Effect of Curing Light Barrier on Radiant Energy Delivery

Objectives: To determine the effect of curing tip barrier on loss of radiant energy delivery. Methods: The spectral irradiance of dental light curing units (Blue-only LED [MAGNA, S10]; Blue/Violet LED (Bluephase 20i, VALO]; Broadband [Optilux 501, ARCIIM] where obtained through a variety of curing tip barriers: no barrier (control), two different types of commercial barriers (Curelastic; Cure Sleeve), or when covered by either 1 or 3 layers of a clear plastic food wrap. Irradiance values were obtained using a 6” integrating sphere and spectroradiometer calibrated to a NIST-traceable source. N=5. The energy density for each condition was calculated using 10-second exposures from each light (20s for the OP501). The percentage decrease in energy relative to the non-barrier covered tip was then calculated. A 2-way ANOVA tested the effect of barrier type and light unit on proportion of non-barrier energy delivery. Tukey's post-hoc test was used to pair-wise means comparison.  Comparison of average loss values among barriers used the Kruskal-Wallis test on ranks and Tukey's post-hoc procedure. All statistical testing was performed using a pre-set alpha of 0.05. Results: ANOVA indicated significant effect of both main factors, as well as their interaction (all p < 0.001). Table displays mean loss of energy relative to non-barrier control (sd) and statistical groupings within a given barrier (vertical, Upper Case letters) or within a curing light (horizontal, lower case letters).

The CureLastic barrier produced the greatest energy loss, followed by the Cure Sleeve. Least energy loss was observed using 1 layer of clear wood wrap, and 3 layers results in approximately twice the energy loss as 1 layer. However, within a barrier, energy loss is not similar among light units. Conclusions: Energy loss through barriers is affected by both selection of barrier as well as the specific light curing unit.