IADR Abstract Archives
Failure Analysis of Clinically Fractured Zirconia Implants
Objectives: A prospective single-arm clinical trial was performed on custom-made zirconia implants in the maxillary premolar region. At the 5-year follow-up interval, the study revealed a Kaplan-Meier survival probability of 75.8 %. In total, nine out of 30 implants were lost, including mechanical failures (n = 5) [1]. The aim of this study was to investigate the fracture surfaces of the retrieved implant fragments and to identify possible reasons for failure.
Methods: Four zirconia implants (ZV3 individual implants, Zircon Vision GmbH, Wolfratshausen, Germany) were retrieved from the above clinical trial, carefully documented and cleaned. The fracture surfaces were inspected using light-, digital-, and scanning electron microscopy as well as high-precision non-contact profilometry.
Results: The fractographic patterns found on the fracture surfaces of the four investigated implants were similar. All fractures emanated at the palatal face of the implant, which might be induced by a clinical overload on the buccal cusp of the premolars. The palatal fracture origins were traced back to the root of at the first thread of the enossal implant in three cases and in the root of the second thread in one occasion, most likely due to a reduced bone level. The external implant surface around the fracture origins was characterized by severe machining damage. Further, large processing defects were observed in the bulk and surface zirconia microstructure. Profilometry revealed a notch-type screw design (small thread-angle), accounting for stress concentration around the fracture origins.
Conclusions: The fracture events occurred as a consequence of multiple factors. Stress concentration combined with a weak material performance (severe machining and processing defects) were found to release early failures. Possible design issues due to a too concave crown preparation on the buccal side and excessive off-center occlusal load might have further contributed to fracture events. Further numerical simulations are underway to highlight this factor.
[1] Beus, J.H.W.d., Cune, M.S., Meijer, H.J.A., Raghoebar, G.M. and Schepke, U. (2025), Metal-Free Custom-Made Zirconia Implants—A Prospective 5-Year Follow-Up Single-Arm Clinical Trial. Clin Implant Dent Relat Res. https://doi.org/10.1111/cid.13404
Methods: Four zirconia implants (ZV3 individual implants, Zircon Vision GmbH, Wolfratshausen, Germany) were retrieved from the above clinical trial, carefully documented and cleaned. The fracture surfaces were inspected using light-, digital-, and scanning electron microscopy as well as high-precision non-contact profilometry.
Results: The fractographic patterns found on the fracture surfaces of the four investigated implants were similar. All fractures emanated at the palatal face of the implant, which might be induced by a clinical overload on the buccal cusp of the premolars. The palatal fracture origins were traced back to the root of at the first thread of the enossal implant in three cases and in the root of the second thread in one occasion, most likely due to a reduced bone level. The external implant surface around the fracture origins was characterized by severe machining damage. Further, large processing defects were observed in the bulk and surface zirconia microstructure. Profilometry revealed a notch-type screw design (small thread-angle), accounting for stress concentration around the fracture origins.
Conclusions: The fracture events occurred as a consequence of multiple factors. Stress concentration combined with a weak material performance (severe machining and processing defects) were found to release early failures. Possible design issues due to a too concave crown preparation on the buccal side and excessive off-center occlusal load might have further contributed to fracture events. Further numerical simulations are underway to highlight this factor.
[1] Beus, J.H.W.d., Cune, M.S., Meijer, H.J.A., Raghoebar, G.M. and Schepke, U. (2025), Metal-Free Custom-Made Zirconia Implants—A Prospective 5-Year Follow-Up Single-Arm Clinical Trial. Clin Implant Dent Relat Res. https://doi.org/10.1111/cid.13404