Peri-implant Marginal Bone Loss Reduction with Platform-switching Components: 5-Year Post-loading Results of an Equivalence Randomized Clinical Trial

Aim: To compare the clinical performance and marginal bone levels of implants restored with platform-switching (PS) or platform-matching (PM) abutments.

Materials And Methods: Adult patients missing two or more adjacent teeth in the posterior mandible received 2-4 CAMLOG SCREW-LINE implants and were randomly allocated to the PM or PS group, receiving the corresponding prosthetic components from surgery onwards. Implants were conventionally loaded with single cemented crowns. Patients were followed annually for 5 years. Outcome measures were marginal bone level changes, implant survival, performance of the prosthetic components and clinical parameters plaque index, sulcus bleeding index and pocket probing depth.

Results: Thirty-three patients received 72 implants in the PM group, and thirty-five patients received 74 implants in the PS group. Sixty patients attended the final appointment, 31 had received PS components and 29 had received PM components with 65 and 63 implants, respectively. Global survival rate was 96.6% with no differences between groups (p = 0.647). After 5 years of functional loading, PS restored implants presented 0.23mm (95% CI: [0.03, 0.43], p = 0.025) lower marginal bone level changes. The two groups were declared non-equivalent.

Conclusion: Patients requiring implant supported restorations in healed bounded or free end edentulous gaps of the mandible benefit from the use of PS components in terms of peri-implant marginal bone level maintenance, though it may not be clinically noticeable.