Clinical and microbiological effects of aPDT compared with systemic Amoxicillin/ Metronidazole in the treatment of chronic periodontitis in smokers: a randomized controlled study

AIM: The aim of this study was to evaluate the clinical and microbiological effects of Metronidazolecombined with Amoxicillin (MTZ+AMX) and multiple applications of antimicrobial photodynamic therapy (aPDT) as adjuvant treatment of smokers with chronic periodontitis. METHODS: A double-blind controlled, randomized clinical trial was conducted in 51 smoking patients who received: SRP Group (n=17): scaling and root planning and placebo; MTZ+AMX Group (n=17) and SRP with systemic use of Metronidazole (400 mg 3 X per day 7 days) and Amoxicillin (500 mg 3 X per day 7 days); aPDT Group (n=17): SRP and three aPDT applications at two sites (one moderate and one deep pocket) per quadrant, immediately 48 and 72 hours after scaling and MTZ and AMX (placebo) during 7 days. Clinical and microbiologic examinations were performed at Baseline, 3 and 6 months post-therapy. Clinical parameters of visible plaque index (VPI), bleeding on probing (BOP), probing depth (PD), and clinical attachment level (CAL) were measured. Samples were collected from a subgingival pocket ≥ 4mm ≤ 6mm (pocket moderate) and another ≥ 7mm (pocket deep) in each quadrant of each patient, in the groups SRP, MTZ+AMX and aPDT. The APDT was carried out using methylene blue and the laser low level after 1 minute (GaAlAs 660 nm, 100 mW, 48 seconds, 160 J/cm²) 48 and 72 hours immediately after treatment, into the same sites of the collection. For microbiological analysis, three periodontal pathogens were assessed by polymerase chain reaction in real time (PCR-real time): Porphyromonas gingivalis (Pg), Prevotella nigrescens (Pn) e Prevotella intermedia (Pi).The statistical analysis was performed (α=5%). RESULTS: Treatments with MTZ + AMX and aPDT promoted improvements in PD, CAL, BOP and VPI parameters after treatment. Patients who received the treatment with aPDT showed a higher reduction of CAL and PD in pockets collected, when compared to SRP only. The aPDT promoted greater reduction in CAL in moderate pockets when compared to SRP alone. All treatments were effective in reducing the residual pockets of the collected sites. Comparing the periods of MTZ + AMX group in moderate pocket, there was a decrease of levels of Pg and Pn between Baseline and 180 days and, in aPDT group, there was a decrease of Pn to 180 days. Regarding deep pockets, there was a decreased of Pg, Pi and Pn to 180 days in MTZ + AMX group compared to Baseline and levels of Pi and Pn at 180 days and Pn to 90 days. CONCLUSION: The combination of MTZ + AMX or aPDT to SRP promoted additional clinical benefits in periodontal treatment of smokers. Significant clinical benefits were observed with the use of aPDT as adjunctive therapy in the treatment of periodontal disease in smokers, while the antibiotic was more effective in reducing microorganisms.