Degree of Conversion in Bulk Fill and Conventional Composites Cured with Different Dental Curing Light Sources: An in vitro Study

Abstract

Objective: This in vitro study aimed to compare the degree of conversion (DC) of bulk-fill and conventional composite resins cured by Quartz Tungsten Halogen (QTH) and poly wave Light-emitting diode (LED) curing units.

Materials and Methods: Thirty-two cylindrical specimens were fabricated in eight groups (n=4): (I) X-tra fil packable cured with the poly wave, (II) X-tra fil packable cured with QTH, (III) X-tra base cured with a poly wave, (IV) X-tra base flow cured with QTH, (V) Grandio packable cured with a poly wave, (VI) Grandio packable cured with QTH, (VII) Grandio flow cured with a poly wave, and (VIII) Grandio flow cured with QTH curing unit. Light-curing was performed with LED or QTH. Fourier-transform infrared spectroscopy (FTIR) was performed to assess the DC of the samples. Data were analyzed using one-way ANOVA and a post-hoc Tukey test.

Results: XtraBase flow bulk-fill composite/poly-wave was the only composite with no significant difference between the DC of its first and fourth layers. The highest depth of cure was noted in the first layer of Grandio flow/QTH, X-tra base/QTH, and X-tra base/poly-wave, and the fourth layer of Grandio flow/QTH, and Grandio flow/poly wave.

Conclusion: The degree of conversion decreased by an increase in depth. The poly-wave curing unit was more efficient for bulk-fill composites. QTH curing unit was more efficient for the conventional composites demonstrating a greater depth of cure. Composites with higher flow showed a higher depth of cure due to higher translucency.