Effects of light emitting diode (LED) therapy at 940 nm on inflammatory root resorption in rats

The effects of LED therapy at 940 nm on periodontal healing, inflammatory cell infiltration, and root resorption were analyzed in an experimental model of orthodontic tooth movement in rats. Twenty-five male Wistar rats were allocated into four experimental groups: Control animals (Co, n?=?5), Controls + LED therapy (CoLED, n?=?6), animals submitted to orthodontic force (RR, n?=?7) and submitted to orthodontic force + LED therapy (RRLED, n?=?7). All procedures were approved by the Committee for Ethics in Animal Experimentation of the Universidade Estadual de Londrina (protocol CEEA 5/2010 37359). A force of 50 g was applied to the right upper molars of RR and RRLED groups. On days 2, 3, and 4 after orthodontic treatment, the CoLED and RRLED groups received LED irradiation (940 nm, 4 J/cm²). The animals were killed on day 7 for histological analysis. An increased number of root resorption lacunae was found only in the RR group (p?p?p?p?p?p?p?