Immunomodulators, associated or not with systemic antibiotics, to treat periodontitis: A 1‐year multicenter, placebo‐controlled, double‐blind, randomized clinical trial

BACKGROUND: Immunomodulatory agents such as omega-3 (ω-3) and low-dose aspirin (ASA) have been proposed as effective adjuncts in the treatment of periodontitis. However, they still lack long-term studies and head-to-head evaluation with metronidazole (MTZ) and amoxicillin (AMX), the adjunct protocol with the strongest scientific evidence of clinical benefit. This study aimed to evaluate the clinical effects of (ω)-3 and ASA, alone or combined with MTZ + AMX, to treat periodontitis. METHODS: Adults with stage III/IV periodontitis were randomly allocated to receive: (i) subgingival instrumentation (SI) and placebo; (ii) SI with adjunctive MTZ (400 mg) + AMX (500 mg) three times/day for 14 days (ATB); (iii) SI with adjunctive ω-3 (3 g) + ASA (100 mg/day) for 6 months (IM); and (iv) SI with adjunctive ATB and IM (ATB + IM). The patients were followed for 1 year post-therapy. RESULTS: 109 patients were included. At 1 year, 58.6%, 57.7%, and 57.1% of patients receiving ATB, IM, and ATB+IM, respectively, achieved the treatment endpoint [≤4 sites with a probing depth (PD) of ≥5 mm], compared with 23.1% in the SI group (p = 0.023). Each adjunctive therapy resulted in a greater reduction in the number of sites with PD≥5 mm compared with SI (p < 0.05). CONCLUSION: Adjunctive ATB, IM, or ATB+IM each provided clinically meaningful benefits beyond mechanical therapy. The results suggested no added benefit from combining ATB and IM. These findings support MTZ + AMX or ω-3 + ASA, without routine combination, as effective adjuncts in periodontal treatment and provide a basis for precision-based trials and data-driven models to identify patients most likely to benefit from each approach. ensaiosclinicos.gov.br RBR-7nh566t PLAIN LANGUAGE SUMMARY: This study explored whether adding antibiotics or anti-inflammatory supplements (omega-3 and low-dose aspirin), either alone or in combination, could enhance the results of subgingival instrumentation (non-surgical periodontal therapy) in patients with severe periodontitis. All participants received the standard periodontal treatment and were randomly assigned to also take a placebo, antibiotics, omega-3 with aspirin, or a combination of both therapies. After 1 year, patients who received any of the additional therapies showed greater improvements, with fewer sites of deep periodontal pockets, compared with those who received subgingival instrumentation alone. However, combining antibiotics with omega-3 and aspirin did not lead to better outcomes than using either one of them individually. These findings suggest that in patients with more severe forms of periodontitis, adding either antibiotics or omega-3 with low-dose aspirin to standard care can provide meaningful clinical benefits.