In previous studies verifying the usefulness of offset placement, one set of FEA models was created and analyzed by changing the conditions or settings. Few studies used different FEA models with the same placement models. In the present study, we carried out the same experiments with both the models to verify the validity of each analysis.

Moreover, considering the possibility of error while using an implant placement guide, we created many FEA models for each placement to compare the accuracy between the same placement models used with different FEA models.

Use of multiple analyses

Most studies verifying the usefulness of offset placement used a single technique for analysis. Therefore, the results regarding the usefulness of offset placement vary depending on the techniques used in the studies, and hence, the issue remains controversial. The present study aimed to evaluate the usefulness of offset placement objectively by using two analyses—experimental and FEA models—and to verify the validity of each analysis. The limitation with experimental models is that it is not possible to observe internal stress, while FEA models have the disadvantage that it is required to confirm the agreement of the results with those obtained from the oral cavity of the living body. In the present study, we believe that it was possible to evaluate the usefulness of offset placement objectively by using multiple analyses so that the disadvantage of each analysis was compensated for by the other.

Sites of strain measurement

There is reportedly a concentration of stress in the surrounding cortical bone when occlusal load is applied to an implant. Based on this, the strain gauges were applied to the peri-implant bone surface in the present study as well.

Experimental results

Amount of compressed displacement

The experimental models and FEA models were similar and exhibited the same trends for compressed displacement based on differences in loading sites. In all placements, central loading resulted in the least compressed displacement and buccal loading the greatest.