A new implant system with directly screwed supraconstructions: impact of restoration material and artificial aging on the bending moment

Purpose: To inves)gate the bending moment of implants restored with a directly screwed single-unit fixed dental prosthesis (FDP) compared to implants restored with an FDP polymerized to a)tanium base before and aBer thermomechanical aging. Materials and Methods: A total of 240 implants (120 with and 120 without a)tanium base) were restored with FDPs manufactured from conven)onally sintered 3Y-TZP, 5Y-TZP, 4Y-TZP, and CoCrMo, as well as high-speed sintered 4Y-TZP. Half the specimens per subgroup were aged using chewing simula)on combined with thermocycling (1,200,000 cycles at 50 N; 6,000 cycles at 5 degrees C to 55 degrees C). Ini)al and aged fracture load were measured. The bending moment was calculated and subjected to sta)s)cal analysis (Kolmogorov-Smirnov test, one-way ANOVA followed by post hoc Scheffe, t, and chi-square tests; P <.05). Failure types were analyzed. Results: Implants without a)tanium base showed higher bending moments for all ini)ally tested zirconia groups compared to implants with a)tanium base. The highest ini)al values were observed for 4Y-TZP FDPs regardless of implant type. High-speed sintered FDPs demonstrated higher ini)al bending moments compared to conven)onally sintered FDPs. Ar)ficial aging led to a decrease of the bending moment in most subgroups. ABer aging, no differences were found within the restora)on materials, sintering protocols, or implant types. Implant deforma)on occurred mainly with directly screwed FDPs, whereas FDP mobility was predominantly observed among implants with a)tanium base. FDP fractures were mainly observed for 5Y-TZP. Conclusions: Both implant types exhibited similar values aBer aging. Thus, implants without a)tanium base seem to show equally sufficient stability for clinical applica)ons with all tested materials.