Bacteremia represents the presence of live germs in the blood stream. Patients with gum disease show damaged tissues and seem to be more susceptible to bacteremia. In fact, daily activities such as mastication can induce bacteremia in these patients. Dental procedures related to bleeding also induce bacteremia. However, there are many questions that should be clarified. Among them, clinical strategies that are able to reduce the levels of germs in blood should be determined. This desirable effect could be particularly important for some patients, for example, for those at higher risk for endocarditis. Therefore, this study tested if 0.12% chlorhexidine solution used as a single mouth rinse before dental instrumentation could reduce the levels of bacteria in the blood. In addition, the occurrence and magnitude of bacteremia in patients with gum disease were investigated by two different laboratorial techniques. After receiving verbal and written explanations and after signed the informed consent form, 80 systemically healthy volunteers diagnosed with gum disease having dental plaque and tartar were randomly allocated in one the following groups: a) mouth-rinse use and dental instrumentation and b) dental instrumentation with no mouth rinse. In a preliminary visit volunteers underwent a complete periodontal examination which included clinical measurements (inflammatory and debris accumulation indicators), microbial (tongue and dental plaque samples collected with paper points), saliva (to determine volume and biological indicators) and gingival crevicular fluid sampling (to monitor gingival inflammation profile). In the next visit, dental instrumentation was performed under local anesthesia, after the mouth rinse single use in the most diseased periodontal teeth/quadrant. Blood samples were collected before any dental procedure, 2 and 6 minutes after dental instrumentation. Oral hygiene instructions and periodontal treatment were performed in additional visits according to individual needs. Finally, the relation between bacteremia and several indicators of periodontal status was investigated.

Inclusion Criteria:

• mild to moderate plaque related gingivitis (gingivitis group)
• mild to moderate periodontitis (periodontitis group)
• at least 20 natural teeth
• with no recognized systemic risk related to bacteremia
• no need for antibiotic prophylaxis before dental procedures

Exclusion Criteria:

• systemic diseases or other conditions that could influence the periodontal status;
• alcohol or other drugs abuse;
• orthodontic devices;
• extended prosthetic fixed devices, removable partial dentures or overhanging restorations;
• pregnancy or breast-feeding;
• history of sensitivity or suspected allergies following the use of chlorhexidine;
• antibiotics and/or anti-inflammatory drug use in the three months prior to the beginning of the study;
• regular use of chemotherapeutic antiplaque/antigingivitis products;
• any furcation lesions;
• periodontal treatment performed within six months prior to study initiation;
• unwillingness to return for follow-up.