Longitudinal Evaluation of Regenerative Treatment of Peri-implantitis Assited by Er,Cr:YSGG Laser: up to 10 Years Follow-up

Research design and Methods This double-blinded, two-armed and placebo-controlled study will be conducted at Guarulhos University (UNG; Guarulhos/São Paulo, Brazil). This protocol was elaborated according to the Standard Protocol Items: Recommendations for Interventional Studies (SPIRIT) guidelines (Chan et al. 2013). This trial will be conducted according to the principles of the Declaration of Helsinki for studies in humans. The protocol will be approved by the Institutional Review Board of UNG. All eligible volunteers will be informed about the nature, potential risks and benefits of their participation in this study and will sign a term of free and informed consent.

Subject population and inclusion/exclusion criteria Systemically healthy volunteers with untreated peri-implantitis will be selected from the Oral Implantology Clinic - UNG. Subjects will be selected according to the following inclusion criteria: males and females from 18-70 years old, in general good health, with at least one dental implant in function for at least one year with untreated peri-implantitis defined as: presence of bleeding and/or suppuration on gentle probing, probing depths (PD) ≥ 6 mm, and bone levels ≥3 mm apical of the most coronal portion of the intraosseous part of the implant (Berglundh et al. 2018). The exclusion criteria will be as follows: subjects with ≥ 6 sites with PD ≥5 mm or individuals that received periodontal treatment within three months prior to entering the study, inability to perform proper supramucosal and supragingival plaque control (e.g., due to improper restoration design or lack of skills), poorly adapted implant-supported restoration, diabetes, pregnancy, nursing, history of allergies to MTZ and AMX, or any other ingredient of oral care products, alcohol or drug abuse, any systemic diseases that could affect post-operative healing or that required antibiotic premedication for routine dental therapy, long-term use of mouthrinses, anti-inflammatory medications, or any other drug that could interfere with the study outcomes within three months prior to entering the study and use of antibiotics within six months prior to entering the study.

Interventions At baseline, all volunteers will fill out a structured questionnaire comprised of information about demographic, oral and general health data. Subsequently, they will be submitted to a complete periodontal clinical assessment and collection of submucosal biofilm. In addition, oral hygiene instructions (OHI), full-mouth supramucosal plaque removal, and prophylaxis will be provided. Subgingival scaling will be administered to all sites exhibiting PD ≥4 mm. Partial and total fixed prosthesis on implants will be removed before treatment. Subjects will be given a soft bristle adult toothbrush, dental floss, and interdental toothbrushes, according to their individual needs.

Subsequently, each volunteer will be randomly allocated to one of the following therapeutic groups:

(i) Control: anti-infectious surgical treatment plus placebo. (ii) Test: anti-infectious surgical treatment plus systemic MTZ (400 mg) and AMX (500 mg).