The antibacterial effect of photodynamic therapy (PDT) has been shown in several in vitro studies, but human clinical results on the microbiological changes following periodontal therapy have been conflicting.
Objectives:
To validate the effectiveness of adjunctive PDT in the reduction of subgingival periopathogens Porphyromonas gingivalis (P.g) and Aggregatibacter actinomycetemcomitans (A.a) in the treatment of periodontitis.
Methods:
49 patients with chronic periodontitis were included in this single blind, split mouth design study.. Two quadrants were randomly assigned to either receive oral hygiene instructions and scaling and root planing alone (control) or with adjunctive PDT (test). At baseline and 3 months after therapy, probing depths (PD) of selected sites were recorded and quantitative analysis of subgingival concentrations of P.g and A.a was performed using quantitative real-time polymerase chain reaction (PCR). The results were analysed using non-parametric tests.
Results:
A general trend in the reduction of PD and microbial counts were found following both modalities of periodontal treatment at 3 months. Using Wilcoxon signed rank test, PD and P.g were significantly reduced in both groups ( P<0.O5). The reduction of A.a in both groups however did not reach statistical significance (P>0.05). At 3 months, when sites that demonstrated improvement in PD of at least 2mm were selected, significant reductions in concentrations of A.a was only found in the PDT group.
Conclusions:
Improvement in probing depth with a corresponding reduction in P.g concentrations were found following periodontal treatment with or without adjunctive PDT. At sites showing reduction of at least 2mm probing depth, adjunctive PDT may confer additional reductions in A.a as compared with scaling and root planing alone.