L-ornithine supplementation in periodontitis treatment yields greater benefits than L-arginine after one year: Part II of a randomized controlled pilot study

Abstract

L-arginine and L-ornithine have previously shown limited short-term immunological benefits in the treatment of periodontitis. The aim of this study was to assess the extended efficacy and durability of the response to L-arginine or L-ornithine as adjuncts to periodontal therapy in adults with periodontitis. Materials and methods In this study, 75 patients who previously received the course of L-arginine or L-ornithine as adjuncts to professional mechanical plaque removal (PMPR) during a preliminary randomized short-term part of a clinical trial (NCT05042024) were assessed clinically and immunologically (nested) after 12 months follow-up. The immunological assay included immunohistochemical identification of densities of CD68 + and CD163 + single-positive gingival macrophages. All patients did not receive new prescriptions or dietary changes and underwent personalized steps of periodontal treatment during observation. Results After one year, patients who received L-arginine or L-ornithine exhibited a significant reduction of sites with periodontal pocket depth of 4–5 mm compared to PMPR (p < 0.0001). L-ornithine was associated with BoP decreasing compared to PMPR and L-arginine (95 % CI of odds ratio [1.12–1.46], p = 0.0002; CI [0.72–0.94], p = 0.004), CD68 + and CD163 + macrophages density increasing compared to PMPR (p < 0.001) and L-arginine (p < 0.05). L-arginine resulted in increased density of CD68 + macrophages and elevated CD68 + /CD163 + ratio compared to the PMPR and L-ornithine; CI [0.41–0.63], p = 0.009, CI [1.45–2.72], p < 0.0001. Conclusion After one year, L-ornithine supplementation demonstrated more pronounced clinical benefits than L-arginine, although both can modulate gingival CD68 + and CD163 + macrophages.