one lithium disilicate glass-ceramic were considered in two different shades. Optical properties (transmittance, T; absorbance, A; and opacity, O) of each material were calculated from the relationship between incident and transmitted irradiance [I(d)] using a violet-blue light-curing unit. Incident and transmitted irradiance were assessed in real time on a spectrophotometer. A multivariate analysis (general linear model) assessed the effects of various parameters on the optical properties. Results: A very strong influence of the parameter material was identified on I(d) (p&lt;0.001; partial eta squared, ηP2=0.953), T (p&lt;0.001; ηP2=0.951), A (p&lt;0.001; ηP2=0.925), and O (p&lt;0.001; ηP2=0.886), while the effect of the parameter material type was not significant (p=0.079, p=0.05, p=0.05, and p=0.051, respectively). Light attenuation differed significantly by material within each shade category and by shade category within the analyzed material. Conclusions: Attenuation of light through restorative materials and tooth structure is high (59.9% to 94.9%); thus, deficits in polymerization are difficult to compensate for by additional light exposure at the end of the restorative process.

scholarly journals Effect of Thermocycling, Surface Treatments and Microstructure on the Optical Properties and Roughness of CAD-CAM and Heat-Pressed Glass Ceramics

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 381 ◽  
Author(s):  
Roxana-Diana Vasiliu ◽  
Sorin Daniel Porojan ◽  
Mihaela Ionela Bîrdeanu ◽  
Liliana Porojan
Keyword(s):  
Surface Roughness ◽  
Optical Properties ◽  
Glass Ceramic ◽  
Glass Ceramics ◽  
Lithium Disilicate ◽  
Ceramic Materials ◽  
Surface Treatments ◽  
Lithium Silicate ◽  
Before And After ◽  
Cad Cam

Dental ceramic restorations are widely spread nowadays due to their aesthetics and biocompatibility. In time, the colour and structure of these ceramic materials can be altered by aging processes. How does artificial aging affect the optical and surface roughness of ceramics? This study aims to assess the effect of thermocycling, surface treatments and microstructure upon translucency, opalescence and surface roughness on CAD-CAM and heat-pressed glass-ceramic. Forty-eight samples (1.5 mm thickness) were fabricated from six types of A2 MT ceramic: heat-pressed and milled glass-ceramic (feldspathic, lithium disilicate and zirconia reinforced lithium silicate). The samples were obtained respecting the manufacturer’s instructions. The resulted surfaces (n = 96) were half glazed and half polished. The samples were subjected to thermocycling (10,000 cycles) and roughness values (Ra and Rz), colour coordinates (L*, a*, b*) and microstructural analyses were assessed before and after thermocycling. Translucency (TP) and opalescence (OP) were calculated. Values were statistically analysed using ANOVA test (one way). TP and OP values were significantly different between heat-pressed and milled ceramics before and also after thermocycling (p < 0.001). Surface treatments (glazing and polishing) had a significant effect on TP and OP and surface roughness (p < 0.05). The heat-pressed and milled zirconia reinforced lithium silicate glass-ceramic experienced a loss in TP and OP. Ra and Rz increased for the glazed samples, TP and OP decreased for all the samples after thermocycling. Microstructural analyse revealed that glazed surfaces were more affected by the thermocycling and especially for the zirconia reinforced lithium silicate ceramic. Optical properties and surface roughness of the chosen ceramic materials were affected by thermocycling, surface treatments and microstructural differences. The least affected of the ceramics was the lithium disilicate ceramic heat-pressed polished and glazed.

scholarly journals Surface Characterization and Conductivity of Two Types of Lithium-Based Glass Ceramics after Accelerating Ageing

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5632
Author(s):  
Marko Jakovac ◽  
Teodoro Klaser ◽  
Borna Radatović ◽  
Željko Skoko ◽  
Luka Pavić ◽  
...  
Keyword(s):  
Surface Characterization ◽  
Glass Ceramics ◽  
Structural Defects ◽  
Lithium Silicate ◽  
Dental Ceramics ◽  
Ion Diffusion ◽  
X Ray ◽  
The Impact ◽  
Non Destructive ◽  
Scanning Electron

In this study, two different dental ceramics, based on zirconia-reinforced lithium-silicate (LS1) glass-ceramics (Celtra Duo, Dentsply Sirona, Bensheim, Germany) and lithium disilicate (LS2) ceramics (IPS e.max CAD, Ivoclar, Vivadent, Schaan, Liechtenstein) were examined. They were tested prior to and after the crystallization by sintering in the dental furnace. Additionally, the impact of ageing on ceramic degradability was investigated by immersing it in 4% acetic acid at 80 °C for 16 h. The degradability of the materials was monitored by Impedance Spectroscopy (IS), X-Ray Powder Diffraction (XRPD), and Field Emission Scanning Electron Microscope (FE-SEM) techniques. It was detected that LS2 (vs. LS1) samples had a lower conductivity, which can be explained by reduced portions of structural defects. XRPD analyses also showed that the ageing increased the portion of defects in ceramics, which facilitated the ion diffusion and degradation of samples. To summarize, this study suggests that the non-destructive IS technique can be employed to probe the ageing properties of the investigated LS1 and LS2 ceramics materials.

scholarly journals Biocompatibility of Polymer and Ceramic CAD/CAM Materials with Human Gingival Fibroblasts (HGFs)

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1446 ◽  
Author(s):  
Rizo-Gorrita ◽  
Herráez-Galindo ◽  
Torres-Lagares ◽  
Serrera-Figallo ◽  
Gutiérre-Pérez
Keyword(s):  
Collagen Type ◽  
Tetragonal Zirconia ◽  
Collagen Type I ◽  
Human Gingival Fibroblasts ◽  
Lithium Silicate ◽  
Type I ◽  
Gingival Fibroblasts ◽  
Collagen Secretion ◽  
Computer Aided ◽  
Cad Cam

Four polymer and ceramic computer-aided design/computer-aided manufacturing (CAD/CAM) materials from different manufacturers (VITA CAD-Temp (polymethyl methacrylate, PMMA), Celtra Duo (zirconia-reinforced lithium silicate ceramic, ZLS), IPS e.max CAD (lithium disilicate (LS2)), and VITA YZ (yttrium-tetragonal zirconia polycrystal, Y-TZP)) were tested to evaluate the cytotoxic effects and collagen type I secretions on human gingival fibroblasts (HGFs). A total of 160 disc-shaped samples (Ø: 10 ± 2 mm; h: 2 mm) were milled from commercial blanks and blocks. Direct-contact cytotoxicity assays were evaluated at 24, 48, and 72 h, and collagen type I (COL1) secretions were analysed by cell-based ELISA at 24 and 72 h. Both experiments revealed statistically significant differences (p < 0.05). At 24 and 48 h of contact, cytotoxic potential was observed for all materials. Later, at 72 h, all groups reached biologically acceptable levels. LS2 showed the best results regarding cell viability and collagen secretion in all of the time evaluations, while Y-TZP and ZLS revealed intermediate results, and PMMA exhibited the lowest values in both experiments. At 72 h, all groups showed sharp decreases in COL1 secretion regarding the 24-h values. According to the results obtained and the limitations of the present in vitro study, it may be concluded that the ceramic materials revealed a better cell response than the polymers. Nevertheless, further studies are needed to consolidate these findings and thus extrapolate the results into clinical practice.

ANALYSIS OF THE IMPACT OF BIOMATERIAL AND THE TECHNOLOGY OF PROSTHETIC CROWNS MANUFACTURING ON THE CONNECTION WITH VENEERING CERAMICS

Tribologia ◽  
2021 ◽  
Vol 293 (5) ◽  
pp. 17-25
Author(s):  
Anna M. RYNIEWICZ ◽  
Andrzej Ryniewicz ◽  
Łukasz Bojko ◽  
Wojciech Ryniewicz
Keyword(s):  
Penetration Depth ◽  
Cross Sections ◽  
Glass Ceramic ◽  
Testing Machine ◽  
Layered Structures ◽  
Micro Hardness ◽  
Hardness Tester ◽  
Cad Cam ◽  
The Impact

The aim of the study is to identify the endurance parameters of prosthetic crowns veneered with dedicated ceramics on metal, glass-ceramic, and ceramic frameworks. Metal frameworks were made using CAD/CAM milling technology and SLM technology, while the glass-ceramic and ceramic frameworks were produced using only the CAD/CAM milling technology. The research materials are samples replicating the layered structures of prosthetic crowns. The veneering procedure must ensure the adhesion of the ceramics to the loadbearing framework. The tests modelling the conditions of concentrated loads during chewing were carried out using the Instron 3345 testing machine. Determination of microhardness in cross-sections through layered structures of crowns was performed using the HMV Micro Hardness Tester. The comparison of force loading the indenter as a function of penetration depth indicates that the value of the maximum depth depends on the configuration of microhardness of the framework and dentine. The zirconium ceramics ZrO2 (3Y-TZP) – veneered with Elephant Sakura silica ceramics – should be indicated as the most advantageous material composition.

scholarly journals Vickers Micro-Hardness of New Restorative CAD/CAM Dental Materials: Evaluation and Comparison after Exposure to Acidic Drink

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1246 ◽  
Author(s):  
Marco Colombo ◽  
Claudio Poggio ◽  
Alessandro Lasagna ◽  
Marco Chiesa ◽  
Andrea Scribante
Keyword(s):  
Glass Ceramic ◽  
Lithium Silicate ◽  
Micro Hardness ◽  
Percentage Loss ◽  
Computer Aided ◽  
Cad Cam ◽  
Nanohybrid Composite ◽  
Hybrid Ceramic ◽  
Hardness Values ◽  
Lithium Silicate Glass

CAD/CAM (computer-aided design/computer-aided manufacturing) for indirect restorative materials has been recently introduced in dentistry. The purpose of this study was to evaluate the change of the surface micro-hardness of different restorative CAD/CAM materials after exposure to a carbonated acidic drink (Coca-Cola, Coca-Cola Company, Milan, Italy). One hundred and eighty specimens of identical size (2 mm thickness) were obtained by sectioning each tested CAD/CAM block of four materials: a hybrid ceramic (CERASMART™, GC Corporation, Tokyo, Japan), a resin nano ceramic (Lava™ Ultimate, 3M, Monrovia, CA, USA), a nanohybrid composite (Grandio blocs, VOCO GmbH, Cuxhaven, Germany), and a zirconia-reinforced lithium silicate glass ceramic (VITA SUPRINITY® PC; VITA Zahnfabrik, Bad Sackingen, Germany). Forty-five specimens of each material were tested. Micro-hardness was measured at baseline, after 7 days and after 28 days. The data were analyzed. The micro-hardness of each material varied significantly after immersion in Coca-Cola. The nanohybrid composite had a high initial micro-hardness and the greatest percentage loss after acid exposure. The hybrid ceramic and the resin nano ceramic had similar percentage losses of micro-hardness values even if the second material had higher initial values. The zirconia-reinforced lithium silicate glass ceramic had the highest baseline values and the lowest percentage loss of micro-hardness. The different CAD/CAM materials presented different micro-hardness values before and after acid exposure.

scholarly journals In Vitro Study of Comparative Evaluation of Marginal and Internal Fit between Heat-Pressed and CAD-CAM Monolithic Glass-Ceramic Restorations after Thermal Aging

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4239
Author(s):  
Roxana-Diana Vasiliu ◽  
Sorin Daniel Porojan ◽  
Liliana Porojan
Keyword(s):  
Thermal Aging ◽  
Glass Ceramic ◽  
In Vitro Study ◽  
Vitro Study ◽  
Lithium Silicate ◽  
Computer Aided ◽  
Cad Cam ◽  
Internal Fit ◽  
Ceramic Restorations

The accuracy of newly developed ceramic materials is still being studied. Marginal and internal adaptation are known factors that have an essential impact on the long term success of dental restorations. The aim of this in vitro study was to evaluate the marginal and internal fit of heat-pressed and milled monolithic glass-ceramic restorations based on their ceramic type, processing technique, and in vitro thermocycling. Thirty-two crowns were studied and divided into four groups (n = 8), according to the ceramic material (feldspathic glass-ceramic (F) and zirconia reinforced lithium silicate glass-ceramic (ZLS)) and to their technological obtaining processes (milling (M) and heat-pressing (P)). A typodont preparation was scanned with a D2000 3D scanner to obtain identical 32 resin 3D-printed abutment teeth. Marginal and internal gaps were measured using the silicone replica technique under 40× magnification. The crowns were further cemented and thermally aged for 10,000 cycles After cementation and thermocycling of the samples, marginal and internal gaps were assessed using micro-CT (micro-computed tomography)) analysis. Data were statistically analyzed using statistical tests. Significant differences were found before and after cementation and thermocycling among the tested materials (p < 0.05). Related to technological processing, significant differences were seen in the marginal area between FP and FM (p < 0.05) Significant differences were also found in the axial and occlusal areas between the ZLSP and ZLSM. Thermocycling and cementation did not have a significant effect on the tested materials (p < 0.05). The technological processes influenced the marginal and internal fit of the crowns in favor of the CAD/CAM (computer aided design/computer aided manufacturing)technologies. Thermal aging had little effect on marginal adaptability; it increased the values for all the tested samples in a small way, but the values remained in their clinically acceptable range for all of the crowns.

Characterization of Reinforced and Unreinforced Glass-Ceramic Veneers

2021 ◽  
Author(s):  
AR Oliveira ◽  
KS Jodha ◽  
SM Salazar Marocho ◽  
GA Galhano
Keyword(s):  
Surface Roughness ◽  
Residual Stresses ◽  
Glass Ceramic ◽  
Optical Microscope ◽  
Lithium Silicate ◽  
Atomic Force ◽  
Before And After ◽  
Cad Cam ◽  
Topographical Analysis ◽  
Post Hoc

SUMMARY This study aimed to characterize the surface topography, effect of polishing on surface roughness, residual stresses, and hardness in two glass-ceramic veneers. Fifty-two (52) upper incisors were collected, prepared, and scanned for ceramic veneers. Half of the teeth were restored with veneers made up of feldspathic ceramic (FE), and the other half with zirconia-reinforced lithium silicate ceramic (SZ). All the veneers were designed and milled using a CAD/CAM system and later cemented following the manufacturer’s guideline. An optical microscope analyzed the topography of the specimens before and after polishing. The surface roughness was measured using the roughness meter (n=12) and the topographical analysis was carried out using an atomic force microscope (n=6). The residual stresses and Vickers’ hardness were evaluated by the indentation method in a micro-hardness indenter (n=6). The surface roughness was analyzed using a three-way analysis of variance (ANOVA) followed by a post hoc Tukey test. The Student t-test was used to compare the residual stresses and hardness between the two ceramics. The topographical analysis revealed that both glass-ceramic veneers had similar percentages of specimens with cracks, before (34.6%) and after (42.3%) polishing. The surface roughness decreased after polishing (p&lt;0.001), and the polishing smoothed out the surface of the veneers. The zirconia-reinforced lithium silicate veneer had a lower roughness as compared to the feldspathic one after polishing, while the residual stresses (p=0.722) and hardness (p=0.782) were statistically similar for both ceramic veneers.

scholarly journals Effects of Liner-Bonding of Implant-Supported Glass–Ceramic Crown to Zirconia Abutment on Bond Strength and Fracture Resistance

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2798 ◽  
Author(s):  
Yong-Seok Jang ◽  
Sang-Hoon Oh ◽  
Won-Suck Oh ◽  
Min-Ho Lee ◽  
Jung-Jin Lee ◽  
...  
Keyword(s):  
Bond Strength ◽  
Glass Ceramic ◽  
Fracture Resistance ◽  
Tetragonal Zirconia ◽  
Zirconia Ceramic ◽  
Significant Difference ◽  
Computer Aided ◽  
Mode Of Failure ◽  
Cad Cam ◽  
Ceramic Crown

This study was conducted to test the hypothesis that heat-bonding with a liner positively affects the bond strength and fracture resistance of an implant-supported glass–ceramic crown bonded to a zirconia abutment produced by a computer-aided design/computer-aided milling (CAD/CAM) procedure. Lithium disilicate-reinforced Amber Mill-Q glass ceramic blocks were bonded to 3 mol% yttria stabilized tetragonal zirconia polycrystal (3Y-TZP) blocks by heat-bonding with a liner or cementation with a dual-cure self-adhesive resin cement for a microtensile bond strength test. CAD/CAM implant-supported glass ceramic crowns were produced using Amber Mill-Q blocks and bonded to a milled 3Y-TZP zirconia abutments by heat-bonding or cementation for a fracture test. A statistical analysis was conducted to investigate the significant differences between the experimental results. The mode of failure was analyzed using high-resolution field emission scanning electron microscopy. Chemical bonding was identified at the interface between the zirconia ceramic and liner. The mean tensile bond strength of the liner-bonded group was significantly higher than that of the cement-bonded group. The initial chipping strength of the liner-bonded group was significantly higher than that of the cement-bonded group, although no statistically significant difference was found for the fracture strength. The mode of failure was mixed with cohesive fracture through the liner, whereas the cement-bonded group demonstrated adhesive failure at the interface of bonding.

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