ABSTRACTObjectivesThe number of dental implants is constantly on the rise, and inflammation of their surrounding tissues is an increasing problem. In this randomized controlled trial, we investigated the effects of antibacterial dual‐light photodynamic therapy (aPDT) in peri‐implant disease in reduction of inflammation in the peri‐implant tissues.Material and MethodsForty patients with newly diagnosed peri‐implant disease were recruited. The diagnoses were established clinically and by radiological bone loss (RBL). Dual‐light aPDT was provided by indocyanine green mouth rinsing and 50:50, 405 nm, and 810 nm light applicator. The treatment group (n = 20) was randomized to use aPDT treatment at home for 4 weeks. The treatment was carried out once daily for 2 weeks, then twice daily for the next 2 weeks. The control group (n = 20) continued enhanced self‐care during the study period. Traditional measurement methods around the implant were measured at the beginning, at 2 weeks and at 4 weeks.ResultsDuring the study period, VPI decreased in both groups. In the treatment group BOP decreased from mean (SD) 4.7 ± 1.3 to 1.8 ± 1.6, p < 0.0001, but no change was observed in the control group (3.5 ± 2.3 to 3.0 ± 2.3, p = 0.39). In the aPDT treatment group aMMP‐8 decreased from mean (SD) 100 ± 41 to 72 ± 38, p = 0.027, but not in the control group (86 ± 54 to 86 ± 60, p = 0.38).ConclusionsRegularly applied dual‐light aPDT reduces inflammation in the dental implant adjacent tissues. Dual‐light aPDT approach holds promise as an effective home care tool for implant patients.