Background and aims. The aim of this investigation was to compare clinical and microbiological effectiveness of adjunctive
photodynamic therapy (PDT) in the treatment of periodontitis.
Materials and methods. Twenty-four subjects (14 women and 10 men) diagnosed with moderate to severe chronic
periodontitis underwent scaling and root planing (SRP). One tooth in each quadrant (probing depth >4 mm) was selected
for combined PDT and SRP (PDT group) with the contralateral tooth (SRP group), as a control site (SRP-treated site).
Clinical assessment was carried out at baseline and 1 and 3 month later. Microbial assessment was carried out by real-time
PCR. Periodontal probing depth (PPD) was considered as the primary outcome.
Results. Baseline PPDs were 4.86±0.77 and 4.04±0.65 in the SRP and PDT groups, respectively (P>0.05), which decreased
to 3.65±0.58 in the SRP and 3.86±0.56 in the PDT groups after one month and to 3.20±0.68 in the SRP and
3.34±0.56 in the PDT groups three months later. Although values decreased significantly in both groups after one (P=0.001
in the SRP and P=0.001 in the PDT groups) and three months (P=0.001 in the SRP and P=0.001 in the PDT groups) the
inter-group differences were not significant after one (P=0.25) and three months (P=0.51). Clinical measurements showed
significant decreases after one and three months at both sites, without inter-group differences, except for bleeding on probing
after one (P=0.004) and three months (P=0.0001).
Conclusion. Subgingival application of PDT combined with scaling and root planing could not improve clinical and microbiological