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.