Long-Term Stability of Hydrothermally Aged and/or Dynamically Loaded One-Piece Diameter Reduced Zirconia Oral Implants

Abstract

The aim of this in vitro study was to evaluate the long-term stability of one-piece diameter reduced zirconia oral implants under the influence of loading and artificial aging in a chewing simulator as well as the fracture load in a static loading test. Thirty-two one-piece zirconia implants with a diameter of 3.6 mm were embedded according to the ISO 14801:2016 standard. The implants were divided into four groups of eight implants. The implants of group DLHT were dynamically loaded (DL) in a chewing simulator for 107 cycles with a load of 98 N and simultaneously hydrothermally aged (HT) using a hot water bath at 85 °C. Group DL was only subjected to dynamic loading and group HT was exclusively subjected to hydrothermal aging. Group 0 acted as a control group: no dynamical loading, no hydrothermal ageing. After exposure to the chewing simulator, the implants were statically loaded to fracture in a universal testing machine. To evaluate group differences in the fracture load and bending moments, a one-way ANOVA with Bonferroni correction for multiple testing was performed. The level of significance was set to p < 0.05. In the static loading test, group DLHT showed a mean fracture load of 511 N, group DL of 569 N, group HT of 588 N and control group 0 of 516 N. The average bending moments had the following values: DLHT: 283.5 Ncm; DL: 313.7 Ncm; HT: 324.4 Ncm; 0: 284.5 Ncm. No significant differences could be found between the groups. Hydrothermal aging and/or dynamic loading had no significant effect on the stability of the one-piece diameter reduced zirconia implants (p > 0.05). Within the limits of this investigation, it can be concluded that dynamic loading, hydrothermal aging and the combination of loading and aging did not negatively influence the fracture load of the implant system. The artificial chewing results and the fracture load values indicate that the investigated implant system seems to be able to resist physiological chewing forces also over a long service period.

Fracture Resistance of a Two-Piece Zirconia Implant System after Artificial Loading and/or Hydrothermal Aging—An In Vitro Investigation

“…Alumina-toughened zirconia thus seems to be a favorable material for zirconia implant fabrication [53] and was used in our in vitro set-up where hydrothermal aging at 85 • C was performed, which is in accordance with other investigations [27,35]. The intention was to evaluate the impact of hydrothermal aging on phase transformation as was conducted previously on pure 3Y-TZP zirconia oral implants [35]. The crystal structure in pure 3Y-TZP material is usually well-ordered and the slight variation in the contrast that allowed the individual grains to be identified in microscopic images was assumed to be due to the crystal orientations in the individual grains.…”

“…Alumina-toughened zirconia thus seems to be a favorable material for zirconia implant fabrication [53] and was used in our in vitro set-up where hydrothermal aging at 85 • C was performed, which is in accordance with other investigations [27,35]. The intention was to evaluate the impact of hydrothermal aging on phase transformation as was conducted previously on pure 3Y-TZP zirconia oral implants [35].…”

“…For testing the fracture resistance, seven of the eight specimens from each group were inserted in a universal testing machine (ZwickRoell Z010, ZwickRoell AG, Ulm, Germany) at an angle of 30 • to the loading axis and were then loaded to fracture (Figure 5). The crosshead speed of the testing machine was set to 10 mm/min [27,34,35], and the endpoint of loading was defined at the sudden drop in load capacity. The fracture patterns were visually evaluated and defined as a partial or complete fracture of the implant/abutment (Figure 5).…”

Effect of Antirotational Two-Piece Titanium Base on the Vertical Misfit, Fatigue Behavior, Stress Concentration, and Fracture Load of Implant-Supported Zirconia Crowns

“…For implant insertion, centered perforations were made in the resin cylinders using a pilot drill, followed by a drill size 2. The implants were placed inside each resin cylinder using an implant insertion wrench, ensuring that the maximum torque did not exceed 60 N, and the platform was positioned 3 mm above the resin, following the ISO 14801 second edition of 2007 [ 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ].…”

Biocompatibility and Corrosion Resistance of Si/ZrO2 Bioceramic Coating on AZ91D Using Electron Beam Physical Vapor Deposition (EB-PVD) for Advanced Biomedical Applications

“…This phase transformation can cause surface roughening, micro-cracking, and overall degradation, potentially leading to implant failure [20]. These structural changes due to hydrothermal aging compromise the mechanical integrity of zirconia-based implants, affecting their performance [21,22]. Likewise, the low-temperature degradation nature of zirconia may enhance the restoration of surface roughness, thus promoting biofilm development.…”