Analysis of Dental Bridges under Thermomechanical Loading

Abstract

Background: In this research, thermomechanical analysis of a 3D model of dental bridge between the first mandibular premolar and first molar was analyzed in Ansys Workbench software.Materials and Methods: The dental bridge made of lithium disilicate ceramic and type II gold alloy was subjected to fluid at 4°C and 60°C for 5 seconds at occlusal and lingual surfaces. Moreover, the static and impact loads were applied at the center of the dental bridge. The first static load was a vertical force, and the second static load was in the form of an oblique force at an angle of 45° with respect to occlusal plane, oriented towards the buccal side. The impact loading simulation was performed for an impactor with different kinetic energy normal to the occlusal plane.Results: The maximum thermal stress in the bridge and dental tissue at 4°C is obtained at more than 60°C, yet dependent on the coefficient of thermal expansion, the elastic modulus, and the temperature field. The maximum thermal stress in gold bridges is about 30% higher than in ceramic bridges. In addition, it was found that in the case when only vertical occlusion forces are acting, there is a significant underestimation of the maximum stress of 40% compared to the case of an oblique force. The stress intensity under rigid impactor with an initial kinetic energy of 2.2, 8.6, and 19.4 mJ was obtained at 1.35, 2.2, and 3 times the static stress, respectively, and the reaction force at roots was proportional to the magnitude of the kinetic energy of the impactor. Conclusion: As evidenced in this study, the stress created in the dental bridge in impact loading and cold thermal stimulation is more critical than other loadings. On average, the ceramic dental bridge demonstrates less stress in both tooth tissue and dental bridge.

Keywords

• ceramic
• dental bridge
• finite element method
• gold
• thermomechanical stress