Earlier work revealed that creep of a particular dental amalgam can be described by the model F(t) = F0 exp (t/t0)m. Here F(t) is the creep compliance at time t, whereas F0, t0 and m are constants of the model. In the previous study only three alloys were used. It was the aim of this study to investigate the factor alloy more thoroughly. After specimen preparation, the nineteen different amalgams were aged at 37 degrees C for either one day or one week. Then creep was determined at a temperature of 22.5 degrees C and a compressive stress of 117 MN/m2. F0 turns out to depend upon both the ageing time as well as on the choice of the alloy. As expected, t0 shows up substantial differences between the respective amalgams, whereas the differences between the two ageing are absent or relatively small. The factor alloy significantly influences m. However, the ageing time exerts no significant influence upon m.
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http://dx.doi.org/10.1111/j.1365-2842.1983.tb00129.x | DOI Listing |
Dent Res J (Isfahan)
November 2024
Department of Orthodontics and Dentofacial Orthopedics, SRM Dental College and Hospital, Chennai, Tamil Nadu, India.
Background: The aim of this study was to compare the mechanical properties of the polymer brackets with metal and ceramic brackets and verify if the polymer brackets could be used clinically.
Materials And Methods: A thorough search was conducted in four electronic databases, including Scopus, PubMed, Cochrane, Ovid, and Lilacs, with article selection based on Preferred Reporting Items for Systematic Reviews and Meta-Analysis standards. A computerized search of the database was done from January 1990 to June 2024.
J Clin Exp Dent
November 2024
Ph.D. Postdoc. Titular Professor. Biomedical Stomatology Research Group, School of Dentistry. Universidad de Antioquia U de A, Medellín Colombia.
Background: Previous studies have identified the effects of light curing techniques on both shrinkage strain and contraction stress buildup in composite restorations. Finite Element Analysis (FEA) has several advantages over other experimental methods for evaluating the mechanical properties of direct dental resins. The objective of this systematic review is to assess the impact of light curing protocols on the shrinkage behaviors and other mechanical properties of direct restorative composites utilizing FEA.
View Article and Find Full Text PDFDent Mater
December 2024
Division of Dentistry, School of Medical Sciences, University of Manchester, Manchester, UK; Photon Science Institute, University of Manchester, Manchester, UK. Electronic address:
Objective: Investigate the effect of solvent-storage on surface hardness and bulk creep of fast photo-cured bulk-fill resin-based composite (RBC) compared to conventionally irradiated bulk-fill RBCs.
Methods: Three bulk-fill RBCs were studied: Tetric® PowerFill (fast photo-cured bulk-fill RBC) (TPF), Tetric EvoCeram® (EVO), and GrandioSO® x-tra (GSOx) (conventional). Disk-shaped specimens of clinically realistic thickness (4 mm) were prepared from each material for: Group A: surface measurements (18 mm diameter) and Group B: 4 mm diameter for bulk compressive creep measurements.
Clin Oral Implants Res
January 2025
Barts and the London School of Medicine and Dentistry, Institute of Dentistry, Queen Mary University of London, London, UK.
J Mech Behav Biomed Mater
December 2024
Minnesota Dental Research Center for Biomaterials and Biomechanics, University of Minnesota, Minneapolis, MN, United States. Electronic address:
Purpose: Finite element (FE) models for determining the orthodontic forces delivered by clear aligners often lack validation. The aim of this study was to develop and validate accurate FE models for clear aligners, considering the small but important geometrical variations from the thermoforming process and the creep behavior of the aligner material.
Methods And Materials: The tooth misalignment considered was a 2.
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