Sufficient energy delivery to a photo-curable restoration affects its properties and durability.
Objectives: To measure energy density delivered to a posterior Class I preparation using six different curing lights by 25 dentists before and after instruction.
Methods: A device (MARC, BlueLight, NS, Canada) has been developed to measure the energy density delivered from curing lights to a simulated dental preparation. Uninformed of the exercise purpose, 25 dentists at a professional meeting were asked to position a mannequin head, containing light measuring instruments, as they would for a patient, and then to expose the simulated Class I maxillary second molar preparation for the specified amount of time. Mouth opening was fixed at 43mm at the incisors. Each participant used three lights and the energy density (J/cm2) delivered to the preparation was recorded in real-time. Participants were then told the purpose of the exercise, and instructed to use ‘blue blocker' glasses, directly observe what they were doing, stabilize the light close to and perpendicular to the preparation, after which they re-exposed the same preparation using the same lights. Pre- and Post-instruction energy density values were compared using a 1-way ANOVA (alpha=0.05), and also within each light among all operators using a 2-tailed, paired Student's t-test at a family-wise alpha of 0.05. Within a light, a significance level was set to 0.008 (0.05/6).
Results: Energy density delivery significantly (p<0.001) increased by 18% as a result of training. Table provides mean (sd) ED delivery (J/cm2).
For 2 of the 6 lights tested(*), participants delivered significantly more energy density (~30% increase) following training: an average of 2.4 J/cm2, (both LED lights using fiberoptic guides).
Conclusions: A clinically applicable, training instrument (MARC) proved effective in quantifying the improvement in radiant energy density delivered to a simulated restoration as a result of training in proper photocuring methods.