Influence of framework configuration on the marginal adaptation of zirconium dioxide ceramic anterior four-unit frameworks

Abstract

Within the limitations of this study, the framework configuration influences the marginal adaptation of anterior four-unit FPD frameworks that are manufactured from partially sintered ZrO2 ceramics independently of CAD/CAM system.

Influence of Cervical Finish Line Type on the Marginal Adaptation of Zirconia Ceramic Crowns

“…It has been previously shown that green and pre-sintered four-unit zirconia ceramic FPD frameworks of straight design exhibited better marginal adaptation compared to curved design. 13 These results were attributed largely to the distortion of the framework due to shrinkage of the ceramics during the final sintering stage. However, in that study, the marginal discrepancies of the four-unit FPD frameworks had been measured with no veneering ceramic.…”

“…30 Although detailed cross-sections were obtained, also allowing for internal fit measurements of the crowns, it was not assessed in the current study, since the aim was to offer an appropriate finish line design against debate on the marginal fit of the zirconia crowns. 13 It was reported that there were no significant differences between the shoulder and chamfer preparation types 27 and among the mesial, distal, buccal and lingual aspects in a study conducted on Cerec3 crowns. In that study, each crown margin was evaluated in 360°, and another study revealed non-significant differences in marginal fit between metal-ceramic and all-ceramic crowns, where the margins were evaluated in 360°.…”

“…This may consequently have a negative effect on marginal adaptation. 13 When the coping margin begins to deform under the stress of contracting porcelain, the shrinkage stress has been shown to spread further around the circumference of the margin.…”

“…However, the mechanical properties of zirconia ceramic are affected during the veneering stage that is performed at relatively higher temperatures. 13 The framework is subjected to distortion and shrinkage during the sintering and veneering stages. This may consequently have a negative effect on marginal adaptation.…”

Comparison of the marginal fit of different coping materials and designs produced by computer aided manufacturing systems

“…Marginal adaptation is essential in increasing the long-term success of a restoration 11) . Optimal marginal adaptation is an important factor in the biologic and mechanical stabilization of the fixed prosthesis.…”