Fracture behavior of inlay and onlay fixed partial dentures - An in-vitro experimental and XFEM modeling study.
OBJECTIVES
This study aimed to explore the "sensitivity" of the fracture load and initiation site to loading position on the central occlusal surface of a pontic tooth for both all-ceramic inlay retained and onlay supported partial denture systems.


MATERIALS AND METHODS
Three dimensional (3D) finite element (FE) inlay retained and onlay supported partial denture models were established for simulating crack initiation and propagation by using the eXtended Finite Element Method (XFEM). The models were subjected to a mastication force up to 500N on the central fossa of the pontic. The loading position was varied to investigate its influence on fracture load and crack path.


RESULTS
Small perturbation of the loading position caused the fracture load and crack pattern to vary considerably. For the inlay fixed partial dentures (FPDs), the fracture origins changed from the bucco-gingival aspect of the molar embrasure to the premolar embrasure when the indenter force location is slightly shifted from the mesial to distal side. In contrast, for onlay FPDs, cracking initiated from bucco-gingival aspect of the premolar embrasure when the indenter is slightly shifted to the buccal side and from molar embrasure when the indenter is shifted to the lingual side.


CONCLUSIONS
The fracture load and cracking path were found to be very sensitive to loading position in the all-ceramic inlay and onlay FPDs. The study provides a basis for improved understanding on the role of localized contact loading of the cusp surface in all-ceramic FPDs.
['Zhang|Zhongpu|Z|', 'Thompson|Mark|M|', 'Field|Clarice|C|', 'Li|Wei|W|', 'Li|Qing|Q|', 'Swain|Michael V|MV|']
D002516:Ceramics D003776:Dental Porcelain D003799:Dental Stress Analysis D003779:Denture Design D003830:Denture, Partial, Fixed D020342:Finite Element Analysis D007284:Inlays
XFEM Fracture load All-ceramic Inlay retained Onlay supported Crack