Renvert 2011.

Methods	6‐month follow‐up, randomised, parallel group study. Blinded outcome assessor. No withdrawals.
Participants	Patients having at least 1 implant affected by peri‐implantitis, showing bone loss > 3 mm, PPD > 5 mm, BOP and/or pus. Exclusion criteria were poorly controlled diabetes mellitus, use of anti‐inflammatory prescription medications, or antibiotics within the preceding 3 months or during the study, use of medications known to have an effect on gingival growth and subjects requiring prophylactic antibiotics. Adults treated at the at the Specialty Clinic for Periodontology, Kristianstad, Sweden. 42 patients enrolled (21 in each group) and results given for 42.
Interventions	Before enrolment in the study, any periodontal lesions at remaining teeth were treated. Before the treatments, the supra‐structures were removed. One group was treated with an air‐abrasive device (Perio‐Flow®, EMS, Nyon, Switzerland). The nozzle was placed in the pocket and used for approximately 15 seconds in each position circumferentially around the implant. Careful attempts were made to cover the full circumference of the implant. The Perio‐Flow® device utilizes a 25 mm hydrophobic powder and a flexible tip allowing access to periodontal and implant pockets. The other group was treated with an Er:YAG laser (Key Laser 3 Perio, KaVo, Biberach, Germany) at an energy level of 100 mJ/pulse and 10 Hz (12.7 J/cm2) using a cone‐shaped sapphire tip. The instrument tip was used in a parallel mode using a semicircular motion around the circumferential pocket area of the implant. Routine local anaesthesia was used as needed.The trial included implants with machined (Brånemark System®) or medium rough surfaces (Astra).
Outcomes	Implant failure, recurrence of peri‐implantitis, peri‐implant marginal bone level changes, PPD, plaque, BOP, bleeding index at baseline and 6 months.
Notes	Authors provided data for patients outcomes: changes in probing pocket depth and recurrence of peri‐implantitis.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "The randomized allocation was performed using a computer software program (SPSS Inc., Chicago, IL, USA)."
Allocation concealment (selection bias)	Unclear risk	Quote: "A clinician not involved with the study sequenced the study subjects to the therapy allocated." No reply to further request of clarifications.
Blinding (performance bias and detection bias) All outcomes	Low risk	Quote: "When performing their study tasks, the study examiner (M. N.) and the therapist (C. L.) were not jointly present with the study subjects. Study subjects were instructed not to discuss therapy with the study examiner. The study examiner was unaware of study treatment allocations, and performed all clinical measurements."
Incomplete outcome data (attrition bias) All outcomes	Low risk	No drop‐outs.
Selective reporting (reporting bias)	Unclear risk	Data data at patient level not presented.
Other bias	Low risk	None apparent. Interestingly the trial was sponsored by both biomaterial manufacturers whose products were compared.