13th World Congress for Laser Dentistry
26-28, April 2012
Barcelona, Spain
Meeting Abstract
Sponsors: World Federation for Laser Dentistry
- Poster 106
TITLE: Evaluation of photodynamic antimicrobial
chemotherapy cytotoxicity on pulp cell cultures in vitro.
AUTHORS: Diniz IMA, Teixeira KIR, Araújo
PV, Marques MM, Poletto LTA, Cortes ME.
Universidade Federal de
Minas Gerais/Universidade de São Paulo
SOURCE: Med
Oral Patol Oral Cir Bucal.
2012 May 1;17(Supplement1):S254.
* doi:10.4317/medoral.17643754
http://dx.doi.org/10.4317/medoral.17643754
Abstract
Photodynamic
antimicrobial chemotherapy (PACT) has been used successfully to eradicate
cariogenic microorganisms, but there is a lack of knowledge regarding PACT effects on dental pulp tissue. To
evaluate the cytotoxicity of PACT with methylene blue (MB) associated to a
diode laser on primary pulp cell cultures, 1.5 x 105 cells/well were seeded in
96-well plates for 48 h, incubated with MB (12.5, 25 e 50 μg/ml) and irradiated
with red laser (660 nm; 1000 mW/cm2) for 1 minute. Cell metabolism was evaluated
by the MTT (methyltetrazolium), NR (neutral red) and
ALP (alkaline phosphatase activity) assays. The type of cell death was
evaluated by annexin-V and propidium
iodide assay by flow cytometry. Analysis of variance
(ANOVA) followed by Tukey ́s test were performed
to compare all groups. Only MB at 12.5 μg/ml exposed to red laser caused
slightly cytotoxic effects on pulp cells. There was a statistically significant
decrease of cell metabolism after PACT at MB con centrations
of 25 and 50 μg/ml. After 24 h, toxic effects were even more severe with
cell detachment and morphological alterations observed under light microscope.
PACT with MB at 50 μg/ml showed a predominance of necrotic cell death,
whereas at 25 μg/ml there was a predominance of apoptotic cell death. MB
at 12.5 and 25 μg/ml exposed to red laser seems to have the potential to
be applied in vivo. However, news studies should be performed to further optimization
of light dosimetry of PACT directly applied on pulp
cells.