Proceedings Article | 12 February 2008
Proc. SPIE. 6846, Mechanisms for Low-Light Therapy III
KEYWORDS: Phototherapy, Laser therapeutics, Pathology, Laser applications, Semiconductor lasers, Laser irradiation, Absorbance, Laser dentistry, Dentistry, In vitro testing
Laser phototherapy has proven to improve treatment of several pathologies in dentistry. The aim of the
present study was to analyze the low power laser phototherapy effects comparing multiple irradiations with
the same total energy at once. This in vitro study focuses on the biostimulation of cellular growth of pulp
fibroblasts (FP5 cell lineage). The cells were grown in Dulbecco's Modified Eagle's (DME) medium with
either 5% (nutritional deficit) or 10% fetal bovine serum (FBS). Laser irradiation was carried out with
diode lasers with the following parameters: 685 nm, 40 mW, spot size 0.019 cm2. The groups were:
G1(6.3J/cm2, 3 s, 0.12J), G2 (12.6J/cm2, 6 s, 0.24J), G3 (18.9J/cm2, 9 s, 0.36J), G4 (2 irradiations of
6.3J/cm2, 0.24J), G5 (3 irradiations of 6.3J/cm2, 0.36J), G6 (5% SFB, negative control, without irradiation),
and G7 (10% SFB, positive control, without irradiation). On groups G4 and G5 the irradiation was
performed with 6h-intervals. For growth analysis, the MTT test was used 24 hours after the last irradiation.
The data from spectrophotometer were analyzed by ANOVA followed by the Tukey's test. The groups
submitted to multiple irradiations presented significantly higher cell growth than the groups with single
irradiation. This cell growth was similar to that of positive control group. The laser phototherapy with
multiple irradiations is more effective on cellular growth.
