Fracture resistance of prepared premolars restored with bonded new lab composite and all-ceramic inlay/onlay restorations: Laboratory study

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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Mechanical behavior of posterior all-ceramic hybrid-abutment-crowns versus hybrid-abutments with separate crowns-A laboratory study

Clinical Oral Implants Research ◽

10.1111/clr.13395 ◽

2018 ◽

Vol 30 (1) ◽

pp. 90-98 ◽

Cited By ~ 7

Author(s):

Ingy Nouh ◽

Matthias Kern ◽

Ahmed E. Sabet ◽

Ahmad K. Aboelfadl ◽

Amina M. Hamdy ◽

...

Keyword(s):

Mechanical Behavior ◽

Laboratory Study ◽

All Ceramic

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Fracture resistance of all-ceramic crowns based on different preparation designs for restoring endodontically treated molars

Journal of Esthetic and Restorative Dentistry ◽

10.1111/jerd.12410 ◽

2018 ◽

Vol 31 (1) ◽

pp. 72-79

Author(s):

Aaron Krance ◽

Nicholas DuVall ◽

John Brewster ◽

Howard Roberts

Keyword(s):

Fracture Resistance ◽

All Ceramic ◽

Ceramic Crowns

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Fifteen-year outcome of posterior all-ceramic inlay-retained fixed dental prostheses

Journal of Dentistry ◽

10.1016/j.jdent.2019.07.012 ◽

2019 ◽

Vol 89 ◽

pp. 103174 ◽

Cited By ~ 1

Author(s):

Merlind Becker ◽

M. Saad Chaar ◽

Anne Garling ◽

Matthias Kern

Keyword(s):

Dental Prostheses ◽

All Ceramic ◽

Fixed Dental Prostheses ◽

Ceramic Inlay

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A Comparative in vitro Study of the Load at Fracture of All-ceramic Crowns with Various Thicknesses of In-Ceram Core

The Journal of Contemporary Dental Practice ◽

10.5005/jcdp-9-4-17 ◽

2008 ◽

Vol 9 (4) ◽

pp. 17-25 ◽

Cited By ~ 1

Author(s):

Ilser Turkyilmaz ◽

Suat Gokce ◽

Emine Celik-Bagci

Keyword(s):

Fracture Resistance ◽

Testing Machine ◽

In Vitro Study ◽

Chromium Alloy ◽

Dental Practitioners ◽

Significant Difference ◽

All Ceramic ◽

Feasible Option ◽

Ceramic Crowns

Abstract Aim The aim of this study was to investigate the influence of three different thicknesses of In-Ceram core on the load at fracture of all-ceramic crowns. Methods and Materials Thirty standardized crown-shaped nickel-chromium alloy dies were fabricated using a milling machine. Twenty dies were prepared with a 1 mm shoulder for Groups A and B. The only difference in the ten dies used for Group C was a smaller 0.5 mm lingual shoulder. The thicknesses of In-Ceram were 0.5 mm, 1.5 mm, and 0.75 mm for Groups A, B, and C. All all-ceramic crowns were fabricated in accordance with the manufacturer's instructions. After cementation of the crowns, their fracture resistance was tested with a universal testing machine. The load was directed to a point located 3 mm from the lingual aspect of the incisal edge at 30 degrees to the long axis of each specimen until catastrophic failure occurred. Results The mean loads at fracture for Groups A, B, and C were 1117±388 N, 2083±385 N, and 1439±368 N, respectively. No statistically significant difference in load at fracture between Groups A and C was found (p>0.05). However, the differences were statistically significant between Groups A and B (p<0.001) and Groups B and C (p<0.001). Conclusion Under the guidelines of this study, increasing the thickness of the In-Ceram core increased the fracture resistance of the all-ceramic crowns. Clinical Significance The sufficient thickness of the In-Ceram core of all-ceramic crowns is an important factor in fracture resistance. Therefore, dental practitioners should be careful in patient selection; if the horizontal overlap of a tooth to be restored is too limited, then all-ceramic crowns may not be a feasible option. Citation Gokce S, Celik-Bagci E, Turkyilmaz I. A Comparative in vitro Study of the Load at Fracture of Allceramic Crowns with Various Thicknesses of In-Ceram Core. J Contemp Dent Pract 2008 May; (9)4:017-025.

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