Micro-Raman spectroscopic analysis of the degree of conversion of composite resins containing different initiators cured by polywave or monowave LED units

Effect of the irradiance distribution from light curing units on the local micro-hardness of the surface of dental resins

“…Increasing hardness and DC were reported in studies comparing the curing performance of mono-and polywave LCUs [34,36,51].…”

“…Several authors have described the problem of inhomogeneous irradiance output from LCUs, the effect on the curing of VLC RBCs and the consequences of the light output measurement as part of the quality management [31][32][33][34]. Currently two different types of light-emitted diode (LED) LCUs are in use: Firstly, monowave blue-LED units emitting a relatively sharp blue light peak and secondly, polywave LED units emitting a broader spectrum with at least two peaks at different wavelengths.…”

Curing Effectiveness of Single-Peak and Multi-Peak Led Light Curing Units on Tpo-Containing Resin Composites With Different Chromatic Characteristics

“…However other initiators have been introduced such as trimethylbenzoyl-diphenyphosphine oxide (TPO) mainly to overcome problems derived from CQ's intensive yellow color and relative color instability. TPO-containing RBCs showed comparable or higher DC and greater color stability than those containing CQ and tertiary amines (8,9). Moreover TPO has a higher value of light absorption than CQ: this indicate that the use of such a photoinitiator confers higher polymerization efficiency (8).…”

“…Therefore, DC plays an important role in determining the ultimate success of restorations (4)(5)(6). Several parameters influencing polymerization of RBCs should be considered: RBCs' chemical composition, amount and size of filler particles, type of photoinitiators, spectral output emitted by light curing units (LCUs), light intensity delivered by LCUs to the polymer (power density), exposure time, total amount of light transmitted by LCUs (energy density), and distance between light guiding tip and RBCs (5)(6)(7)(8)(9). Shade and translucency of RBCs should also be considered because light passing through the material is absorbed and scattered, resulting in an attenuation of the intensity and subsequent reduction of light available for activate curing process (10)(11)(12)(13).…”

Optimizing the concentration of 2,4,6-trimethylbenzoyldiphenylphosphine oxide initiator in composite resins in relation to monomer conversion

“…Unfilled methacrylate mixtures containing Lucirin ® TPO showed comparable or higher degrees of conversion (DC) and color stability than CQ-amine and phenylpropanedione containing resins 2) . Lucirin ® TPO resulted in higher DC than CQ-amine in composite resins cured with halogen 12) or polywave light-curing units (LCUs) 13) . In dental adhesives, the use of Lucirin ® TPO instead of CQ-amine results in similar DC and mechanical properties when cured with a polywave LED LCU 11) .…”