Clinical peri-implant health and biological bone marker levels in tobacco users treated with photodynamic therapy

•A 6-month clinical study was performed.•PDT helped in reducing clinical inflammation around dental implants among tobacco smokers.•Tobacco smoking could interfere in the reduction in bone biological biomarkers. What impact does tobacco smoking have on photodynamic therapy (PDT) outcome is still unknown. The aim of the present clinical trial was to evaluate the clinical, radiographic, and biological bone markers after provision of PDT in cigarette, e-cigarette, and never-smokers with peri-implantitis (PI) at 6 months post treatment. Twenty-five healthy patients with PI were divided into three groups: Group I: cigarette smokers; Group II: e-cigarettes users; Group III: never-smokers. Full-mouth mechanical debridement with adjunctive methylene blue-mediated PDT was performed. Clinical recordings included peri-implant plaque index (Pi), bleeding on probing (BOP) and probing depth (PD). Peri-implant sulcular fluid was collected for the assessment of biological bone biomarkers including receptor activator of nuclear factor-ligand (RANK-L) and osteoprotegrin (OPG). All assessments were performed at baseline, 3 months and 6 months. P-value of