Antimicrobial photodynamic action on dentin using a light-emitting diode light source.
OBJECTIVE
The aim of this study was the evaluation of two different photosensitizers activated by red light emitted by light-emitting diodes (LEDs) in the decontamination of carious bovine dentin.


METHODS
Fifteen bovine incisors were used to obtain dentin samples which were immersed in brain-heart infusion culture medium supplemented with 1% glucose, 2% sucrose, and 1% young primary culture of Lactobacillus acidophilus 10(8) CFU/mL and Streptococcus mutans 10(8) CFU/mL for caries induction. Three different concentrations of the Photogem solution, a hematoporphyrin derivative (1, 2, and 3 mg/mL) and two different concentrations of toluidine blue O (TBO), a basic dye (0.025 and 0.1 mg/mL) were used. To activate the photosensitizers two different light exposure times were used: 60 sec and 120 sec, corresponding respectively to the doses of 24 J/cm(2) and 48 J/cm(2).


RESULTS
After counting the numbers of CFU per milligram of carious dentin, we observed that the use of LED energy in association with Photogem or TBO was effective for bacterial reduction in carious dentin, and that the greatest effect on S. mutans and L. acidophilus was obtained with TBO at 0.1 mg/mL and a dose of 48 J/cm(2). It was also observed that the overall toxicity of TBO was higher than that of Photogem, and that the phototoxicity of TBO was higher than that of Photogem.


CONCLUSIONS
Based on our data we propose a mathematical model for the photodynamic effect when different photosensitizer concentrations and light doses are used.
Giusti
Juçaíra S M
JS
Faculdade de Odontologia de Araraquara, Universidade do Estado de São Paulo, Araraquara, SP, Brazil.
Santos-Pinto
Lourdes
L
Pizzolito
Antonio C
AC
Helmerson
Kristian
K
Carvalho-Filho
Eurico
E
Kurachi
Cristina
C
Bagnato
Vanderlei S
VS
D000818:Animals; D002417:Cattle; D003731:Dental Caries / Q000188:drug therapy*; D003804:Dentin / Q000187:drug effects* / Q000382:microbiology*; D017324:Hematoporphyrin Derivative / Q000008:administration & dosage*; D006414:Hematoporphyrin Photoradiation; D007779:Lactobacillus acidophilus / Q000187:drug effects; D008954:Models, Biological; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000008:administration & dosage*; D013295:Streptococcus mutans / Q000187:drug effects; D014048:Tolonium Chloride / Q000008:administration & dosage*
D017319:Photosensitizing Agents; D014048:Tolonium Chloride; D017324:Hematoporphyrin Derivative