scholarly journals Evaluation of Marginal/Internal Fit and Fracture Load of Monolithic Zirconia and Zirconia Lithium Silicate (ZLS) CAD/CAM Crown Systems

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6346
Author(s):  
Haneen A. Sadeqi ◽  
Mirza Rustum Baig ◽  
Mohammad Al-Shammari
Keyword(s):  
Fracture Strength ◽  
Fatigue Loading ◽  
Fracture Load ◽  
Lithium Silicate ◽  
Cad Cam ◽  
Monolithic Zirconia ◽  
Axial Compressive Strength ◽  
The Individual ◽  
Internal Fit ◽  
Mechanical Aging

Fit accuracy and fracture strength of milled monolithic zirconia (Zi) and zirconia-reinforced lithium silicate (ZLS) crowns are important parameters determining the success of these restorations. This study aimed to evaluate and compare the marginal and internal fit of monolithic Zi and ZLS crowns, along with the fracture load, with and without mechanical aging. Thirty-two stone dies acquired from a customized master metal molar die were scanned, and ceramic crowns (16 Zi Ceramill Zolid HT+ and 16 ZLS Vita Suprinity) were designed and milled. Absolute marginal discrepancies (AMD), marginal gaps (MG), and internal gaps (IG) of the crowns, in relation to the master metal die, were evaluated using x-ray nanotomography (n = 16). Next, thirty-two metal dies were fabricated based on the master metal die, and crowns (16 Zi; 16 ZLS) cemented and divided into four groups of eight each; eight Zi with mechanical aging (MA), eight Zi without mechanical aging (WMA), eight ZLS (MA), and eight ZLS (WMA). Two groups of crowns (Zi-MA; ZLS-MA) were subjected to 500,000 mechanical cycles (200 ± 50 N, 10 Hz) followed by axial compressive strength testing of all crowns, until failure, and the values were recorded. Independent sample t tests (α = 0.05) revealed no significant differences between Zi and ZLS crowns (p > 0.05); for both internal and marginal gaps, however, there were significant differences in AMD (p < 0.005). Independent samples Mann–Whitney U and Kruskal–Wallis tests revealed significant differences between the two materials, Zi and ZLS, regardless of fatigue loading, and for the individual material groups based on aging (α = 0.05). Multiple comparisons using Bonferroni post-hoc analysis showed significant differences between Zi and ZLS material groups, with or without aging. Within the limitations of this study, the ZLS crown fit was found to be on par with Zi, except for the AMD parameter. As regards fracture resistance, both materials survived the normal range of masticatory forces, but the Zi crowns demonstrated greater resistance to fracture. The monolithic Zi and ZLS crowns seem suitable for clinical application, based on the fit and fracture strength values obtained.

Comparison of Fracture Strength and Fracture Modes of Zirconia Dental Ceramics Manufactured by Four Different CAD/CAM Systems

2011 ◽  
Vol 492 ◽  
pp. 30-34
Author(s):  
Dan Wang ◽  
Yuan Zhi Xu ◽  
Cheng Lin Lu ◽  
Qi Xiang Yang ◽  
Dong Sheng Zhang ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Critical Load ◽  
Fracture Strength ◽  
Fracture Load ◽  
Image Correlation ◽  
Zirconia Ceramic ◽  
Dental Ceramics ◽  
High Fracture ◽  
Fracture Modes ◽  
Cad Cam

Four sorts of zirconia dental ceramic systems including Cercon smart, Lava, Porcera, and CEREC 3 were studied to analyze fracture mechanism of different CAD/CAM zirconia ceramic. In each system, 12 sectioned specimens were prepared, 6 specimens were taken as controlled group, 6 as experimental group. Quasi-statistic loading before and after cyclic loading was applied at the veneer surface of the specimen. Deformation and crack initiation were monitored with camera in order to carry out digital image correlation (DIC) analysis. The results showed that median cracks were observed under the yielding zone. Specimens fractured along the core/veneer interface with the crack growth. No cone crack was confirmed and fracture only existed in veneer layer. After cyclic loading there were no significant differences for the four ceramic systems in terms of the critical load, while significant differences existed in terms of the fracture load. Both critical load and fracture load were lowered after cyclic loading. After cycling loading, the 4 tested zirconia CAD/CAM ceramic possess high fracture strength to meet the requirement for oral functions. The fracture modes of the four zirconia ceramic systems indicate that the strength of the veneer should be enhanced.

Fracture Strength and Fracture Patterns of Root-filled Teeth Restored With Direct Resin Composite Restorations Under Static and Fatigue Loading

2014 ◽  
Vol 39 (2) ◽  
pp. 181-188 ◽  
Author(s):  
NA Taha ◽  
JE Palamara ◽  
HH Messer
Keyword(s):  
Fracture Strength ◽  
Resin Composite ◽  
Glass Ionomer Cement ◽  
Fatigue Loading ◽  
Test System ◽  
Fracture Load ◽  
Composite Restorations ◽  
Fracture Patterns ◽  
Lower Load ◽  
Number Of Cycles

SUMMARY Aim To assess fracture strength and fracture patterns of root-filled teeth with direct resin composite restorations under static and fatigue loading. Methodology MOD cavities plus endodontic access were prepared in 48 premolars. Teeth were root filled and divided into three restorative groups, as follows 1) resin composite; 2) glass ionomer cement (GIC) core and resin composite; and 3) open laminate technique with GIC and resin composite. Teeth were loaded in a servohydraulic material test system. Eight samples in each group were subjected to stepped fatigue loading: a preconditioning load of 100 N (5000 cycles) followed by 30,000 cycles each at 200 N and higher loads in 50-N increments until fracture. Noncycled teeth were subjected to a ramped load. Fracture load, number of cycles, and fracture patterns were recorded. Data were analyzed using two-way analysis of variance and Bonferroni tests. Results Fatigue cycling reduced fracture strength significantly (p&lt;0.001). Teeth restored with a GIC core and a laminate technique were significantly weaker than the composite group (379±56 N, 352±67 N vs 490±78 N, p=0.001). Initial debonding occurred before the tooth underwent fracture. All failures were predominantly adhesive, with subcrestal fracture of the buccal cusp. Conclusions Resin composite restorations had significantly higher fracture strength than did other restorations. Fatigue cycled teeth failed at lower load than did noncycled teeth.

Fracture Strength and Precision of Fit of Implant-Retained Monolithic Zirconia Crowns

2018 ◽  
Vol 44 (5) ◽  
pp. 330-334 ◽  
Author(s):  
Pauliina Moilanen ◽  
Jenni Hjerppe ◽  
Lippo V. J. Lassila ◽  
Timo O. Närhi
Keyword(s):  
Fracture Strength ◽  
Computer Aided Design ◽  
Testing Machine ◽  
Implant Surface ◽  
Computer Aided ◽  
Cad Cam ◽  
Zirconia Crowns ◽  
Failure Loads ◽  
Monolithic Zirconia ◽  
Aided Design

New monolithic zirconia materials can be used to fabricate full-contour fixed dental prostheses with the computer-aided design/computer-aided manufacturing (CAD/CAM) method. The aim of this study was to examine the fracture strength and precision of fit of screw-retained monolithic zirconia crowns made directly on implants or by cementing on prefabricated titanium (Ti) bases. Monolithic screw-retained implant crowns (n = 6) were produced by CAD/CAM method using partially (PSZ) and fully stabilized (FSZ) zirconia. Industrially produced zirconia crowns were used as a reference. A lateral incisor study model was made onto an implant replica. Crowns were produced either directly on the implant or through cementing on a prefabricated titanium base (PSZ+Ti, FSZ+Ti). The crowns were tightened to implant replicas with a torque of 35 Ncm. The gap between the replica and the abutment or crown was measured from ×400 scanning electron microscope images for precision of fit. Mechanical testing until failure was completed with a universal testing machine with loading angle of 45°. Statistical analysis was performed (analysis of variance). Mean (±SD) failure loads were 259 ± 23 (PSZ), 140 ± 13 (FSZ), 453 ± 25 (PSZ+Ti), 439 ± 41 (FSZ+Ti), and 290 ± 39 (Procera). Mean (±SD) gap values were 2.2 ± 0.2 (PSZ), 2.5 ± 1.0 (FSZ), 7.0 ± 1.0 (PSZ+Ti), 7.7 ± 1.6 (FSZ+Ti), and 6.7 ± 1.7 (Procera). Monolithic zirconia crowns with a Ti base clearly show higher fracture strengths than the crowns fixed directly on the implant surface. Better marginal fit can be achieved with direct zirconia crowns than with crowns on a titanium base or industrially produced zirconia crowns.

scholarly journals In Vitro Comparison of Marginal and Internal Fit of Zirconia Copings Fabricated by One CAD/CAM System with Two Different Scanners

2021 ◽  
Author(s):  
Zahra Khamverdi1 ◽  
Elmira Najafrad ◽  
Maryam Farhadian
Keyword(s):  
T Test ◽  
Marginal Fit ◽  
Significant Difference ◽  
Computer Aided ◽  
Cad Cam ◽  
Zirconia Crowns ◽  
Monolithic Zirconia ◽  
The Mean ◽  
Internal Fit ◽  
Paired T Test

Objectives: Marginal and internal fit of restorations are two important clinical factors for assessing the quality and durability of computer-aided design/computer-aided manufacturing (CAD/CAM)-fabricated monolithic zirconia restorations. The purpose of this study was to evaluate the marginal and internal fit of CAD/CAM zirconia crowns with two different scanners (i3D scanner and 3Shape D700). Materials and Methods: Twelve extracted sound human posterior teeth were prepared for full zirconia crowns. Two different extraoral scanners namely i3D scanner and 3Shape D700 were used to digitize type IV gypsum casts poured from impressions. The crowns were milled from presintered monolithic zirconia blocks by a 5-axis milling machine. The replica technique and MIP4 microscopic image analysis software were utilized to measure the marginal and internal fit by a stereomicroscope at ×40 magnification. The collected data were analyzed by paired t-test. Results: The mean marginal gap was 203.62 μm with 3Shape D700 scanner and 241.07 μm with i3D scanner. The mean internal gap was 192.30 μm with 3Shape D700 scanner and 196.06 μm with i3D scanner. The results of paired t-test indicated that there was a statistically significant difference between the two scanners in marginal fit (P=0.04); while, there was no statistically significant difference in internal fit (P=0.761). Conclusion: Within the limitations of this study, the results showed that type of extraoral scanner affected the marginal fit of CAD/CAM fabricated crowns; however, it did not have a significant effect on their internal fit.

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.

scholarly journals Fracture Strength of Zirconia and Alumina Ceramic Crowns Supported by Implants

2015 ◽  
Vol 41 (S1) ◽  
pp. 352-359 ◽  
Author(s):  
Tonino Traini ◽  
Roberto Sorrentino ◽  
Enrico Gherlone ◽  
Federico Perfetti ◽  
Patrizio Bollero ◽  
...  
Keyword(s):  
Fracture Strength ◽  
Glass Ceramic ◽  
Ceramic Materials ◽  
Fracture Load ◽  
Fractographic Analysis ◽  
Core Material ◽  
Loading Test ◽  
Significant Difference ◽  
Cad Cam ◽  
Ceramic Crowns

Due to the brittleness and limited tensile strength of the veneering glass-ceramic materials, the methods that combine strong core material (as zirconia or alumina) are still under debate. The present study aims to evaluate the fracture strength and the mechanism of failure through fractographic analysis of single all-ceramic crowns supported by implants. Forty premolar cores were fabricated with CAD/CAM technology using alumina (n = 20) and zirconia (n = 20). The specimens were veneered with glass-ceramic, cemented on titanium abutments, and subjected to loading test until fracture. SEM fractographic analysis was also performed. The fracture load was 1165 (±509) N for alumina and 1638 (±662) N for zirconia with a statistically significant difference between the two groups (P = 0.026). Fractographic analysis of alumina-glass-ceramic crowns, showed the presence of catastrophic cracks through the entire thickness of the alumina core; for the zirconia-glass-ceramic crowns, the cracks involved mainly the thickness of the ceramic veneering layer. The sandblast procedure of the zirconia core influenced crack path deflection. Few samples (n = 3) showed limited microcracks of the zirconia core. Zirconia showed a significantly higher fracture strength value in implant-supported restorations, indicating the role played by the high resistant cores for premolar crowns.

scholarly journals Arithmetic Relationship between Fracture Load and Material Thickness of Resin-Based CAD-CAM Restorative Materials

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 58
Author(s):  
Tobias Graf ◽  
Josef Schweiger ◽  
Jan-Frederik Güth ◽  
Thomas Sciuk ◽  
Oliver Schubert ◽  
...  
Keyword(s):  
Fracture Load ◽  
Coefficient Of Determination ◽  
Material Thickness ◽  
Regression Curves ◽  
Cubic Equation ◽  
Computer Aided ◽  
Restorative Materials ◽  
Cad Cam ◽  
The Individual ◽  
Long Term Behavior

Data on the long-term behavior of computer-aided designed/computer-aided manufactured (CAD-CAM) resin-based composites are sparse. To achieve higher predictability on the mechanical behavior of these materials, the aim of the study was to establish a mathematical relationship between the material thickness of resin-based materials and their fracture load. The tested materials were Lava Ultimate (LU), Cerasmart (GC), Enamic (EN), and Telio CAD (TC). For this purpose, 60 specimens were prepared, each with five different material thicknesses between 0.4 mm and 1.6 mm (N = 60, n = 12). The fracture load of all specimens was determined using the biaxial flexural strength test (DIN EN ISO 6872). Regression curves were fitted to the results and their coefficient of determination (R2) was computed. Cubic regression curves showed the best R2 approximation (LU R2 = 0.947, GC R2 = 0.971, VE R2 = 0.981, TC R2 = 0.971) to the fracture load values. These findings imply that the fracture load of all tested resin-based materials has a cubic relationship to material thickness. By means of a cubic equation and material-specific fracture load coefficients, the fracture load can be calculated when material thickness is given. The approach enables a better predictability for resin-based restorations for the individual patient. Hence, the methodology might be reasonably applied to other restorative materials.

scholarly journals The Influence of Three Different Digital Cement Spacers on the Marginal Gap Adaptation of Zirconia-Reinforced Lithium Silicate Crowns Fabricated by CAD-CAM System

2021 ◽  
Vol 11 (22) ◽  
pp. 10709
Author(s):  
Gil Ben-Izhack ◽  
Asaf Shely ◽  
Sarit Naishlos ◽  
Ari Glikman ◽  
Liad Frishman ◽  
...  
Keyword(s):  
Regions Of Interest ◽  
Lithium Silicate ◽  
Marginal Gap ◽  
Cad Cam ◽  
Monolithic Zirconia ◽  
Bonferroni Test ◽  
Ceramic Crowns ◽  
Post Hoc ◽  
One Way Anova ◽  
Electronic Microscope

Background: This study compared the influence of three different radial spacers (60,90,120 microns) on the marginal gap adaptation by using computer-aided manufacturing (CAD-CAM) for producing monolithic zirconia reinforced lithium silicate (ZLS) ceramic crowns. Methods: A total of 45 abutment acrylic teeth were divided into three groups of different radial spacers (60, 90, and 120 microns). In each group 15 teeth were scanned by Omnicam intra oral scanner and ZLS crowns were ground. For each unit the marginal gap was evaluated at four regions of interest by scanning electronic microscope (SEM). To compare the marginal gap between the three groups a one-way ANOVA with post-hoc Bonferroni test was preformed (α = 0.05). Results: The marginal gap for a 60 microns (162.99 ± 16.25 µm) radial spacer was found significantly higher than 90 (41.85 ± 3.57 µm) and 120 (41.85 ± 5.3 µm) microns radial spacers (p < 0.05). Between 90- and 120-micron radial spacers no difference was obtained. (p < 0.05). Conclusions: A radial spacer of 60 microns showed a significantly higher marginal gap compared to 90 and 120 microns and was not clinically accepted (>120 microns). For both 90 and 120 microns the marginal gap was clinically accepted (<120 microns) with no difference between the groups. The radial spacer which should be optimum for CELTRA® DUO crowns is 90 microns.

Sign in / Sign up

Export Citation Format

Share Document