Marginal and internal fit evaluation of conventional metal-ceramic versus zirconia CAD/CAM crowns

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.

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Marginal and internal fit evaluation of conventional metal-ceramic versus zirconia CAD/CAM crowns

Journal of Clinical and Experimental Dentistry ◽

10.4317/jced.55946 ◽

2020 ◽

pp. e31-e37

Author(s):

N. Paul ◽

KN. Raghavendra Swamy ◽

MR. Dhakshaini ◽

S. Sowmya ◽

M. Meravini

Keyword(s):

Metal Ceramic ◽

Cad Cam ◽

Internal Fit

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

Applied Sciences ◽

10.3390/app11020857 ◽

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.

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Clinical Evaluation of CAD/CAM Metal-Ceramic Posterior Crowns Fabricated from Intraoral Digital Impressions

The International Journal of Prosthodontics ◽

10.11607/ijp.3607 ◽

2014 ◽

Vol 27 (4) ◽

pp. 331-337 ◽

Cited By ~ 31

Author(s):

Hazem Tamim ◽

Henrik Skjerven ◽

Anders Ekfeldt ◽

Hans Rønold

Keyword(s):

Clinical Evaluation ◽

Digital Impressions ◽

Metal Ceramic ◽

Cad Cam

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Evaluation of Marginal and Internal Fit of CAD/CAM Endocrowns with Different Cavity Tapers

The International Journal of Prosthodontics ◽

10.11607/ijp.6877 ◽

2021 ◽

Author(s):

Safoura Ghodsi ◽

Sasan Raseipour ◽

Mohammedreza Hajimahmoodi ◽

Mohammad Mroue

Keyword(s):

Cad Cam ◽

Internal Fit

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Effect of Incisal Porcelain Veneering Thickness on the Fracture Resistance of CAD/CAM Zirconia All-Ceramic Anterior Crowns

International Journal of Dentistry ◽

10.1155/2019/6548519 ◽

2019 ◽

Vol 2019 ◽

pp. 1-12 ◽

Cited By ~ 1

Author(s):

Noha Badran ◽

Sanaa Abdel Kader ◽

Fayza Alabbassy

Keyword(s):

Fracture Resistance ◽

Testing Machine ◽

Mode Iii ◽

Nickel Chromium ◽

Significant Difference ◽

All Ceramic ◽

Metal Ceramic ◽

Cad Cam ◽

Ceramic Crown

Statement of Problem. In some clinical situations, the vertical length of either a prepared tooth or an implant abutment is short, while the occlusal clearance to be restored by a porcelain crown is large. Incisal thickness of the veneering porcelain should be considered to prevent mechanical failure of the crown. Purpose. The aim of this study is to evaluate the effect of two different incisal veneering porcelain thickness on the fracture resistance of the anterior all-ceramic CAD/CAM zirconia crown system as compared with the conventionally used metal ceramic crown system. Method. CAD/CAM zirconia all-ceramic and metal ceramic crowns were fabricated on the prepared dies with standardized dimensions and designs using standardized methods according to the manufacturer’s instructions. All crowns were then adhesively luted with resin-based cement (Multilink cement system), subjected to thermal cycling and cyclic loading, and were loaded until fracture using the universal testing machine to indicate the fracture resistance for each crown material in each veneering thickness. Results. Statistical analysis was carried out, and the results showed that the fracture resistance of the nickel-chromium metal ceramic group was significantly higher than that of the CAD/CAM zirconia all-ceramic group. Also, the fracture resistance of crowns with 1.5 mm incisal veneering thickness was significantly higher than those with 3 mm incisal veneering thickness in both groups. Furthermore, there was no significant difference in the fracture mode of the two groups where 50% of the total specimens demonstrated Mode II (veneer chipping), while 35% demonstrated Mode I (visible crack) and only 15% demonstrated Mode III (bulk fracture). Conclusion. High failure load values were demonstrated by the specimens in this study, which suggest sufficient strength of both incisal veneering thickness in both crown systems to withstand clinical applications; however, the fracture patterns still underline the requirement of a core design that support a consistent thickness of the veneering ceramic, and it is recommended to conduct long-term prospective clinical studies to confirm findings reported in the present study.

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