Effects of 3 different light-curing units on the physico-mechanical properties of bleach-shade resin composites

Abstract

Objectives This study investigated the microhardness, flexural strength, and color stability of bleach-shade resin composites cured with 3 different light-curing units. Materials and Methods In this in vitro experimental study, 270 samples were fabricated of bleach and A2 shades of 3 commercial resin composites (Point 4, G-aenial Anterior, and Estelite Sigma Quick). Samples ( n = 5 for each trial) were cured with Bluephase N, Woodpecker LED.D, and Optilux 501 units and underwent Vickers microhardness and flexural strength tests. The samples were tested after 24 hours of storage in distilled water. Color was assessed using a spectrophotometer immediately after preparation and 24 hours after curing. Data were analyzed using 3-way analysis of variance and the Tukey test ( p ≤ 0.001). Results Samples cured with Optilux exhibited the highest and those cured with LED.D exhibited the lowest microhardness ( p = 0.023). The bleach shade of Point 4 composite cured with Optilux displayed the highest flexural strength, while the same composite and shade cured with Sigma Quick exhibited the lowest ( p ≤ 0.001). The color change after 24 hours was greatest for the bleach shade of G-aenial cured with Bluephase N and least for the A2 shade of Sigma Quick cured with Optilux ( p ≤ 0.001). Conclusions Light curing with polywave light-emitting diode (LED) yielded results between or statistically similar to those of quartz-tungsten-halogen and monowave LED in the microhardness and flexural strength of both A2 and bleach shades of resin composites. However, the brands of light-curing devices showed significant differences in color stability.

Effects of Dental Bleaching Agents on the Surface Roughness of Dental Restoration Materials

“…Regarding the working procedure, in the present study, the samples were made according to the instructions given by the manufacturer and the data found in the specialized literature, namely studies made on the same types of composites or on similar ones. Moreover, increasing the photopolymerization time of the composites did not have negative effects and even improved the mechanical properties of the composites [ 41 , 42 ].…”

Depth of Cure of Bulk-fill Resin Composites with Different Photo-initiator Systems Cured by Monowave and Polywave Light Curing Units

“…11,23 CQ is cured by conventional light cure units, and the effective wavelength range to activate it has been observed to be between 410 nm and 500 nm, with a peak wavelength of 470 nm. 14,23 CQ has a chromatic group in its molecular structure that makes it photoactive but also gives the substance its intense yellow hue. 45 This yellow color affect the restoration's absolute beauty.…”

“…26 Due to the low spectrum sensitivity, the alternative initiators may not work with the widely used monowave LCUs. 14 There are several light curing units (LCUs) available based on various physical principles, including lasers, plasma arc lamps, quartz-tungsten-halogen (QTH) bulbs, and light emitting diodes (LEDs). 3,19 The development of LED LCUs with multiple diodes, which offer a wider range of output wavelengths necessary to coincide with the absorption of CQ and alternative photo-initiator systems, is an advantage of materials that use short wavelengths.…”

Effect of hard segment chemistry and structure on the self‐healing properties of UV‐curable coatings based on the urethane acrylates with built‐in Diels–Alder adduct

“…3,17 Urethane acrylates (UA) are one of UV technology's most commonly used oligomers. [18][19][20][21][22] UA oligomers are obtained in a two-step process from diisocyanates (used in excess) and diols, resulting in a prepolymer containing terminal isocyanate groups, and then reacting the prepolymer with hydroxy acrylate. 1,[23][24][25][26] Consequently, these types of polymers have a favorable set of mechanical properties characteristic of polyurethanes 27 and partially exhibit optical properties typical of acrylates, 28 as well as the possibility of curing them with UV radiation.…”

“…It is well known that UV technology is appreciated for its “5E” characteristics, that is, efficiency, enhanced quality, energy savings, economics, and environmental friendliness 3,17 . Urethane acrylates (UA) are one of UV technology's most commonly used oligomers 18–22 . UA oligomers are obtained in a two‐step process from diisocyanates (used in excess) and diols, resulting in a prepolymer containing terminal isocyanate groups, and then reacting the prepolymer with hydroxy acrylate 1,23–26 .…”