The Stress-strain Analysis Of Denture’s Adhesive Interface And Bone Bonding Interface Based On Cohesion Zone Model

In recent years, dental problems always trouble people. Good repaired teeth often appear as stretch porcelain denture prosthesis loosening, bad bite efficiency and so on due to the complex environment in the mouth, which need to be repaired again. For aesthetic, controllability and simple structure and other considerations, the majority of denture fixed on the abutment by selecting adhesively bonded manner. When the crown is removed using a crown lifter, taking the crown force, the impacting times and direction, and the effects of these factors on the denture adhesive interface bone bonding interface in the crown removal process, etc, these problems are mostly based on the doctor’s clinical experience to judge, there is no more accurate theoretical research data as a guide.Aiming to solve these problems, an analysis was conducted for the denture adhesive interface and bone bonding interface based on the finite element software ABAQUS, ANSYS. Firstly, we selected the established mandibular first molar denture three-dimensional model and the dental crown neck lingual position(P4point) as a application point, and selected the glass ionomer cement as a binder material to calculate its finite element analysis. In the finite element simulation, complex dental crown removal process was simulated by no the thickness of the cohesion zone model for the first time, producing more accurate description of the whole process about the adhesive layer of crack initiation, softening, fully formed during the denture crown removal process. With the increase of impact times, the stress value of adhesive layer interface increases gradually. When the fracture strength is0.17MPa, even if the impact number of times increases, maximum stress value of adhesive layer stays the same. But the displacement of the crack tip increases with the increase of impact times, until the fracture can reach0.039mJ/mm2, fracture crack formation. The mises stress and the equivalent deformation of base stations surface and bone interface increase with the increase of impact times. They are more likely to be damaged.Secondly, the single transient impact was put on the denture crown about the cohesion model in ABAQUS software and the non-cohesive zone model of workbench module in ANSYS, the impact direction and the long axis of the crown are respectively direction of0°,30°,45°,60°were analyzed. The analysis results comparison shows that:when the direction of the force and the crown long axis of30°and45°, the adhesive layer is smaller stress and they are not suitable as the force direction; when the direction of force and the crown long axis at an angle of0°, the adhesive layer is subjected to the greatest stresses, and the base station, less damage to the crown, so select the crown to0°direction as the direction of the dynamic impact effect, you can get a better crown removal effect.The results of this study have some guidance about clinical crown restoration, and provide some theoretical guidance for clinicians to select the appropriate force to take the crown, the proper impact of the number and the appropriate direction to take the crown forces in the process of removing the denture crowns.