Peri-implant mucositis (PM) over dental implants is a highly prevalent disease characterized by inflammation of the peri-implant mucosa without loss of supporting bone around implants. If untreated, PM may progress into peri-implantitis, which may ultimately lead to implant loss. Multiple clinical studies have described a cause-effect relationship between the accumulation of biofilm and the development of PM and therefore effective oral hygiene practices and professional biofilm control are fundamental in their prevention and management. As it was stated in the latest expert consensus on the prevention and treatment of peri-implant diseases, up to date, the treatment of PM includes mechanical professional cleaning associated with oral hygiene instructions (OHI). However, the impact of OHI by itself is not known. This randomized clinical trial over 56 patients aims to identify if there is any superiority of individualized OHI and mechanical/physical instrumentation over OHI alone. The main objective is to evaluate the resolution of the disease, by means of reduction of modified bleeding index (mBI) 1 and 3 months after treatment. Secondary objectives include evaluating microbiological changes and determining if the extent of inflammation measured as the initial mBI could have any impact on PM resolution after different treatment modalities.In addition, the hypotheses formulated are as follows;

• The proper oral hygiene measures conducted by the patient after individualized OHI will achieve resolution of PM in a clinically relevant proportion of patients.
• The proper oral hygiene measures conducted by the patient after individualized OHI will reduce the expression of peri-implant pathogens as much as the combination of individualized OHI and professional mechanical debridement in a clinically relevant proportion of patients.
• The proper oral hygiene measures conducted by the patient after individualized OHI will reduce mBI as much as the combination of individualized OHI and professional mechanical debridement in a clinically relevant proportion of patients.
• The extent of inflammation measured as the mBI could be related with the degree of resolution of the disease according to the treatment.

Inclusion Criteria:

1. Presence of, at least, one titanium implant that have been more than one year in function and exhibits PM, defined as bleeding on gentle probing (0.20 N) in at least one peri-implant site.
2. No signs of loss of supporting bone after initial bone remodelling. In cases where baseline radiograph is available, it will be used for comparison, otherwise a maximum of 2 mm of crestal bone loss will be accepted
3. Presence of >1 mm of keratinized peri-implant mucosa.
4. Absence of systemic diseases that could influence the outcome of the therapy (i.e. controlled diabetes, with HbA1c<7, patients will be included).
5. Non-smoker or light smoking status in smokers (<10 cigarettes/day)

Exclusion Criteria:

1. Untreated periodontal conditions.
2. Pregnant or lactating women.
3. Patients who received systemic antibiotics in the last 3 months.
4. Patients who received treatment of PM in the past 3 months.
5. Patients receiving corticoids or medications known to have effect on gingival growth (i.e., calcium channel antagonists, immunosuppressants or antiepileptic drugs)

The results obtained are expected to be published in both national and international journals. In addition, the results will be disseminated national and international scientific events.