All P-values < .05 were considered statistically significant. Lopes Cde C, Rodrigues RB, Silva AL, Simamoto Jnior PC, Soares CJ, Novais VR. The investigation of the surface hardness of a resin-based material is an accepted method for evaluating physical properties and degree of conversion.28,29,30,31 Many previous studies have used surface hardness, such as Knoop or Vickers, to test the degree of polymerization efficacy of resin cements, and a correlation has been reported;29,31,32 as the degree of conversion increases, the hardness also increases.29. Hofmann N, Papsthart G, Hugo B, Klaiber B. According to the measurement time, all resin cements showed significantly higher mean VHNs of 24 h group than the 0 h group (P < .05), but most of the values were not significantly different when compared with 48 h group (P > .05). 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. 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). Four zirconia specimens from each translucency were prepared. Aging resistance, mechanical properties and translucency of different yttria-stabilized zirconia ceramics for monolithic dental crown applications. Yan YL, Kim YK, Kim KH, Kwon TY. According to the measurement times, almost all groups showed a significantly higher VHN at 24 h than 0 h, while the values were not significantly higher from 24 h to 48 h, except for VL and RD under zirconia T. Consequently, the third null hypothesis was partially rejected. government site. This result may be explained by the less content of inorganic filler in the base paste of Variolink N but more dimethacrylates compared to its catalyst paste. Further studies of increasing the light curing time or intensity for low-translucency zirconia should be conducted to clarify the relationship of curing time and polymerization of the underlying cement. Sulaiman TA, Abdulmajeed AA, Donovan TE, Ritter AV, Vallittu PK, Nrhi TO, Lassila LV. Marghalani HY. Hofmann et al.30 also reported that VHNs of dual-cured resin cements by using light-curing mode with base paste alone showed lower VHNs than by using dual-curing mode with the mixture of base and catalyst paste through leucite-reinforced glass-ceramic. 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. Pekkan G, Saridag S, Pekkan K, Helvacioglu DY. 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. and transmitted securely. CAD/CAM ceramic restorative materials for natural teeth. 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). As the yttria content increases, cubic phase increases, which were reported to correlate with high translucency values.15 The isotropic property of the cubic phase reduces light scattering from grain boundaries and results in more translucent zirconia than the early generations.12 Nevertheless, transformation toughening occurs less in 5Y-PSZ,13,16 and is absent in 8Y-FSZ,16 as the stabilized cubic phase does not transform at room temperature, resulting in inferior flexural strength and toughness.13,16, Resin cements have been promoted for the cementation of conventional zirconia restorations due to their superior properties over conventional cements.17,18,19 The opacity of conventional zirconia masks the light transmission, and thus, dual-cured resin cements are preferable in clinical applications with the benefit of being both auto-cured and light-cured, resulting in a sufficient degree of conversion underneath the restoration. Microhardness of composite resins at different depths varying the post-irradiation time. For Variolink N, the VHNs in light-curing mode (VL) were significantly lower than the dual-curing mode (VD). 2). The shade of a cement has been reported to affect polymerization; darker shades showed lower microhardness.31,46 So-called transparent shades of resin cement exhibited more light absorption than opaque shades, being associated with increased curing depth and microhardness.47 In the present study, the transparent shades of Variolink N (VL and VD) and the translucent shade of RelyX (RL and RD) were used to minimize the impact of shade on the VHN and focused on the effect of the translucency of the zirconia and the post-curing interval. Translucency percentage = 100 - Opacity percentage. Note that the translucency percentage of zirconia HT and ST (19.7%) were closer to that of zirconia XT. Note: The same lower-case letters indicate no significant column differences (Brown-Forsythe ANOVA, P > .05). An official website of the United States government. Ciccone-Nogueira JC, Borsatto MC, de Souza-Zaron WC, Ramos RP, Palma-Dibb RG. This may imply that using Variolink N in light curing mode showed the slowest initial polymerization, as mentioned above, which were much slower than using in dual curing mode of VD. Received 2021 May 12; Revised 2021 Aug 13; Accepted 2021 Aug 20. Hn0E0K$cjVbA A~umV?Ll',q/egq8+4dKM W"p;~4|j9[pIG,Hek rp *According to the manufacturers' information. This property disallows pure zirconia to be used as a dental restorative material. At each post curing time of each translucency, VD showed higher VHN than VL (P < .05), and RD also showed higher VHN than RL (P < .05). The VHN percentage was calculated from the mean VHNs of each experimental group and compared with the VHN of its control group at the final measurement of 48 h. The data were analyzed by IBM SPSS Statistics for Windows version 22 (IBM SPSS Statistics, IBM Corp, Chicago, IL, USA). Before BisGMA: Bisphenol-A-diglycidylether dimethacrylate; UDMA: Urethane Dimethacrylate; TEGDMA: triethylene glycol dimethacrylate. The VHN tended to be less in the lower translucency groups of ST, HT and T, respectively). Zhang F, Inokoshi M, Batuk M, Hadermann J, Naert I, Van Meerbeek B, Vleugels J. The site is secure. The translucency of zirconia has an effect on the VHN for light-cured resin cements, but has no effect on dual-cured resin cements. 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. The purpose of this study was to investigate the Vickers hardness number (VHN) of light- and dual-cured resin cements after light transmission through various translucencies of monolithic zirconia at three different times after curing. Blatz MB, Phark JH, Ozer F, Mante FK, Saleh N, Bergler M, Sadan A. The interface of the resin cement and the gypsum surface was marked as the zero point. Changes in degree of conversion and microhardness of dental resin cements. Vagkopoulou T, Koutayas SO, Koidis P, Strub JR. Zirconia in dentistry: part 1. Manziuc MM, Gasparik C, Negucioiu M, Constantiniuc M, Alexandru B, Vlas I, Dudea D. Optical properties of translucent zirconia: a review of the literature. Typically, dual-cured resin cement seems to have different relative contributions of light- and chemical-cured mechanisms depending on brands.33,43,44 This might be the differences in material specifications that influence the different initial rates of conversion after light activation and affect the final degree of conversion.33,45. The translucency percentage of zirconia T was the lowest (11.3%) and was lower than zirconia HT (18.4%), which contain the same amount of yttria, while its value was about half of zirconia XT (22.9%). Nanocrystalline zirconia-yttria systema raman study. Furthermore, fewer amounts of initiators and stabilizers may contribute its slow rate of polymerization. Camposilvan E, Leone R, Gremillard L, Sorrentino R, Zarone F, Ferrari M, Chevalier J. They showed that the degree of conversion and the VHN values significantly increased during the first one hour and the values were not significantly different from 24 h to 7 days. Kumbuloglu O, Lassila LV, User A, Vallittu PK. Shahmiri R, Standard OC, Hart JN, Sorrell CC. Degree of conversion of dual-polymerizing cements light polymerized through monolithic zirconia of different thicknesses and types. Zhang Y. 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. Effect of alumina dopant on transparency of tetragonal zirconia. The zirconia specimens from the same manufacturer were used in this study to eliminate the influence from the differences in brands as reported in the study of Sulaiman et al.22 Therefore, the influence of the translucency level can be emphasized. A study of the physical and chemical properties of four resin composite luting cements. Zhang Y, Lawn BR. 8600 Rockville Pike Ichikawa Y, Akagawa Y, Nikai H, Tsuru H. Tissue compatibility and stability of a new zirconia ceramic in vivo. Dual-cured resin cement exhibited higher VHN than the light-cured resin cement from the same manufacturer. sharing sensitive information, make sure youre on a federal To maintain the beneficial mechanical properties of the tetragonal phase at room temperature, stabilization can be achieved by adding various oxides such as calcium oxide (CaO), magnesium oxide (MgO), yttrium oxide (Y2O3), and cerium oxide (CeO2). In vitro comparative bond strength of contemporary self-adhesive resin cements to zirconium oxide ceramic with and without air-particle abrasion. In contrast, the highest translucency of zirconia XT showed the highest VHN percentage among all translucencies for every cement and measurement time. 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. At each measurement time, the mean VHNs of both dual cured resin cements were significantly higher than those of light cured resin cements from the same manufacturer at each level of the same translucency (P < .05). However, opacity was still a problem as the early monolithic zirconia was limited to posterior teeth.7 To improve the translucency, various techniques have been developed such as a decrease in grain size,8,9 elimination or reduction of the concentration of some additives such as alumina,10 addition of 0.2 mol% lanthanum oxide,11 and an increase in sintering temperature.12 Presently, greater percentage of yttria is added to monolithic zirconia to achieve a transparent phase. This study aimed to investigate the Vickers Hardness Number (VHN) of light- and dual cured resin cements cured through monolithic zirconia specimens (VITA YZ) of various translucencies: translucent (T); high translucent (HT); super translucent (ST); and extra translucent (XT) at 0, 24, and 48 h after curing. Alovisi M, Scotti N, Comba A, Manzon E, Farina E, Pasqualini D, Michelotto Tempesta R, Breschi L, Cadenaro M. Influence of polymerization time on properties of dual-curing cements in combination with high translucency monolithic zirconia. The cement was light-cured for 20 s at an intensity of 800 mW/cm2, and the light intensity was checked before each curing. Strength, toughness and aging stability of highly-translucent Y-TZP ceramics for dental restorations. According to the data of VHN percentage, at 48 h, the range of the value of light-cured resin cements (91.4 99.6%) was higher than dual-cured resin cements (88.5 98.0%), depending on the zirconia translucency. 1A). The .gov means its official. Two-way repeated-measured ANOVA was performed to determine the effect of different translucencies of zirconia and resin cements and their interactions on the mean VHNs, with different measurement time as a repeated factor. The translucency percentage of each specimen was calculated from the obtained opacity percentage measured by the spectrophotometer (Ultrascan PRO 74-SD-03-10, HunterLab, Reston, VA, USA) subtracted from 100. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (, {"type":"entrez-nucleotide","attrs":{"text":"Y15347","term_id":"4218494","term_text":"Y15347"}}. Five measurements of each sample were obtained and the mean VHN was calculated. This might due to the higher percentage of initiators and stabilizers in catalyst paste that can accelerate the initial polymerization immediately after light activation. PMC legacy view Ghosh A, Suri AK, Pandey M, Thomas S, Rama Mohan TR, Rao BT. Degree of conversion and bond strength of resin-cements to feldspathic ceramic using different curing modes. Optical properties and light irradiance of monolithic zirconia at variable thicknesses. :FL8aay")}t]dgaZ-l68P9`Z~ vm=-3$_scq+n"Em=]l.Vez:+}}toq8dOiaZPX \(T endstream endobj 100 0 obj << /Type /FontDescriptor /Ascent 714 /CapHeight 714 /Descent -182 /Flags 262176 /FontBBox [ -166 -218 1078 975 ] /FontName /PJLONH+HelveticaNeue-Bold /ItalicAngle 0 /StemV 142 /XHeight 517 /StemH 107 /CharSet (/P/R/O/D/U/C/T/B/A/N/M/E/I/S/space/Y/K/V/G/e/l/y/X/n/i/c/m/f/hyphen/d/h/\ s/v/r/a/t/L/u/g/p/o/slash/F/period/comma/three) /FontFile3 128 0 R >> endobj 101 0 obj << /Type /Font /Subtype /Type1 /FirstChar 32 /LastChar 121 /Widths [ 278 278 463 556 556 1000 685 278 296 296 407 600 278 407 278 371 556 556 556 556 556 556 556 556 556 556 278 278 600 600 600 556 800 685 704 741 741 648 593 759 741 295 556 722 593 907 741 778 667 778 722 649 611 741 630 944 667 667 648 333 371 333 600 500 259 574 611 574 611 574 333 611 593 258 278 574 258 906 593 611 611 611 389 537 352 593 520 814 537 519 ] /Encoding /WinAnsiEncoding /BaseFont /PJLONH+HelveticaNeue-Bold /FontDescriptor 100 0 R >> endobj 102 0 obj 506 endobj 103 0 obj << /Filter /FlateDecode /Length 102 0 R >> stream Denry I, Kelly JR. State of the art of zirconia for dental applications. 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. Department of Prosthodontics, Faculty of Dentistry, Chulalongkorn University, 34 Henri-Dunant Road, Pathumwan, Bangkok, 10330 Thailand. According to the VHN percentage (Table 6), the lowest translucency of zirconia T had the lowest mean VHN percentage among all translucencies for every cement and measurement time. Tel +6622188532. Moreno MBP, Costa AR, Rueggeberg FA, Correr AB, Sinhoreti MAC, Ambrosano GMB, Consani S, Correr Sobrinho L. Effect of ceramic interposition and post-activation times on knoop hardness of different shades of resin cement. 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. Fonseca RG, Cruz CA, Adabo GL. will also be available for a limited time. 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. 1B. Spitznagel FA, Boldt J, Gierthmuehlen PC. Re D, Augusti D, Sailer I, Spreafico D, Cerutti A. Xiong Y, Fu Z, Pouchly V, Maca K, Shen Z. High amounts of yttria in Y-TZP were reported to correlate with high translucency values,15 which were associated with its microstructural character and chemical composition.23 The increasing yttria content from 3 9 wt% was related to the increased grain size and cubic phase, thus leading to an increase in translucency of zirconia.35 The same materials used in this present study (VITA YZ HT, ST, and XT) were investigated by Sen and Isler23 for the crystalline phases after sintering, by using X-ray Diffraction (XRD). Correlation between hardness and degree of conversion during the setting reaction of unfilled dental restorative resins. Then, a thin glass slide (0.15 mm thick) was placed over the mold using finger pressure to expel excess cement. The VHN reflects the curing state of the resin material and perform a continuation of the polymerization reaction,39 which were explained by the presence of free monomers with potential in mobility to allow low rate interaction.40 For light-cured resin materials, light exposure causes a rapid increase in viscosity, especially with high-intensity curing lights.41 Even though the first exposure to the light curing unit produces immediate curing and hardening, polymerization still proceeds for a period of up to 24 h.33,41 The so-called dark polymerization of unreacted monomers can continue the after the cessation of light activation.42 During the early period of polymerization, the cement with a slow rate of conversion required a longer time to be completely polymerized.33 Note that the VHNs of VL at 0 h was relatively low (15.5919.03) compared to those of VD, RL and RD which range from 30.19 to 40.27. The cement was mixed and loaded in a mold and cured for 20 s through the zirconia specimen. Making yttria-stabilized tetragonal zirconia translucent. Reges RV, Moraes RR, Correr AB, Sinhoreti MA, Correr-Sobrinho L, Piva E, Nouer PR. Five specimens were prepared for each group, as this setup provided sufficient statistical power (using = .05 and a power of 99%) from the pilot study by using statistical power analysis program (G Power 3.1, Heinrich-Heine-Universitt, Dsseldorf, Germany). Light energy transmission through composite influenced by material shades. Prof. Soranun Chantarangsu and Dr. Nareudee Limpuangthip, Chulalongkorn University, for their assistance in statistical analysis. The same upper-case letters indicate no significant row differences (repeated-measured ANOVA in row, P > .05). http://creativecommons.org/licenses/by-nc/4.0, Barium glass filler and mixed oxide (48.4%), dimethacrylates (BisGMA, UDMA, and TEGDMA) (26.3%), ytterbium trifluoride (25.0%), initiators and stabilizers (0.3%), pigments (< 0.1%), Base: Barium glass filler and mixed oxide (48.4%), dimethacrylates (BisGMA, UDMA, and TEGDMA) (26.3%), ytterbium trifluoride (25.0%), initiators and stabilizers (0.3%), pigments (< 0.1%), Catalyst: Barium glass filler and mixed oxide (52.2%), dimethacrylates (22.3%), ytterbium trifluoride (25.0%), initiators and stabilizers (0.8%), pigments (< 0.1%), BisGMA and TEGDMA polymer, Zirconia/silica, and fumed silica fillers (66%), Base: methacrylate monomers containing phosphoric acid groups, TEGDMA, silanated fillers, initiator components, stabilizers, rheological additives, Catalyst: methacrylate monomers, alkaline (basic) fillers, silanated fillers, initiator components, stabilizers, rheological additives, pigments.