Objective To compare the differences in stress on maxillary anterior implants and labial cortical bone under varying thicknesses of palatal bone plates through three-dimensional finite element analysis.Methods Using CBCT scan data and finite ele-ment software,a three-dimensional finite element model of maxillary central incisor implant restoration was constructed.The thickness of the palatal bone plate at the cervical region of the implant was set to 0,0.5,1.0 mm,respectively.The effects of different palatal bone plate thicknesses on the equivalent stress of the implant and the minimum principal stress(compressive stress)of the labial corti-cal bone under normal occlusal conditions were simulated.Results Under normal occlusion,when the palatal cervical bone plate thickness was 0,0.5,1.0 mm,the maximum equivalent stress of the implant was consistently located at the midline of the labial cervi-cal region at the implant-abutment interface,with values of 106.8,103.5,99.71 MPa,respectively.Meanwhile,the minimum princi-pal stress of the cortical bone appeared at the alveolar crest at the junction of the implant-abutment and labial alveolar bone,measuring 107.8,103.2,95.55 MPa,respectively.The results indicated that as the palatal cervical bone plate thickness decreased,both the maximum equivalent stress of the implant and the minimum principal stress of the labial cortical bone exhibited an increasing trend,though they remained below their respective yield strengths.Conclusion From a biomechanical perspective,maxillary anterior implant restoration remains feasible even when the thickness of the palatal bone plate at the cervical region of the implant is 0 mm.

Objective To compare the stress difference of the resin with different thicknesses in the screw access hole using three-dimensional finite element method.Methods A three-dimensional finite element model of the implant at the site of the mandibular first molar was established by computer aided design(CAD)software.A static load of 200 N was applied to the resin models with different thicknesses(1,2,3,4,5 mm)to analyze the effect of thickness on the von Mises stress and shear stress of the resin.Results In a certain range,the maximum von Mises stress and the maximum shear stress of the resin decreased with the increase of the thickness.At the thickness of 1mm,the maximum von Mises stress and shear stress of the resin were 23.85 MPa and 11.82 MPa,respectively.When the thickness was 2 mm,the maximum von Mises stress and shear stress of the resin were 18.75 MPa and 9.73 MPa respectively.At the thickness of 3 mm,the maximum von Mises stress and shear stress of the resin were 17.46 MPa and 9.04 MPa,respectively.When the thickness of the resin was more than 3 mm,the stress on it was in a stable level trend.When the thickness was 4 mm,the maximum von Mises stress and shear stress of the resin were 17.38 MPa and 9.04 MPa,respectively.When the thickness was 5 mm,the maxi-mum von Mises stress and maximum shear stress of the resin were 17.18 MPa and 8.85 MPa,respectively.Conclusion When the res-in reaches a certain thickness,the stress is small and stable.This study provides a new design strategy for reducing the complications after implant restoration caused by stress fatigue of the resin.

Objective To compare the stress difference of the resin with different thicknesses in the screw access hole using three-dimensional finite element method.Methods A three-dimensional finite element model of the implant at the site of the mandibular first molar was established by computer aided design(CAD)software.A static load of 200 N was applied to the resin models with different thicknesses(1,2,3,4,5 mm)to analyze the effect of thickness on the von Mises stress and shear stress of the resin.Results In a certain range,the maximum von Mises stress and the maximum shear stress of the resin decreased with the increase of the thickness.At the thickness of 1mm,the maximum von Mises stress and shear stress of the resin were 23.85 MPa and 11.82 MPa,respectively.When the thickness was 2 mm,the maximum von Mises stress and shear stress of the resin were 18.75 MPa and 9.73 MPa respectively.At the thickness of 3 mm,the maximum von Mises stress and shear stress of the resin were 17.46 MPa and 9.04 MPa,respectively.When the thickness of the resin was more than 3 mm,the stress on it was in a stable level trend.When the thickness was 4 mm,the maximum von Mises stress and shear stress of the resin were 17.38 MPa and 9.04 MPa,respectively.When the thickness was 5 mm,the maxi-mum von Mises stress and maximum shear stress of the resin were 17.18 MPa and 8.85 MPa,respectively.Conclusion When the res-in reaches a certain thickness,the stress is small and stable.This study provides a new design strategy for reducing the complications after implant restoration caused by stress fatigue of the resin.

Objective To compare the differences in stress on maxillary anterior implants and labial cortical bone under varying thicknesses of palatal bone plates through three-dimensional finite element analysis.Methods Using CBCT scan data and finite ele-ment software,a three-dimensional finite element model of maxillary central incisor implant restoration was constructed.The thickness of the palatal bone plate at the cervical region of the implant was set to 0,0.5,1.0 mm,respectively.The effects of different palatal bone plate thicknesses on the equivalent stress of the implant and the minimum principal stress(compressive stress)of the labial corti-cal bone under normal occlusal conditions were simulated.Results Under normal occlusion,when the palatal cervical bone plate thickness was 0,0.5,1.0 mm,the maximum equivalent stress of the implant was consistently located at the midline of the labial cervi-cal region at the implant-abutment interface,with values of 106.8,103.5,99.71 MPa,respectively.Meanwhile,the minimum princi-pal stress of the cortical bone appeared at the alveolar crest at the junction of the implant-abutment and labial alveolar bone,measuring 107.8,103.2,95.55 MPa,respectively.The results indicated that as the palatal cervical bone plate thickness decreased,both the maximum equivalent stress of the implant and the minimum principal stress of the labial cortical bone exhibited an increasing trend,though they remained below their respective yield strengths.Conclusion From a biomechanical perspective,maxillary anterior implant restoration remains feasible even when the thickness of the palatal bone plate at the cervical region of the implant is 0 mm.