Assessment of LED-light-polymerization units/techniques dentists use in Toronto – Pilot study

Objectives: To determine irradiance of LED light-polymerization units used by dentists in greater Toronto area (GTA). To assess techniques used by dentists to deliver radiant energy with LED lights to anterior and posterior simulated cavities.
Methods: Dental offices in GTA were recruited to participate in the study according to protocol approved by Research Ethics Board of University of Toronto. MARC® Patient Simulator (BlueLight Analytics, Halifax NS) was used in 25 private dental offices. Participating dentists were asked to position MARC-PS as they would for a patient, and then to apply LED-light to the simulated anterior and posterior cavities for 10 seconds. Participants used their own LED lights and the irradiance (mW/cm²) and radiant exposure (J/cm2) delivered to cavities were recorded. Participants were then given specific light-polymerization instructions/training (IT) using MARC-PS, after which they re-applied light to cavities using same LED-light. Data were analyzed with 2-Way ANOVA and Tukey-Kramer post-hoc test (p=0.05).
Results: Radiant exposure range was 205-1,374 mW/cm² in anterior region and 189-1,092 mW/cm² in posterior region among 25 offices. Mean irradiance in anterior cavities was 837.6 (373.5) before IT and increased to 1,026.3(312.3) after. In posterior cavities it was 583.6(255.7) before IT and increased to 740(270.5) after. LED irradiance after IT improved by 19.4% in anterior region and by 26.5% in posterior.
Conclusions: A wide range of irradiances was found among 25 dental office visited in the GTA. Before IT some participating dentists delivered an inadequate amount of radiant energy to MARC-PS. After IT energy delivered was significantly increased. There is need to increase dentists awareness of proper photo-polymerization to ensure longevity of resin-based composite restorations.