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.

scholarly journals Effect of manufacturing protocol on the internal fit and marginal discrepancy of metal ceramic and full ceramic dental crowns

2018 ◽  
Vol 63 (01) ◽  
pp. 69-74
Author(s):  
Katerina V. Geshoska ◽  
Jagoda Bajevska
Keyword(s):  
Manufacturing Process ◽  
Two Phase ◽  
Marginal Fit ◽  
Manufacturing Method ◽  
Dental Crowns ◽  
Metal Ceramic ◽  
Marginal Discrepancy ◽  
Ceramic Crowns ◽  
Internal Fit

The accuracy of internal fit and marginal precision plays important role of clinical quality and success of dental crowns. Complications caused by marginal discrepancies such as caries, gingivitis, hypersensitivity are highlighted in dental literature. Despite marginal fit, internal fit and precision have a significant role in the persistence of full ceramic and metal ceramic crowns. As the technology evolves, it’s questionable which impression and manufacturing method is giving most accurate dental crowns. Therefore, the main purpose of this study is to get some information and data about marginal and internal fitting of dental crowns made by conventional, two-phase impression technique with polyvinyl siloxanes, and using different manufacturing process. Keywords: internal fit, marginal discrepancy, metal ceramic, full ceramic crowns

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 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 Evaluation of the Bond Strengths between Dental Porcelain and Cobalt-Chromium Metal Frameworks Manufactured with Different Techniques after the Thermal Aging Process

Scanning ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Elif Ece Yoldan ◽  
Nurullah Türker ◽  
Ulviye Ş. Büyükkaplan ◽  
Mehmet M. Özarslan ◽  
Recep Karalı ◽  
...  
Keyword(s):  
Bond Strength ◽  
Thermal Aging ◽  
Aging Process ◽  
Bending Test ◽  
Single Type ◽  
Cobalt Chromium ◽  
Dental Porcelain ◽  
Manufacturing Method ◽  
Significant Difference ◽  
Cad Cam

Purpose. The present study is aimed at examining the bond strength of cobalt-chromium (Co-Cr) metal frameworks, prepared through different techniques, to a single type of low-temperature porcelain system after the thermal aging process. Methods. A hundred and twenty Co-Cr alloy framework specimens were prepared using conventional casting, CAD/CAM, and two commercially different laser sintering devices, and dental porcelain was applied to the specimens. A single type of dental porcelain (Kuraray Noritake Dental Inc., Tokyo, Japan) was applied to the specimens. After the subgroups were determined, half of the specimens were subjected to a thermal aging process. Bond strength of specimens was evaluated using a 3-point bending test. The surfaces of the fractured specimens were evaluated using a stereomicroscope. The metal-porcelain bonding area of samples randomly selected from 8 groups has been examined with SEM under ×1000 magnifications. Normality distribution of obtained data was examined using by a Kolmogorov-Smirnov test. The obtained data of the present study was statistically analyzed with a statistical package program (SPSS for Windows 22.0, Chicago, IL, USA). Results. There was a statistically significant difference between CAD/CAM and the other three methods, and the bonding value of the CAD/CAM group was the highest among the groups. Besides, the bond strength between dental porcelain and 4 differently produced metal frameworks was high enough to surpass the acceptable threshold (>25 MPa) according to the ISO 9693. There was no statistically significant difference between thermal aging applied and nonapplied groups. Conclusions. Based on this study, it could be shown that the metal-ceramic bond strength is dependent on the manufacturing method used, but it is independent of the thermal aging application. It was found that the bond strength values of all samples with and without thermal aging application exceeded the minimum acceptable value of 25 MPa recommended by the ISO 9693.

scholarly journals Analysis of vertical marginal discrepancy in feldspathic porcelain crowns manufactured with different CAD/CAM systems: Closed and open

2018 ◽  
Vol 12 (01) ◽  
pp. 123-128
Author(s):  
Fabio Kricheldorf ◽  
Cleuber Rodrigo de Souza Bueno ◽  
Wilson da Silva Amaral ◽  
Joel Ferreira Santiago Junior ◽  
Hugo Nary Filho
Keyword(s):  
Computer Aided Design ◽  
Manufacturing Systems ◽  
Marginal Adaptation ◽  
Significance Level ◽  
Significant Difference ◽  
Computer Aided ◽  
Cad Cam ◽  
Marginal Discrepancy ◽  
Feldspathic Porcelain ◽  
Ceramic Crowns

ABSTRACT Objective: The objective of this study is to compare the marginal adaptation of feldspathic porcelain crowns using two computer-aided design/computer-aided manufacturing systems, one of them is open and the other is closed. Materials and Methods: Twenty identical titanium abutments were divided into two groups: open system (OS), where ceramic crowns were created using varied equipment and software, and closed system (CS), where ceramic crowns were created using the CEREC system. Through optical microscopy analysis, we assess the marginal adaptation of the prosthetic interfaces. The data were subjected to the distribution of normality and variance. The i-test was used for the analysis of the comparison factor between the groups, and the one-way ANOVA was used to compare the variance of crown analysis regions within the group. A significance level of 5% was considered for the analyses. Results: There was a significant difference between the systems (P = 0.007), with the CS group having the higher mean (23.75 pm ± 3.05) of marginal discrepancy when compared to the open group (17.94 pm ± 4.77). Furthermore, there were no differences in marginal discrepancy between the different points between the groups (P > 0.05). Conclusions: The studied groups presented results within the requirements set out in the literature. However, the OS used presented better results in marginal adaptation.

Comparison of the Marginal Fit of Cobalt-Chromium Metal-Ceramic Crowns Fabricated by CAD/CAM Techniques and Conventional Methods at Three Production Stages

2017 ◽  
Vol 30 (3) ◽  
pp. 304-305 ◽  
Author(s):  
Francisco Real-Voltas ◽  
Elisabeth Romano-Cardozo ◽  
Oscar Figueras-Alvarez ◽  
Magi Brufau-de Barbera ◽  
Josep Cabratosa-Termes
Keyword(s):  
Cobalt Chromium ◽  
Marginal Fit ◽  
Metal Ceramic ◽  
Cad Cam ◽  
Production Stages ◽  
Ceramic Crowns ◽  
Conventional Methods

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 Comparison of Mechanical Properties of PMMA Disks for Digitally Designed Dentures

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1745
Author(s):  
Tamaki Hada ◽  
Manabu Kanazawa ◽  
Maiko Iwaki ◽  
Awutsadaporn Katheng ◽  
Shunsuke Minakuchi
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Water Sorption ◽  
Water Solubility ◽  
Flexural Modulus ◽  
Manufacturing Method ◽  
Heat Curing ◽  
Significant Difference ◽  
Cad Cam ◽  
Curing Method

In this study, the physical properties of a custom block manufactured using a self-polymerizing resin (Custom-block), the commercially available CAD/CAM PMMA disk (PMMA-disk), and a heat-polymerizing resin (Conventional PMMA) were evaluated via three different tests. The Custom-block was polymerized by pouring the self-polymerizing resin into a special tray, and Conventional PMMA was polymerized with a heat-curing method, according to the manufacturer’s recommended procedure. The specimens of each group were subjected to three-point bending, water sorption and solubility, and staining tests. The results showed that the materials met the requirements of the ISO standards in all tests, except for the staining tests. The highest flexural strength was exhibited by the PMMA-disk, followed by the Custom-block and the Conventional PMMA, and a significant difference was observed in the flexural strengths of all the materials (p < 0.001). The Custom-block showed a significantly higher flexural modulus and water solubility. The water sorption and discoloration of the Custom-block were significantly higher than those of the PMMA-disk, but not significantly different from those of the Conventional PMMA. In conclusion, the mechanical properties of the three materials differed depending on the manufacturing method, which considerably affected their flexural strength, flexural modulus, water sorption and solubility, and discoloration.

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