The purpose of the study is to evaluate the impact of oral hygiene changes (drastic plaque and gingival inflammation reduction) on markers of systemic inflammation and indicators of oral health related quality of life and other aspects related to overall well-being.

The primary objective is to assess a possible reduction of systemic inflammation as measured through blood bio-markers one month after drastic changes of plaque accumulation. As primary outcome measure, the level of high-sensitive C-reactive protein (hs-CRP) will be assessed.

This study is a single-center, 2 arms, randomized parallel group double-blind clinical trial with one month follow-up, involving patients with no conditions capable of alteration of the systemic inflammatory levels as measured by C-reactive protein (CRP).

Screening will be actuated through a two-step procedure: a careful dental and medical examination will be collected. Subjects with negative history for the conditions tested will undergo blood testing to further confirm the anamnestic findings. Center investigators will document in a screening log reasons for ineligibility or exclusion of subjects. Thus, subjects fulfilling the inclusion criteria will be invited to participate. Clinical center will enroll probands, assigning a unique study subject number and allocating an opaque randomization envelope.

Informed consent will be obtained by the center investigator who will describe the objectives of the study, the alternatives and risks associated with study participation as well as the possibility to withdraw at any time without compromise for the treatment. Consent procedures and documentation of consent will be performed at the screening visit in the national language of the patient and in accordance with local best practice and regulations.

Patients included in the study will undergo a thorough clinical examination aiming at collecting all the data desired (oral and systemic parameters, blood sampling and questionnaires fulfilment). After examinations, the opaque envelope with associated the code of the patient will be opened identifying whether the patient enters Test or Control group.

Patients will also receive a session of professional supragingival scaling and polishing: instrumentation will be performed by a trained dental hygienist/periodontist with great care in performing exclusively coronal maneuver. No instrumentation or exploring of the gingival crevice/ sulcus will be performed.

Subjects in the Test group will receive a thorough session of oral hygiene instruction (OHI) and a full oral hygiene kit.

OHI will be given focusing on electric toothbrushing as first instance and subsequently focusing on interdental cleaning. OHI will be delivered by trained dental hygienist/periodontist.

OHI will be given directly on the patient's mouth. In the first phase the clinician will explain and show the technique to the patient. The patient will be then invited to perform the technique. Each phase will be assisted and monitored by the clinician. Overall, this sequence may be repeated as many times as the clinician would deem appropriate.

Subjects in the control group will be invited to attend another examination in 4 weeks (T28)

Every week, included subjects in the Test group will attend session of OHI re-enforcement and plaque control in order to achieve optimal plaque control. Ideally a value below 20% should be aimed as shown already to be consistent with findings from our research group.

Patients of both groups will undergo clinical examinations, questionnaires and blood withdrawal. The clinical examinations will be performed by examiners blind to group allocation. Participants will be asked by the study coordinators not to disclose to the examiners whether they belong to Test or Control group.

Any periodontal treatment, or professional scaling will be forbidden after the inclusion (T0). For patient allocated in the Test group any pharmacological treatment prescription, or any devices administration different from this study protocol guidelines will be prohibited. In particular, if the patients, in both test or control group, will have to undergo treatment capable of influencing CRP (statins) this will be highlighted and the patient excluded from the study. If withdrawal for prohibited intervention occurs, a new patient enrolment will be activated.

Individuals will be free to quit the study at any time. Patients who will fail to comply with T28 VISIT will be excluded from the study.

Inclusion Criteria:

• male or female, 18 to 79 of age, of any race/ethnicity;
• presence of at least 20 teeth;
• ≤ 2 untreated dental caries;
• presence of relevant plaque accumulation as shown by Full Mouth Plaque Scores (FMBS) >50%.
• presence of relevant periodontal/gingival inflammation as shown by FMBS > 35%

Exclusion Criteria:

• • pregnancy and breast feeding;

  • patients undergoing pharmacological treatment capable of reducing CRP such as statins or chronic anti-inflammatory treatment,
  • current or past (≤ 30 days) systemic or local antibiotic therapy;
  • heavy smokers (over 20 cigarettes per day or pipe or cigar);
  • patients undergoing orthodontic treatment;
  • patients not capable to comply with given instruction or administrative issues related to the study
  • dental or periodontal conditions (e.g., deep caries, periodontal abscess) requiring urgent treatment

Outcome assessor will not be present during explanation of oral hygiene maneuvers. Moreover, participants will be asked not to mention about techniques and group participation to the outcome assessors.