A pattern of peri-implantitis affecting middle implants in 3-implant splinted prostheses.

Background: Previous investigators have noted an increased risk of crestal bone loss and failure of the middle implant of 3-implant-splinted (3-IS) fixed dental prostheses (FDPs). Possible causes have included ill-fitting prostheses, unhygienic prosthetic contours, and discrepancies in prosthetic platform heights.

Methods & results: We identified four cases in which the middle implant of a 3-IS multiunit FDP suffered advanced bone loss, ultimately leading to implant removal. While more than one possible risk for implant failure existed in each case, a common thread was that the prosthetic platform of the middle implant for all patients was coronally positioned relative to the corresponding mesial and/or distal implants.

Conclusions: Splinting three adjacent implants into one prosthesis may add risk for a variety of reasons possibly including small differences in the heights of the three prosthetic tables.

Key points: Why are these cases new information? Our observations suggest that discrepancies between implant prosthetic platforms supporting 3-implant splinted, multiunit FDPs may be an added risk factor for middle implant failure. What are the keys to successful management of these cases? It is possible that small differences in apico-coronal implant positioning with 3-implant splinted multiunit FDPs may affect the success of the middle implants. What are the primary limitations to success in these cases? There is limited literature involving precise protocols and long-term outcomes of 3-implant splinted implant restorations. Studies comparing 3-implant splinted FDPs to other configurations are needed.