Statement Of Problem: Lithium disilicate and 5 mol% yttria partially stabilized zirconia (5Y-PSZ) are commonly used for anterior restorations. However, studies comparing the durability of 5Y-PSZ and lithium disilicates are sparse.
Purpose: The purpose of this in vitro study was to investigate the fracture load of anterior monolithic crowns made of 2 lithium disilicates and a 5Y-PSZ under dynamic loading.
Material And Methods: Titanium abutments of the maxillary incisors were prepared (N=48, 8 for each group). Monolithic anterior crowns were made from the lithium disilicates (e.max CAD, Rosetta SM) and 5Y-PSZ (Katana UTML). After cementation, the specimens were stored in water for 24 hours and then thermocycled 10 000 times. Dynamic loading (70 N, 200 000 cycles, 1 Hz) was applied to half the specimens. The fracture load was measured by using a universal testing machine. The fracture patterns were analyzed and fractography applied. Two-way ANOVA and the Fisher exact test were used for statistical analysis (α=.05).
Results: The material and dynamic loading affected the fracture load of the anterior monolithic crowns (P<.05). However, there was no interaction between the material and the dynamic loading (P=.079). Both lithium disilicates had higher fracture loads than 5Y-PSZ (P<.05). The fracture load of each specimen was reduced after dynamic loading (P<.05). Lithium disilicate showed marginal and bulk fractures, and 5Y-PSZ presented catastrophic fractures (P<.001).
Conclusions: 5Y-PSZ materials with large grains and low flexural strength may be less resistant to fractures under dynamic loading than lithium disilicates.
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http://dx.doi.org/10.1016/j.prosdent.2021.09.034 | DOI Listing |
J Funct Biomater
January 2025
Department of Gerodontology and Oral Rehabilitation, Graduate School of Medical and Dental Sciences, Institute of Science Tokyo, Tokyo 113-8549, Japan.
Highly translucent zirconia (TZ) is frequently used in dentistry. The properties of several highly translucent zirconia materials available in the market require an in-depth understanding. In this study, we assessed the translucency, crystalline phase, mechanical properties, and microstructures of three newly developed highly translucent zirconia materials (Zpex 4.
View Article and Find Full Text PDFJ Esthet Restor Dent
December 2024
Analysis of Techniques, Material and Instruments Applied to Digital Dentistry and CAD/CAM Procedures Research Group, University Complutense of Madrid, Madrid, Spain.
Objective: This clinical case describes a multidisciplinary retreatment of a patient with anterior fixed dental prostheses (FDPs) using minimally invasive restorations and a biologically oriented preparation technique (BOPT).
Clinical Considerations: A 56-year-old female patient, treated 30 years ago with a metal-ceramic FDP due to dental agenesis, presented a misfit prosthesis at the gingival margin, black spaces, and food retention at the pontics. Notably, tooth number 2.
J Esthet Restor Dent
December 2024
Department of Dentistry, Federal University of Rio Grande Do Norte (UFRN), Natal, Brazil.
Introduction: Ultratranslucent zirconia combines high mechanical strength and esthetics, making it ideal for monolithic restorations. This case report describes a total rehabilitation of the upper dental arch with single-unit crowns made of multilayer ultratranslucent zirconia (Prettau 4 Anterior, Zirkonzahn), as well as the use of a simplified adhesive cementation protocol for this type of ceramic.
Materials And Methods: A 64-year-old female patient sought rehabilitative treatment, after planning in a semi-adjustable articulator, interim prostheses, from tooth 2 to 15, were installed to restore occlusal vertical dimension and esthetics.
J Esthet Restor Dent
December 2024
Department of Reconstructive Dentistry, University Center for Dental Medicine Basel UZB, University of Basel, Basel, Switzerland.
Clin Oral Implants Res
November 2024
Department of Reconstructive Dentistry, University Center for Dental Medicine Basel UZB, University of Basel, Basel, Switzerland.
Objectives: To investigate if the fracture load of implant-supported cantilever fixed dental prostheses (ICFDPs) in the anterior region is affected by the implant type and the aging protocol.
Materials And Methods: Sixty ICFDPs were prepared using multilayer monolithic zirconia for restoring bone-level (BL) and tissue-level (TL) titanium-zirconium implants. Fracture load was measured at baseline (no aging) or after aging in a chewing simulator loading the implant crown or the cantilever in a 30° angle (n = 10 per group).
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