Maximum Insertion Torque, Stress, and Strain in Bone during Insertion of Three Dental Implants with Different Macroscopic Designs: A Dynamic Finite-Element Analysis.

Using finite element analysis, this study assesses maximum insertion torque, stress, and strain in bone during insertion of three dental implant types with different macroscopic designs. We model a bone block including cancellous and cortical bones and an osteotomy hole matching the size of the final implant drill. We then model three implants of the same length and diameter but with different thread and body designs. Model I has a conical body with greater apical region tapering and specifically designed threads, model II has wedge-shaped threads and a conical body, and model III is a conical implant with progressive threads. We place models into the bone block at 30 rounds/min and evaluate the implant insertion process in three equal phases of apical, middle, and coronal thirds. We record mean maximum von Mises stress, strain, and insertion torque at 10 points in each third of the osteotomy hole (total of 30 points). In all three implant models, increasing fixture insertion depth into the osteotomy hole results in augmented maximum von Mises stress, strain, and insertion torque in bone. Maximum values are recorded in model I, whereas minimum values are recorded in model III. The dental implant model with crestal microthread design shows maximum von Mises stress, strain, and insertion torque, whereas the model with progressive thread design and absence of coronal threads shows minimum stress, strain, and torque.