Morphological Changes in Oral Mucosa of Rabbits Induced by Light Emitting Diode (led) Used as Dental Curing Light

A dental curing light is a piece of dental tool that is used for the hardening of light cure composites. Many studies have shown these lights induce changes in DNA, mitosis and mitochondria through free radicals production. Light emitting diode (LED) are most commonly used and claim less hazards to the adjacent soft tissues. Current study was therefore designed to observe the morphological changes induced by light emitting diode (LED) as a dental curing light source in oral mucosa of experimental animals. Fifty rabbits were divided into 5 groups (4 experimental and 5th as a control group). Cervical margin of central incisors of each animal in the experimental groups was exposed 3 times with LED light; duration of each exposure being 40 seconds with a gap of 30 seconds. Punch biopsies were taken after 24 hours, 48 hours, 1week and 2weeks from group 1, 2, 3 and 4 animals respectively. Results showed ulceration (4%), acanthosis and vascular pathological changes (100%), enlarge (bulbous) rete ridges (97.5%), basal layer vacuolization (85%), acantholysis (27.5%) and atypical mitosis (10%) in all the experimental animals. With passage of time, a significant increase (P=0.000) in frequency of basal cell hyperplasia (90% in group 1 to 100% in group 4) and basal layer atypia (70% in group 1 to 90% in group 4) was observed. While inflammation dropped from 100% in group 1 to 0% in group 4 (P=0.000) due to healing of tissues. Changes were similar to the previous studies except some severe effects like atypical mitosis and basal layer atypia were observed which may be attributed to increase in number of light exposures in our study that is in compliance with the clinical practice in our set up. These findings may help in creating awareness among the dental practitioners to use dental curing lights with caution keeping appropriate safety measures for the adjacent oral soft tissue in consideration.