The aim of this study was to evaluate dynamic micromotion at the implant-abutment interface for 3 different implant neck designs. Five samples each from 3 implant types with different neck designs were subjected to 1 x 10⁶ cycles under simulated oral conditions. Load magnitudes varied from 10 to 250 N at 15 Hz. The results revealed a significant main effect for type of implant (P .0001). The main effect for level of cycles proved to be nonsignificant (P = .9999), as did the interaction between type of implant and level of cycles (P = .9989). Differences in neck design among the 3 implant types resulted in differences in micromotion at the implant-abutment interface under simulated oral conditions.