Multiaxial fatigue life assessment of dental implants.

As screwed joints, dental restorations may suffer mechanical failures such as screw loosening and implant or prosthetic screw failure due to fatigue. This work is focused on the failure of the implant and develops a numerical methodology to predict its fatigue life under cyclic loading conditions. This methodology is based on the combination of Critical Plane Methods and the Theory of Critical Distances to account for stress multiaxiality and notch effects.

Evaluation of Implant Body Diameter, Platform Diameter, and the Use of a Transepithelial Component on Implant-Abutment Connection Microgap: An In Vitro Study with In Situ Hard X-Ray Radiography.

Purpose: To evaluate the effect of implant body diameter, platform diameter, and the use of transepithelial components on implant-abutment connection (IAC) microgap width.

Materials And Methods: In total, 16 tests were performed on four commercial dental restoration models (BTI Biotechnology Institute). Different static loads were applied to the embedded implants according to the International Organization for Standardization (ISO) 14801, using a customized loading device.

Effect of the geometry of butt-joint implant-supported restorations on the fatigue life of prosthetic screws.

Statement Of Problem: Dental implant geometry affects the mechanical performance and fatigue behavior of butt-joint implant-supported restorations. However, failure of the implant component has been generally studied by ignoring the prosthetic screw, which is frequently the critical restoration component.

Purpose: The purpose of this in vitro study was to evaluate the effect of 3 main implant geometric parameters: the implant body diameter, the platform diameter, and the implant-abutment connection type (external versus internal butt-joint) on the fatigue life of the prosthetic screw.

Fatigue performance of prosthetic screws used in dental implant restorations: Rolled versus cut threads.

Statement Of Problem: Cold rolling is widely used for screw thread manufacturing in industry but is less common in implant dentistry, where cutting is the preferred manufacturing method.

Purpose: The purpose of this in vitro study was to compare the surface finish and mechanical performance of a specific model of prosthetic screw used for direct restorations manufactured by thread rolling and cutting.

Material And Methods: The thread profiles were measured in an optical measuring machine, the residual stresses in an X-ray diffractometer, the surface finish in a scanning electron microscope, and then fatigue and static load tests were carried out in a direct stress test bench according to the International Organization for Standardization (ISO) 14801.

Influence of vertical misfit in screw fatigue behavior in dental implants: A three-dimensional finite element approach.

Misfit is unavoidable in dental implant-supported prostheses due to machining process or inappropriate assembling, and the definition of an admissible misfit is still a controversial issue. This work aims to understand the behavior of the screws in dental implant-supported prostheses to estimate an admissible vertical misfit value in terms of screw fatigue failure. For that purpose, a finite element model of a dental implant-supported prosthesis was created and analyzed.