Stress-deformed state of a non-removable prosthesis on implants under mustering load depending on the angle of abutment wall tilt

Abstract

Despite the widespread use of implant-supported fixed prostheses, a number of issues related to their manufacture remain debatable. Many authors raise the question of the necessary degree of inclination of the abutment walls to improve the passive fit and stability of the prosthesis, which determined the relevance and purpose of this publication. >. A study of the stress-strain state of the components of a fixed prosthesis during cementation on an abutment (ceramic veneer, frame, cement, abutment) was carried out using the finite element method (FEM), depending on the design of the fixed prosthesis, the height and angle of inclination of the abutment walls. A total of 99 models were studied and analyzed. >. The analysis of the obtained results showed that with three differently directed chewing loads on fixed prostheses, with an increase in the angle of inclination of the abutment walls, the level of stress-strain state values in the ceramic veneer statistically significantly (p≤0.05) decreases over the entire surface. Also, with an increase in the angle of inclination of the walls of the abutments, the level of maximum tensile stresses over the entire volume of the framework decreases statistically significantly (p≤0.05). When analyzing the results of studying stresses in the cement layer with an increase in the angle of inclination of the abutment walls, the level of tangential and tensile stresses in the cement layer increases statistically significantly (p≤0.05) with a masticatory load at an angle of 30° — 200 N and a transverse masticatory load of 100 N at an increase in the angle of inclination of the walls of the abutment as a result of the excessive conical surface of the abutment, these stresses can lead to decementation of the fixed prosthesis. The study of the stress-strain state of abutments under three differently directed masticatory loads showed a sharp surge of stresses in their upper part at an inclination angle of 10° and a diameter of 4.5 mm in fixed metal-ceramic prostheses on a single support, on two supports, on three supports, and statistically significant (p≤0.05) a 3.7-fold decrease in stress values with a decrease in the angle of inclination to 8°. >. It has been established that the height and angle of inclination of the abutment walls affect the uneven distribution of stresses in the ceramic veneer, framework, cement layer and abutment.