Production of reactive oxygen species from photosensitizers activated with visible light sources available in dental offices.
OBJECTIVE
The aim of this study was to assess the ability of commonly available red- or blue-light dental sources to generate reactive oxygen species (ROS) from photosensitive chemicals that might be useful for photodynamic antimicrobial chemotherapy (PACT).


BACKGROUND
Although the use of red diode lasers is well documented, there is limited information on how useful blue-light sources might be for PACT in dental contexts.


METHODS
A diode laser (Periowave; see Table 1 for material and equipment sources) emitting red light (660-675 nm) was used to activate toluidine blue; riboflavin and pheophorbide-a polylysine (pheophorbide-a-PLL) were photoactivated using an Optilux 501 curing unit emitting blue light (380-500 nm). Ozone gas (generated by OzoTop, Tip Top Tips, Rolle, Switzerland), sodium hypochlorite, and hydrogen peroxide were used for comparison. ROS production was estimated using an iodine-triiodide colorimetric assay, and ROS levels were plotted versus concentration of chemicals to determine each chemical's efficiency in ROS production. One-way ANOVA with Tukey post hoc analysis (alpha = 0.05) was used to compare the efficiencies of ROS production for the various chemicals.


RESULTS
Sodium hypochlorite, hydrogen peroxide, and ozone gas produced ROS spontaneously, whereas pheophorbide-a-PLL, riboflavin, and toluidine blue required light exposure. The efficiency of ROS production was higher for pheophorbide-a-PLL and toluidine blue than for ozone gas or riboflavin (p < 0.05). Hydrogen peroxide was the least efficient ROS producer.


CONCLUSIONS
The results of the current study support the use of blue- or red-light-absorbing photosensitizers as candidates to produce ROS for clinical applications. Blue-light photosensitizers were as efficient as red-light photosensitizers in producing ROS and more efficient than the oxidant chemicals currently used for dental disinfection.
Bouillaguet
Serge
S
Endodontics Unit, Section of Dental Medicine, University of Geneva, Geneva, Switzerland. Serge.Bouillaguet@unige.ch
Wataha
John C
JC
Zapata
Oscar
O
Campo
Marino
M
Lange
Norbert
N
Schrenzel
Jacques
J
D002734:Chlorophyll / Q000031:analogs & derivatives / Q000494:pharmacology; D003770:Dental Offices; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D054023:Lasers, Semiconductor; D016877:Oxidants / Q000494:pharmacology; D010126:Ozone / Q000494:pharmacology; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000494:pharmacology*; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000032:analysis*; D012256:Riboflavin / Q000494:pharmacology; D012973:Sodium Hypochlorite / Q000494:pharmacology; D014048:Tolonium Chloride / Q000494:pharmacology
D016877:Oxidants; D017319:Photosensitizing Agents; D011838:Radiation-Sensitizing Agents; D017382:Reactive Oxygen Species; D002734:Chlorophyll; D014048:Tolonium Chloride; D010126:Ozone; D006861:Hydrogen Peroxide; D012973:Sodium Hypochlorite; C032623:pheophorbide a; D012256:Riboflavin