Implant-retained Removable Partial Dentures: A 17-Year Retrospective Study
Objectives: The purpose of this 17-year retrospective study was to evaluate the long-term outcomes of implant-retained removable partial dentures (IR-RPDs). The strategic placement of one or two implants per arch allowed to avoid clasps, obtaining therefore (1) a better esthetics and (2) the preservation of residual teeth, preventing dangerous forces.
Methods: 32 partially edentulous patients (mean age 58.2 years) received 64 dental implants (SET; Mech&Human, Italy), from one to three two-stages fixtures each, and the relative ball-attachments to retain removable partial dentures (RPDs). Surgeries were performed by three independent operators and required three months of healing for mandibular implants and six months for maxillary. After prosthetic fabrication and insertion, patients underwent annual recall program consisting in (1) implant hygiene and check-up, (2) replacement of the resilient component of the attachment (regardless of wear) and (3) relining, if needed after evaluation of the bases with pressure-indicating paste. Failures and maintenance were recorded during the follow-up (207.3±2.4 months).
Results: Of the original 32 patients, 6 dropped out during follow-up; of the remaining 26 patients and 51 implants, four fixtures were lost: two did not osteointegrated and two failed during the follow-up due to excessive bone resorption. The 17-year implant survival rate is therefore 92.15%. Implant failures did not led to prosthesis failure because in all four cases was possible to place other fixtures: therefore, prosthesis success is 100%. A total of 154 relinings were performed during 17 years, with an average of one denture relined every 2.9 years. At year 13 of follow-up, an additional fixture was inserted to modify a patient's mandibular IR-RPDa into overdenture prosthesis.
Conclusions: IR-RPDs are a reliable intermediate solution that can reduce biological and economic costs, while maintaining implant treatment benefits and the ease of RPDs procedures.