Periodontitis is a biofilm depended oral infection. It leads to inflammatory destruction of periodontal tissues and if left untreated to tooth loss. Porphyromonas gingivalis (P.g.) is one of the major pathogens associated with the onset and progression of periodontitis. Previous in vitro studies have shown that a proanthocyanidin-enriched extract from Rumex acetosa L. inhibits the adhesion of P.g. and acts in a cytoprotective manner. Since the the bacterial adhesion to oral mucosa cells is a pivotal step for the P.g. mediated tissue destruction, its inhibition may be helpful in preventing the colonization with P.g. or its eradication in P.g. infected patients. Therefore, the aim of this controlled, randomized and double blinded study was to analyze the effects of a Proanthocyanidin-enriched extract from Rumex acetosa L. on the intraoral colonization with Porphyromonas gingivalis in individuals harboring P.g. intramurally.

During screening phase plaque samples of healthy individuals were tested via polymerase chain reaction for the prevalence of P.g..

At baseline those identified P.g. positive participants received a supragingival debridement (professional tooth cleaning) and were randomly assigned to the test- or control-group. Afterwards the study participants are instructed to rinse 3 times per day with 10 ml of either Rumex acetosa L. extract mouth rinse or the placebo mouth rinse for 7 days in addition to their oral hygiene procedures. Plaque samples were taken at different visits (screening, baseline, 2, 4, 7 and 14 days after baseline) and P.g. was identified and quantified by real-time polymerase chain reaction (qrt-PCR). Also the relative quantity of eight other oral pathogenic microorganisms (Aggregatibacter actinomycetemcomitans, Treponema denticola, Tannerella forsythia, Prevotella nigrescens, Prevotella intermedia, Eikenella corrodens, Streptococcus mutans and Candida albicans) and four commensal bacteria (Streptococcus sanguinis, Streptococcus mitis, Veillonella parvula and Actinomyces viscosus) was determined over the whole study period by qrt-PCR. Additionally clinical parameters, i.e. the Approximal Plaque Index (API) and the modified Sulcular Bleeding Index (SBI) were recorded at baseline, 7 and 14 days. For identifying any dysplastic changes and mutations as a potential reaction to the tested mouthwash solutions brushing biopsies of the oral mucosa were taken at baseline and day 7 and were histologically examined.

Inclusion Criteria:

• generally healthy
• periodontally healthy with Periodontal Screening Index ≤ 2

Exclusion Criteria:

• antibiotic therapy within the previous 6 months
• allergies against mouthrinse components
• pregnancy or lactation
• soft tissue lesions (e.g. lichen planus, leukoplakia)
• history of periodontal disease and/ or PSI ≥ 3 or more
• any topical or systemical medication, that potentially influence any immunological parameters
• any systemic disease or medical condition (e.g. diabetes or immunological disorders), that potentially influence the immune response or compromise the study results
• any systemic conditions, that require an antibiotic coverage for routine dental procedures (e.g. endocarditis)