In- vitro-activity of additive application of hydrogen peroxide in antimicrobial photodynamic therapy using LED in the blue spectrum against bacteria and biofilm associated with periodontal disease.
BACKGROUND
Although antimicrobial photodynamic therapy (aPDT) has been shown to be efficient in killing planktonic periodontopathogenic bacteria, its activity on established biofilms is very limited. The aim of the present in-vitro study was to evaluate the potential effect of hydrogen peroxide as a pretreatment for aPDT.


METHODS
aPDT consisting of riboflavin as photosensitizer and illumination by a LED lamp emitting in the blue spectrum for 30 s and 60 s (aPDT60) was combined with a pretreatment with 0.25% and 3% hydrogen peroxide. The antimicrobial activity of these treatments was determined against eight oral species (incl. Porphyromonas gingivalis and Tannerella forsythia) and against eight-species biofilms. Treatment of biofilms in an artificial pocket model included a mechanical removal of the biofilm.


RESULTS
Against planktonic bacteria, pretreatment with hydrogen peroxide increased killing of planktonic bacteria, after aPDT60 no viable bacteria were detected in 7 of 8 strains. In biofilms formed on well-plates, aPDT60 reduced bacterial counts only by 0.53 log10 cfu, whereas reduction was closed to 4 log10 or higher when 3% hydrogen peroxide was used. When biofilms were treated in the periodontal-pocket model, reduction of cfu was less than 0.5 log10 after mechanical therapy or aPDT60 only, however no bacteria were detected after mechanical biofilm removal followed by the use 3% of hydrogen peroxide and aPDT60.


CONCLUSIONS
aPDT using riboflavin and blue LED light applied after mechanical removal of biofilm and adjunctive 3% hydrogen peroxide solution appears to represent an alternative for antimicrobial periodontal therapy.
['Kunz|Daniel|D|', 'Wirth|Jessica|J|', 'Sculean|Anton|A|', 'Eick|Sigrun|S|']
D000900:Anti-Bacterial Agents D000890:Anti-Infective Agents D018441:Biofilms D006861:Hydrogen Peroxide D066298:In Vitro Techniques D010510:Periodontal Diseases D010778:Photochemotherapy D017319:Photosensitizing Agents D012256:Riboflavin
Hydrogen peroxide Antimicrobial photodynamic therapy Biofilms Periodontopathogens Riboflavin