Comparison of stress distributions in different cement thicknesses of implant-retained fixed restorations produced with current CAD-CAM materials
Project no. 23070 · Status: Kapanmış (Yayın bekleniyor) · 2021
Summary
Purpose: This study aims to evaluate the effects of the prosthetic single crown restorations on the implant prepared using current CAD-CAM materials and the effects of the differences in the cement layer thickness on the stress distributions in the restoration, implant and bone as a result of the application of static and dynamic forces. Materials and Methods: In this study, a total of 24 models which are 3D of the implant placed in the mandibular right first molar region and its restorations were created using 6 different superstructure materials and 4 different cement intervals using the modelling software of finite element analysis. Zirconia Supported Listium Silicate (Celtra Duo, Dentsply Sirona), Monolithic Zirconia (Lava Plus, 3M ESPE, St. Paul, USA), Resin Nano Ceramic (Vita Enamic, Vita Zahnfabrik), Lithium Disilicate (IPS Emax CAD, Ivoclar Vivadent AG) which are among the current CAD-CAM materials for prosthetic restoration were used as monolithic. For layered prosthetic restorations; zirconia (ZirCAD, Ivoclar Vivadent AG) in the Veneer zirconia restoration as infrastructure and Lithium Disilicate (IPS Emax CAD, Ivoclar Vivadent AG) as superstructure were used. For metal-supported ceramic restoration; chromium-cobalt alloy (Wiron 99; Bego, Bremen, Germany) as infrastructure and feldspathic porcelain (Ceramco II; Dentsply, Burlington, USA) as superstructure were used. 25-40-100-200 µm were determined as different cement layer thicknesses. A force of 100 N occlusal, 36.485 N mesiodistal and 13.45 N lingual at the same time was applied first linearly to represent chewing over the restoration with the logic of food-stuff. These values were analyzed using the three-dimensional finite element stress analysis method to represent chewing over restoration with the food-stuff logic. Results: When the stress distributions of superstructure materials were evaluated, the highest von Mises value appeared in the monolithic zirconia model of cement thickness of 25 µm. When the stress distributions in all abutments were examined, the highest von Mises value was observed in the metal-supported ceramic model with a cement thickness of 40 µm. Among all abutment screws, the highest von Mises stress value was seen in the metal-supported ceramic model with a cement thickness of 100 µm. When the stress distributions in all implants were examined, the highest von Mises value was observed in the metal-supported ceramic model with a cement layer thickness of 100 µm. Stress values in cortical and cancellous bone showed similar stress distributions for all models. When clinical failure values were compared as a result of fatigue analysis, the highest value was found in the metal-supported ceramic model with a cement thickness of 100 µm. However, the lowest value was determined in the metal-supported ceramic model with a cement thickness of 40 µm. Conclusion: According to the results, the use of zirconia-reinforced lithium silicate, monolithic zirconia, resin-infiltrated ceramic, lithium disilicate, veneer zirconia and metal-supported ceramics as an implant supported fixed restoration, 4 different cement thicknesses of 25, 40, 100, 200 µm did not differ in terms of stress transmission to the implant, abutment, cortical and cancellous bone. Keywords: Finite Element Analysis, Cement Thickness, CAD-CAM