FATIGUE RESISTANCE, FRACTURE STRENGTH AND MARGINAL INTEGRITY OF THREE TYPES OF CAD/CAM HYBRID CERAMIC CROWNS

Document Type : Original Article

Authors

1 Assistant Lecturer, Department of Crown and Bridge, Faculty of Dentistry, Suez-Canal University, Ismailia, Egypt

2 Lecturer, Department of Crown and Bridge, Faculty of Dentistry, Suez-Canal University, Ismailia, Egypt

3 Professor, Department of Crown and Bridge, Faculty of Dentistry, Suez-Canal University, Ismailia, Egypt

Abstract

Aim:To assess fatigue resistance,fracture strength and marginal integrity of three different CAD/CAM resin-based ceramic materials.Materials & methods:A maxillary premolar tooth was prepared to receive an all-ceramic crown, scanned with Omnicam intraoral scanner.A STL file was transferred to Formlabs 3D-printer to print fifteen resin dies.One die was scanned with Cerec Omnicam and fifteen hybrid ceramic crowns were milled with Cerec MCXL milling machine.Crowns were divided into three groups (n=5) according to their material type;group A (Vita Enamic),group B (Brilliant Crios) and group C (Shofu Hc).Crowns vertical marginal gaps were measured using a USB digital microscope.Crowns were bonded using Panavia F2.0 adhesive resin cement then their vertical marginal gaps were remeasured.Thermocycling of the crowns was done for 5000 cycles and crows were subjected to fatigue using a chewing simulator by applying cyclic loading of 50 N for 250,000 cycles with a frequency of 1.6 Hz.Vertical marginal gaps of survived crowns were measured.Survived crowns were subjected to static load to fracture using a universal testing machine at a crosshead speed of 1 mm/min.Data were analyzed by one way ANOVA and Post Hoc Tests at p  0.05.Results:There was a statistically significant difference between mean vertical marginal gap of all groups where group C showed the highest mean vertical marginal gap through all stages;before or after bonding and after thermomechanical aging.All crowns survived fatigue testing.Group C showed the highest mean fracture strength followed by group A then Group B.Conclusions:Tested materials showed vertical marginal gaps, fatigue resistance and fracture strength within the clinically acceptable range

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Egyptian Dental Journal
Volume 69, Issue 1 - Serial Number 4
January (Fixed Prosthodontics, Removable Prosthodontics and Dental Materials)
January 2023
Pages 523-531

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