Clinical and Microbiological Effects of Weekly Supragingival Irrigation with Aerosolized 0.5% Hydrogen Peroxide and Formation of Cavitation Bubbles in Gingival Tissues after This Irrigation: A Six-Month Randomized Clinical Trial

Abstract

Introduction: The study investigated the effect of weekly supragingival irrigation with aerosolized 0.5% hydrogen peroxide (H₂O₂) solution as a maintenance periodontal therapy on clinical and microbiological parameters in patients with chronic periodontitis. The other purpose was to investigate whether cavitation bubbles can penetrate not only into periodontitis-damaged tissues but also into ex vivo porcine healthy periodontal tissues.

Materials and methods: The study included 35 systemically healthy patients with chronic periodontitis (CP). After nonsurgical periodontal debridement (NSPD), all patients were randomized into two groups: the Control group (NSDP alone, n = 18) and the Test group (NSDP plus supragingival irrigation, n = 17). Clinical (Approximal Plaque Index (API), Bleeding Index (BI), and Modified Gingival Index (MGI)) and microbiological (Polymerase Chain Reaction technology (using a micro-IDent® kit)) measurements were performed at the initial time point, 3 months, and 6 months after NSPD. The impact of supragingival irrigation on diseased gingival tissues of CP patients (n = 5) and on ex vivo porcine healthy gingival tissue samples (n = 3) was evaluated to estimate morphological changes in healthy and diseased gingival tissues.

Results: Morphological data revealed that supragingival irrigation caused the formation of cavitation bubbles in diseased gingival tissue of CP patients and in healthy porcine gingival tissues. The decrease in API, BI, and MGI scores after 6 months in the Test group significantly (p ≤ 0.01, p ≤ 0.05, and p ≤ 0.01, respectively) exceeded that in the Control group. Test group patients demonstrated a decrease in periodontal sites showing Pocket Probing Depth > 4 mm and, after 6 months, a statistically significant decrease in the proportion of periopathogenic bacteria.

Conclusion: The effectiveness of mechanical periodontal treatment combined with weekly supragingival irrigation with aerosolized 0.5% H₂O₂ solution on clinical and microbiological parameters of periodontal tissues of periodontitis patients is reliably higher than that of mechanical periodontal debridement alone. It has been found that cavitation bubbles as a result of irrigation with the aerosolized 0.5% hydrogen peroxide solution can form not only in periodontal tissues of periodontitis patients but also in ex vivo porcine healthy gingival tissues.

Figure 1

Proportions of patients (%) with low and high bacteria levels at the initial time point, 3 months, and 6 months of following up sorted by periopathogen and control versus test. ^∗Within-group differences: 0.005 < p ≤ 0.05 (between initial time point and follow-up visits). ⁺Within-group differences: p ≤ 0.005. ^#Between-group differences: 0.005 < p ≤ 0.05.

Figure 2

Microscopic study of the investigated human and porcine gingival tissues. (a, c) Healthy porcine gingival tissue with regular histological structure; (b, d) the investigated porcine gingival samples show cavities of irregular shape and size (arrows) in the connective tissue created after the irrigation procedures; (e, f) gingiva of periodontitis patients with prominent infiltration of inflammatory cells in the connective tissue beneath the epithelium; (g, h) irrigated gingiva of periodontitis patients shows spherical bubbles (arrows) in the connective tissue and a decreased infiltration of inflammatory cells. Arrowheads indicate blood vessels. Scale bars: (a, b, e, g) 500 μm; (c, d, f, h) 100 μm.