Photodynamic therapy(PDT) has been demonstrated to effectively kill human periopathogens in vitro. To evaluate the
efficacy of PDT in vivo a series of clinical trials was carried out in multiple centers and populations. Clinical parameters
including clinical attachment level, pocket probing depth and bleeding on probing were all evaluated. All groups
received the standard of care, scaling and root planing, and the treatment group additionally received a single treatment
of PDT. Of the total 309 patients and over 40,000 pockets treated in these 5 trials it was determined that photodynamic
therapy provided a statistically significant improvement in clinical parameters over scaling and root planing alone.
Photodynamic therapy has been demonstrated to effectively kill human periopathogens in vitro. However, the translation
of in vitro work to in vivo clinical efficacy has been difficult due to the number of variables present in any given patient.
Parameters such as photosensitizer concentration, duration of light therapy and amount of light delivered to the target
tissue all play a role in the dose response of PDT in vivo. In this 121 patient study we kept all parameters the same except
for light dose which was delivered at either 150 mW or 220 mW. This clearly demonstrated the clinical benefits of a
higher light dose in the treatment of periodontitis.
Periodontitis affects half of the U.S. population over 50, and is the leading cause of tooth loss after 35. It is believed to
be caused by growth of complex bacterial biofilms on the tooth surface below the gumline. Photodynamic therapy, a
technology used commonly in antitumor applications, has more recently been shown to exhibit antimicrobial efficacy.
We have demonstrated eradication of the periopathogens Porphyromonas gingivalis, Fusobacterium nucleatum, and
Aggregatibacter actinomycetemcomitans in vitro using Periowave<sup>TM</sup>; a commercial photodisinfection system. In
addition, several clinical studies have now demonstrated the efficacy of this treatment. A pilot study in the U.S. showed
that 68% of patients treated with Periowave<sup>TM</sup> adjunctively to scaling and root planing (SRP) showed clinical attachment
level increase of >1 mm, as opposed to 30% with SRP alone. In a subsequent larger study, a second Periowave<sup>TM</sup>
treatment 6 weeks after initial treatment led to pocket depth improvements of >1.5 mm in 89% of patients. Finally, in the
most recent multicenter, randomized, examiner-blinded study conducted on 121 subjects in Canada, Periowave<sup>TM</sup>
treatment produced highly significant gains in attachment level (0.88 mm vs. 0.57 mm; p=0.003) and pocket depth (0.87
mm vs. 0.63 mm; p=0.01) as compared to SRP alone. In summary, Periowave<sup>TM</sup> demonstrated strong bactericidal
activity against known periopathogens, and treatment of periodontitis using this system produced significantly better
clinical outcomes than SRP alone. This, along with the absence of any adverse events in patients treated to date
demonstrates that PDT is a safe and effective treatment for adult chronic periodontitis.