Abstract :
[en] Residual stresses can substantially affect veneering ceramic performance. The hole drilling method is an industrial method to measure these stresses, and it has been adapted here for dental use. The method was successfully applied on bilayer disc samples of veneering ceramic sintered either on Co–Cr alloy or on Y-TZP framework characteristic of dental prostheses. The method allows stress depth profile measurement in a range of 1.2 mm of depth from surface. Because of the small stresses present in dental prostheses, sensitive and stable measurement equipment is required.
The residual stress measurements confirm the expectation from the previous literature of compressive residual stresses in the veneering ceramic surface on VM and VZr prostheses. The results showed a gradual shift to tensile residual stresses at 0.5–1 mm depth from the surface. The measured stress profiles in the VZr samples showed residual stresses of larger magnitude and concentration of tensile stresses in a smaller area, which could be a potential source of the problems encountered in clinical practice.
Future studies on the mechanical behavior of Y-TZP restorations need to focus on the influence of each independent parameter, such as veneering ceramic thickness, expansion coefficient mismatch, heat treatment parameters and cooling rate, on residual stress profile. The hole-drilling residual stress measurement method described here provides an effective method for studying these parameters. It would then be possible to compare the experimental measurements with the results of finite element analyses of crowns and bridges.
Scopus citations®
without self-citations
61