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

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 restora-tions (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 abutment screw were less than those of segmented abutment (87 vs. 100, and 375 vs. 430 mpa under axial and non-axial loading, respectively). the maximum stresses in the peri-implant bone for the model with segmented abutment were less than those of non-segmented ones (21 vs. 24 mpa, and 31 vs. 126 mpa under vertical and angular loading, respectively). in addition, the micro-strain of peri-implant bone for the segmented abut-ment restoration was less than that of non-segmented abutment. conclusion. under axial and non-axial loadings, non-segmented abutment showed less stress concentration in the screw, while there was less stress and strain in the peri-implant bone in the segmented abutment.