Purpose: To evaluate how periodontitis patients perceive the outcome after long-term supportive therapy. Materials and Methods: 281 patients (150 women/131 men) with a mean age of 55 years (range: 45-86 years) were randomly selected and consecutively interviewed using a questionnaire designed for laypersons. All patients had shown high compliance with the recommended supportive periodontal therapy (SPT) for up to 16 years (mean observation period: 12.5 years). Statistical evaluation was performed using the 2-sided t-test. Results: A very high degree of confidence in the periodontal treatment (mean: 9.24, range 0-10) was found. Women noticed a higher positive impact on their social environment (P 0.05). Patients who underwent SPT 3 years showed a higher positive perception of treatment success than patients with SPT > 3 years (P 0.01) and reported a greater impact on appearance (P 0.01). Regenerative treatment demonstrated advantages over resective open flap debridement (OFD) procedures (P 0.05) and scaling and root planing (SRP) (P 0.05). However, treatment costs (P 0.001) and time required (P 0.01) for regenerative procedures were perceived as a burden. Periodontal treatment by a specialised team led to a significant reduction in the patients' complaints (P 0.01). The SPT interval did not influence patients' perception of treatment success. Conclusions: Systematic periodontal therapy with subsequent SPT met the patients' demand to preserve oral health. Regenerative procedures prompt the perception in patients of better remission of periodontitis symptoms. Further trials should investigate clinical results of periodontal therapy regarding patient expectations. Keywords: compliance, lifestyle, long-term maintenance, patients' perception, Periodontal Health Quality of Life (PHQoL), regenerative therapy