0DMOU ePOSTER BASIC RESEARCH
Background: In 2017, a ceria‐stabilized zirconia‐alumina‐aluminate composite material was developed to prevent low temperature degradation (LTD) of yttria‐stabilized zirconia ceramics (1). In different studies, this material was evaluated regarding its mechanical properties and cellular response with promising results (1, 2). So far, oral implants fabricated out of this material have not been evaluated regarding their stability and fracture resistance.
Aim/Hypothesis: The aim of this in‐vitro study was the evaluation of the long‐term stability and fracture resistance of one‐piece oral implants made from ceria‐stabilized zirconia‐alumina‐aluminate composite in an artificial chewing simulator.
Materials and Methods: Implant prototypes made of the above mentioned composite with diameters of 3.4 mm (group A: 32 samples) and 4 mm (group B: 16 samples) were tested. The artificial long‐term aging was performed in a chewing simulator. The samples were loaded with 98 N for 107 chewing cycles. In addition, some samples were hydrothermally treated in an 85 °C hot water bath. In order to assess the mechanical and hydrothermal impacts, the samples were divided into test groups of 8 samples each: A0/B0‐control group (no treatment); Ad‐dynamic loading only; At‐hydrothermal treatment only; Adt/Bdt‐combined treatment. From group B, only B0 and Bdt were executed. After treatment, all samples were statically loaded to fracture. Fracture loads and lever arms were recorded and bending moments were calculated for each sample. Descriptive statistical analysis as well as a one‐way analysis of variance (ANOVA) and pairwise comparisons (Bonferroni correction) were performed. The level of significance was set at P < 0.05.
Results: All samples withstood the artificial long‐term aging and no implant fractures occurred. The average bending moment of each group was calculated from the fracture load and the lever arms: A0 476.5 Ncm; Ad 448.3 Ncm; At 427.0 Ncm; Adt 348.7 Ncm; Bo 465.9 Ncm; Bdt 431.9 Ncm. Group Adt showed statistically significant lower bending moment values than group A0 (P = 0.000), At (P = 0.028) and Ad (P = 0.004). A0, Ad and At were not significantly different from each other. The bending moment values of the groups A0 and B0 showed no statistically significant difference (P = 0.7321). Group Bdt did not show a statistically significant lower bending moment value than group B0 (P = 0.1224). Compared to group Adt, group Bdt showed statistically significant higher torque values (P = 0.0005).
Conclusions and Clinical Implications: From this investigation, it can be concluded that combining dynamic loading and hydrothermal treatment reduces the mechanical properties of the implants. However, bending moments of ≥ 348 Ncm for a narrow diameter implant of this material are encouraging. This implant design seems to be stable enough for anterior implant placement. Regarding stability, the results of this study justify future in‐vivo studies for the evaluation of clinical applicability.
Keywords: ceramic implants, long‐term, fracture resistance, ceria stabilized, chewing simulator