J Prosthet Dent. 2022 Nov 2:S0022-3913(22)00637-0. doi: 10.1016/j.prosdent.2022.09.018. Online ahead of print.
ABSTRACT
STATEMENT OF PROBLEM: Studies that compared the fracture strength of monolithic lithium disilicate and 5-mol% yttria partially stabilized zirconia multiunit fixed dental prostheses are sparse.
PURPOSE: As the connector is the weakest part of a fixed dental prosthesis, the purpose of this in vitro study was to investigate the effect of connector designs and material on the fracture strength of 3-unit monolithic fixed dental prostheses.
MATERIAL AND METHODS: Resin-ceramic canine and premolar teeth (N=144) were prepared for fixed dental prosthesis abutments. Prostheses with 3 connector designs (width=height, width<height, and width>height) were made from 2 types of lithium disilicate (IPS e.max CAD and Amber Mill) and 5-mol% yttria partially stabilized zirconia (3M Lava Esthetic and Katana Zirconia UTML). Fracture strengths were measured after 200 000 cycles of dynamic loading of 50 N and thermocycling at 5 °C and 55 °C, and the fracture patterns were analyzed. Two-way analysis of variance and the Fisher exact test were used for statistical analysis (α=.05).
RESULTS: The material and connector design affected the fracture strength of fixed dental prostheses (P<.05), and a significant interaction was found between the material and connector design (P<.05). The IPS e.max CAD material had significantly lower fracture strength than Amber Mill, 3M Lava Esthetic, or Katana Zirconia UTML (P<.05). Connector designs with a greater width versus height showed significantly lower fracture strengths than other designs (P<.05).
CONCLUSIONS: The connector design of 3-unit fixed dental prostheses, particularly the connector height, may affect fracture strength depending on the prosthesis material.
PMID:36334990 | DOI:10.1016/j.prosdent.2022.09.018
