Comparative stress analysis of delayed and immediate loading of a single implant in an edentulous maxilla model

Stress distribution in peri-implant bone in an edentulous maxilla following delayed and immediate loading implant and the effect of implant length on the maximum stress were evaluated by using two kinds of finite element analyses. A threaded implant was loaded with a 100 N vertical force, either immediately or delayed, and examined by finite element analysis with a simple contact relation or a bonding interaction between the implant and the bone, respectively. Higher stresses were observed in cortical bone around the implant neck following delayed loading and in the trabecular bone around the implant threading in the immediate loading model. The maximum stress in the immediate loading model was dramatically higher than in delayed loading. Increased implant length caused decrease in bone stresses in both loading models. Though the stress level was higher, the decrease in the maximum trabecular bone stress in immediate loading was profound.