Effects of low level laser fractionated energy irradiation in the growth and viability of fibroblasts from pulp tissue of human primary teeth

Abstract

The low level laser therapy (LLLT) has shown accelerate fibroblast proliferation and collagen synthesis, and stimulate bone regeneration process and neovascularization. Due to the paucity of investigations in the literature about the influence of LLLT on the pulp tissue of primary teeth, the aim of this study is to evaluate the in vitro effects of fractionated energy irradiation compared to total energy of low level laser on the growth and viability of fibroblasts. Fibroblasts will obtained by explants from pulp tissue of human primary teeth. After the fourth passage, the cells will be irradiated with low level laser in accordance with the following groups: total energy applied in single irradiations of 0.1 J (GI), 0.2 J (GII) and 0.3 J (GIII); and multiple irradiations of 0.1 J, 2 applications - 0.2 J (GIV) and 3 applications - 0.3 J (GV) at intervals of 6 hours between irradiations. Non-irradiated cells grown in nutritional deficit - 1% Fetal Bovine Serum (FBS) (GVI) and at regular nutritional conditions - 10% FBS (GVII) will be used as negative and positive controls respectively. Then, the cell growth analysis will be assessed by measuring the cell mitochondrial activity through the MTT reduction-based cytotoxicity assay. The results will be submitted to appropriate statistical analysis. Statistical significance will be established at 5%.