Stress distribution pattern of screw-retained restorations with segmented vs. non-segmented abutments: A finite element analysis

摘要

>Background. Screw-retained restorations are favored in some clinical situations such as limited inter-occlusal spaces. This study was designed to compare stresses developed in the peri-implant bone in two different types of screw-retained restorations (segmented vs. non-segmented abutment) using a finite element model. > Methods. An implant, 4.1 mm in diameter and 10 mm in length, was placed in the first molar site of a mandibular model with 1 mm of cortical bone on the buccal and lingual sides. Segmented and non-segmented screw abutments with their crowns were placed on the simulated implant in each model. After loading (100 N, axial and 45° non-axial), von Mises stress was recorded using ANSYS software, version 12.0.1. >Results. The maximum stresses in the non-segmented abutmentscrew were less than those of segmented abutment (87 vs. 100, and 375 vs. 430MPa under axial and non-axial loading, respectively). The maximum stresses inthe peri-implant bone for the model with segmented abutment were less thanthose of non-segmented ones (21 vs. 24 MPa, and 31 vs. 126 MPa under verticaland angular loading, respectively). In addition, the micro-strain ofperi-implant bone for the segmented abutment restoration was less than thatof non-segmented abutment.>Conclusion. Underaxial and non-axial loadings, non-segmented abutment showed less stressconcentration in the screw, while there was less stress and strain in theperi-implant bone in the segmented abutment.