Clinical Outcomes of Implant-Assisted Removable Partial Dentures According to Implant Strategic Position.

Purpose: To retrospectively analyze the success of implant-assisted removable partial dentures (IARPDs) according to three types of strategic positions in distal extension areas of Kennedy Class I and II arches.

Materials And Methods: The data included 102 arches in 95 patients with Kennedy Class I/II arches treated with IARPDs with implants in three strategic positions: Type 1a, assisted by P-1a implants on the anterior area adjacent to the abutment tooth; Type 1b, assisted by P-1b implants on the anterior area apart from the abutment tooth with or without P-1a; Type 2, assisted by P-2a implants on the posterior area adjacent to the natural tooth or P-2b implants on the posterior area apart from the abutment tooth to modify from Kennedy Class I /II to Class III. The success was defined as the IARPDs without abutment tooth-related, denture-related, and implant-related complications. Kaplan-Meier curves and the multivariable Cox regression model were used to analyze the success of IARPDs and implants.

Results: The overall success rate of IARPD treatment was 66.7%; 77.8% in Type 1a, 60.0% in Type 1b, and 68.0% in Type 2. There was no significant effect of treatment type on success rate of IARPDs. However, there was significant differences at the level of implant supporting IARPDs: 83.3% in Type 1a implants, 62.6% in Type 1b implants, and 73.2% in Type 2 implants. The implants of IARPD's adjacent to the natural tooth abutments (P-1a and P-2a) had higher success rates than those away from the natural tooth abutments.

Conclusions: Within the limitations of this study, there was no significant difference in the prosthodontic complications of IARPDs depending on the treatment type. However, the success of implants of IARPD is associated with the strategic position. Strategic implant abutments adjacent to the natural tooth had higher success rates than those away from the natural teeth abutments.