Effect of Light-Curing Using Different Wavelengths on Odontoblasts Metabolic Response
Objectives: This study evaluated the light-transmittance of different wavelengths through composite restorations and its influence on odontoblasts metabolic response.
Methods: Class I preparations with 5 mm x 4 mm and 4 mm in depth were performed in third molars, leaving 0.5 mm of dentin at the pulpal floor. The light-transmittance at the pulpal chamber of the preparation was recorded using a spectrophotometer (MARC Light-Collector) to calculate the overall radiant exposure (J/cm2) through the restorative procedures (n=5). The light-activation procedures were performed with different wavelengths (blue, green, or red) and 1000 mW/cm2. Then, MDPC-23 cells were seeded using DMEM, supplemented with 10% fetal bovine serum (FBS). After 12h, the culture medium was replaced with DMEM containing 0.5% FBS. After an additional 12h, these cells were irradiated with either of the different wavelengths using the overall radiant exposure (J/cm2) previously pre-determined (n=5). Non-irradiated MDPC-23 cells were used as control. 72h after, cell viability was evaluated using MTT. A power analysis was conducted to determine the sample size to provide a power of at least 0.8 at a significance level of α=0.05. Statistical analyses were performed using ANOVA and Tukey’s tests.
Results: The overall radiant exposure upon the pulp chamber using blue, green, and red light was 3.88 (0.6), 6.50 (0.8), and 10.52 (1.2) J/cm2, respectively. Red light irradiation promoted an increase in cell metabolism at the energy dose of 4 J/cm2. Conversely, green and blue lights showed reduced viability.
Conclusions: Red light irradiation through restorative procedures bio-stimulated the metabolism of odontoblast-like cells, while blue and green lights promoted unfavorable effects.