efficacy of photodynamic therapy as an adjunct to full-mouth root planing in the treatment of periodontitis assessed by real-time pcr: a microbiological and clinical study

background and aims. the aim of this investigation was to compare clinical and microbiological effectiveness of ad-junctive 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 mi-crobiological results.