Clinical, bacterial, and inflammatory outcomes of indocyanine green-mediated photodynamic therapy for treating periimplantitis among diabetic patients: A randomized controlled clinical trial

• ICG-PDT significantly improved clinical peri‑implant parameters in DM. • ICG-PDT significantly reduced microbial species in periimplantitis with DM. • No change was seen with ICG-PDT for proinflammatory cytokines in DM. Background This 6-months randomized controlled clinical trial aimed to assess the efficacy of indocyanine green mediated photodynamic therapy (ICG-PDT) as an adjunct to peri‑implant manual debridement (PIMD) versus PIMD alone among Diabetes Mellitus (DM) patients in the treatment of peri‑implantitis. Methods A total of 48 DM patients having 64 implants were treated with either ICG-PDT + PIMD ( n = 35 implants) or PIMD alone ( n = 29 implants). Clinical (probing depth [PD], bleeding on probing [BOP], and plaque index [PI]) and radiographic (peri‑implant crestal bone loss [PCBL]) peri‑implant variables were recorded. Bacterial species including Porphyromonas gingivalis and Treponema denticola were evaluated from peri‑implant plaque biofilms. Levels of interleukin (IL)-1β and IL-6 were assessed after the collection of peri‑implant sulcular fluid. All the evaluations were carried out at baseline, 3- and 6-months. The significance level was set to p < 0.05. Results All clinical parameters significantly reduced within both treatment groups ( P <0.05). Intra-group comparison indicates that there was statistically significant reduction in PD and suppuration for ICG-PDT group ( P <0.05). There was a statistically significant difference in the BOP between ICG-PDT and PIMD groups at both follow-up periods ( P <0.001). However, there was a significant difference for PD ( P = 0.001), suppuration ( P = 0.01), and PCBL ( P = 0.04) on 6 months follow-up between ICG-PDT and PIMD groups, respectively. Only ICG-PDT showed a significant reduction in P. gingivalis and T. denticola on both 3 months and 6 months follow-up compared to baseline. PIMD showed a statistically significant reduction only on 3 months follow-up compared to baseline. This reduction was maintained for both the species when dental implants were treated with ICG-PDT. However, PIMD failed to maintain this reduction until 6 months. Only at 3 months assessment that both treatment groups showed statistically significant reduction in IL-1β and IL-6 with no significant difference between the groups. Both biomarkers failed to maintain the reduction in both groups and significantly increased levels for IL-1β was noted at 6 months follow up Conclusion Multiple application of indocyanine-green mediated photodynamic therapy resulted in improved clinical and microbial parameters among type 2 DM subjects in the treatment of peri‑implantitis. This clinical trial was registered in the ClinicalTrials.gov Protocol Registration and Results System with registration record number: NCT04833569