IADR Abstract Archives
Impact of Light Transmittance Mode on Polymerisation Kinetics in Bulk-fill-composites
Objectives: Modern bulk-fill resin-based composites (RBC) are designed to turn during polymerization either progressively opaque or transparent. The study aims therefore to determine the mode of light transmittance and its impact on the polymerisation kinetic at clinical relevant filling depths.
Methods: Four low-viscosity methacrylate-based and one high-viscosity ormocer-based bulk-fill RBCs were considered. One material was evaluated in three different shades. Polymerization kinetic (real-time degree of cure, DC) and light transmittance were assessed at 2 and 4-mm specimen depths. Incident and transmitted irradiance and radiant exposure (Bluephase Style) were measured in real-time on a laboratory-grade spectrometer.
Results: A progressive enhanced light transmittance was identified during polymerisation in all materials except for TEF, which became in all shades progressively opaque. DC variation in time was best described by an exponential sum function (R2>0.95) indicating a steeper begin of polymerization in V, while AFx and FF initiated the polymerization slower. The quantified parameters attested a faster initiation of polymerization and a slower transition into the glass-phase in materials with low filler volume. A moderate invers correlation was found among DC measured 300s post light irradiation and filler volume% (-0.644) or filler weight% (-0.403). No correlation was identified among DC and transmitted irradiance or radiant exposure. An independent t-test revealed similar DC at 2-mm or 4-mm depths, while highest loss in radiant transmittance was identified in the most translucent material (V).
Conclusions: The mode of light transmittance during polymerization does not alter polymerization kinetics in bulk-fill RBCs.
Methods: Four low-viscosity methacrylate-based and one high-viscosity ormocer-based bulk-fill RBCs were considered. One material was evaluated in three different shades. Polymerization kinetic (real-time degree of cure, DC) and light transmittance were assessed at 2 and 4-mm specimen depths. Incident and transmitted irradiance and radiant exposure (Bluephase Style) were measured in real-time on a laboratory-grade spectrometer.
Results: A progressive enhanced light transmittance was identified during polymerisation in all materials except for TEF, which became in all shades progressively opaque. DC variation in time was best described by an exponential sum function (R2>0.95) indicating a steeper begin of polymerization in V, while AFx and FF initiated the polymerization slower. The quantified parameters attested a faster initiation of polymerization and a slower transition into the glass-phase in materials with low filler volume. A moderate invers correlation was found among DC measured 300s post light irradiation and filler volume% (-0.644) or filler weight% (-0.403). No correlation was identified among DC and transmitted irradiance or radiant exposure. An independent t-test revealed similar DC at 2-mm or 4-mm depths, while highest loss in radiant transmittance was identified in the most translucent material (V).
Conclusions: The mode of light transmittance during polymerization does not alter polymerization kinetics in bulk-fill RBCs.