Download PDF
CC BY 4.0 · Eur J Dent 2024; 18(01): 196-207
DOI: 10.1055/s-0043-1764233
Original Article

Optical Characteristics of Monochrome and Multilayer Fully Stabilized Zirconia Upon Sintered Cooling Speed

Pithiwat Uasuwan 
1   Division of Biomaterials and Prosthodontics Research, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand
,
Niwut Juntavee 
2   Department of Prosthodontics, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand
,
Apa Juntavee 
3   Division of Pediatric Dentistry, Department of Preventive Dentistry, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand
› Author Affiliations Funding Faculty of Dentistry, Khon Kean University, Ministry of Higher Education, Science, Research and Innovation, Royal Thai Government for the grant supporting this study. (Grant No. DTR6410/23112564)
› Further Information
   Permissions and Reprints

Abstract

Objectives Firing protocols influence optical properties of dental ceramics. Effects of varying cooling rates of monochrome and multilayer 5 mol% yttria-stabilized tetragonal polycrystalline (5YTZP) on optical properties are subjected for investigation.

Materials and Methods Ninety specimens (width, length, thickness = 10 × 20 × 2 mm) were prepared from monochrome (Mo: Cercon xt) and multilayer (Mu: Cercon xt ML with cervical (C) and incisal (I) zoning) 5YTZP. Specimens were sintered and randomly treated with three cooling rates (n = 15/group): slow (S: 5°C/min), normal (N: 35°C/min), and fast (F: 70°C/min). Color appearance (∆EW), color appearance difference (∆E diff), translucency parameter (TP), contrast ratio (CR), and opalescence parameter (OP) were evaluated in CIEL*a*b* (Commission International de I'Eclairage) system. ∆E diff was achieved from the coordinate difference of specimen to VITA classic shade A2. Microstructures and compositions were evaluated by scanning electron microscope and energy dispersive spectroscopy. Monoclinic (m), tetragonal (t), and cubic (c) phases were investigated with X-ray diffraction.

Statistical Analysis An analysis of variance and Bonferroni multiple comparisons were determined for significant differences (p < 0.05).

Results ΔEW of MoF was highest (66.04 ± 1.86), while MuN-I was lowest (62.60 ± 0.86). TP and OP of MoS were highest at 2.85 ± 0.11, and 2.25 ± 0.10, while MuF-I was lowest at 2.16 ± 0.10 and 1.60 ± 0.12. CR of MuF-I was highest (0.948 ± 0.005), while MoS was lowest (0.936 ± 0.005). ΔEdiff of MoF was highest (3.83), while MuN-I was lowest (0.93). Limited grain growth and m-phase composition were indicated upon fast cooling. There were significant differences for all color parameters due to varied materials, cooling rates, and their interactions (p < 0.05) except for interaction in ∆EW and OP.

Conclusions Translucency of monochrome and multilayer 5YTZP were different, possibly due to colorant additives. Incisal layer of multilayer 5YTZP was perfectly matched with VITA shade. Increasing cooling speed resulted in smaller grain size, t-m transformation, and finally lower translucency and opalescence. Therefore, to achieve most favorable optical properties, slow cooling rate is recommended.

Keywords

color appearance - contrast - cooling - opalescence - translucency

Clinical Significance

Clinicians should consider modifying firing parameters. The fast-cooling protocol was not suggested since it reduced the translucency and opalescence as well as increased color difference from the color shade tab. Prolonging the sintering time by reducing the cooling speed showed better optical properties. Moreover, the monochrome 5YTZP had better optical properties than both layers of multilayer 5YTZP. The incisal layer of multilayer 5YTZP was proved to be the best match for the VITA shade tab.




Publication History

Article published online:
14 April 2023

© 2023. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/)

Thieme Medical and Scientific Publishers Pvt. Ltd.
A-12, 2nd Floor, Sector 2, Noida-201301 UP, India

 

  • References

  • 1 Bilgin MS, Baytaroğlu EN, Erdem A, Dilber E. A review of computer-aided design/computer-aided manufacture techniques for removable denture fabrication. Eur J Dent 2016; 10 (02) 286-291
    Article in Thieme ConnectPubMedGoogle Scholar
  • 2 Gracis S, Thompson VP, Ferencz JL, Silva NR, Bonfante EA. A new classification system for all-ceramic and ceramic-like restorative materials. Int J Prosthodont 2015; 28 (03) 227-235
    CrossrefPubMedGoogle Scholar
  • 3 Özkurt-Kayahan Z. Monolithic zirconia: a review of the literature. Biomed Res 2016; 27 (04) 1427-1436
    Google Scholar
  • 4 Lughi V, Sergo V. Low temperature degradation -aging- of zirconia: a critical review of the relevant aspects in dentistry. Dent Mater 2010; 26 (08) 807-820
    CrossrefPubMedGoogle Scholar
  • 5 Studart AR, Filser F, Kocher P, Gauckler LJ. Fatigue of zirconia under cyclic loading in water and its implications for the design of dental bridges. Dent Mater 2007; 23 (01) 106-114
    CrossrefPubMedGoogle Scholar
  • 6 Denry I, Kelly JR. Emerging ceramic-based materials for dentistry. J Dent Res 2014; 93 (12) 1235-1242
    CrossrefPubMedGoogle Scholar
  • 7 Tuncel İ, Turp I, Üşümez A. Evaluation of translucency of monolithic zirconia and framework zirconia materials. J Adv Prosthodont 2016; 8 (03) 181-186
    CrossrefPubMedGoogle Scholar
  • 8 Sailer I, Fehér A, Filser F, Gauckler LJ, Lüthy H, Hämmerle CH. Five-year clinical results of zirconia frameworks for posterior fixed partial dentures. Int J Prosthodont 2007; 20 (04) 383-388
    PubMedGoogle Scholar
  • 9 Abdulazeez MI, Majeed MA. Fracture strength of monolithic zirconia crowns with modified vertical preparation: a comparative in vitro study. Eur J Dent 2022; 16 (01) 209-214
    Article in Thieme ConnectPubMedGoogle Scholar
  • 10 Juntavee N, Attashu S. Effect of sintering process on color parameters of nano-sized yttria partially stabilized tetragonal monolithic zirconia. J Clin Exp Dent 2018; 10 (08) e794-e804
    PubMedGoogle Scholar
  • 11 Alghazali N, Burnside G, Moallem M, Smith P, Preston A, Jarad FD. Assessment of perceptibility and acceptability of color difference of denture teeth. J Dent 2012; 40 (Suppl 1): e10-e17
    CrossrefPubMedGoogle Scholar
  • 12 Baldissara P, Llukacej A, Ciocca L, Valandro FL, Scotti R. Translucency of zirconia copings made with different CAD/CAM systems. J Prosthet Dent 2010; 104 (01) 6-12
    CrossrefPubMedGoogle Scholar
  • 13 Della Bona A, Nogueira AD, Pecho OE. Optical properties of CAD-CAM ceramic systems. J Dent 2014; 42 (09) 1202-1209
    CrossrefPubMedGoogle Scholar
  • 14 Cho MS, Yu B, Lee YK. Opalescence of all-ceramic core and veneer materials. Dent Mater 2009; 25 (06) 695-702
    CrossrefPubMedGoogle Scholar
  • 15 Lee YK, Yu B. Measurement of opalescence of tooth enamel. J Dent 2007; 35 (08) 690-694
    CrossrefPubMedGoogle Scholar
  • 16 Stawarczyk B, Keul C, Eichberger M, Figge D, Edelhoff D, Lümkemann N. Three generations of zirconia: From veneered to monolithic. Part I. Quintessence Int 2017; 48 (05) 369-380
    PubMedGoogle Scholar
  • 17 Juntavee N, Uasuwan P. Influence of thermal tempering processes on color characteristics of different monolithic computer-assisted design and computer-assisted manufacturing ceramic materials. J Clin Exp Dent 2019; 11 (07) e614-e624
    PubMedGoogle Scholar
  • 18 Juntavee N, Uasuwan P. Flexural strength of different monolithic computer-assisted design and computer-assisted manufacturing ceramic materials upon different thermal tempering processes. Eur J Dent 2020; 14 (04) 566-574
    Article in Thieme ConnectPubMedGoogle Scholar
  • 19 Zhang F, Inokoshi M, Batuk M. et al. Strength, toughness and aging stability of highly-translucent Y-TZP ceramics for dental restorations. Dent Mater 2016; 32 (12) e327-e337
    CrossrefPubMedGoogle Scholar
  • 20 Chevalier J, Gremillard L, Deville S. Low-Temperature Degradation of zirconia and implications for biomedical implants. Annu Rev Mater Res 2007; 37 (01) 1-32
    CrossrefGoogle Scholar
  • 21 Kolakarnprasert N, Kaizer MR, Kim DK, Zhang Y. New multi-layered zirconias: Composition, microstructure and translucency. Dent Mater 2019; 35 (05) 797-806
    CrossrefPubMedGoogle Scholar
  • 22 Tuncel I, Eroglu E, Sari T, Usumez A. The effect of coloring liquids on the translucency of zirconia framework. J Adv Prosthodont 2013; 5 (04) 448-451
    CrossrefPubMedGoogle Scholar
  • 23 Čokić SM, Cóndor M, Vleugels J. et al. Mechanical properties-translucency-microstructure relationships in commercial monolayer and multilayer monolithic zirconia ceramics. Dent Mater 2022; 38 (05) 797-810
    CrossrefPubMedGoogle Scholar
  • 24 Alves M, Abreu L, Klippel G, Santos C, Strecker K. Mechanical properties and translucency of a multi-layered zirconia with color gradient for dental applications. Ceram Int 2020; 47: 301-309
    CrossrefGoogle Scholar
  • 25 Ban S, Suzuki T, Yoshihara K, Sasaki K, Kawai T, Kono H. Effect of coloring on mechanical properties of dental zirconia. J Med Biol Eng 2014; 34: 24-29
    CrossrefGoogle Scholar
  • 26 Yu N-K, Park M-G. Effect of different coloring liquids on the flexural strength of multilayered zirconia. J Adv Prosthodont 2019; 11 (04) 209-214
    CrossrefPubMedGoogle Scholar
  • 27 Sailer I, Holderegger C, Jung RE. et al. Clinical study of the color stability of veneering ceramics for zirconia frameworks. Int J Prosthodont 2007; 20 (03) 263-269
    PubMedGoogle Scholar
  • 28 Herrera LJ, Pulgar R, Santana J. et al. Prediction of color change after tooth bleaching using fuzzy logic for Vita Classical shades identification. Appl Opt 2010; 49 (03) 422-429
    CrossrefPubMedGoogle Scholar
  • 29 Stefanic G, Grzeta B, Popović S, Musić S. In situ phase analysis of the thermal decomposition products of zirconium salts. Croat Chem Acta 1999; 72 (02) 395-412
    Google Scholar
  • 30 Toraya H, Yoshimura M, Somiya S. Quantitative analysis of monoclinic-stabilized cubic ZrO2 systems by x-ray diffraction. J Am Ceram Soc 2006; 67 (09) C183-C184
    Google Scholar
  • 31 Zhang Y. Making yttria-stabilized tetragonal zirconia translucent. Dent Mater 2014; 30 (10) 1195-1203
    CrossrefPubMedGoogle Scholar