title: Fracture resistance of three-unit zirconia fixed partial denture with modified framework.
abstract: Obtaining ideal prosthetic framework design is at times hindered by anatomical limitations in the posterior region that might increase the risk for zirconia restoration fracture. Modification such as increasing the bulk thickness especially in the connector region could result in strengthening the zirconia framework. Three-unit zirconia fixed partial dentures replacing mandibular molars were fabricated using the following two techniques: CAD/CAM technology and manual copy milling. Modified framework with unveneered full thickness connectors were designed and fabricated with the aforementioned methods. Conventional frameworks (0.5 mm thick with rounded 3 mm connectors) served as control (N = 20). After cementation on epoxy dies, the frameworks were loaded to fracture in a universal testing machine. Fractured surfaces were prepared for examination using scanning electron microscopy. Statistical analysis revealed significant differences in fracture resistance between conventional and modified framework design for both fabrication techniques tested. SEM examination indicated that critical crack originated at the tensile surface of the connectors for conventional frameworks. The critical crack for modified frameworks occurred on the axial wall of the abutments. The modification of the zirconia framework design presented significant improvement of the fracture resistance compared to the conventional design.
authors.affiliation: Department of Oral Rehabilitation Sciences, Faculty of Dentistry, Beirut Arab University, Beirut, Lebanon.
authors.forename: Arthur
authors.initials: A
authors.lastname: Partiyan
authors.affiliation: Department of Oral Rehabilitation Sciences, Faculty of Dentistry, Beirut Arab University, Beirut, Lebanon.
authors.forename: Essam
authors.initials: E
authors.lastname: Osman
authors.affiliation: Department of Oral Rehabilitation Sciences, Faculty of Dentistry, Beirut Arab University, Beirut, Lebanon.|Department of Fixed Prosthodontics, Faculty of Dentistry, Misr University for Science and Technology, 6th of October City, Egypt.
authors.forename: Mohammad M
authors.initials: MM
authors.lastname: Rayyan
authors.affiliation: Dental Biomaterials Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt.
authors.forename: Moustafa
authors.initials: M
authors.lastname: Aboushelib
authors.affiliation: Public Health Service (Folktandvården), Gefle County, Sweden.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Ibrahim
authors.affiliation: Department of Oral and Maxillofacial Surgery and Oral Medicine, Malmö University, Malmö, Sweden. ryo.jimbo@mah.se.
authors.forename: Ryo
authors.initials: R
authors.lastname: Jimbo
mesh_terms: D001641:Bicuspid; D017076:Computer-Aided Design; D003764:Dental Materials / Q000737:chemistry; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D003779:Denture Design; D003830:Denture, Partial, Fixed; D006801:Humans; D066298:In Vitro Techniques; D008334:Mandible; D008855:Microscopy, Electron, Scanning; D008963:Molar; D015040:Zirconium / Q000737:chemistry*
chemical_list: D003764:Dental Materials; D015040:Zirconium; C028541:zirconium oxide
keywords: Connector morphology; Fracture resistance; Framework design; Zirconia