Novel zirconia materials in dentistry. For the RelyX groups, RD contains a greater proportion of filler particles (72 wt% filler) than RL (66 wt% filler).34,36 A higher filler loading results in a higher post-curing surface hardness, as rigid inorganic particles provide a strong interfacial bond between the filler particles and resin matrix, which directly contributes to higher hardness.37,38 Apart from filler content, the filler size also plays a role in the surface hardness of cement.30. Ghosh A, Suri AK, Pandey M, Thomas S, Rama Mohan TR, Rao BT. Hn0E0K$cjVbA A~umV?Ll',q/egq8+4dKM W"p;~4|j9[pIG,Hek rp The cement was light-cured for 20 s at an intensity of 800 mW/cm2, and the light intensity was checked before each curing. Changes in degree of conversion and microhardness of dental resin cements. The site is secure. Ichikawa Y, Akagawa Y, Nikai H, Tsuru H. Tissue compatibility and stability of a new zirconia ceramic in vivo. Shahmiri R, Standard OC, Hart JN, Sorrell CC. Thus, when using the mixed pastes in dual-cured mode, a higher amount of fillers and less resin matrix contents from catalyst paste might explain for higher VHNs than using in light-cured mode. De Souza G, Braga RR, Cesar PF, Lopes GC. Two light-cured resin cements (Variolink N LC by Ivoclar Vivadent AG, Schaan, Liechtenstein; VL and RelyX Veneer by 3M-ESPE, St. Paul, MN, USA; RL) and two dual-cured resin cements (Variolink N DC by Ivoclar Vivadent AG; VD and RelyX U200 by 3M-ESPE; RD) were used (Table 2). The light-cured cements showed higher VHN percentage (VL = 99.1% and RL = 99.6%) than the dual-cured cements from the same manufacturer (VD = 94.9% and RD = 98.0%) at 48 h. The surface hardness of a resin-based luting cement has been shown to be correlated with its degree of conversion, and therefore, the microhardness test is a reliable indirect method to evaluate the degree of conversion of the resin cement.28,29,31,33 As the degree of conversion increases, a higher hardness of the material will be evident.29 A lower degree of conversion of resin cement could lead to poor properties such as marginal leakage, lower color stability, increased water sorption, change in dimensional stability, and other factors that can lead to restoration failure.27,32,34, According to the effect of different translucencies of zirconia on the VHN of the resin cements, zirconia XT was associated with a higher VHN than zirconia T, except for the dual-cured cement VD and RD groups; therefore, the first null hypothesis was partially rejected. Lopes Cde C, Rodrigues RB, Silva AL, Simamoto Jnior PC, Soares CJ, Novais VR. *According to the manufacturers' technical data, safety data sheets and instruction for use. Tarumi H, Imazato S, Ehara A, Kato S, Ebi N, Ebisu S. Post-irradiation polymerization of composites containing bis-GMA and TEGDMA. Nanocrystalline zirconia-yttria systema raman study. and transmitted securely. The means and standard deviations of VHN for VL and VD are shown in Table 4, and those for RL and RD are shown in Table 5. Four specimens from the four translucencies of monolithic zirconia (VITA YZ; VITA Zahnfabrik, Bad Sckingen, Germany): translucent (T); super translucent (ST); high translucent (HT); and extra translucent (XT) (Table 1), were prepared using CAD-CAM software (3Shape Dental System, 3Shape A/S, Copenhagen, Denmark) and sintered (VITA Zyrcomat 6000 MS; VITA Zahnfabrik) to the final size of square-shaped specimens (10 10 mm) with 1 0.05 mm thickness, measured by a digital Vernier caliper (Series 500, Mitutoyo, Kanagawa, Japan). However, the dark polymerization of VL could adequately compensate its low initial light polymerization and reach its ultimate value with a slower processing time. Effect of alumina dopant on transparency of tetragonal zirconia. Zhang F, Vanmeensel K, Batuk M, Hadermann J, Inokoshi M, Van Meerbeek B, Naert I, Vleugels J. Highly-translucent, strong and aging-resistant 3Y-TZP ceramics for dental restoration by grain boundary segregation. Three null hypotheses were tested: (1) monolithic zirconia specimens of different translucencies have no effect on the VHN of resin cement; (2) there is no difference in VHN between light- and dual-cured resin cements after light curing through monolithic zirconia; (3) there is no difference in the VHN of a resin cement at three different times after curing. Prof. Soranun Chantarangsu and Dr. Nareudee Limpuangthip, Chulalongkorn University, for their assistance in statistical analysis. The translucency of zirconia has an effect on the VHN for light-cured resin cements, but has no effect on dual-cured resin cements. Akagawa Y, Hosokawa R, Sato Y, Kamayama K. Comparison between freestanding and tooth-connected partially stabilized zirconia implants after two years' function in monkeys: a clinical and histologic study. The specimens were polished by a single operator using VITA Suprinity Polishing Set, as recommended by the manufacturer;s instructions, ultrasonically cleaned (VGT-1990 QTD, GT Sonic, Guangdong, China) in distilled water for 10 min and dried with absorbent paper. Department of Prosthodontics, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand. Ferracane JL. In-depth polymerization of dual-cured resin cement assessed by hardness. Zhang Y, Lawn BR. The dual-cured resin cements might exhibit higher hardness and do not depend on the translucency, while the light-cured resin cements might result in a higher degree of conversion and the hardness depends on the translucency, and some cements may show slow initial rate of polymerization. The upper surface of each cement specimen was uncovered to be tested on Vickers hardness tester (FM-810, Future-Tech Corp., Kawasaki, Japan) with a load of 300 g for 15 s in a linear pattern as shown in Fig. Accessibility McLaren EA, Lawson N, Choi J, Kang J, Trujillo C. New high-translucent cubic-phase-containing zirconia: clinical and laboratory considerations and the effect of air abrasion on strength. They revealed that the highest percentage of the cubic phase was found in VITA YZ XT (32.9 wt%), followed by ST (27.2 wt%) and HT (13.7 wt%), and zirconia XT showed the largest mean grain size, followed by zirconia ST and HT. Translucency percentage = 100 - Opacity percentage. The interface of the resin cement and the gypsum surface was marked as the zero point. This may suggest that the light-cured resin cements exhibit higher degree of conversion than the dual-cured resin cements under any translucency of zirconia. Making yttria-stabilized tetragonal zirconia translucent. The cement was mixed and loaded in a mold and cured for 20 s through the zirconia specimen. Learn more Sen N, Isler S. Microstructural, physical, and optical characterization of high-translucency zirconia ceramics. Light energy transmission through composite influenced by material shades. Yan YL, Kim YK, Kim KH, Kwon TY. All resin cements showed significantly higher VHN from 0 h to 24 h. Zirconia (zirconium dioxide, ZrO2) ceramic has been routinely used in many all-ceramic dental restorations, due to its flexural strength, combined with esthetics and good biocompatibility.1,2 Zirconia is a polymorphic material that occurs in three different crystal structures, depending on the temperature: a monoclinic phase (room temperature to 1170) with brittle and low mechanical properties; a tetragonal phase (1170 2370) with higher mechanical properties; and a cubic phase (2370).3 A volume expansion (3 5%) occurs during the cooling process when the tetragonal phase transforms into the monoclinic phase, leading to high stress and crack formation, and a decrease in strength and toughness. Zhang F, Inokoshi M, Batuk M, Hadermann J, Naert I, Van Meerbeek B, Vleugels J. The new PMC design is here! Before Tel +6622188532. 1A). At 48 h, the light-cured cement VL and RL showed higher VHN percentage (91.4 and 95.7) than dual-cured VD and RD (88.5 and 89.6). Xiong Y, Fu Z, Pouchly V, Maca K, Shen Z. Zhang H, Li Z, Kim B-N, Morita K, Yoshida H, Hiraga K, Sakka Y. This might due to the higher percentage of initiators and stabilizers in catalyst paste that can accelerate the initial polymerization immediately after light activation. In contrast, the highest translucency of zirconia XT showed the highest VHN percentage among all translucencies for every cement and measurement time. BisGMA: Bisphenol-A-diglycidylether dimethacrylate; UDMA: Urethane Dimethacrylate; TEGDMA: triethylene glycol dimethacrylate. Therefore, the amount of yttria content might be one of the factors that affect the light transmission through monolithic zirconia. Comparison of photo-activation versus chemical or dual-curing of resin-based luting cements regarding flexural strength, modulus and surface hardness. Federal government websites often end in .gov or .mil. Microhardness of composite resins at different depths varying the post-irradiation time. Corresponding author: Prarom Salimee. Zirconia specimens in the experimental groups, or a 1-mm thick glass slide in the control group, were placed over the thin glass slide, and the tip of a light curing unit, which delivers light between 400 and 515 nm (Elipar Trilight, 3M-ESPE, St. Paul, MN, USA), was positioned directly on the top of the of the assembly specimen (Fig. Barbon FJ, Moraes RR, Calza JV, Perroni AP, Spazzin AO, Boscato N. Inorganic filler content of resin-based luting agents and the color of ceramic veneers. The upper surface of cements was tested for VHN using a microhardness tester at 0, 24, and 48 h after curing. Ciccone-Nogueira JC, Borsatto MC, de Souza-Zaron WC, Ramos RP, Palma-Dibb RG. Blatz MB, Phark JH, Ozer F, Mante FK, Saleh N, Bergler M, Sadan A. Reges RV, Moraes RR, Correr AB, Sinhoreti MA, Correr-Sobrinho L, Piva E, Nouer PR. Optical properties and light irradiance of monolithic zirconia at variable thicknesses. CAD/CAM ceramic restorative materials for natural teeth. Translucency and strength of high-translucency monolithic zirconium oxide materials. Moreover, longer storage time might be evaluated since some studies had reported the significantly increased in the degree of conversion and VHN value after 7 days.48,49. This showed the same trend of translucent level obtained in this study and zirconia XT showed the highest translucency and significantly allowed a greater VHN value, which related to the degree of conversion of resin cements underneath. This property disallows pure zirconia to be used as a dental restorative material. *According to the manufacturers' information. The VHN were analyzed using two-way repeated, Brown-Forsythe ANOVA with Games Howell post-hoc analysis and independent t-tests (P < .05). Two light-cured resin cements (Variolink N LC; VL and RelyX Veneer; RL) and two dual-cured resin cements (Variolink N DC; VD and RelyX U200; RD) were used. The ZrO2: zirconium oxide; Y2O3: yttrium oxide; HfO2: Hafnium dioxide; Al2O3: Aluminium oxide; ERDO3: Erbium oxide; Fe2O3: Iron (III) oxide. Among these stabilizers, the addition of 3 mol% diyttrium trioxide (Y2O3; also termed yttrium (III) oxide or yttria) is widely used for dental zirconia, and is known as 3% yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP).4 When zirconia is subjected to heat or low stress such as grinding, sandblasting, or steam sterilizing, the tetragonal phase can transform into the monoclinic phase and influence its mechanical properties by a 3 5% of volume expansion which generates a compressive stress layer around the progressing internal crack tip. The VHN was significantly affected by all independent variables of translucency, resin cement, and measurement time, all two-way interactions except the measurement time and translucency, and the three-way interaction of all parameters. The effect of surface treatment on the adhesion of resin cements to Y-TZP. Kim KH, Ong JL, Okuno O. Marghalani HY. Within the limitations of this study, it can be concluded that different translucencies of zirconia have an effect on the VHN for light-cured resin cements (RL and VL), but do not have an effect on dual-cured resin cements (RD and VD). 1B. This study was supported by Chulalongkorn University graduate school thesis grant, Chulalongkorn University, Bangkok, Thailand (Grant No: GCUGR1225632039M-039). At 48 h, the VHN of light-cured cements were significantly lower when cured under the T groups than under XT groups (P = .001 in VL, P = .014 in RL). Camposilvan E, Leone R, Gremillard L, Sorrentino R, Zarone F, Ferrari M, Chevalier J. The specimens of the 0 h groups were subjected to test immediately for the mean VHNs, while for the 24 h and 48 h groups, they were left dry in a dark chamber at 37 until testing. Church TD, Jessup JP, Guillory VL, Vandewalle KS. Sulaiman TA, Abdulmajeed AA, Donovan TE, Ritter AV, Lassila LV, Vallittu PK, Nrhi TO. Bandca MC, El-Mowafy O, Saade EG, Rastelli ANS, Bagnato VS, Porto-Neto ST. Changes on degree of conversion of dual-cure luting light-cured with blue LED. Other characteristics of the zirconia variants may have contributed to these results, including the grain size or the sintering parameters.23, Since the new generation of monolithic zirconia provides high translucency similar to lithium disilicate ceramic,24 more anterior applications, such as crowns, bridges, and veneers, become possible.25,26 It would be advantageous for light polymerization of resin cement below the restorations, enhancing the use of light-cured resin cements with the advantages of easier excess cement removal, extended working time, and good color stability, compared to dual-cured cements.27 The degree of light transmission through the translucent monolithic zirconia should be investigated in order to assess the degree of conversion of light- compared to dual-cured resin cements, with respect to the different levels of translucency available.