Purpose : This in vitro study investigated the influence of implant splinting on stress distribution in two experimental implant-bone models.
Materials and Methods : Two experimental implant-bone models simulated the original Brånemark model with four implants between the mental foramina and one additional implant placed on each side posterior to the mental foramen. The stress distribution on each implant in the models was examined by applying a static load to the superstructure. Three types of superstructures were studied to determine the effect of additional implants in the posterior region : 1) a metal superstructure supported by all six implants (Full dental arch ; Metal FDA) ; 2) the same type of superstructure made of resin instead of metal (Resin FDA) ; and 3) the metal superstructure supported by four anterior implants, with the conical abutments removed from the two posterior implants (Short dental arch ; Metal SDA).
Results : Regardless of the type of superstructure tested, high stress was observed around each loaded implant. The highest stress was concentrated on the distal implants of the FDA compared to the stress on the anterior implants.
Conclusion : The elevated stress concentration around the implants found in the present in vitro study is considered to be one of the reasons for the high failure rate of additional posterior mandibular implants.