Influence of implant design (Cylindrical and conical) in the load transfer surrounding long (13mm) and short (7mm) length implants : A photoelastic analysis

Purpose: This study compared the influence of implant design (cylindrical and conical) in the load transfer on bone surrounding 13mm and 7mm length implants under simulated occlusal loading, using photoelastic analysis. Method: Dental implants of 4mm diameter were divided into four groups, which varied in length and design: Group 1 - standard (13 mm) cylindrical implant; Group 2 - standard conical implant; Group 3 - short (7 mm) cylindrical implant, and Group 4 - short conical implant. After the inclusion of the implant models in a photoelastic resin, they were subjected to a static load of 100 N. The lengths of the fringes that were generated were measured in three portions since the implants body: crestal, central and apical portion, parallel to the implant long axis. Furthermore, the entire extension area of dissipation of force was measured. Data were analyzed by one-way ANOVA (α = 0.05). Results: Lower stress was observed at the crestal bone in groups 2 and 4, while the stress levels in groups 1 and 3 were higher with significant differences compared to the other groups (p<0.05). Conclusion: The total amount of stress transmitted to the bone was not affected by implant length under axial loading condition, but changed in relation to the implant design with respect to the concentration of the fringes, which corresponded to the load distribution, with even more dissipation by conical implants.