Abstract
ObjectivesTo test the null hypothesis that polymerization-induced stress was not influenced by cavity dimensions and geometries. MethodsFour experimental groups, with different C-factors and specimen volumes were defined using bottom-less glass disks (height: 1 or 2mm) with a central hole 3 or 6mm in diameter, and 3mm wall thickness. Another four groups were created by bonding a glass plate to the bottom of the disks. Additionally, disks with 2-mm height, 3mm in cavity diameter, and 4.5-mm thick walls were prepared. Vickers indents (9.8N, 20s) were made at the top surface at 600μm from the cavity margin. The lengths of the indentation diagonal and the corner cracks parallel to the cavity margin were measured. Ten minutes after restoration (Majesty Esthetic, Kuraray), cracks were re-measured. Stresses at the indent site were calculated based on glass fracture toughness and increase in crack length. Data were subjected to ANOVA/Tukey or Kruskal–Wallis/Mann–Whitney tests (alpha: 5%, n=8). Finite element analysis (FEA) was used to estimate stress at the interface and the effective structural rigidity of the substrate. ResultsOverall, for experimental and FEA results, cavities developed higher stress than bottom-less disks. Increasing wall thickness did not affect stress. When similar geometries and C-factors were compared, higher volumes developed higher stress and had greater incidence of margin cracking. Clinical significanceC-factor is a suitable predictor for polymerization stress in low compliance environments, particularly due to its simplicity. However, the influence of cavity size cannot be disregarded especially for the development of marginal cracking. The interaction between size, geometry and stiffness is likely to become more complex according to the complexity of the cavity shape.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.