Effect of sub‐marginal instrumentation before surgical treatment of peri‐implantitis: A multi‐centre randomized clinical trial

AIM: The present multi‐centre randomized clinical trial with 12 months of follow‐up aimed at studying the added effect of sub‐marginal instrumentation before surgical treatment of peri‐implantitis. MATERIALS AND METHODS: Forty‐two patients diagnosed with peri‐implantitis were recruited. After a behavioural intervention phase including oral hygiene instructions, patients were randomized to either receiving supra‐ and sub‐marginal instrumentation on their affected implants (control group: 21 patients and 29 implants) or only supra‐marginal instrumentation (test group: 21 patients and 24 implants), before undergoing surgery. Changes in the deepest probing pocket depth (PPD) with respect to baseline and a composite outcome of treatment success (no implant loss, no bone loss > 0.5 mm, no bleeding or suppuration on probing [BoP/SoP], and PPD ≤ 5 mm) at the 12‐month examination were regarded as the primary outcomes of the trial. RESULTS: At the 12‐month examination, changes in the deepest PPD with respect to baseline amounted to −2.96 mm in the control group and to −3.11 mm in the test one (MD = −0.16; SE = 0.56; p = .769), while 21.4% of the implants in the control group and 33.3% in the test group presented treatment success (OR = 1.83; SE = 1.15; p = .338). With the exception of a longer non‐surgical treatment duration in the control group (differences in = −14.29 min; SE = 2.91; p < .001), no other secondary (e.g., soft‐tissue recession, keratinized mucosa height, and bone level changes, as well as BoP, SoP, profuse bleeding and implant loss rates) or exploratory (i.e., early wound healing, aesthetics, surgical and total treatment duration, surgery difficulty, intra‐operative bleeding, and adverse events) outcome demonstrated statistically significant differences between groups. CONCLUSIONS: The present multi‐centre randomized clinical trial did not demonstrate an added effect of performing sub‐marginal instrumentation 6 weeks before the surgical treatment of peri‐implantitis. Larger clinical trials are however needed to confirm the present findings (Clinicaltrials.gov: NCT03620331).