A 3D finite element analysis of glass fiber reinforcement designs on the stress of an implant-supported overdenture

Statement of problem. Evidence regarding the effect of different glass fiber reinforcement designs on the biomechanical behavior of implant-supported overdentures is lacking. Purpose. The purpose of this finite element analysis was to analyze the stress distribution in an implant-supported overdenture reinforced with a cast metal reinforcement bar and 4 different designs of unidirectional glass fiber to minimize the risk of denture base fracture. Material and methods. A 3D edentulous mandible incorporating an implant-supported overdenture model without reinforcement (control, CT) or reinforced with 1 cast metal bar reinforcement (CM) was placed over the top of the implants and 4 unidirectional glass fiber reinforcements. The glass fiber bundle was placed over the top of the implants (GF), or 2 bundled halves were placed over the top (GO) of, between (GB), or distal (GD) to implants. Three patterns of occlusal loading were simulated: L1, all artificial teeth loaded in the long axis; L2, all left-side teeth loaded in the long axis; and L3, posterior left-side teeth loaded obliquely (45 degrees). Results. Under L1 and L3, the tensile stresses were higher for CT, GD, and GO and lower for GF and CM. Under L2, no differences were seen between groups. Stresses were concentrated on the periphery of the O-ring connector, on the basal area, and on the middle-lingual region of the overdenture. Conclusions. Reinforcements placed in the middle region and over the top of the implants provided better load distribution. Unidirectional glass fiber behaved as cast metal when used to reinforce the implant-supported overdenture.