Author:

Keywords:

Science & Technology, Life Sciences & Biomedicine, Technology, Dentistry, Oral Surgery & Medicine, Materials Science, Biomaterials, Materials Science, Zirconia implants, Fracture, Fractography, Clinical failure, One-piece, Two-piece, SHAPED ORAL IMPLANTS, FAILURE ANALYSIS, Y-TZP, RESECTIVE SURGERY, FLEXURAL STRENGTH, PERI-IMPLANTITIS, FOLLOW-UP, TITANIUM, PERFORMANCE, SURVIVAL, Dental Abutments, Dental Implant-Abutment Design, Dental Implants, Dental Restoration Failure, Dental Stress Analysis, Humans, Materials Testing, Powders, Titanium, Zirconium, G0B2618N#54518130, C24/17/084#54270817, G095920N#55522169, 12S8421N#55744119, 09 Engineering, 11 Medical and Health Sciences, Dentistry, 3203 Dentistry

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.