Effect of surface treatments on optical, topographical and mechanical properties of CAD/CAM reinforced lithium silicate glass ceramics

Hanan Al-Johani; Julfikar Haider; Nick Silikas; Julian Satterthwaite

doi:10.1016/j.dental.2023.07.004

Effect of surface treatments on optical, topographical and mechanical properties of CAD/CAM reinforced lithium silicate glass ceramics

Dent Mater. 2023 Sep;39(9):779-789. doi: 10.1016/j.dental.2023.07.004. Epub 2023 Jul 10.

Authors

Hanan Al-Johani¹, Julfikar Haider², Nick Silikas³, Julian Satterthwaite⁴

Affiliations

¹ Division of Dentistry, School of Medical Sciences, University of Manchester, UK; Department of Restorative Dentistry, Division of Biomaterials, Faculty of Dentistry, King Abdulaziz University, Saudi Arabia.
² Division of Dentistry, School of Medical Sciences, University of Manchester, UK; Department of Engineering, Manchester Metropolitan University, Manchester, United Kingdom.
³ Division of Dentistry, School of Medical Sciences, University of Manchester, UK. Electronic address: nikolaos.silikas@manchester.ac.uk.
⁴ Division of Dentistry, School of Medical Sciences, University of Manchester, UK.

PMID: 37438204
DOI: 10.1016/j.dental.2023.07.004

Abstract

Objectives: To investigate the effect of different surface treatments on optical, topographical and mechanical properties of CAD/CAM lithium silicate-based glass ceramics (LSC's) and their combined effect on the output of a light curing unit (LCU).

Methods: Four CAD/CAM LSC's were investigated: Lithium Disilicate (Emax CAD; EC), Zirconia-reinforced silicates (Vita Suprinity; VS and Celtra Duo;CD) and Lithium Aluminum Disilicate (CEREC Tessera; CT). Ceramic specimens (n = 240) were divided into six subgroups according to their surface treatment: (a) Control, (b) Hydrofluoric acid (HF) 5%, (c) HF 5% + Neutralizing agent (N), (d) HF 9%, (e) HF 9% +N and (f) Self-etching ceramic primer (SEP). Irradiance, power and radiant exposure of a LCU were measured with MARC-LC following ceramic specimen interposition. Direct light transmission (T%) and absorbance (Abs%) of the specimens were measured with UV-Vis spectrophotometry. Roughness (Sa, Sq) and wettability (θ°) were measured with optical profilometry and sessile drop profile analysis, respectively. Biaxial flexural strength (σ) of the ceramic specimens was measured by the ball-on-three-balls method and ceramic specimens were examined microscopically. Statistical analyses was performed by two-way ANOVA followed by post hoc multiple comparisons (α = 0.05).

Results: Acid neutralization decreased T% and increased Abs% in all LSC's and highest T% was exhibited with VS. Neutralized EC, VS and CD displayed higher Sa in HF9, while neutralized CT displayed higher Sa in HF5. Self-etch primer significantly reduced θ° (p < 0.001). σ was observed in the followed ascending order: HF9 +N < HF9 < HF5 +N < HF5 < SEP < Control for all LSC's.

Significance: Optical, topographical and mechanical properties of the CAD/CAM ceramic blocks were strongly dependent on the type of surface treatment. Results of neutralization post-etching indicate promising potential for future investigations.

Keywords: Acid neutralization; Biaxial flexural strength; CAD/CAM Ceramic; Lithium aluminum disilicate; Lithium disilicate; Photometry; Surface treatment; Topography; Zirconia-reinforced lithium silicate.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Ceramics*
Computer-Aided Design
Dental Porcelain
Lithium*
Materials Testing
Silicates
Surface Properties

Substances

Glass ceramics
Lithium
Dental Porcelain
Silicates