The benefit of antimicrobial photodynamic therapy to mechanical debridement in the treatment of smokers with peri-implant diseases: a systematic review and meta-analysis

Antimicrobial photodynamic therapy (aPDT) has been proposed as an adjunctive treatment strategy for peri-implant diseases. This systematic review aimed to determine whether aPDT as an adjunct to mechanical debridement has an additional benefit for smokers with peri-implant diseases. Randomized controlled trials (RCTs), which evaluated the clinical outcomes of mechanical debridement alone versus mechanical debridement + aPDT among smokers, were considered eligible to be included. The primary outcome was bleeding on probing (BOP) and secondary outcomes included probing depth (PD), plaque index (PI), and crestal bone loss (CBL). Meta-analyses using a random-effects model were conducted to calculate the mean difference (MD) with a 95% confidence interval (CI). The quality of evidence was assessed according to Grading of Recommendations Assessment, Development and Evaluation (GRADE). A total of four RCTs (188 participants) were included. The aPDT group showed significantly improved PD (MD =  − 1.26, 95% CI =  − 2.19 to − 0.32, p = 0.008) and PI (MD =  − 10.6%, 95% CI =  − 14.46 to − 6.74%, p = 0.0001) compared with mechanical debridement group at 3-month follow-up. No significant difference in bleeding on probing (BOP) was observed at 3-month follow-up (MD =  − 0.60%, 95% CI =  − 2.36 to 1.16%, p = 0.50). The subgroup analyses on photosensitizers demonstrated significant differences between the two groups on PD (MD =  − 1.23, 95% CI =  − 2.41 to − 0.05, p = 0.04) and PI (MD =  − 12.33, 95% CI =  − 14.74 to − 9.92, p < 0.00001) by the use of methylene blue (MB). Within the limitation of this study, compared with mechanical debridement alone, combined use of aPDT was more effective in reducing PD and PI in smokers at 3-month follow-up. MB was a predictable photosensitizer for aPDT. However, the findings should be interpreted with caution due to the limited number of included studies, methodological deficiencies, and heterogeneity between studies.