Carbon fiber-reinforced PEEK as a framework material for single implant-retained mandibular overdentures

This study aimed to assess the biomechanical behavior of reinforcement materials [cobalt chromium alloy (CoCr) and carbon fiber-reinforced polyether ether ketone (CFR-PEEK)] and their extensions (short: 15 mm and long: 25 mm) of single implant-retained mandibular overdentures (MO-1) by 3D finite element analysis (FEA), comparing them with MO-1 without a framework. Five models (CoCr-Short, CFR-PEEK-Short, CoCr-Long, CFR-PEEK-Long, and no framework) were created using the McNeel Rhinoceros 3D software, version 7.0. Stress distribution analysis by FEA was performed using the Optstruct solver, and a 30° oblique load (100 N) was applied in the anterior region (50 N on each central incisor). Biomechanical behavior was analyzed by overdenture displacement, maximum (MaxP) and minimum principal (MinP) stress, and von Mises stress. The MO-1 model 'without a framework' produced the largest dislocation, MinP stress on the mucosa, and MaxP stress in the cortical bone. Regardless of the extension of the framework, CFR-PEEK had minor MinP stress in the mucosa and lower overdenture displacement. The 'CoCr-Long' and 'CFR-PEEK-Long' models had higher von Mises stress on the implant housing, and MaxP stress on the O'ring nylon conventional implant and overdenture. The 'CoCr-Short' and ' CFR-PEEK-Short' models showed a greater tendency for tension concentration solely in the framework. The incorporation of a framework into MO-1 decreased stress concentration on the overdenture, resulting in lower stress on the attachment, mucosa, implant, and peri-implant bone, irrespective of the material used. The short framework, however, performed better biomechanically in MO-1, and it is therefore the most recommended option. CFR-PEEK showed favorable biomechanical outcomes, and is suggested for reinforcement of MO-1.