Air-polishing in the Treatment of Peri-implantitis - a Randomized Controlled Trial

The project will be conducted as a two-armed randomized controlled clinical trial of 5-year duration in three clinical centers. 80 systemically healthy patients diagnosed with moderate/severe peri-implantitis at ≥1 implant will be enrolled.

Upon enrolment, all patients will receive instructions in oral hygiene measures until adequate plaque control has been established (Plaque Index ≤20%). If required, supraconstructions will be adjusted to facilitate adequate oral hygiene measures. Thereafter, study participants will be randomized into two groups, stratified for smoking (yes/no) and number of implants in need of treatment (single/multiple).

The control group will be subjected to professionally administered non-surgical, mechanical infection control including the use of hand instruments and polishing cups aiming at the removal of all supra-mucosal soft and hard deposits from the target sites. In the test group the aforementioned treatment will be supplemented by the use of an air-polishing device (AirFlow Master, EMS, Nyon, Switzerland) with a specially designed nozzle for sub-mucosal application (PerioFlow Handpiece, EMS, Nyon, Switzerland). Following local anesthesia, the instrument will be used sub-mucosally at all aspects (ie mesial, distal, buccal, lingual) of the affected implant(s) at a power setting reduced to 60% and with a erythritol powder (14 mikrometer, AirFlow Plus Powder, EMS, Nyon, Switzerland). The handpiece will be guided in a circular motion in a corono-apical direction not in contact with the implant surface. Instrumentation time will be limited to 5 seconds at each aspect. Implant-supported supraconstructions will not be removed for the non-surgical treatment. Patients are recalled two weeks later for assessment of patient-experienced outcomes, professional supramucosal cleaning and reinforcement of oral hygiene.

Peri-implant soft tissues will be evaluated at three months. Implant sites with remaining signs of pathology (PPD ≥6 mm and presence of BOP at ≥3 aspects per implant will be subjected to re-treatment according to the initial allocation. The clinical evaluation will be repeated at 6 months. In case of residual signs of pathology, affected sites will be subjected to surgical therapy of peri-implantitis within the subsequent 4 weeks. Full thickness flaps will be elevated and inflamed tissues will be removed. Mineralized deposits on the implant surfaces will be removed with titanium-coated curettes. Surface decontamination will be performed using a rotating titanium brush under irrigation with saline. No bone recontouring of bony walls is intended. Flaps will be sutured to the level of the bone and sutures will be removed after 2 weeks. Implant-supported supraconstructions will be removed for the surgical intervention, if possible.

Maintenance therapy will be provided at 9 and 12 months and based on individual needs during the subsequent follow-up. A renewed evaluation will be performed at 12 and 18 months. Long-term assessments will be carried out annually from years 3 to 5. Should any implant site present with signs of disease progression (increase of PPD >2 mm and additional bone loss >1 mm compared to baseline) at any of the follow-up examinations, the implant will be exited from the study and appropriate additional therapy will be provided.