All-ceramic resin-bonded bridges A 3-dimensional finite-element analysis study


Peter Pospiech, Department of Prosthodontics. LMU München, Goethestr. 70, D-80336 Munich Germany Telefax: +49-8951604782 E-mail:


Resin-bonded fixed partial dentures (FPD) with a metal framework have some disadvantages: a grey shimmer of the metal wings through the abutment teeth, a higher corrosion rate, and an allergenic potential of the non-precious alloys used. The Al2O3, ceramic In-Ceram© seems to be strong enough to serve as a framework for resin-bonded all-ceramic FPDs. Because of the fact that ceramic wings often don't have enough inter-occlusal space, a new preparation design was developed. The objective of this study was to determine the influence of load orientation (45° and 60°) and the design of the interproximal connector on the stress distribution in the bridges. A 3-dimensional finite-element model was developed to simulate the anatomical situation. The biting force was assumed as 250 N and oriented in oro-buccal direction. The loading-point was palatal 1.5 mm beneath the incisal edge. It was found that stress generally increased with an angle of the biting force of 60°. A small interdental connector (3 mm height) and/or strong interdental separation resulted in stresses of up to 455 MPa (45°) or 534 MPa (60°). Less separation with rounded edges and a higher connector (4 mm) reduced the stress to 122 MPa (45°) and 143 MPa (60°). Due to an average tensile strength of In-Ceram at 340–400 MPa. an all-ceramic resin-bonded FPD may only be recommended it the height of the connector could be minimum 4 mm. Rounded edges and little interdental separation are significant for stress reduction.