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: To measure stress and strain concentrations on four different RBFDP designs and its effect on cement layer and the Periodontal tissues using FEA. : Using CBCT data, two 3D models of a maxilla with missing lateral Incisor were printed. Tooth preparation for RBFDP was done. One model had proximal-groove of 4mm and other had 3mm proximal-groove. Four designs of cantilever RBFDPs were designed. Model-1: #21 abutment/ 3x3mm connector; Model-2: #21 abutment/ 3x4mm connector; Model-3: #23 abutment/ 3x3mm connector and; Model-4: #23 abutment/ 3x4mm connector. All Models were converted into FEA models, occlusal force of 200N was loaded at 450 to long axis of pontic and FEA was carried out. Maximum Principal Strain(MPS) in the RBFDP framework, periodontal tissues and Maximum Shear Stress(MSS) in cement layer were measured to evaluate the impact on periodontal tissues and the risk for framework-debonding respectively. : The MPS of framework in decreasing order was: Model-1Model-2Model-3Model-4. The MPS of PDL: Model-1 and Model-2 Model-3 and Model-4. MSS in cement layer: Model-1 and Model-2 Model-3 and Model-4. Adhesion area with shear stress 11MPa: Model-1 and Model-2 Model-3 and Model-4. MPS and MMS values were lower in models with 3×4mm connector than models with 3x3mm connector. : Adequate Connector dimension and adhesion-area are critical for success of RBFDP. Within the limitations of this study, RBFDP design with 3x4mm connector and Maxillary Canine as abutment for replacing Maxillary Lateral Incisor is better option in terms of framework-debonding risk and preservation of periodontal tissues.
Patel et al. (Fri,) studied this question.