Biomechanical Outcomes of Tooth-Implant-Supported Fixed Partial Prostheses (FPPs) in Periodontally Healthy Patients using Root Shape Dental Implants

Background: Connecting an osseointegrated implant and a natural tooth is a treatment alternative for partially edentulous patients in some clinical situations. The main issue of a connected tooth-implant system is derived from the dissimilar mobility patterns of the osseointegrated fixtures and natural abutments causing potential biomechanical problems within the entire system. Purpose: The aim of this review was to multilaterally analyze and discuss the main biomechanical factors that may question the reliability of splinted tooth-implant system and the long-term success of fixed partial prostheses (FPPs) supported by both teeth and implants with an emphasis on the disparity of mobility of these two different abutments. Material and methods: An electronic MEDLINE (PubMed) search supplemented by manual searching was performed to retrieve relevant articles. An assessment of the identified studies was performed, the most valuable articles were selected and biomechanical outcomes of tooth-implant splinting system were analyzed. Results: 3D FEM stress analyses and photoelastic studies show uneven load distribution between the tooth and the implant and stress concentration in the crestal bone around the implant neck when connected to a natural tooth by FPPs. However, clinical studies demonstrate good results for both the implants and FPPs supported by splinted implant-totooth abutments. Conclusion: Connecting implants to natural teeth is not a preferable treatment option because of possible inherent biomechanical complications. Whenever possible, this treatment option should be avoided.