Characterization of Conventional and High-Translucency Y-TZP Dental Ceramics Submitted to Air Abrasion

Abstract

This study evaluated the effect of air-abrasion on t→m phase transformation, roughness, topography and the elemental composition of three Y-TZP (Yttria-stabilized tetragonal zirconia polycrystal) dental ceramics: two conventional (Lava Frame and IPS ZirCad) and one with high-translucency (Lava Plus). Plates obtained from sintered blocks of each ceramic were divided into four groups: AS (as-sintered); 30 (air-abrasion with 30 mm Sicoated Al 2 O 3 particles); 50 (air-abrasion with 50 mm Al 2 O 3 particles) and 150 (air-abrasion with 150 mm Al 2 O 3 particles). After the treatments, the plates were submitted to X-ray diffractometry; 3-D profilometry and SEM/EDS. The AS surfaces were composed of Zr and t phases. All treatments produced t→m phase transformation in the ceramics. The diameter of air-abrasion particles influenced the roughness (150>50>30>AS) and the topography. SEM analysis showed that the three treatments produced groove-shaped microretentions on the ceramic surfaces, which increased with the diameter of air-abrasion particles. EDS showed a decrease in Zr content along with the emergence of O and Al elements after air-abrasion. Presence of Si was also detected on the plates air-abraded with 30 mm Si-coated Al 2 O 3 particles. It was concluded that irrespective of the type and diameter of the particles, air-abrasion produced t→m phase transformation, increased the roughness and changed the elemental composition of the three Y-TZP dental ceramics. Lava Plus also behaved similarly to the conventional Y-TZP ceramics, indicating that this high translucency ceramic could be more suitable to build monolithic ceramic restorations in the aesthetic restorative dentistry field.

Does the application of surface treatments in different sintering stages affect flexural strength and optical properties of zirconia?

“…Different micromechanical (mechanical, chemical, and laser treatments) and chemical bonding techniques (silicon coatings, use of coupling agents) have been developed as attempts to achieve superior bond quality between zirconia and luting cement . Among these techniques, the drive to use micromechanical‐based protocols such as air‐borne particle abrasion (APA), diamond grinding (G), multiphase glass ceramic coating, low fusing porcelain coating, selective infiltration etching, application of zirconia particle suspension, gas plasma treatment, application of phosphate monomers with fusing glass beads, argon‐ion bombardment, acid‐etching with highly corrosive acid combinations, and laser irradiation (LI) has increased in intensity. Acid‐etching is commonly recommended as a surface treatment to roughen the intaglio of silica‐based ceramics, but zirconia ceramic does not susceptible to chemical conditioning with acid due to the lack of silica content .…”

“…Among these techniques, the drive to use micromechanical‐based protocols such as air‐borne particle abrasion (APA), diamond grinding (G), multiphase glass ceramic coating, low fusing porcelain coating, selective infiltration etching, application of zirconia particle suspension, gas plasma treatment, application of phosphate monomers with fusing glass beads, argon‐ion bombardment, acid‐etching with highly corrosive acid combinations, and laser irradiation (LI) has increased in intensity. Acid‐etching is commonly recommended as a surface treatment to roughen the intaglio of silica‐based ceramics, but zirconia ceramic does not susceptible to chemical conditioning with acid due to the lack of silica content . Although favorable effects of surface treatments on the bond strength have been well‐documented in a systematic review, the possibility that surface treatments may compromise mechanical and optical properties of zirconia restorations has also been asserted.…”

Wear of Glass-ceramic-veneered Zirconia Posterior FPDS After 10 Years

“…With the aid of pro lometry, the surfaces of dental ceramics can be visualized and the surface roughness due to mechanical action illustrated. This involves a surface scan of the test specimen and the generation of a roughness pro le [19,20]. To visualize and demonstrate structural changes in the ceramic surface, a scanning electron microscope can be used [19], which can reveal even microstructural changes in the individual crystal phases of ceramics [21].…”

“…Another method is X-ray diffraction, with which the various crystal phases can be investigated and graphically illustrated depending on temperature or mechanical impact [20,21]. Further perspective on the detailed reproduction of surfaces is provided by light-optical, contact-free precision scanning methods with which, after scanning an object surface, digital and three-dimensional (3D) information can be obtained using special computer software [24][25][26].…”

Bond to Zirconia Ceramic: Evaluation of Different Primers and a Universal Adhesive

“…Regarding the zirconia ceramic, neither etching with hydrofluoric acid [9,10] nor silane application, such as 3-Methacryloyloxypropyltrimethoxysilane (MPS) are effective [11,12], as this ceramic consists of Yttrium-stabilized Tetragonal Zirconia Polycrystals (Y-TZP) and has no silica in its composition [13]. Thus, various surface treatments have been proposed for zirconia ceramic, such as aluminum oxide sandblasting [9,14], tribochemical silica coating [15,16], selective infiltration-etching technique [17], and CO 2 laser irradiation [18]. Primers containing functional monomers have also been developed which promote bonding to metal oxides such as zirconia [19 -21].…”