Clinical, host-derived immune biomarkers and microbiological outcomes with adjunctive photochemotherapy compared with local antimicrobial therapy in the treatment of peri-implantitis in cigarette smokers

•Peri-implant, radiographic, cytokines and bacterial levels were assessed after PCT and LAT.•Hard tissue changes were not indicated for both PCT and LAT.•Both PCT and LAT showed equal efficacies in improving peri-implant inflammation in smokers. The aim of this study was designed to assess the peri-implant oral hygiene parameters, clinical, radiographic, host-derived immune biomarkers and microbiological levels after photochemotherapy (PCT) and local antibiotic therapy (LAT) in peri-implantitis lesions among cigarette smokers. Fifty current cigarette smokers with peri-implantitis were divided into two groups: PCT and LAT. Test implants received PCT that consisted of toluidine blue photosensitizer and application of 660 nm diode laser with a total of 100 mW power and 124.3 W/cm2 energy using continuous mode of irrigation for 60 s. Control implants received one-unit subgingival application of metronidazole gel in viscous consistency. Clinical measurements included the assessment of plaque scores (PS), bleeding on probing (BOP), probing depth (PD) and clinical attachment level (CAL). Intraoral standardized digital peri-apical radiographs were taken at baseline and at 12 months. Interleukin (IL)-1β and matrix metalloproteinase (MMP)-1 in the PICF were determined using the manufacturers guide from one-step enzyme-linked immunosorbent assay. Real-time polymerase chain reaction (PCR) for Parvimonas micra, Porphyromonas gingivalis and Tannerella forsythia was performed and counts evaluated at baseline, 3, 6 and 12-months. Plaque scores reduced in both groups (p 0.05). CAL did not change over the period and between both groups (p > 0.05). The differences from baseline to 12 months and between the groups for mesial and distal crestal bone levels did not show any statistical significance (p > 0.05). The levels of IL-1β significantly dropped from baseline to 12 months in the LAT group (p