HOME - Clinical cases - Digital Dentistry
25 September 2019

Zirconia VS Lithium disilicate

Simona Chirico

With the development of CAD/CAM system, nowadays the most used materials in the prosthetic fields are: zirconia and lithium disilicate. In particular, in a review published in 2015, monolithic zirconia was reported as the most prescribed material for posterior single crowns and lithium disilicate for the anterior single crowns.

If we want to compare these two materials, which is the best one?      

In a study published in the Journal of Prosthetic Dentistry in July 2018, Kwon et al. compare the flexural strength, translucency parameters, early and long-term of lithium disilicate with zirconia with 5 mol% yttria (5Y-ZP) and zirconia with 3 mol% yttria (3Y-TZP).  

 The 5Y-ZP material selected for this study was Katana UTML shade A1 (Kuraray Noritake Dental). As it is a multilayer shaded material, the bottom (cervical) surface of the disk was selected for the bonded surface of the bond strength specimen, and the top (occlusal) surface of the disk was selected to receive all other experimental conditions. The reference 3Y-TZP material selected was Katana HT shade HT10. The reference lithium disilicate material selected was e.max CAD LT shade A1 (Ivoclar Vivadent AG). For the translucency parameter, e.max CAD HT shade A1 was also included. Flexural strength bars were sectioned (n=10, 25×4×2 mm), sintered or crystallized, polished, and fractured at 1 mm/ min. Translucency specimens (1 mm thick) were fabricated (n=10). Their L*a*b* values were measured against a black-and-white background with a spectrophotometer, and DE00 was calculated. Zirconia bond strength specimens were airborne-particle abraded with 50 mm alumina followed by the application of a 10-methacryloxydecyl dihydrogen phosphateecontaining primer (Clearfil Ceramic Primer). Lithium disilicate bond strength specimens were etched with 5% hydrofluoric acid followed by application of a silane-containing primer (Clearfil Ceramic Primer). A Tygon tube filled with resin cement (Panavia SA) was fixed to the surface of the ceramics and light-polymerized. After 1 day or 150 days of water storage, the resin cement was debonded in a macroshear test (n=10). The cusps of extracted human molars were isolated and mounted into the University of Alabama at Birmingham wear-testing device. Wear testing was performed with a 20-N load for 300 000 cycles in 33% glycerin. The volumetric wear of polished zirconia, lithium disilicate, and enamel were measured along with the wear of the opposing enamel cusps using a noncontact profilometer (n=8). The data were compared by ANOVA and Tukey-Kramer analysis (a=.05).

- flexural strength: Katana HT (1194 ±111 MPa) > Katana UTML (688 ±159 MPa) > IPS e.max CAD LT (460 ±53 MPa) (p < 0.01).
translucency parameters: IPS e.max CAD HT (12.64 ±0.48) > IPS e.max CAD LT (9.28 ±0.36) > Katana UTML (8.30 ±0.24) > Katana UTML (8.30 ±0.24) (p < 0.01)
- bond strength to: Katana HT was 34.22 ±5.14 MPa (1 day) and 28.37 ±6.03 MPa (150 days), Katana UTML was 35.04 ±5.69 MPa (1 day) and 25.03 ±6.44 MPa (150 days), and e.max CAD LT was 35.50 ±3.45 MPa (1 day) and 22.32 ±3.45 MPa (150 days).
- materials wear: No measurable wear could be detected on the zirconia materials. Instead, E.max CAD LT wear (0.28 ±0.13 mm3) was significantly greater than the wear of flat labial enamel (0.09 ±0.03 mm3) (p < 0.01).
- wear to opposing enamel cusps: the volumetric wear measured on enamel cusps opposing Katana HT was 0.24 ±0.19 mm3, Katana UTML was 0.23 ±0.09 mm3, emax.CAD LT was 0.31 ±0.10 mm3, and natural labial enamel was 0.31 ±0.14 mm3.

All of these materials are a good choice for prosthetic rehabilitations. Therefore, the choice between these materials depends on the mechanical, functional, parafuncional and aesthetical characteristics of the patient.

(Photo credit: Dr. Cesare Robello)

For additional informations:
Comparison of the mechanical properties of translucent zirconia and lithium disilicate Comparison of the mechanical properties of translucent zirconia and lithium disilicate

Related articles

Several prosthodontics rehabilitation processes are needed to recreate a correct masticatory function. The provisional stage is quite important and materials employed in this phase are not completely...

CAD/CAM technology has been used in industry for long time and has increased in popularity over the past years in dentistry from making impressions, casts, provisional and final restorations. The...

Inlay and overlay are a good and right choice in case of large carious and restorative defects. The introduction of CAD/CAM system gives the possibilities to...

Premolars are the most difficult elements to restore and have a high failure rate due to their anatomical position and the forces they undergo. Therefore the choice of the material to restore...

Contemporary computer-aided design and manufacturing (CAD/CAM) systems involve a wide range of dental restoration indications such as inlays, onlays, laminate...

Read more

In the last decade, the development of new technologies has moved in parallel with a rapid evolution of restorative materials on the rails of Digital...

In the latest issue of European Journal of Orthodontics (April 2020) a clinical practice guideline on orthodontically induced external apical root resorption ...

Title: Luting strategies for adhesive dentistryAuthor: Prof. Lorenzo BreschiWhen: September 17 th, 2020Time: 11am west coast - 2pm east coast - 8pm GTM+2 Price: $ 49.99...

Prosthetic treatments require dental impressions which during the Covid-19 pandemic are considered to have a high risk of contagion (both for dental operators and for reference dental technicians),...

It is commonly known that a root canal-treated tooth (RCTT) has more possibilities to fracture than a tooth with vital pulp. Several factors must be...




Most popular