Load-bearing capacity of screw-retained fixed dental prostheses made of monolithic zirconia on different abutment designs and abutment-free implant connection
Tobias Schäfer , Kiren J Mätzener , Ronald E Jung , Mutlu Özcan , Jenni Hjerppe
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引用次数: 0
Abstract
Objectives
A new abutment-free implant connection allows for direct screwing of FDPs on implants to avoid complications caused by cement rests or screw loosening, which may affect to screw torque and load distribution. The objective of this study was to test the initial (Fi) and final failure (Ff) loads and torque changes of abutment-free monolithic zirconia CAD-CAM fixed dental prostheses (FDPs) compared to titanium FDPs on different abutment designs.
Methods
Three-unit screw-retained FDPs (n = 50) on two implants (n = 100) were divided into groups (n = 10) based on the implant-abutment connection and material of the supra-structure: (1) abutment-free monolithic CAD-CAM zirconia FDP (Abut-free-Zr), (2) abutment-free veneered titanium FDPs (Abut-free-Ti), (3) monolithic zirconia FDPs with titanium base abutments (Zr-Ti-Base), (4) monolithic zirconia FDPs on multi-unit abutments (Zr-MU), (5) veneered titanium FDP on multi-unit abutments (Ti-MU). All specimens were subjected to thermo-mechanical aging (1′200’000 Cycles, 49 N, 1.67 Hz, 5º to 50º C, dwelling time 120 s). Torque of the screws was measured, and static loading was performed. Data were tested using ANOVA and Tukey's tests (p < 0.05).
Results
After thermo-mechanical aging, all screws showed reduced torque, Ti-MU significantly more reduction compared to Abut-Free-Ti (p = 0.0021). Titanium groups showed significantly lower Fi (N) values (171.4–230 vs 1272–1358,) due to veneering porcelain fractures (p = 0.0001) and significantly higher Ff (N) (2922 –3029 N vs. 1272–1358) values than zirconia groups (p < 0.0001).
Conclusions
Three-unit abutment-free monolithic zirconia FPDs showed similar failure loads compared to other zirconia groups, while the titanium groups exhibited superior final failure loads. Different abutment designs did not seem to affect the failure loads.
Clinical Significance
The specific design of the novel implant interface allows for the fabrication of implant supported FDPs with personalized design directly on implant level without abutments. The monolithic zirconia FDPs on abutment-free implant connection can be used with good confidence since they exhibit similar mechanical stability as monolithic zirconia FDPs on titanium-base or multi-unit abutments.
期刊介绍:
The Journal of Dentistry has an open access mirror journal The Journal of Dentistry: X, sharing the same aims and scope, editorial team, submission system and rigorous peer review.
The Journal of Dentistry is the leading international dental journal within the field of Restorative Dentistry. Placing an emphasis on publishing novel and high-quality research papers, the Journal aims to influence the practice of dentistry at clinician, research, industry and policy-maker level on an international basis.
Topics covered include the management of dental disease, periodontology, endodontology, operative dentistry, fixed and removable prosthodontics, dental biomaterials science, long-term clinical trials including epidemiology and oral health, technology transfer of new scientific instrumentation or procedures, as well as clinically relevant oral biology and translational research.
The Journal of Dentistry will publish original scientific research papers including short communications. It is also interested in publishing review articles and leaders in themed areas which will be linked to new scientific research. Conference proceedings are also welcome and expressions of interest should be communicated to the Editor.