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Article Citation - WoS: 9Citation - Scopus: 8Biomechanical Evaluation of Different Fixation Methods for Mandibular Anterior Segmental Osteotomy Using Finite Element Analysis, Part One: Superior Repositioning Surgery(Lippincott Williams & Wilkins, 2016) Kilinc, Yeliz; Erkmen, Erkan; Kurt, AhmetThe aim of the current study was to comparatively evaluate the mechanical behavior of 3 different fixation methods following various amounts of superior repositioning of mandibular anterior segment. In this study, 3 different rigid fixation configurations comprising double right L, double left L, or double I miniplates with monocortical screws were compared under vertical, horizontal, and oblique load conditions by means of finite element analysis. A three-dimensional finite element model of a fully dentate mandible was generated. A 3 and 5mm superior repositioning of mandibular anterior segmental osteotomy were simulated. Three different finite element models corresponding to different fixation configurations were created for each superior repositioning. The von Mises stress values on fixation appliances and principal maximum stresses (P-max) on bony structures were predicted by finite element analysis. The results have demonstrated that double right L configuration provides better stability with less stress fields in comparison with other fixation configurations used in this study.Article Citation - WoS: 7Citation - Scopus: 7Biomechanical Evaluation of Different Fixation Methods for Mandibular Anterior Segmental Osteotomy Using Finite Element Analysis, Part Two: Superior Repositioning Surgery With Bone Allograft(Lippincott Williams & Wilkins, 2016) Kilinc, Yeliz; Erkmen, Erkan; Kurt, AhmetIn this study, the biomechanical behavior of different fixation methods used to fix the mandibular anterior segment following various amounts of superior repositioning was evaluated by using Finite Element Analysis (FEA). The three-dimensional finite element models representing 3 and 5mm superior repositioning were generated. The gap in between segments was assumed to be filled by block bone allograft and resignated to be in perfect contact with the mandible and segmented bone. Six different finite element models with 2 distinct mobilization rate including 3 different fixation configurations, double right L (DRL), double left L (DLL), or double I (DI) miniplates with monocortical screws, correspondingly were created. A comparative evaluation has been made under vertical, horizontal and oblique loads. The von Mises and principal maximum stress (P-max) values were calculated by finite element solver programme. The first part of our ongoing Finite Element Analysis research has been adressed to the mechanical behavior of the same fixation configurations in nongrafted models. In comparison with the findings of the first part of the study, it was concluded that bone graft offers superior mechanical stability without any limitation of mobilization and less stress on the fixative appliances as well as in the bone.Article Citation - WoS: 3Citation - Scopus: 3Using Servo-Drive Presses to Determine the Effect of Blank Holder Pressure on Temperature Change in Warm Forming of Sheet(Asme-amer Soc Mechanical Eng, 2011) Kaya, SerhatHeat transfer coefficient (HTC) is one of the most important and difficult-to-obtain parameter in high temperature environment. Contact pressure and workpiece surface roughness are among important parameters that affect the heat transfer in elevated temperature forming of sheets. In this study, HTCs are investigated experimentally by using a servo-drive press. With the flexibility that the servo-drive press offers, effect of various blank holder pressures on temperature change is determined. Before and after surface roughness conditions of aluminum and magnesium (from two different manufacturers) alloy sheets are compared. Experimental setup was modeled using deform 2D, and measured temperature curves were compared with the finite element analysis (FEA) predictions and a window of heat transfer coefficients were determined for warm forming of sheets. Determined heat transfer coefficients were implemented in a nonisothermal deep drawing FE model in deform 2D and results were compared with experiments. Good agreement was obtained between FEA predictions and experiments.Article Citation - WoS: 1Citation - Scopus: 2Evaluation of Biomechanical Effects of Different Implant Thread Designs and Diameters on All-On Concept(Ariesdue Srl, 2021) Zor, Z. F.; Kilinc, Y.; Erkmen, E.; Kurt, A.Aim All-on-four concept involves the use of four anterior dental implants in the edentulous jaw to overcome anatomic limitations of residual alveolar bone. The impact of implant thread design and diameter on the biomechanical performance of all-on-four concept is not yet fully understood. The purpose of this study was to investigate the biomechanical behavior of all-on-four concept with different combinations of thread designs and diameters through a three dimensional Finite Element Analysis. Materials and methods Six three-dimensional finite element models of edentulous mandible were developed. The models included the combinations of 3.5 and 4.3 mm diameter implants with active and passive thread designs. Vertical, oblique and horizontal loads were applied anterior to the end of the cantilever. Von Mises, maximum principal and minimum principal stresses were analysed. Results The results indicated a tendency towards stress reduction in Von Mises stress values of dental implants with the increase in diameter for both mesial and distal implants. In narrow implants active thread design resulted in lower Von Mises stress values than passive thread design. Active thread design demonstrated higher bone stress when compared to passive thread design. The analysis also revealed the importance of mesial implant for diminishing stresses on the distal implant and their surrounding bone under horizontal and oblique loading. Conclusion The comparison of the models suggest that use of wide implant is advantageous in the all-on-four concept. There is a biomechanical advantage in using narrow implants with active thread design in horizontally inadequate bone. The thread design was more significant in terms of increasing bone stress than implant diameter. The mesial implant influences the biomechanical behavior of the whole design, contributing to a more favorable stress distribution under horizontal and oblique loading conditions.Article Citation - WoS: 2Citation - Scopus: 2Finite Element Analysis of Stress Distribution on Modified Retentive Tips of Bar Clasp(Taylor & Francis Ltd, 2012) Oyar, P.; Soyarslan, C.; Can, G.; Demirci, E.This study used finite element analysis to evaluate the retentive tips of bar clasps made from different alloys and using different designs in order to determine whether or not different materials and tip forms are suitable for bar clasp applications. Co-Cr, Ti and Type IV Au alloys were selected based on their physical and mechanical properties. The 3D finite element models of three different bar clasp retentive tip geometries prepared from Co-Cr, Ti and Type IV Au alloys were constructed using the finite element software package MSC. Marc. Analysis of a concentrated load of 5N applied to the removable partial denture approach arms in an occlusal direction was performed. Although stress distribution and localisation within bar clasps with different retentive tips were observed to be similar and were concentrated in the approach arm, stress intensities differed in all models.Article Citation - WoS: 3Citation - Scopus: 3How Do Implant Threads and Diameters Affect the All-On Success? a 3d Finite Element Analysis Study(IOS Press BV, 2022) Zor,Z.F.; Klllnç,Y.; Erkmen,E.; Kurt,A.BACKGROUND: The effect of different thread designs and diameters on the all-on-four concept is unclear. OBJECTIVE: The aim of the study was to clarify the differences in stress distribution of dental implants with various thread designs and diameters based on the all-on-four concept with three dimensional (3D) finite element analysis (FEA). METHODS: A 3D model of a totally edentulous mandible was used to perform the FEA. Four different models (M1, M2, M3, and M4) including 3.5 and 4.3 mm diameter dental implants with active and passive threaded designs were generated. The dental implants were positioned according to the all-on-four concept. The Von Mises stresses on dental implants and maximum and minimum principal stresses (Pmax and Pmin) on bony structures were calculated under vertical, oblique and horizontal loads. RESULTS: For Von Mises stresses, the highest stress values were detected on the distal implants for all models. Distal implants had also the highest stress values for vertical loading. The Von Mises stresses were found to be concentrated around the implant's neck. In all models the highest Pmax and Pmin stresses occurred in the bone surrounding the distal implant. It was noted that the active threaded implants showed the highest Pmax and Pmin stress values. CONCLUSION: The implant thread design and diameter might have a strong influence on the stress values in the all-on-four concept. © 2022 - IOS Press. All rights reserved.Article Citation - WoS: 11Citation - Scopus: 15Biomechanical Comparison of Sinus Floor Elevation and Alternative Treatment Methods for Dental Implant Placement(Taylor & Francis Ltd, 2017) Kucukkurt, Sercan; Alpaslan, Goekhan; Kurt, AhmetObjective: In this study, we compared the success of sinus lifting and alternative treatment methods in applying dental implants in cases lacking adequate bone due to pneumatization of the maxillary sinus. Methods: In a computer environment, 3D models were created using computerized tomography data from a patient. Additionally, implants and abutments were scanned at the macroscopic level, and the resulting images were transferred to the 3D models. Five different models were examined: a control model, lateral sinus lifting (LSL), short dental implant placement (SIP), tilted implant placement (TIP) and distal prosthetic cantilever (DC) use. Vertical and oblique forces were applied in each model. The compression, tension and von Mises stresses in each model were analyzed by implementing a finite element analysis method. Results: In our study, the LSL method was observed to be the closest to the control model. The TIP model showed high stress values under conditions of oblique forces but showed successful results under conditions of vertical forces, and the opposite results were observed in the SIP model. The DC model provided the least successful results among all models. Conclusions: Based on the results of this study, the LSL method should be the first choice among treatment options. Considering its successful results under conditions of oblique forces, the SIP method may be preferable to the TIP method. In contrast, every effort should be made to avoid the use of DCs.
