There are not published studies evaluating the incidence, nature, magnitude and/or duration of bacteremia after periodontal treatment. The pre-surgical antibiotics have been studied particullary over Gram positive bacterial but not over gram negative bacterial and their secondary effects over the systemic pro-inflamation. Objective: to evaluate the efficacy of intensive periodontal therapy and pre-medication with oral amoxicilline on inflammatory bio-markers and the incidence, duration and magnitude of bacteremia in patients with chronic periodontitis.

A randomized, triple-blind clinical trial with 90 participants will be conducted (age range18-65 years) with chronic periodontitis will be received and intensive periodontal therapy under local anaesthesia. Participants will be randomly assigned using block randomization in two groups. Test group premedication with 2 gr of oral amoxicilline 1 hour before periodontal treatment and control group with 2 gr of placebo 1 hour before treatment. High-sensitivity assays will be used to quantify serum concentrations of inflammatory marker (Interleukin (IL-1β), Interleukin 6, Tumour necrosis factor α, MCP 1, C Reactive Protein (CRP), plasma haemostatic (D-dimer), and von Willebrand factor antigen (r-WF:Ag).

Samples of blood will be taken at baseline (before treatment), inmediatly finished the treatment, 30 minutes and 1, seven and 30 days after treatment to asses bacteremia and inflammatory markers.

Bacterial isolation and identification: Bacterial colonies will be isolated on both selective and nonselective culture medium for aerobes and anaerobes bacteria. Sensitive Digital quantitative polymerase chain reaction will be used to quantify bacteria.

Concentrations of CPRus, inflammatory, haemostatic and endotellial cell activation markers will be quantified by high-sensitive enzyme liked inmunosorbent assays according to the manufacturer´s protocol. For each cytokine, comparisons between groups will be made by time. The levels of cytokines expressed in picograms will be transformed into international units for the statistical analysis.

In case it follows a normal distribution, an analysis of variance (ANOVA) for repeated measurements between groups with post hoc corrections made by Wilcoxon test will be used. In case it doesn´t follow a normal distribution, Non parametric test such as Friedman´s test will be used. Values of p<0.05 will be accepted as statiscally significant.

Inclusion Criteria:

• Subjects with chronic periodontitis (Ameriacam Academy of Periodontology 2015), having at least 2 teeth for quadrant with periodontal probing pockets depth ≥ 5 mm.

Exclusion Criteria:

• Pregnant and lactating women, Diabetes, hypertension, Obesity, Allergy to penicillin, consumption of systemic antimicrobial or anti-inflamatory drugs in the last 2 months, Autoimmune diseases, patients with medical conditions that required antibiotic premedication such as prosthetic heart valve replacement, skeletal joint replacement, previous history of infective endocarditis and history of rheumatic fever.

Participant, care provider, Investigator, Outcomes Assessor and Statistic. The treatment codes of the study were not accessible to the investigators and to the examiner until the data will be analyzed.