The purpose of this study is to assess the clinical and microbiological effectiveness of the moxifloxacin compared with the combination ciprofloxacin - metronidazole, when used as adjunctive therapy to scaling and root planning for the treatment of advanced chronic periodontitis.

Periodontitis is an endemic inflammatory disease caused by a mixed bacterial biofilm infection that is followed by destruction of tooth supporting tissues. Standard of care consists of lifelong mechanical removal of the biofilm. However, outcome is variable. According to recent EFP and AAP reviews, adjunctive antimicrobial therapy may be beneficial.However, bearing in mind that Colombia has reported the frequent presence of Enterobacteriaceae (Klebsiella and Enterobacter) in subgingival plaque of patients with chronic periodontitis, the response to treatment may be different.The enteric have shown resistance to amoxicillin, amoxicillin / clavulanate, metronidazole and tetracycline in studies conducted in the United States, Norway, Brazil and Colombia.Although the combination ciprofloxacin metronidazole has been recommended in the dental literature are not known publications that demonstrate its effectiveness against periodontopathogens and enteric present in subgingival plaque of subjects with chronic periodontitis.On the other hand, some in vitro studies have demonstrated the effectiveness of moxifloxacin against periodontopathogens, but was not aware of any clinical trials or in vitro studies on antibiotic resistance and susceptibility to enteric isolated subgingival plaque of patients with chronic periodontitis in which employs moxifloxacin.

Inclusion Criteria:

• 18 years of age and up
• clinical and radiographic signs of severe (CAL 5 mm or more) chronic periodontitis.
• at least 20 natural teeth in situ
• pocket probing depths (PPDs) of ≥ 5 mm at a minimum of eight tooth sites
• willingness to participate and to be available at all times required for participation
• over 30% of the teeth present must have a PPDs)≥ 4 mm and insertion loss ≥ 5 mm evaluated by an experienced periodontist
• informed consent signed by the patient

Exclusion Criteria:

• if they (or parents or siblings) show confirmed or assumed allergies or hyper-sensitive skin reactions against moxifloxacin, ciprofloxacin (or other quinolones as listed in the "summary of product characteristics, Version Juli 2005"), metronidazole (or other 5-nitroimidazoles and ingredients of Flagyl® 400mg as listed in the "summary of product characteristics, Version Juli 2007"), systemic diseases or conditions as listed in the above mentioned "summary of product characteristics"
• subjects who have undergone antibiotic therapy three months before the start of the study under interrogation
• have Down's syndrome
• known AIDS/HIV
• regularly take systemic medication affecting the periodontal conditions, e.g. phenytoin, nifedipine, and/or steroid drugs
• professional periodontal therapy during 6 months prior to baseline
• require antibiotic treatment for dental appointments
• are pregnant or breastfeeding