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Updated: Sep 30, 2026
Quasistatic Mechanical Testing for Computer-Aided Design and Manufacturing Occlusal Veneers Cemented to Milled Dentin Analog Material
Published on: December 20, 2024
Influence of framework design on fracture strength of mandibular anterior all-ceramic resin-bonded fixed partial
Spiridon Oumvertos Koutayas1, Matthias Kern, Franco Ferraresso
1Department of Prosthodontics, Propaedeutics and Dental Materials, School of Dentistry, Christian-Albrechts University, Kiel, Germany.
Purpose:
The purpose of this in vitro study was to evaluate the influence of the framework design on the fracture strength of all-ceramic resin-bonded fixed partial dentures (RBFPD) in the mandibular incisor region.
Materials And Methods:
Twenty-four aluminum oxide ceramic frameworks were copy milled with the Celay system, glass infiltrated, and veneered with feldspathic porcelain to replace a mandibular incisor. Forty-eight extracted human incisors were used as abutments by embedding them in a polyester resin. The master casts were fabricated according to a typical clinical case. The sandblasted restorations were bonded to the acid-etched abutment teeth with a composite resin. Twelve RBFPDs had a conventional two-retainer design, and 12 had a cantilevered single-retainer design. Subgroups of eight specimens were subjected to a quasistatic load in the direction of the long axis of the abutment teeth in a universal testing machine. Additional subgroups of four specimens were subjected under 0 degrees to dynamic loading of 25 N in a dual-axis chewing simulator.
Results:
The mean fracture strengths under quasistatic loading were 313 N (SD 42) for the two-retainer design and 291 N (SD 100) for the single-retainer design. The mean cycles sustained by specimens subjected to dynamic loading at 25 N were 50,081 (SD 42,705) for the two-retainer design and 297,099 (SD 508,439) for the single-retainer design. There was no statistically significant influence of the framework design on the fracture strength of the restorations under quasistatic or dynamic loading.
Conclusion:
The clinical application of cantilevered all-ceramic RBFPDs in the mandible may be an alternative to all-ceramic RBFPDs with two retainers.
