Ten-year hard and soft tissue results of a pilot double-blinded randomized controlled trial on immediately loaded post-extractive implants using platform-switching concept

Abstract

Aim: To evaluate the 10-year post-loading radiological and esthetic outcomes of implants inserted in post-extraction sites and restored with or without platform-switching protocol.

Material and methods: Twenty-two patients were scheduled for maxillary post-extractive implant, using a 13 mm in length and 5.5 mm in diameter implant (Global, Sweden & Martina, Padua, Italy). They randomly received definitive restorations using platform-switching concept (abutment 3.8 mm in diameter: test group) or standard restoration (abutment 5.5 mm in diameter: control group). Outcome measures were survival rates of implants and prostheses, peri-implant marginal bone loss and periodontal indices 10 years after prosthetic loading. Moreover, esthetic parameters including soft tissue buccal peri-implant mucosal levels (REC) and mesial and distal papilla height (PH) were taken at definitive restoration, 2 and 10 years thereafter.

Results: Nineteen implants were analyzed after 10 years of follow-up. No implants nor prostheses failed. The postoperative radiographs demonstrated an overall mean bone loss of 0.18 ± 0.14 mm in the test group and of 0.80 ± 0.40 mm in the control group (P = 0.00108). Test group showed 0.23 ± 0.51 mm of REC gain and PH was of 0.21 ± 0.33 mm on average. On the other side, the control group presented a REC = -0.59 ± 0.80 mm with PH = -1.12 ± 0.55 mm, demonstrating a slight continuous soft tissue shrinkage during the entire follow-up. The mean values were statistically significant different between test and control group for both REC gain (P = 0.01174) and PH (P = 0.0009).

Conclusions: With the limitations of this study, immediate single implant restorations rehabilitated with platform-switching protocol may provide peri-implant alveolar bone-level stability and avoid continuous soft tissue shrinkage after 10 years of prosthetic loading compared to a platform-matching restoration. Further studies involving larger sample sizes are required to confirm these preliminary results.

Keywords: marginal tissue reaction; non-functional immediate loading; platform switching; post-extractive implant.