Influence of thickness and translucency of lithium disilicate ceramic on degree of conversion of resinous materials

Abstract

Background In this study was assessed the degree of conversion (DC) of amine-free resin cements light cured through lithium disilicate-reinforced ceramics at different thicknesses and translucency. Material and Methods Specimens were divided into 21 groups (n = 5) according to luting agent used: Variolink Esthetic LC (Light shade), RelyX Ultimate (A1 shade), and Filtek Z350 XT Flow (A1 shade); the ceramic translucency: low (LT) and high (HT); and the ceramic thickness: no ceramic (control), 0.5 mm, 1 mm, and 2 mm. A Teflon mold with (5 x 5 x 0.5 mm) was used to standardize the cement and over it the ceramic block from each group was placed. Set was cured using a polywave LED light (1200 mW/cm2 - Bluephase G2) for 40 s. FTIR spectra of uncured and cured materials was obtained and DC calculated from the height of the peaks 1610 and 1640 cm-1. Data were submitted to ANOVA followed by Tukey’s test (α = 0.05). Results There was a significant difference for luting agents ( p < 0.0001) and translucency ( p = 0.025), but not for thickness ( p = 0.73). Dual amine-free RelyX Ultimate showed the lowest DC values and higher translucency promoted higher DC. Conclusions Dual amine-free cement showed the lowest monomer conversion and higher translucency ceramics promoted a higher DC. Key words: Ceramic, degree of conversion, resin cement, thickness, translucency.

Effect of thickness on the translucency of resin-based composites and glass-ceramics

“…The translucency of intracoronal restorative materials also affects clinical performance especially in ceramic restoration by influencing the physicochemical properties of adhesive cementation underlying the materials. During cementation in indirect restoration, the light-curing unit's irradiance at the luting agent is impaired as ceramic restorations are more opaque and thicker, which may reduce the physicochemical properties of these materials [16][17][18] . Reductions in translucency by increasing resin composites' thickness and dental ceramics have been reported [19][20][21][22][23][24][25][26][27] .…”

Effect of thickness of CAD/CAM materials on light transmission and resin cement polymerization using a blue light‐emitting diode light‐curing unit

“…As demonstrated by the beam profile and THF results, the passage of light emitted by the LCU through indirect materials improved the light homogeneity for most materials and may have yielded higher DC of the LCC. Other factors might have also positively affected the high DC values, such as: (1) The clinically relevant resin cement thickness; 45 (2) A translucent resin cement; 35,40 (3) HT indirect materials; 29,30,34 (4) The use of a high irradiance LCU, which delivered a high radiant exposure 23,41 …”

“…Finally, the third and fourth hypotheses were also accepted since the IR affected the DC and Rp max of the LCC. Different brands of commercial LCCs have already been evaluated 4–12,16,17,22–24,29–42 . However, few assessed the DC of the same commercial LCC tested in this study activated by a monowave LCU 9,29,30,32,36 .…”

“…Many variables can influence the DC of the resin cement: (1) Resin cement's type, 7 shade/translucency; 35,40 (2) Indirect material's thickness, 7 type, 38,41 and shade/translucency; 29,30,34 ; (3) LCU's type and emittance 23,41 . This study evaluated only one commercial translucent LCC, light‐activated through nine different HT CAD/CAM materials, having up to 2‐mm thicknesses, by a commercial monowave LCU, using a 30 s exposure, at a 4‐mm‐distance from the resin cement.…”

Degree of conversion and cohesive strength of conventional dual resin and self-adhesive cements by using of different forms of activation

“…Moreover, Variolink II and RelyX U200 showed lower DC values in the LI mode of activation in comparison with L, and once again the dependence on exposure to light of these cements was demonstrated, in order to achieve high DC values. Therefore, care must be taken with the distance between the light source and the cement, thickness (Hardy et al, 2018;Jang et al, 2017;Lise et al, 2018;Martins et al, 2019;Rizzante et al, 2018;Tafur-Zelada et al, Research, Society and Development, v. 10, n. 9, e20910917850, 2021 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v10i9.17850 2021; Turp et al, 2018), color (Tafur-Zelada et al, 2021 , translucency (Liporoni et al, 2020;Shim et al, 2017) and type of restorative material of the prosthetic part (Lise et al, 2018;Majumder et al, 2019;Rizzante et al, 2018;Shim et al, 2017;Turp et al, 2018) to be cemented, since they could interfere in the DC, leading to low chemical stability, resulting in color instability and compromised mechanical properties.…”