Brotthållfastheten på långtids-vattenförvarade monolitiska 3-leds-broar i flerskiktad zirkonia med olika konnektordimensioner och placering i disk.

Sammanfattning: Aim: The aim is to evaluate the fracture strength and fracture type of long-term water-stored monolithic 3-unit multilayered zirconia fixed dental prostheses (FDPs) depending on connector dimension and placement in disc. Material and method: Thirty-two 3-unit FDPs (212223) of KATANATM Zirconia Yttria Multilayered (YML) were divided into four groups (n=8/group). The EB-groups were placed in Enamel layer/Body layer 1 in the disc, with connector dimensions of 12 mm2 (EB12), or 7 mm2 (EB7). The BB-groups were placed in Body layer 2/Body layer 3, with connector dimensions 12 mm2 or 7 mm2 (BB12 and BB7). All FDPs were long-term water-stored (37° C, one year). They were cemented on die models, cyclic mechanical preloaded (10,000 cycles), followed by fracture strength test. The results were analyzed with one-way ANOVA, Tukey's test, significance level α = 0.05. Fracture type analysis was performed visually and presented descriptively. Result: Group BB12 showed significantly higher strength (2660 N) compared to EB7 with the lowest mean value (1044 N) (p < 0.05). There was no significant difference between the remaining groups. Conclusion: Design and placement of monolithic 3-unit FDPs in multilayered zirconia affects the fracture strength and fracture type.With increased connector dimension the location can be in the upper layer of the disc, and with reduced connector dimension, the location can be in the lower layer. The fractures occur in the connectors of the pontic. With an increased connector dimension and the FDP located in the lower layer, a total fracture will occur