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Article Citation - WoS: 8Citation - Scopus: 10Biomechanical Effects of Two Different Collar Implant Structures on Stress Distribution Under Cantilever Fixed Partial Dentures(Taylor & Francis Ltd, 2011) Meric, Gokce; Erkmen, Erkan; Kurt, Ahmet; Eser, Atilim; Ozden, Ahmet UtkuObjective. The purpose of the study was to compare the effects of two distinct collar geometries of implants on stress distribution in the bone around the implants supporting cantilever fixed partial dentures (CFPDs) as well as in the implant-abutment complex and superstructures. Materials and methods. The three-dimensional finite element method was selected to evaluate the stress distribution. CFPDs which was supported by microthread collar structured (MCS) and non-microthread collar structured (NMCS) implants was modeled; 300 N vertical, 150 N oblique and 60 N horizontal forces were applied to the models separately. The stress values in the bone, implant-abutment complex and superstructures were calculated. Results. In the MCS model, higher stresses were located in the cortical bone and implant-abutment complex in the case of vertical load while decreased stresses in cortical bone and implant-abutment complex were noted within horizontal and oblique loading. In the case of vertical load, decreased stresses have been noted in cancellous bone and framework. Upon horizontal and oblique loading, a MCS model had higher stress in cancellous bone and framework than the NMCS model. Higher von Mises stresses have been noted in veneering material for NMCS models. Conclusion. It has been concluded that stress distribution in implant-supported CFPDs correlated with the macro design of the implant collar and the direction of applied force.Article Citation - WoS: 55Biomechanical Comparison of Implant Retained Fixed Partial Dentures With Fiber Reinforced Composite Versus Conventional Metal Frameworks: a 3d Fea Study(Elsevier, 2011) Erkmen, Erkan; Meric, Gokce; Kurt, Ahmet; Tunc, Yahya; Eser, AtilimFiber reinforced composite (FRC) materials have been successfully used in a variety of commercial applications. These materials have also been widely used in dentistry. The use of fiber composite technology in implant prostheses has been previously presented, since they may solve many problems associated with metal alloy frameworks such as corrosion, complexity of fabrication and high cost. The hypothesis of this study was that an FRC framework with lower flexural modulus provides more even stress distribution throughout the implant retained fixed partial dentures (FPDs) than a metal framework does. A 3-dimensional finite element analysis was conducted to evaluate the stress distribution in bone, implant-abutment complex and prosthetic structures. Hence, two distinctly different models of implant retained 3-unit fixed partial dentures, composed of Cr-Co and porcelain (M-FPD model) or FRC and particulate composite (FRC-FPD model) were utilized. In separate load cases, 300 N vertical, 150 N oblique and 60 N horizontal forces were simulated. When the FRC-FPD and M-FPD models were compared, it was found that all investigated stress values in the M-FPD model were higher than the values in the FRC-FPD model except for the stress values in the implant-abutment complex. It can be concluded that the implant supported FRC-FPD could eliminate the excessive stresses in the bone-implant interface and maintain normal physiological loading of the surrounding bone, therefore minimizing the risk of peri-implant bone loss due to stress-shielding. (C) 2010 Elsevier Ltd. All rights reserved.Article Citation - WoS: 14Citation - Scopus: 20Biomechanical Comparison of Two Different Collar Structured Implants Supporting 3-Unit Fixed Partial Denture: a 3-D Fem Study(Taylor & Francis Ltd, 2012) Meric, Gokce; Erkmen, Erkan; Kurt, Ahmet; Eser, Atilim; Oezden, Ahmet UtkuObjective. The purpose of the study was to compare the effects of two distinct collar geometries of implants on stress distribution in the bone as well as in the fixture-abutment complex, in the framework and in the veneering material of 3-unit fixed partial denture (FPD). Material and methods. The 3-dimensional finite element analysis method was selected to evaluate the stress distribution in the system composed of 3-unit FPD supported by two different dental implant systems with two distinct collar geometries; microthread collar structure (MCS) and non-microthread collar structure (NMCS). In separate load cases, 300 N vertical, 150 N oblique and 60 N horizontal, forces were utilized to simulate the multidirectional chewing forces. Tensile and compressive stress values in the cortical and cancellous bone and von Mises stresses in the fixture-abutment complex, in the framework and veneering material, were simulated as a body and investigated separately. Results. In the cortical bone lower stress values were found in the MCS model, when compared with NMCS. In the cancellous bone, lower stress values were observed in the NMCS model when compared with MCS. In the implant-abutment complex, highest von Mises stress values were noted in the NMCS model; however, in the framework and veneering material, highest stress values were calculated in MCS model. Conclusions. MCS implants when compared with NMCS implants supporting 3-unit FPDs decrease the stress values in the cortical bone and implant-abutment complex. The results of the present study will be evaluated as a base for our ongoing FEA studies focused on stress distribution around the microthread and non-microthread collar geometries with various prosthesis design.
