Optical properties and light irradiance of monolithic zirconia at variable thicknesses

Taiseer A. Sulaiman, Aous A. Abdulmajeed, Terrence E. Donovan, André V. Ritter, Pekka K. Vallittu, Timo O. Närhi, Lippo V. Lassila

Research output: Contribution to journalArticlepeer-review


Objectives The aims of this study were to: (1) estimate the effect of polishing on the surface gloss of monolithic zirconia, (2) measure and compare the translucency of monolithic zirconia at variable thicknesses, and (3) determine the effect of zirconia thickness on irradiance and total irradiant energy. Methods Four monolithic partially stabilized zirconia (PSZ) brands; Prettau® (PRT, Zirkonzahn), Bruxzir® (BRX, Glidewell), Zenostar® (ZEN, Wieland), Katana® (KAT, Noritake), and one fully stabilized zirconia (FSZ); Prettau Anterior® (PRTA, Zirkonzahn) were used to fabricate specimens (n = 5/subgroup) with different thicknesses (0.5, 0.7, 1.0, 1.2, 1.5, and 2.0 mm). Zirconia core material ICE® Zircon (ICE, Zirkonzahn) was used as a control. Surface gloss and translucency were evaluated using a reflection spectrophotometer. Irradiance and total irradiant energy transmitted through each specimen was quantified using MARC® Resin Calibrator. All specimens were then subjected to a standardized polishing method and the surface gloss, translucency, irradiance, and total irradiant energy measurements were repeated. Statistical analysis was performed using two-way ANOVA and post-hoc Tukey's tests (p < 0.05). Results Surface gloss was significantly affected by polishing (p < 0.05), regardless of brand and thickness. Translucency values ranged from 5.65 to 20.40 before polishing and 5.10 to 19.95 after polishing. The ranking from least to highest translucent (after polish) was: BRX = ICE = PRT < ZEN < KAT < PRTA (p < 0.05). The ranking from least to highest total irradiant energy was: BRX < PRT < ICE = ZEN < KAT = PRTA (p < 0.05). There was an inverse relationship between translucency, irradiant energy, and thickness of zirconia and the amount was brand dependent (p < 0.05). Significance Brand selection, thickness, and polishing of monolithic zirconia can affect the ultimate clinical outcome of the optical properties of zirconia restorations. FSZ is relatively more polishable and translucent than PSZ.

Original languageEnglish (US)
Pages (from-to)1180-1187
Number of pages8
JournalDental Materials
Issue number10
StatePublished - Oct 1 2015


  • Contrast ratio
  • Light cure irradiance
  • Monolithic zirconia
  • Surface gloss
  • Translucency parameter

ASJC Scopus subject areas

  • General Materials Science
  • General Dentistry
  • Mechanics of Materials


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