Fracture-behavior of CAD/CAM ceramic crowns before and after cyclic fatigue aging

2021 ◽  
Author(s):  
Sufyan Garoushi ◽  
Eija Säilynoja ◽  
Pekka Vallittu ◽  
Lippo Lassila
Keyword(s):  
Fracture Behavior ◽  
Cyclic Fatigue ◽  
Before And After ◽  
Cad Cam ◽  
Ceramic Crowns

scholarly journals A base-line study of the wear of burs used for chairside milling of ceramic crowns of different hardness: effect on internal fit and surface roughness

2020 ◽  
Author(s):  
Ayman Abd Alla Ahmed
Keyword(s):  
Surface Roughness ◽  
Tungsten Carbide ◽  
Diamond Particle ◽  
Base Line ◽  
Replica Technique ◽  
Before And After ◽  
Cad Cam ◽  
Ceramic Crowns ◽  
Internal Fit ◽  
And Tungsten

Abstract Background: In the CAD/CAM environment, wear of the milling burs may affect the accuracy of the milled crown. However, no studies have related bur wear to both the resultant internal fit of the crown or to the surface roughness. The aim of this study was to study this, using diamond burs and a feldspathic ceramic (Sirona Blocs C, Dentsply Sirona, Germany) and tungsten carbide burs and Zirconia (inCoris TZI puck, Dentsply Sirona, Germany).Methods: Thirty of each of the two materials were milled from the same standard preparation. One set of diamond burs was used for the feldspathic ceramic and one set of tungsten-carbide burs for the Zirconia. Before and after the 10th, 20th and 30th milling times, diamond particle loss was counted and cutting blade changes of the tungsten-carbide burs measured. Internal fit was measured using a silicone replica technique and surface roughness with a 3D measuring laser microscope.Results: Increasing wear of the diamond burs as measured by an average 26% loss of diamond particles after 30 crowns, which resulted in a 6% decrease in internal luting space and a 16% increase in surface roughness. Increasing wear of the tungsten-carbide burs resulted in a 13% decrease in the luting space, but there was an overall 16% increase in surface roughness. Conclusions: This is the first study to compare the wear of diamond and tungsten-carbide milling burs with the internal fit and surface roughness of the crown. The wear of milling burs affects the luting space, reducing it as the burs wear, and therefore the milling parameters must be adjusted to compensate for this.

scholarly journals Influence of the fabrication method on the fracture behavior of all-ceramic prosthesis

Cerâmica ◽  
2018 ◽  
Vol 64 (370) ◽  
pp. 284-287
Author(s):  
A. C. Piccoli ◽  
M. Borba
Keyword(s):  
Fracture Behavior ◽  
Testing Machine ◽  
Slip Casting ◽  
Fracture Load ◽  
Resin Cement ◽  
Fabrication Method ◽  
All Ceramic ◽  
Cad Cam ◽  
Ceramic Crowns ◽  
Student’S T

Abstract Different methods are available to produce all-ceramic dental prosthesis. Each processing step may introduce flaws to the material, which compromises its properties and reliability. The objective of this study was to evaluate the effect of fabrication method on the fracture behavior of prosthetic crowns produced with an alumina-based glass-infiltrated zirconia-reinforced ceramic. Two groups of all-ceramic crowns were produced according to the fabrication method of the infrastructure (IS) (n=30): IZC - IS produced by CAD-CAM; IZS - IS produced by slip-casting. The IS were veneered with porcelain and cemented to fiber-reinforced composite dies with resin cement. Crowns were loaded in compression to failure using a universal testing machine, at 1 mm/min crosshead speed and 37 ºC distilled water. Fractography was performed using stereomicroscope and SEM. Data were statistically analyzed with Student’s t test (α=0.05) and Weibull analysis. There were no significant differences among the experimental groups for fracture load (p=0.481) and Weibull modulus. For both groups, the failure mode was catastrophic failure involving IS and porcelain. It was concluded that the fabrication methods evaluated resulted in all-ceramic crowns with similar fracture behavior and reliability.

scholarly journals Fit of metal-ceramic crowns

2021 ◽  
Vol 21 ◽  
pp. e225136
Author(s):  
Patrícia Valéria Manozzo Kunz ◽  
Gabriela Andrade Serpa ◽  
Leonardo Fernandes da Cunha ◽  
Gisele Maria Correr ◽  
Carla Castiglia Gonzaga
Keyword(s):  
Cobalt Chromium ◽  
Manufacturing Method ◽  
Significant Difference ◽  
Metal Ceramic ◽  
Before And After ◽  
Cad Cam ◽  
Marginal Discrepancy ◽  
Ceramic Crowns ◽  
Student’S T ◽  
Internal Fit

Aim: To evaluate the influence of cobalt-chromium (Co-Cr) coping fabrication methods and ceramic application on the marginal and internal fit of metal-ceramic crowns. Methods: Co-Cr copings for metal-ceramic crowns were prepared by lost wax casting or CAD-CAM machining of sintered blocks. The fit was analyzed using the silicone replica technique at four assessment points: marginal gap (MG), axial wall (AW), axio-occlusal (AO) angle, and central occlusal (CO) wall. After the initial analysis, the copings were ceramic-veneered with the layering technique, and the fit was again determined. Data were statistically analyzed by paired and unpaired Student’s-t test (α=0.05). Results: Marginal and internal fit before ceramic application according to the coping manufacturing method showed significant differences only at CO (p < 0.001), with milled copings (137.98±16.71 μm) showing higher gap values than cast copings (112.86±8.57 μm). For cast copings, there were significant differences at MG (before 109.13±8.79 μm; after 102.78±7.18 μm) and CO (before 112.86±8.57 μm; after 104.07±10.63 μm) when comparing the fit before and after ceramic firing. For milled copings, there was significant difference only at AO (before 116.39±9.64 μm; after 108.54±9.26 μm). Conclusion: This study demonstrated that the coping fabrication method influenced the internal fit. Ceramic firing maintained or improved the fit of the metal-ceramic crowns. The marginal discrepancy of all restorations, before and after ceramic firing, can be considered clinically acceptable.

Fracture behavior, marginal gap width, and marginal quality of vented or pre-cemented CAD/CAM all-ceramic crowns luted on Y-TZP implants

2017 ◽  
Vol 29 (2) ◽  
pp. 175-184 ◽  
Author(s):  
Lucia K. Zaugg ◽  
Simon Meyer ◽  
Nadja Rohr ◽  
Isabella Zehnder ◽  
Nicola U. Zitzmann
Keyword(s):  
Fracture Behavior ◽  
Marginal Gap ◽  
All Ceramic ◽  
Cad Cam ◽  
Ceramic Crowns ◽  
Gap Width

Marginal and internal fit of CAD-CAM composite resin and ceramic crowns before and after internal adjustment

2020 ◽  
Vol 123 (3) ◽  
pp. 500-505 ◽  
Author(s):  
Lucas F. Tabata ◽  
Taiana A. de Lima Silva ◽  
Alessandra C. de Paula Silveira ◽  
Ana Paula D. Ribeiro
Keyword(s):  
Composite Resin ◽  
Before And After ◽  
Cad Cam ◽  
Ceramic Crowns ◽  
Internal Fit

scholarly journals Adaptability Evaluation of Metal-Ceramic Crowns Obtained by Additive and Subtractive Technologies

2020 ◽  
Vol 10 (16) ◽  
pp. 5563
Author(s):  
Cristina Elena Savencu ◽  
Costela Șerban ◽  
Liliana Porojan
Keyword(s):  
New Technologies ◽  
Selective Laser Sintering ◽  
Critical Factor ◽  
Cost Effective ◽  
Metal Ceramic ◽  
Before And After ◽  
Cad Cam ◽  
Ceramic Crowns ◽  
Internal Gap ◽  
Ceramic Restorations

(1) Background: Traditional metal-ceramic restorations are considered as a standard in the evaluation of new technologies. A critical factor in their longevity is represented by their adaptability; The purpose of this study was to evaluate the marginal and internal gap of ceramic-fused to metal crowns with frameworks obtained by additive manufacturing (AM) technologies and the influence of veneering process on their fit; (2) Methods: Metal-ceramic crowns have been produced by conventional lost-wax technology (T), digital milling (F), selective laser sintering (SLS) and selective laser melting (SLM). The adaptability was assessed using silicone replicas before and after ceramic veneering; (3) Results: The best values were obtained for the milled group followed closely by SLM and SLS, and a significantly higher gap for casted copings. The veneering process did not significantly influence the adaptability of the crowns, regardless of the manufacturing process used for frameworks. The present study promotes additive technologies (AT) as a fast, efficient, and cost-effective alternative to traditional technology. There are fewer steps in which errors can occur when digital technologies are used and the risk of distortion is diminished. (4) Conclusions: CAD/CAM technologies, both additive and subtractive, represent an excellent option to produce time-effective, precise metal-ceramic crowns with excellent adaptation.

scholarly journals Effect of the Crystallization Process on the Marginal and Internal Gaps of Lithium Disilicate CAD/CAM Crowns

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Jae-Hong Kim ◽  
Seunghan Oh ◽  
Soo-Hyuk Uhm
Keyword(s):  
Computer Aided Design ◽  
Crystallization Process ◽  
Lithium Disilicate ◽  
Mean Values ◽  
Computer Aided ◽  
Before And After ◽  
Cad Cam ◽  
Ceramic Crowns ◽  
Aided Design ◽  
Internal Fit

The aim of this study is to quantify the effect of the crystallization process on lithium disilicate ceramic crowns fabricated using a computer-aided design/computer-aided manufacturing (CAD/CAM) system and to determine whether the effect of crystallization is clinically acceptable by comparing values of fit before and after the crystallization process. The mandibular right first molar was selected as the abutment for the experiments. Fifteen working models were prepared. Lithium disilicate crowns appropriate for each abutment were prepared using a commercial CAD/CAM system. Gaps in the marginal area and 4 internal areas of each crown were measured twice—before and after crystallization—using the silicone replica technique. The mean values of fit before and after crystallization were analyzed using a pairedt-test to examine whether the conversion that occurred during crystallization affected marginal and internal gaps (α=0.05). Gaps increased in the marginal area and decreased in the internal areas after crystallization. There were statistically significant differences in all of the investigated areas (P<0.05). None of the values for marginal and internal fit of lithium disilicate CAD/CAM crowns after crystallization exceeded 120μm, which is the clinically acceptable threshold.

scholarly journals Marginal and Internal Fit of Ceramic Prostheses Fabricated from Different Chairside CAD/CAM Systems: An In Vitro Study

2021 ◽  
Vol 11 (2) ◽  
pp. 857
Author(s):  
Keunbada Son ◽  
Kyu-Bok Lee
Keyword(s):  
Computer Aided Design ◽  
In Vitro Study ◽  
Vitro Study ◽  
Marginal Gap ◽  
Significant Difference ◽  
Cad Cam ◽  
Ceramic Crowns ◽  
Internal Fit ◽  
Cam Systems

The purpose of this in vitro study was to evaluate marginal and internal fits of ceramic crowns fabricated with chairside computer-aided design and manufacturing (CAD/CAM) systems. An experimental model based on ISO 12836:2015 was digitally scanned with different intraoral scanners (Omnicam (CEREC), EZIS PO (DDS), and CS3500 (Carestream)). Ceramic crowns were fabricated using the CAD/CAM process recommended by each system (CEREC, EZIS, and Carestream systems; N = 15). The 3-dimensional (3D) marginal and internal fit of each ceramic crown was measured using a 3D inspection software (Geomagic control X). Differences among the systems and various measurements were evaluated using the Kruskal–Wallis test. Statistically significant differences were validated using pairwise comparisons (α = 0.05). Occlusal gaps in the CEREC, EZIS, and Carestream groups were 113.0, 161.3, and 438.2 µm, respectively (p < 0.001). The axial gaps were 83.4, 78.0, and 107.9 µm, respectively. The marginal gaps were 77.8, 99.3, and 60.6 µm, respectively, and the whole gaps were 85.9, 107.3, and 214.0 µm, respectively. Significant differences were observed with the EZIS system compared with the other two systems in terms of the marginal gap sizes. The CEREC system showed no significant differences among the four measured regions. However, the EZIS and Carestream systems did show a statistically significant difference (p < 0.05). All three systems were judged to be capable of fabricating clinically acceptable prostheses, because the marginal gap, which is the most important factor in the marginal fit of prostheses, was recorded to be below 100 µm in all three systems.

scholarly journals Shaping and Centering Ability, Cyclic Fatigue Resistance and Fractographic Analysis of Three Thermally Treated NiTi Endodontic Instrument Systems

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5823
Author(s):  
Saulius Drukteinis ◽  
Vytaute Peciuliene ◽  
Ruta Bendinskaite ◽  
Vilma Brukiene ◽  
Rasmute Maneliene ◽  
...  
Keyword(s):  
Fatigue Resistance ◽  
Cyclic Fatigue ◽  
Fractographic Analysis ◽  
Significance Level ◽  
Root Canals ◽  
Topographic Features ◽  
New Instrument ◽  
Before And After ◽  
Number Of Cycles ◽  
Thermally Treated

The better understanding of the clinically important behavioral features of new instrument systems has an important significance for the clinical endodontics. This study aimed to investigate the shaping and centering ability as well as cyclic fatigue resistance of HyFlex CM (CM), HyFlex EDM (EDM) and EdgeFile (EF) thermally treated nickel–titanium (NiTi) endodontic instrument systems. Sixty curved root canals of the mesial roots of mandibular molars were randomly assigned into three groups (n = 20) and shaped using CM, EDM and EF files up to the size 40 and taper 04 of the instruments. µCT scanning of the specimens before and after preparation was performed and the morphometric 2D and 3D parameters were evaluated in the apical, middle and coronal thirds of root canals. In each group, 40.04 instruments (n = 20) were subjected to the cyclic fatigue resistance test in artificial root canals at 37 °C temperature until fractures occurred, and the number of cycles to failure (NCF) was calculated. The fractographic analysis was performed using a scanning electron microscope, evaluating topographic features and surface profiles of the separated instruments. The one-way analysis of variance with post hoc Tuckey’s test was used for statistical analysis of the data; the significance level was set at 5%. All systems prepared the comparable percentage of root canal surface with the similar magnitude of canal transportation in all root thirds (p > 0.05), but demonstrated significantly different resistance to cyclic fatigue (p < 0.05). The most resistant to fracture was EF, followed by EDM and CM. The length of the fractured fragments was not significantly different between the groups, and fractographic analysis by SEM detected the typical topographic features of separated thermally treated NiTi instrument surfaces.

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