IS LED DENTAL CURING LIGHT INNOCUOUS FOR ORAL MUCOSA – FACTS UNCOVERED

Objectives: Curing light is employed in many aspects of modern dentistry like restorative, preventive and orthodontic dentistry. In addition to curing the material, this high intensity light can damage adjacent oral mucosa through its biological effects and rise in temperature. 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.
Methods: Fifty rabbits were divided into 5 groups (4 experimental and 5^th 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: Gingival epithelium of rabbits revealed hyperplastic changes in all experimental group animals (100%) while basal layer hyperplasia was found to be increasing among the groups (90% in group1 to 100% in group 3 and 4 each). Basal layer atypia with nuclear pleomorphism and prominent nucleoli was shown by 70% (group 1, 3 each), 50% (group 2) and 90% (group 4) of rabbits. Dysplastic keratinocytic changes like nuclear hyperchromasia and atypical mitoses were found to be 0% in group1, 20% in group 2 and 10% in group 3 and 4 animals each which marked the development of these changes right from the 48 hours after exposure. No direct relationship was found between atypical keratinocytic changes and stromal inflammation (p=0.557)
Conclusions: Being used in various routine dental procedures, LED curing light is not innocuous; a common perception about this light. Hence, apart from their own safety measures, appropriate protection of the adjacent oral soft tissue should be practiced by the dentists while using this device.