Dose Finding Study to Assess Octenidine Mouthwash Concentrations in Comparison to Placebo

Inclusion Criteria: * Patients with mild gingivitis (mean GI: 0.2 - 1.0) * Patients with complete natural "Ramfjord-teeth" or their replacement teeth * Caucasian * Signed Informed Consent Exclusion Criteria: * Patients with severe systemic diseases (diabetes, hepatitis, HIV, tuberculosis, cancer) * Patients who require endocarditis prophylaxis for dental examination and treatment * Caries requiring treatment (e.g. caries with cavity) or other oral diseases (incl. gingival hyperplasia, diseases of the oral mucosa, periodontal screening index PSI \> 2) * Patients with orthodontic appliances and removable dentures * Patients treated with antibiotics less than 3 months prior to the baseline examination at V1 and/or such a treatment planned for the duration of the trial * Patients chronically treated with steroids * Patients who suffer from xerostomia * Patients who regularly smoke more than 10 cigarettes per day * Patients who have a known hypersensitivity or allergy to the test product and its ingredients or to medications that have a similar chemical structure * Participation of the patient in another clinical trial within the last four weeks before enrollment in this trial * Incapability of assessing essence and possible consequences of the trial (e.g. alcoholism) * Pregnant or breastfeeding women * Women with childbearing potential except those who fulfill the following criteria: * Post-menopausal (12 month of natural amenorrhoea or 6 months of amenorrhoea with Serum FSH \> 40 U/ml) * Postoperative (6 weeks after bilateral ovariectomy with or without hysterectomy) * Continuous and correct application of a contraception method with a Pearl Index \< 1% (e.g. implants, depots, oral contraceptives, intrauterine device - IUD)