Evaluation of Biaxial Flexural Strength and Translucency of Multichromatic Translucent Zirconia and Lithium Disilicate Ceramics

Abstract

INTRODUCTION: Full-contour (monolithic) zirconia restorations are gaining in popularity. High translucent zirconia materials and multilayered zirconia blocks might help to overcome the aesthetic drawbacks of traditional zirconia for fabrication of monolithic restorations OBJECTIVES: Were to evaluate the biaxial flexural strength and translucency of CAD/CAM: multichromatic ultra-translucent zirconia and comparing it with multichromatic high translucency Lithium Disilicate glass-ceramic. MATERIALS AND METHODS40 ceramic specimens were divided into two main groups; Group I: CAD/CAM multichromatic ultratranslucent Zirconia( UTML KATANA Zirconia) & Group II: Pressable multichromatic high translucent Lithium Disilicate glass-ceramic (e.max press multi). Each group was subdivided into two sub groups; sub group A: disc specimens (12mm diameter×1.5mm thickness) were fabricated (n=10) & thermocycled (500 cycles, 5°/55°C, 15 sec dwell time).Then, biaxial flexural strength was measured in MPa. Sub group B: rectangular specimens (12mm length × 10mm width × 1.5mm thickness) were fabricated (n=10). Spectrophotometric analysis was conducted to evaluate and compare the degree of translucency by translucency parameter (TP). Data were analyzed using student t-test & ANOVA with repeated measures test. RESULTS Statistical analysis of Biaxial flexural strength using student t-test revealed that group I (607.24 ± 71.79) showed higher statistically significant biaxial flexural strength values than group II (290.69 ± 41.19) ( p <0.001*). Results of translucency revealed that there were significant statistical differences between the two subgroups where IPS e.max Press Multi provided better translucency than UTML KATANA zirconia. CONCLUSIONS: Multi layered zirconia showed higher mechanical, but lower optical properties than lithium disilicate. The multi layered zirconia showed four layers with different light transmittance capabilities. It might therefore be useful for enhancing the aesthetic appearance of full-contour zirconia restorations made from this material in stress bearing areas.

The Effect of Two Sintering Cycles and Aging on Biaxial Flexural Strength of Strength Gradient Multi-Layered Zirconia (In vitro Study)

“…Our results were in accordance with a study performed by Eduardo M. Murioz et al (2017) (36) where AMZ (anterior cubic monolithic zirconia) had lower biaxial flexural strength values in comparison with PMZ (posterior non-cubic monolithic zirconia) which was affected by mechanical and hydrothermal aging. Our results were also similar to Jihad G. Hamed et al (37) who stated that Katana UTML group had significantly higher biaxial flexural strength values than those in IPS e.max Press Multi group.…”

Impact of sandblasting on the flexural strength of highly translucent zirconia

“…In order to fulfill the aesthetic requirements, several generations of zirconia ceramics were introduced. Many researchers have already investigated the microstructure and the basic intrinsic properties of these highly translucent Y-PSZ (Hamed et al, 2018;Mao et al, 2018;Kolakarnprasert et al, 2019;Sen and Isler, 2019). The phase composition and mechanical properties (mainly strength and toughness) of new-generation highly translucent zirconia are different from those of conventional zirconia (Zhang et al, 2016).…”

Fracture Resistance of Lithıum Disilicate, Indirect Resin Composite and Zirconıa by Using Dual Cure Resin Cements

“…It was clearly shown in the results presented in Table 4 that Zirconia has a better flexural strength in all the groups followed by E-max and then Gradia. Jihad et al (34) similarly found that Zirconia materials showed superior biaxial flexural strength values than the lithium disilicate glass ceramics. According to Piconi and Maccauro ( 35) Zirconia is strongly dependent on its grain size, thus, it cannot be easily transformed.…”