IADR Abstract Archives
Can The Volume Of The Endodontic Access Cause Enamel Fracture?
Objectives: To evaluate the biomechanical behavior by finite element analysis of premolar teeth with different endodontic accesses, under overload conditions. Also, to assess the effect of enamel anisotropy on fracture risk.
Methods: Based on biomedical images a finite element model of a premolar tooth with its supporting structures was designed. In addition, four models with endodontic accesses were simulated: ultra-conservative -UCEC, conservative -CEC, traditional -TEC, extended -EEC (Jiang, 2018). The material properties were assigned as elastic-linear, homogeneous, and isotropic, except for the enamel that was also represented as anisotropic (Munari, 2015). Two loading conditions were simulated: a physiological load of 150 N and a pathological overload of 500 N consistent with bruxism (Radaelli, 2018). The analysis criterion in enamel was the maximum principal stress, corresponding to a brittle fracture model (Ichim, 2007).
Results: Models with different cavity accesses presented minimal stress differences. For models with physiological load the simulation showed stress differences of 2 MPa, and differences of 7 MPa for models with overload. The stress distribution between the models was similar. The stress peaks in the enamel were located in the cavity walls. Models with pathological overload presented stress peaks of 53 MPa to 60 MPa, exceeding the tensile strength of enamel (47 MPa) (Cavalli, 2004). Physiologically loaded models showed stress peaks less than 20 MPa. When compared to anisotropic models, isotropic models presented higher stress peaks, ranging from 47% to 66%. Representation of enamel microstructure showed similar stress values with experimental studies (Giannini, 2004).
Conclusions: In this study, the volume increase of the endodontic accesses did not cause stress increases in the enamel consistent with brittle fracture. However, under pathological overload, teeth with endodontic accesses exceed the tensile strength of the enamel. For brittle fracture analysis of enamel, anisotropy is a relevant factor in numerical simulation.
Methods: Based on biomedical images a finite element model of a premolar tooth with its supporting structures was designed. In addition, four models with endodontic accesses were simulated: ultra-conservative -UCEC, conservative -CEC, traditional -TEC, extended -EEC (Jiang, 2018). The material properties were assigned as elastic-linear, homogeneous, and isotropic, except for the enamel that was also represented as anisotropic (Munari, 2015). Two loading conditions were simulated: a physiological load of 150 N and a pathological overload of 500 N consistent with bruxism (Radaelli, 2018). The analysis criterion in enamel was the maximum principal stress, corresponding to a brittle fracture model (Ichim, 2007).
Results: Models with different cavity accesses presented minimal stress differences. For models with physiological load the simulation showed stress differences of 2 MPa, and differences of 7 MPa for models with overload. The stress distribution between the models was similar. The stress peaks in the enamel were located in the cavity walls. Models with pathological overload presented stress peaks of 53 MPa to 60 MPa, exceeding the tensile strength of enamel (47 MPa) (Cavalli, 2004). Physiologically loaded models showed stress peaks less than 20 MPa. When compared to anisotropic models, isotropic models presented higher stress peaks, ranging from 47% to 66%. Representation of enamel microstructure showed similar stress values with experimental studies (Giannini, 2004).
Conclusions: In this study, the volume increase of the endodontic accesses did not cause stress increases in the enamel consistent with brittle fracture. However, under pathological overload, teeth with endodontic accesses exceed the tensile strength of the enamel. For brittle fracture analysis of enamel, anisotropy is a relevant factor in numerical simulation.