| Abstract:
Background: Streptococcus mutans is one of the species in the
biofilm adjacent to cariogenic lesions. Photo-activated disinfection
(PAD) is a new method which reduces cariogenic bacterial without
common side effects. The success of PAD depends on the sensitivity
of the organism, type of dyes, a dose of dyes, and the depth of
emitted laser. In this study, effect of PAD on S. mutans reduction
using indocyanine green (ICG) compared with methylene blue was
evaluated.
Materials and Methods: The standard turbidity (0.5 McFarland)
of S. mutans suspension was prepared. Bacterial suspensions
were transferred to the wells. Then, samples were subsequently
divided into 7 groups. 1: Negative control, 2: Only methylene blue
without laser, 3: Only 640 nm laser, 4: PAD by methylene blue,
5: Indocyanine without laser, 6: Only 810 nm laser, and 7: PAD
by ICG. Subsequently, the bacterial suspension from each well was
cultured, colony counts were determined, and data were analyzed
using one-way ANOVA and Tukey’s tests (P < 0.05).
Results: There was a significant decrease of S. mutans colony counts
after PAD using by both methylene blue and ICG photosensitizers.
The highest decreased amount belonged to the ICG (PAD group).
Methylene blue group (without laser application) also had a
significant decrease of S. mutans colony counts (less effective than
both PAD groups). Other groups (laser applications alone and ICG
dye without laser) showed no significant bacterial reduction.
Conclusion: With the parameters of this study PAD by ICG seems
to be more effective than PAD by methylene blue, in reducing
S. mutans bacteria as etiological factors of dental caries. |