Statement Of Problem: Whether the addition of different antifungal nanoparticles to denture base materials may affect physical or esthetic properties of the resulting nanocomposite is unclear.
Purpose: The purpose of this in vitro study was to determine how a new method of adding antifungal nanofiller affects the properties of the processed nanocomposite denture base material.
Material And Methods: Heat-polymerized acrylic resin specimens were prepared according to each test specification. Zirconium dioxide nanoparticles (ZrONPs) and silver nanoparticles (AgNPs) were added in 0.5, 1.0, and 1.5% of acrylic resin powder. The specimens were divided into 2 groups according to the acrylic resin packing method: 1 layer packed conventionally in one step and 2 layers packed in 2 steps, first with unmodified acrylic resin and then by a thin layer of modified acrylic resin before the final closure. The control group was made of unaltered acrylic resin in 1 step. Flexural strength (FS), translucency, and surface roughness (R) were measured. A microbial assay was performed by using the direct culture and slide count methods. Three-way ANOVA and Tukey post hoc tests were used to identify statistical differences among groups (α=.05).
Results: The addition of ZrONPs and AgNPs in the 1- or 2-layer specimens reduced Candida albicans adhesion (P<.001). In the 1- and 2-layer specimens, FS significantly increased with ZrONPs. AgNPs decreased FS only in the 1-layer specimen (P<.001). Surface roughness was not changed for the 1- and 2-layer specimens with ZrONPs or the 1-layer specimen with 0.5% AgNPs (P>.05), while other AgNP groups exhibited increased surface roughness (P<.001). AgNPs significantly lowered translucency in the 1- and 2-layer specimens (P<.001), while ZrONPs decreased translucency only in the 1-layer specimen (P<.001).
Conclusions: The addition of ZrONPs in the double-layer technique decreased Candida adhesion and improved FS without affecting surface roughness, while AgNPs decreased Candida adhesion and FS and increased surface roughness. Both nanofillers decreased the translucency except 0.5% ZrONPs, which did not change translucency when applied in 2 layers.
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http://dx.doi.org/10.1016/j.prosdent.2020.08.021 | DOI Listing |
Imaging Sci Dent
December 2024
Department of Oral Diagnosis, Division of Oral Radiology, Piracicaba Dental School, University of Campinas, Piracicaba, SP, Brazil.
Purpose: This study was performed to evaluate the expression of beam hardening artifacts generated by high atomic number materials in stitched cone-beam computed tomography (CBCT) images, compared to the traditional acquisition mode.
Materials And Methods: CBCT volumes were acquired using an acrylic resin phantom embedded with pairs of cylinders made from amalgam dental alloy, cobalt-chromium alloy, gutta-percha, titanium, and zirconium. These cylinders were placed within the overlapping zones of the stitching reconstruction area.
J Prosthet Dent
December 2024
Professor, Department of Restorative Dentistry, University of Washington School of Dentistry, Seattle, Wash. Electronic address:
Statement Of Problem: The angled screw channel (ASC) design has been well accepted for implant prostheses. However, investigation into the behavior of the ASC connection is sparse.
Purpose: The purpose of this in vitro study was to assess the effect of cyclic loading on the internal connection of an ASC system compared with straight access systems by measuring reverse torque values (RTVs) and using microcomputed tomography (µCT) imaging.
Nat Commun
December 2024
College of Engineering and Applied Sciences, Nanjing National Laboratory of Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing, Jiangsu, China.
Functional nanomaterials with enzyme-mimicking activities, termed as nanozymes, have found wide applications in various fields. However, the deviation between the working and optimal pHs of nanozymes has been limiting their practical applications. Here we develop a strategy to modulate the microenvironmental pHs of metal-organic framework (MOF) nanozymes by confining polyacids or polybases (serving as Brønsted acids or bases).
View Article and Find Full Text PDFBMC Oral Health
December 2024
Department of Prosthodontics, Faculty of Dentistry, Chulalongkorn University, Pathumwan, Bangkok, 10330, Thailand.
Background: The selection guideline for the implant-supported bar connectors (ISBC) of hybrid denture is lacking. This study investigated the maximum von Mises stress (vMS), stress distribution, and displacement of various geometric ISBC in mandibular hybrid dentures, as well as the maximum principal stress (σmax) in the acrylic resin part, through finite element analysis.
Methods: Four different geometric cross-sectional patterns for mandibular ISBC-L, Y, I, and Square-of equal volume, based on the "All-on-4" concept, were created.
Sci Rep
December 2024
Student Research Committee, Department of Epidemiology, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Very high heat is generated during the polymerization of poly (methyl methacrylate) (PMMA) bone cement, which is used for implant fixation in orthopedic surgery. As such, it has been suggested that irrigating the bone cement layer in the surgical site with a saline solution is a way of cooling the layer. In this study, we aimed to determine the influence of irrigation with a saline solution on the flexural strength and the microstructure of the test specimens of two PMMA bone cement brands: Simplex P and FIX 1.
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