Antimicrobial photodynamic therapy associated to nonsurgical periodontal treatment in smokers: Microbiological results

•The effect of antimicrobial photodynamic therapy (aPDT) is evaluated in smokers with periodontitis.•20 smokers received scaling and root planning (SRP) and SRP associated with aPDT.•Levels of 40 subgingival species were measured before and after periodontal treatment.•The treatments were not able to significantly reduce levels of 40 subgingival species.•Smoking impairs periodontal healing after nonsurgical treatment even associated with aPDT.

BackgroundStudies suggest that smokers present more or greater numbers of potential periodontal pathogens than non-smokers. The aim of this study was to investigate the microbiologic effects of adjunctive aPDT on nonsurgical periodontal treatment in smokers with chronic periodontitis (CP).MethodsTwenty smokers with CP had two contralateral teeth randomly assigned in a split-mouth design to receive SRP (CG) or SRP + a single episode of aPDT (TG), with a diode laser and a phenothiazine photosensitizer. Levels of 40 subgingival species were measured using checkerboard DNA–DNA hybridization at baseline and 1, 4 and 12 weeks after periodontal treatment.ResultsAll 40 bacterial species evaluated were detected in different levels at baseline, with no statistic significant differences between groups. After periodontal treatment, the levels of some bacterial species decreased, while some other species presented an increase. Despite this variation, the statistical analysis was not able to identify significant differences neither at intragroup nor at intergroup comparisons.ConclusionPeriodontal treatment with SRP or SRP + aPDT was not able to reduce levels of 40 subgingival species in smokers with CP. These outcomes indicate that smoking impairs periodontal healing after nonsurgical treatment even associated with aPDT.