CHRONIC EFFECT OF HIGH POWER LED IN WISTAR RATS RETINA
Curing Lights; High Potencies; Retina; Rats
Introduction:The increase in the power of light-emitting diode (LED) light cure has contributed to reduce the bonding time of orthodontic brackets. However, the effect of the LED on the retina of those who make the chronic use of light units without using protection filters is unknown. Objective:To evaluate the possible effects of the chronic use of a high power LED light curing device on the retinas of Wistar rats. Material and methods:In this experimental study in vivo, six healthy male rats were used in the research, with their ocular structures being the objects of study. The left eyes of the animals were exposed to high potency LED light, 3200mW / cm2 (Valo Ortho - Ultradent), for 144 seconds at a distance of 30cm, three times a day, for 7 days. The right eyes were covered with removable and opaque PVC tampon, composing the control sample. On the eighth day, the animals were anesthetized, euthanized, the eyes dissected and histologically processed. The slides were scanned using a camera coupled to an optical microscope and their images analyzed stereologically and histomorphometrically. Results:There were no statistically significant intergroup differences in total retinal volume (p = 0.655) or in the volume of the retinal layers ganglionic (p = 0.375), internal plexiform (p = 0.327), internal nuclear (p = 0.693), external plexiform (p = 0,177), external nuclear (p = 0.355) and the extension of cones and rods (p = 0.871), when evaluated individually. The histomorphometric analyzes presented statistically significant differences for the cellular areas of the internal and external nuclear layers and ganglionic layer (p <0.05), although the numerical density did not present this statistically significant difference. Conclusion:Despite the great variability of the data, the risk of retinal damage from eye chronic exposure to high power LED light is possible and emphasizes the need for glasses and/or individual UV protection filter.