Fracture analysis of one/two-piece clinically failed zirconia dental implants. Issue 10 (October 2022)

• Record Type: Journal Article
• Authors: Zhang, Fei; Monzavi, Mona; Li, Maoyin; Čokić, Stevan; Manesh, Al; Nowzari, Hessam; Vleugels, Jef; Van Meerbeek, Bart
• Is Part Of: Dental materials. Volume 38:Issue 10(2022)
• Page Start: 1633
• Page End: 1647
• Publication Date: 2022-10
• Subjects: Zirconia implants -- Fracture -- Fractography -- Clinical failure -- One-piece -- Two-piece; Dentistry -- Periodicals; Dental materials -- Periodicals; 617.695
• DOI: 10.1016/j.dental.2022.08.004
• Languages: English
• ISSNs: 0109-5641

Abstract

Abstract: Objectives: Analyzing factors that may have led to fracture of zirconia implants by macro/micro-fractography. Methods: Six one-piece and ten two-piece full-ceramic zirconia implants from two manufacturers, Z-Systems and CeraRoot, were retrieved after clinical failure. The time-to-failure ranged from 3 to 49 months. Optical and scanning electron microscopy (SEM) were used to analyze the fracture planes at the macro- and microscopic level. Treatment planning, surgical protocol, fracture-origin location and characteristic fracture features were assessed. Results: The fracture of all implants seemed to have been primarily due to overload in bending mode, while the fracture-initiation sites varied for the one- and two-piece implants. The fracture of all one-piece implants originated in the constriction region between two threads in the endosseous implant part. For two-piece implants, the abutment neck, internal abutment-implant connections and inner threads were found to be the main fracture-initiation sites. Surface defects at the root area for one-piece implants and damages at the abutment surface for two-piece implants were connected to the fracture origins. Importantly, the clinical failures of implants were often found to result from combined effects related to patient aspects, treatment planning/protocols, a high bending moment at the weakest link, implant-surface conditions and specific implant designs. Significance: This study provided information to be considered for future optimization of treatment planning and the surgical protocol for zirconia implants. Optimization of the surface conditions and the zirconia-starting powder were also suggested. Highlights: Fracture-initiation sites varied for the one- and two-piece implants. Clinical implant failures resulted from combined effects related to patient-related aspects, treatment planning, surface quality and specific implant designs. Implant surface conditions and zirconia starting powder can be optimized.