microbiological efficacy of photodynamic therapy as an adjunct to non-surgical periodontal treatment: a clinical trial

introduction: the efficiency of routine scaling and root planning is negatively influenced by the tooth anatomy and residual bacteria all possibly affecting the treatment outcomes in future. the present study compared the microbiologic effectiveness of the photodynamic therapy (pdt) as an adjunctive treatment modality for nonsurgical treatment in chronic periodontitis. methods: in this randomized controlled clinical trial, 18 chronic periodontitis patients were selected. four quadrants were randomly treated by scaling and root planning (srp), diode laser (810n m wavelength, 1.5 w and 320 μm fiber, contact and sweeping technique), srp + pdt (with diode laser 808 nm, 0.5 w) and laser + srp (with diode laser 808 nm, 1 w) in each patient. presence of periodontal pathogen species in the treated areas were measured before the treatment, at 1 and 3 months afterwards. the identification and reproduction of the specific genes of pathogen bacteria were done by means of polymerase chain reaction (pcr) technique. presence of oral pathogen bacteria in the treatment groups were analyzed by chi-square test. a semi quantitative analysis was used to measure the intensity of white light in each band. this was calculated by number of pixels in each band. results: in the qualitative analysis, fusobacterium nucleatum (fn) and treponema denticola (td) species were killed after 1 month in all treatment modalities. pdt had more effects to decrease prevotella intermedia (pi) species than srp while tannerella forsythensis count (tf) species increased in all treatments. furthermore, actinobacillus actinomycetemcomitans (aa) species decreased in all treatments and porphyromonas gingivalis (p.g) species increased in all treatments after 1 and 3 months. conclusion: it can be concluded that pdt was more effective as an adjunctive treatment to srp than srp alone; however, no distinct differences were found between both treatment modalities regarding reduction of certain pathogen bacteria.