Peri-implantitis is a growing public health problem that can lead to several complications and sequelae, with a serious impact on the health and quality of life of patients and a high cost for healthcare systems.

Bacterial plaque that accumulates around dental implants leads to peri-implant tissue inflammation that ultimately can result in the loss of the implant, significant bone destruction and infection that can reach other regions. Successful implant decontamination is necessary to preserve the implant and several strategies have been suggested for this purpose, however, there is still no fully effective treatment modality and failures and recurrence are relatively frequent.

To better understand this problem and develop more effective treatment strategies, investigators will first conduct an epidemiological study to understand the factors associated with the development of this pathology. Although there is data at an international level, the incidence of this problem in Portugal has not yet been properly studied. Later investigators will conduct a randomized clinical trial to evaluate the 6-week clinical outcomes of patients treated with a photodynamic therapy as an adjuvant versus the use of conventional titanium implant curettes for implant surface decontamination in the non-surgical treatment. Sixty patients/implants with peri-implantitis and within the established criteria, will undergo non-surgical treatment with one of the two protocols being studied. Various clinical and radiographic parameters will be evaluated, such as probing depth, insertion loss, recession, bleeding on probing, suppuration, peri-implant crevicular fluid volume, alveolar bone loss and peri-implantitis microbiome will be evaluated before surgery and 6 weeks after surgery.

Inclusion Criteria:

• patients over 18 years of age;
• patients with one or more implants diagnosed with peri-implantitis rehabilitated for at least one year;
• PI and GI < 25%.

Exclusion Criteria:

• smoking patients;
• patients with uncontrolled periodontitis;
• systemic diseases that influence the study (diabetes);
• inadequate prosthetic rehabilitation that cannot be modified or that prevents access for physical decontamination;
• implants rehabilitated with cemented crowns;
• pregnant and lactating women;
• previous surgical intervention at the same site;
• therapy with non-steroidal anti-inflammatory drugs (NSAIDs), antibiotics or immunosuppressants in the last 3 months;
• patients previously undergoing chemotherapy or radiotherapy;
• PI and IG > 25%;
• uncooperative patients.