Advisory Committee Chair
Advisory Committee Members
Date of Award
Degree Name by School
Master of Science (MS) School of Dentistry
Statement of the Problem: The existing scientific literature lacks comprehensive information regarding the influence of zirconia crown height on debonding and fracture occurrences between zirconia crowns and titanium base abutments. Additionally, there is a lack of comparative studies evaluating different zirconia materials as restorative options for screw-retained restorations. Purpose: The purpose of this study was to assess the failure modes of the zirconia crown/titanium implant abutment complex by investigating the impact of increasing zirconia crown heights and different zirconia materials. Materials and Methods: The experimental design encompassed six groups, each consisting of 10 specimens. Group 1 included 10 non-anatomical crowns (copings) made of 8mm-tall 3Y-Zirconia, Group 2 included 10 non-anatomical crowns made of 10mm-tall 3Y-Zirconia. Group 3 included 10 non-anatomical crowns made of 12mm-tall 3Y-Zirconia, Group 4 included 10 non-anatomical crowns made of 8mm-tall 5Y-Zirconia. Group 5 included 10 non-anatomical crowns made of 10mm-tall 5Y-Zirconia, and Group 6 included 10 non-anatomical crowns made of 12mm-tall 5Y-Zirconia. All non-anatomical crowns were bonded to 4mm-tall Titanium-Base Abutments using Panavia V5 Cement. The specimens underwent load cycling with an Alabama wear tester, for 100,000 cycles. Subsequently, the specimens were loaded with a steel indenter until failure. The failure mode was visually evaluated. iv Results: The results demonstrated a significant association between increasing zirconia crown heights and an elevated risk of debonding and fracture from the titanium bases. Furthermore, the findings revealed statistically significant differences in failure rates between zirconia materials. Conclusion: The study's findings highlight that taller zirconia crowns exert in-creased leverage forces, leading to elevated stress concentrations. Consequently, this pre-disposes the restoration to mechanical failures such as debonding and fractures. There-fore, meticulous consideration should be given to the selection of crown height and material for cementation on titanium bases to minimize the risk of failure.
Anastasaki, Aiklterini, "Failure Modes of Different Zirconia Crown Heights and Materials on Titanium Base Abutments" (2023). All ETDs from UAB. 464.
Available for download on Sunday, September 01, 2024