Marked differences were observed in the composition of supra- and subgingival biofilm between healthy and diseased implants. The microbiota associated with peri-implantitis was comprised of more periodontal pathogenic bacterial species, including the supragingival biofilm.

There is substantial evidence supporting the role of certain oral bacteria species in the onset and progression of periodontitis. Nevertheless, results of independent-culture diagnostic methods introduced about a decade ago have pointed to the existence of new periodontal pathogens. However, the data of these studies have not been evaluated together, which may generate some misunderstanding on the actual role of these microorganisms in the etiology of periodontitis. The aim of this systematic review was to determine the current weight of evidence for newly identified periodontal pathogens based on the results of "association" studies. This review was conducted and reported in accordance with the PRISMA statement. The MEDLINE, EMBASE, and Cochrane databases were searched up to September 2013 for studies (1) comparing microbial data of subgingival plaque samples collected from subjects with periodontitis and periodontal health and (2) evaluating at least 1 microorganism other than the already-known periodontal pathogens. From 1,450 papers identified, 41 studies were eligible. The data were extracted and registered in predefined piloted forms. The results suggested that there is moderate evidence in the literature to support the association of 17 species or phylotypes from the phyla Bacteroidetes, Candidatus Saccharibacteria, Firmicutes, Proteobacteria, Spirochaetes, and Synergistetes. The phylum Candidatus Saccharibacteria and the Archaea domain also seem to have an association with disease. These data point out the importance of previously unidentified species in the etiology of periodontitis and might guide future investigations on the actual role of these suspected new pathogens in the onset and progression of this infection.

Subjects with GAgP significantly benefit from the adjunctive use of MTZ and AMX. The short-term advantages are observed in the clinical and microbiological parameters.

Significant advantages are observed when systemic antibiotics are combined with SRP in the treatment of smokers with chronic periodontitis. The greatest benefits in clinical and microbiological parameters are achieved with the use of SRP+MTZ+AMX.

Mechanical therapies alone were effective in treating mucositis and peri-implantitis over a period of 3 months. The open debridement procedure showed clinical and microbiological benefits on the treatment of peri-implantitis and could be safely used as a standard control group for future studies.

The adjunctive use of MTZ+AMX offers short-term clinical and microbiological benefits, over SRP alone, in the treatment of non-smokers subjects with generalized ChP. The added benefits of MTZ were less evident.

Metronidazole alone or with amoxicillin as adjuncts to non-surgical treatment of chronic periodontitis: a 1-year doubleblinded, placebo-controlled, randomized clinical trial AbstractAim: To evaluate the effects of the adjunctive use of metronidazole (MTZ) or MTZ + amoxicillin (AMX) in the treatment of generalized chronic periodontitis (ChP). A secondary aim was to examine a possible added effect of chlorhexidine to these therapies. Methods: One hundred and eighteen subjects received scaling and root planing (SRP) only or with MTZ [400 mg/thrice a day (TID)] or MTZ+AMX (500 mg/ TID) for 14 days. Half of the subjects in each group rinsed with 0.12% chlorhexidine twice a day (BID) for 2 months. Subjects were clinically monitored at baseline, 3, 6 and 12-months post-therapy. Results: The two antibiotic groups showed lower mean number of sites with probing depth (PD) 5 mm and fewer subjects exhibiting 9 of these sites at 1-year post-treatment. Logistic regression analysis showed that antibiotics were the only significant predictors of subjects presenting 4 sites with PD 5 mm at 1 year (MTZ+AMX: OR, 13.33; 95%CI, MTZ: OR, 7.26; 95%CI,.30/p = 0.0004). The frequency of adverse events did not differ between the two antibiotic treatments (p > 0.05). The chlorhexidine subgroups showed a trend (p > 0.05) to present fewer residual sites 5 mm compared with the placebo subgroups at 1 year. Conclusion: Treatment of generalized ChP is significantly improved by the adjunctive use of MTZ+AMX and MTZ.

Despite the fact that several clinical studies have shown additional benefits when certain systemic antibiotics are used as adjuncts to periodontal treatment, clear guidelines for the use of these agents in the clinical practice are not yet available. Basic questions concerning the use of systemic antibiotics to treat periodontitis remain unanswered, such as: which drug(s) should be used; which patients would most benefit from treatment; which are the most effective protocols (i.e. doses and durations); and in which phase of the mechanical therapy should the drug(s) be administered? Although not all of those questions have been directly addressed by controlled randomized clinical trials, recent concepts related to the ecology of periodontal diseases, as well as the major advances in laboratory and clinical research methods that have occurred in the past decade, have significantly broadened our knowledge in this field. This article endeavored to provide a 'state of the art' overview on the use of systemic antibiotics in the treatment of periodontitis, based on the most recent literature on the topic as well as on a compilation of data from studies conducted at the Center of Clinical Trials at Guarulhos University (São Paulo, Brazil) from 2002 to 2012.