We report the successful demonstration for low-temperature and high-strain-rate superplastic forming of nanoceramic composites for the first time. Porous preforms of nanoceramic composites that were partially densified at low temperatures were superplastically deformed by SPS at the record low temperatures of approximately 1000 to 1050 degrees C, which are comparable to those of Ni-based superalloys. The maximum strain rate achieved is over 10(-2) s(-1), and a compressive strain over 200% can be obtained without cracking. The final products have nanosized grains with excellent optical properties. The present findings present a new strategy for nanoceramic superplasticity, demonstrating that a more practical application of nanoceramic superplasticity is not in the shaping of already-dense materials but in the near-net-shape forming of partially dense parts.
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http://dx.doi.org/10.1021/nl0520314 | DOI Listing |
J Esthet Restor Dent
January 2025
Operative Department, Faculty of Dentistry, Mansoura University, Mansoura, Egypt.
Objective: To investigate the effect of cervical margin relocation with four different injectable restorative materials on the fracture resistance of molars receiving mesio-occluso-distal CAD/CAM nanoceramic onlay restorations.
Materials And Methods: One hundred and five sound mandibular molars received a standardized mesio-occluso-distal onlay preparation, with cervical margins located 2 mm apical to the cemento-enamel junction. The molars were randomly allocated into five groups (n = 21) according to the cervical relocating materials used: Group I had no cervical margin relocation; Group II used a highly viscous glass ionomer; Group III used a highly-filled injectable resin composite; Group IV used a resin-modified glass ionomer; and Group V used a bioactive ionic resin.
BMC Oral Health
December 2024
Department of Restorative Dentistry, Faculty of Dentistry, Ordu University, Ordu, Turkey.
Background: The aim of this study was to investigate the effects of different types of bleaching methods and repolishing on the whiteness index and staining susceptibility of additive and subtractive production resin-based materials and direct composite resins.
Methods: In this study, a total of 96 samples (8*8*2m) were prepared using a nanohybrid composite resin (Neo Spectra-ST (NS)), a subtractive-manufactured nanoceramic resin (Cerasmart270 (CS)), and an additive-manufactured permanent resin (Saremco print Crowntec (CT)). The samples were randomly divided into four treatment groups: control (distilled water, 14 days), in-office bleaching (Opalescence Boost-40% HP, 3*20min), at-home bleaching (Opalescence PF-16% CP, 6 h, 14 days), and toothpaste group (Opalescence Whitening, 2*5min, 14 days) (n:8).
Cureus
November 2024
Department of Prosthodontics, Faculty of Dentistry, Bolu Abant Izzet Baysal University, Bolu, TUR.
Objectives: This study aimed to examine the impact of the strength and color change of composite materials that could be utilized in the repair of polyetheretherketone (PEEK) veneer fractures.
Methods: The 220 nanoceramic-filled PEEK specimens used in the study were divided into four groups, and color measurements were made on a gray background (n=55): Group N, 1-mm-thick monochromatic composite; Group NN, 2-mm-thick monochromatic composite; Group F, 1-mm-thick 2-mm-diameter short fiber-reinforced composite, placed in the center and polymerized; and Group FF, 2-mm-thick 2-mm-diameter short fiber-reinforced composite, placed in the center and polymerized. The remaining mating surfaces were restored by filling with monochromatic composite and adhesion strength testing by re-measuring the color.
Dent Mater
February 2025
Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt; Division of Dentistry, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK. Electronic address:
Objectives: The growing trend of minimally invasive approaches has encouraged the application of partial coverage designs in restorative dentistry. This study aimed to evaluate the cyclic fatigue performance of different CAD-CAM materials used in various partial coverage designs for premolar restorations.
Methods: A freshly extracted upper premolar was prepared using a high-speed handpiece to create mesio-occluso-distal (MOD) cavities with standardized dimensions.
Compend Contin Educ Dent
November 2024
Adjunct Professor, Division of Restorative Dentistry, University of Pennsylvania School of Dental Medicine, Philadelphia, Pennsylvania.
The advancement of digital technologies, including 3-dimensional (3D) imaging and computer-aided design/computer-aided manufacturing (CAD/CAM), and material science has significantly transformed dentistry. Current CAD/CAM techniques incorporate both subtractive and additive (eg, 3D printing) manufacturing methods, with 3D printing offering such benefits as reduced material waste and the ability to produce complex geometries. Much research has focused on the development of hybrid materials that merge the esthetics and durability of ceramics with the high flexural strength, low abrasiveness, and intraoral repairability characteristics of resin composites.
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