Wear behavior and abrasiveness of monolithic CAD/CAM ceramics after simulated mastication

Ahmed Mahmoud Fouda; Osama Atta; Amr Shebl Kassem; Mohamed Desoky; Christoph Bourauel

doi:10.1007/s00784-022-04611-w

Wear behavior and abrasiveness of monolithic CAD/CAM ceramics after simulated mastication

Clin Oral Investig. 2022 Nov;26(11):6593-6605. doi: 10.1007/s00784-022-04611-w. Epub 2022 Jul 11.

Authors

Ahmed Mahmoud Fouda^{1

2}, Osama Atta³, Amr Shebl Kassem³, Mohamed Desoky³, Christoph Bourauel⁴

Affiliations

¹ Department of Oral Technology, University Hospital Bonn, Welschnonnenstraße 17, 53111, Bonn, Germany. ah.foudaa@gmail.com.
² Department of Fixed Prosthodontics, Suez Canal University, Ismailia, Egypt. ah.foudaa@gmail.com.
³ Department of Fixed Prosthodontics, Suez Canal University, Ismailia, Egypt.
⁴ Department of Oral Technology, University Hospital Bonn, Welschnonnenstraße 17, 53111, Bonn, Germany.

Abstract

Objectives: To evaluate the wear resistance and abrasiveness of monolithic CAD/CAM ceramics.

Materials and methods: Rectangular-shaped specimens (12 mm × 6.5 mm × 1.5 mm) were sectioned from the following CAD/CAM blocks (n = 10); partially crystallized lithium disilicate (PLD), experimental fully crystallized lithium disilicate (FLD), zirconia-reinforced lithium silicate (ZLS), super-translucent monolithic zirconia (SMZ), and ultra-translucent monolithic zirconia (UMZ). Silicon carbide papers were used to mechanically flatten and polish the surfaces. PLD specimens were subjected to a combined crystallization/glazing firing cycle. Ceramic specimens were mounted to the wear device and tested for 200,000 cycles against human premolars at 20 N force and 2 mm sliding distance. Artificial saliva was used as a lubricant. The teeth were scanned using micro-CT before and after the wear test and the generated models were overlapped to determine the volumetric tooth loss. Before and after the test, specimens' weights and surface roughness (R_a) values were measured, and the differences were calculated. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) were utilized for microstructural and chemical analysis. Statistical analysis was performed using one-way ANOVA or an equivalent test for non-parametric results. Significance level was set at P ≤ 0.05.

Results: The type of ceramic material affected the ceramic and antagonist wear rates (P < 0.001). PLD and ZLS had the highest ceramic and antagonist wear, whereas UMZ and SMZ demonstrated the lowest wear values. The FLD group showed comparable antagonist wear and significantly less ceramic wear than PLD and ZLS.

Conclusions: Monolithic zirconia demonstrated the best wear resistance and least abrasiveness to the antagonist. The experimental lithium disilicate was more wear-resistant than other glass-ceramic groups.

Clinical relevance: Monolithic zirconia is wear-resistant and gentle on the antagonist. In contrast, glass-ceramics are more abrasive to enamel.

Keywords: CAD/CAM; Dental ceramics; Micro-CT; Surface roughness; Volumetric enamel loss; Wear.

MeSH terms

Ceramics / chemistry
Computer-Aided Design
Dental Porcelain* / chemistry
Humans
Mastication*
Materials Testing
Surface Properties
Zirconium / chemistry

Substances

zirconium oxide
Dental Porcelain
Zirconium