| Objective: To analyze the three-dimensional finite element models of cystic lesions in different anatomical parts of the mandible,and to provide a reference for clinical operation.Methods: Using healthy female volunteers with normal occlusion relationships,based on the spiral CT scan data of the mandibular,combining Mimics,Geomagic Studio,and other software.After surface treatment,volume meshing,and material assignment,three-dimensional finite element models of cystic lesions in the mandibular central joint and mandibular body were constructed to analyze the maximum values of Von Mises stress in the stress concentration area close to the yield strength of the mandible under certain constraints and load conditions.Results: 1.The three-dimensional finite element models of the cystic lesions in the mandibular central joint and mandibular body established successfully.2.For the three-dimensional finite element model of the mandibular central joint,the maximum stress values were 81.205 MPa when the Von Mises stress values in the stress concentration area was close to the yield strength of the mandible;For the three-dimensional finite element model of the mandibular body,the maximum stress values was 77.295 MPa when the Von Mises stress values in the stress concentration area were close to the yield strength of the mandible.3.When the values of Von Mises stress in the stress concentration area of the model were close to the yield strength of the jawbone,the measurements of the magnitude of cystic lesions in the mandibular central joint was 38.18mm× 9.53mm× 23.49 mm,the measurements of the magnitude of cystic lesions in the mandibular baby was 37.63mm×11.32mm×21.45 mm,.4.The measurements of residual bone thickness in the medial,lateral,and lower margin of the mandible of the mandibular central joint cystic lesion were 1.33 mm,0.66 mm,and 1.69 mm respectively;The measurements of residual bone thickness in the medial,lateral,and lower margin of the mandible of the mandibular body cystic lesion were 0.76 mm,1.52 mm,and 1.04 mm respectively.Conclusion: Residual bone thickness is an important factor affecting pathological fracture after curettage for cystic lesions,when the bone thickness threshold in the medial,the lateral,and the lower margin of the mandible of the mandibular central joint was as low as 1.33 mm,0.66 mm,and 1.69 mm,and when the bone thickness threshold in the medial,the lateral,and the lower margin of the mandibular body was as low as 0.76 mm,1.52 mm,and 1.04 mm,respectively,from the perspective of biomechanics,mandibular strength is significantly reduced due to extensive cortical bone absorption,and the risk of mandibular pathological fracture caused by direct curettage is relatively high.Therefore,this threshold value can provide a certain reference basis for clinical development of one-stage decompression treatment combined with two-stage curettage surgical treatment. |
