The influence of the loading mode on the stress distribution on the connector region of metal-ceramic and all-ceramic fixed partial denture.
Studies pertaining to the mechanical behavior of fixed partial dentures (FPDs) frequently found the highest tensile stress values at the connector region when load is applied at the pontic central region. The connector region is considered the weakest point of the prosthesis with the greatest potential of fractures, regardless of the material used. This 2D finite element study compared the stress distribution on three-element all-ceramic and metal-ceramic FPDs with different loading conditions. Three FPD models were designed: (i) metal-ceramic FPD; (ii) all-ceramic FPD with the veneering porcelain only on the occlusal face; and (iii) all-ceramic FPD with the veneering porcelain on the occlusal and cervical face of the pontic. Loads of 100 N were applied following these simulations: (i) distributed on all working cusps; (ii) only on the abutment teeth; and (iii) only on the pontic. There is a significant change on the stress distribution and on the tensile stress values when the load configuration is changed. The stress distribution from the load applied on the abutments was significantly better compared with the other two load simulations. When the loads were applied on the pontic and distributed on all working cusps, the highest tensile stress values appeared on the cervical region of the connectors between the abutments and the pontic. However, when the load was applied on the abutment teeth, the maximum tensile stress value significantly decreased and was located on the occlusal region of the connectors. In fact, the load applied on the pontic region does not simulate the clinical situation. Studies using this load configuration have overestimated the connector regions as having the highest probability of failures.
Motta
Andréa Barreira
AB
Department of Metallurgy and Materials Engineering and Prosthesis and Dental Materials Department, Federal University of Rio de Janeiro, PEMM/COPPE/UFRJ, Rio de Janeiro, Brazil. amotta@metalmat.ufrj.br
Pereira
Luiz Carlos
LC
da Cunha
Andréia R C C
AR
Duda
Fernando Pereira
FP
D002516:Ceramics / Q000737:chemistry*; D003198:Computer Simulation; D000044:Dental Abutments; D003776:Dental Porcelain; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis / Q000379:methods; D003801:Dental Veneers; D003779:Denture Design; D003830:Denture, Partial, Fixed; D020342:Finite Element Analysis; D008422:Materials Testing; D008670:Metals / Q000737:chemistry*; D008956:Models, Chemical; D013314:Stress, Mechanical; D013718:Tensile Strength
D008670:Metals; D003776:Dental Porcelain