Analysis of the gradient differences in oral health-related quality of life (OHRQoL) among patients with gingivitis and periodontitis after undergoing Phase I treatment

Background: Periodontal diseases, ranging from gingivitis to periodontitis, can significantly impact a patient's oral health-related quality of life (OHRQoL). While previous studies have established that periodontal treatment improves OHRQoL, limited research has analyzed the gradient differences in improvement between patients with varying disease severity. This study aimed to evaluate and compare the changes in OHRQoL among patients with gingivitis versus periodontitis following Phase I (non-surgical) periodontal treatment. Methods: A prospective cohort study was conducted with 124 participants (64 with gingivitis and 60 with periodontitis) who underwent Phase I periodontal therapy. OHRQoL was assessed using the Oral Health Impact Profile-14 (OHIP-14) questionnaire at baseline and 6 weeks post-treatment. Clinical parameters including plaque index (PI), gingival index (GI), probing pocket depth (PPD), bleeding on probing (BOP), and clinical attachment loss (CAL) were recorded. Statistical analyses were performed using paired t-tests, independent t-tests, and multiple regression analysis. Results: Both groups showed significant improvements in all clinical parameters and OHIP-14 scores after Phase I therapy (p<0.001). However, the magnitude of improvement in OHRQoL differed significantly between groups. Periodontitis patients demonstrated a greater percentage reduction in OHIP-14 total scores (52.8% ± 14.3%) compared to gingivitis patients (27.4% ± 11.2%) (p<0.001). The most substantial improvements for periodontitis patients were observed in the psychological discomfort and physical disability domains, while gingivitis patients showed the greatest improvements in the physical pain domain. Regression analysis revealed that baseline disease severity, represented by CAL and PPD, was the strongest predictor of OHRQoL improvement. Conclusion: Phase I periodontal therapy yields significant improvements in OHRQoL for both gingivitis and periodontitis patients, with a more pronounced effect in patients with periodontitis. These findings suggest that the impact of periodontal treatment on quality of life follows a gradient pattern, with greater benefits observed in patients with more severe baseline disease.