stress distribution in peri-implant bone in the replacement of molars with one or two implants: a finite element analysis

Statement of the problem: in most cases, insertion of single implants with a standard diameter is used to replace a molar tooth but placing two implants with a narrow diameter seems to be a viable treatment modality to withstand functional and biomechanical forces.purpose: this study aimed to evaluate and compare stress distribution in the bone surrounding a single molar area rehabilitated by a single implant versus two implants with a narrow diameter.materials and method: the study was conducted by computer-aided in vitro modeling. the initial model used a single implant, 4.8 mm wide in diameter, inserted with a 3.9-mm distance from both sides and 12.6-mm mesiodistal space. the second model used two 3.3-mm narrow-sized implants with a 3-mm distance from one another, 1.5 mm from both sides, and a 12.6-mm mesiodistal space. following the completion of these models, a 100-n force was exerted obliquely, once in three locations and once in the mesial aspect of the implant-supported crown. stress distribution was then measured using finite element analysis (fea) with ansys workbench software package in both models.results: the maximum stress in the bone around the single implant was less than that around double implants. the maximum stress of cortical bone in three-point loading was lower than mesial loading either in one (146.7 vs. 126.72 mpa) or two implants model (186.8 vs. 139.24).conclusion: according to the results, because of more cortical bone contact area, the stress of surrounding bone in wide implant was decreased.