Load at fracture of monolithic and bilayered zirconia crowns with and without a cervical zirconia collar

• Published in: The Journal of prosthetic dentistry 2016-05, Vol.115 (5), p.630-636
• Main Authors: Øilo, Marit, DDS, PhD, Kvam, Ketil, MSc, Gjerdet, Nils Roar, DDS, PhD
• Format: Article
• Language: English
• Subjects: Ceramics; Crowns - adverse effects; Dental Prosthesis Design; Dental Restoration Failure; Dental Stress Analysis; Dentistry; Humans; Weight-Bearing; Zirconium
• ISSN: 0022-3913; 1097-6841
• DOI: 10.1016/j.prosdent.2015.11.017

Abstract Statement of problem The effect of anatomic contour design in all or parts of zirconia crowns is uncertain regarding clinical reliability and survival rates. Purpose The purpose of this in vitro study was to compare the load at fracture of monolithic, anatomic contour zirconia crowns with bilayered crowns with and without a cervical zirconia collar. Material and methods Thirty zirconia crowns were fabricated for a shallow chamfer molar preparation, 10 with a normal core-veneer design, 10 with a core-veneer design with an additional cervical collar of zirconia, and 10 with a monolithic, anatomic contour design. Veneering ceramic was applied to the first 20 specimens to create an anatomic form. All crowns were cemented to epoxy abutments and loaded until complete fracture with a clinically relevant test method. The fracture modes and load at fracture were recorded. Results Statistically significant differences were found in the load at fracture and fracture modes among the test groups ( P