Effects of low-level laser therapy on stem cells from human exfoliated deciduous teeth

Low-level laser therapy stimulates the proliferation of a variety of types of cells. however,very little is known about its effect on stem cells from human exfoliated deciduous teeth (shed). objective: this study aimed to evaluate the influence of different laser therapy energy densities on shed viability and proliferation. material and methods: shed were irradiated according to the groups: i (1.2 j/cm2-0.5 mw – 10 s),ii (2.5 j/cm2– 10 mw – 10 s),iii (3.7 j/cm2 – 15 mw – 10 s),iv (5.0 j/cm2 – 20 mw – 10 s),v (6.2 j/cm2 – 25 mw – 10 s),and vi (not irradiated – control group). cell viability was assessed 6 and 24 h after irradiation measuring the mitochondrial activity and using the crystal violet assay. cell proliferation was assessed after 24,48,and 72 h of irradiation by srb assay. results: mtt assay demonstrated differences from 6 to 24 hours after irradiation. after 24 h,groups i and iv showed higher absorbance values than those of control group. crystal violet assay showed statistically differences in the absorbance rate from 6 to 24 h after irradiation for groups iii and vi. at 24 h after irradiation,group iii absorbance rate was greater than that of groups i,ii,and iv. group vi absorbance rate was greater than that of groups i and iv. srb assay showed that the group i had higher rates than those of groups ii,iii,v,and vi,at 24 h after irradiation. after 48 h,group i exhibited the greatest cell proliferation rate followed by groups iii,v,and vi. after 72 h,group iii exhibited the lowest cell proliferation rate than those of groups ii,iv,and v. conclusions: the low-level laser therapy energy densities used in this study did not cause loss of cell viability and stimulated shed proliferation within the parameters described in this study. © 2016,faculdade de odontologia de bauru. all rights reserved.