ObjectiveTo investigate the biomechanical behavior of three distinct types of narrow-diameter implants (NDIs) supporting a single-cantilever fixed bridge for mandibular central incisors using three-dimensional finite element analysis.MethodsThree commonly used NDIs were selected: group Z1, Osstem one-piece implant with a dia-meter of 2.5 mm; group Z2, Anthogy Morse taper connected two-piece implant with a diameter of 2.8 mm; group Z3, Nobel Active screw-retained two-piece implant with a diameter of 3.0 mm. The three-dimensional finite-element model of cantilever fixed bridge supported by NDIs was constructed using finite element software. Vertical loads of 65 and 130 N and 45° oblique load were applied. von Mises stress of the implants and metal components, principal stress of the bone tissue, and stress distribution cloud map were calculated and analyzed.ResultsUnder vertical load, only Z3 group implant reached a von Mises stress peak of 1 004.5 MPa at a load of 130 N, exceeding the material’s yield strength. Under the 45° oblique load, the von Mises stress peaks of all three groups of NDIs excee-ded the material’s yield strength. The stress cloud map revealed that the implant neck and surrounding bone tissue were the stress concentration areas.ConclusionAll three NDIs groups proved theoretically feasible under a 65 N axial load, with this study delineating the biomechanical safety boundary and highlighting the important risks posed by excessive or oblique loading.
