Effects of the Variation in the Time of Systemic Administration of Metronidazole and Amoxicillin Associated to the Non-surgical Therapy of Chronic Periodontitis.

• Background: Peridontitis is a group of diseases with complex bacterial etiology that affects a large proportion of the Chilean and worldwide population. Its treatment, based on an anti-infective mechanical therapy including scaling and root planning procedures, has been highly effective in numerous short and long term clinical trials. The use of adjunctive systemic antibiotics has shown significant improvements in the initial therapy results of specific periodontal disease types or patient profiles.

The synergic combination of Metronidazole plus amoxicillin has been widely and successfully used for the treatment of aggressive and severe chronic periodontitis, demonstrating additional benefits in clinical and microbiological parameters over scaling and root planning alone. However, and despite its proven efficacy, there is a lack of evidence that evaluates the impact of antimicrobials intake at different times of the mechanical treatment, emphasizing the necessity of a study that compares, simultaneously, the variation of the adjunctive antibiotic effects when they are administered in different moments through the periodontal therapy course.