Often times light-body wash (LB) cannot be added to the heavy-body putty (HB) within 30 minutes when utilizing the two-step reline impression technique. The purpose of this study was to add the LB to the HB at times greater than 30 minutes and test the tensile bond strength. A split aluminum mold which created a bonding area of 1.13 cm2 and tray were filled with Express HB. After HB set the Express LB in a tray was added at varying times. The split molds were then separated and samples tested on the Instron. Ten groups with five samples/group (determined by a pilot study) were made. The times which the LB was added to the set HB and tested were: A) Immediately (one-step procedure); B) 10 minutes and contaminated with saliva (negative control); C) 10 minutes; D) 30 minutes; E) 45 minutes; F) 1 hour; G) 3 hours; H) 24 hours; I) 115 hours; and J) Freshened after 3 months. The results of this study indicate that saliva-contaminated samples were weaker than all other groups (P less than or equal to 0.01) and as far as tensile bond strength between materials is concerned, there appears to be no detrimental effect in tensile bond strength between HB and LB when delaying the application of the light-body material (P less than or equal to 0.01).
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Braz Oral Res
January 2025
Universidade de São Paulo - USP, School of Dentistry, Department of Operative Dentistry, São Paulo, SP, Brazil.
The aim of this study was to assess the effect of a chlorhexidine digluconate solution (CHX) applied as an antiproteolytic agent for controlling erosive tooth wear or as part of the adhesive treatment on long-term bond strength to eroded dentin. Dentin specimens were abraded with a 600-grit silicon carbide (SiC) paper for 1 min (sound dentin - S), subsequently treated with 2% CHX for 1 min (with excess removed, followed by a 6-hour rest), and eroded by exposure to Coca-Cola for 5 min, three times a day, for 5 days (CHX-treated and eroded dentin - CHXE), or only eroded (eroded dentin - E). The specimens were acid-etched (15 s), rinsed (30 s), dried (15 s), and rehydrated with 1.
View Article and Find Full Text PDFSci Rep
January 2025
State Key Laboratory of Structure Analysis, Optimization and CAE Software for Industrial Equipment, Department of Engineering Mechanics, Dalian University of Technology, Dalian, 116024, China.
The biocompatible autonomous self-healing hydrogels have great potential in biomedical applications. However, the fairly weak tensile strength of the hydrogels seriously hinders their application. Here, we introduced chitosan (CS) into the polyvinyl alcohol (PVA)-tannic acid (TA) hydrogel and investigated the effects of the CS content, as CS can not only form reversible H bonds with PVA and TA but also form reversible electrostatic interactions with TA.
View Article and Find Full Text PDFMacromol Rapid Commun
January 2025
State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing, 100029, China.
Thermoplastic polyurethane (TPU) exhibits re-processable properties, but the properties of TPU is deteriorated during the reprocessing for the oxidation and degradation of polymer chains. Meanwhile, although thermoset polyurethane exhibits excellent mechanical properties, it cannot be recycled for permanent crosslinking. Hence, it's still a challenge to obtain PU which exhibits the balance between the recyclability and mechanical properties.
View Article and Find Full Text PDFMaterials (Basel)
January 2025
Laboratoire d'Energétique et des Transferts Thermique et Massique (LETTM), Faculté des Sciences de Tunis, Université de Tunis El Manar, Campus Universitaire El-Manar, El Manar, Tunis 2092, Tunisia.
The viability of using fibers as reinforcement material for developing lightweight sustainable non-structural construction materials in compliance with the valorization of local by-products has been investigated in this work. This study aims to investigate the effect of the chemical treatment of fibers on the mechanical and hygric properties of bio-sourced clay-sand- fiber composite. This lightweight specimen has been produced from a mixture of 60% natural clay and 40% sand by mass, as a matrix, and reinforced with different amounts of Juncus fibers.
View Article and Find Full Text PDFPolymers (Basel)
January 2025
State Key Laboratory of Chemical Safety, Qingdao 266000, China.
Polyurea (PUR) has been widely used as a protective coating in recent years. In order to complete the understanding of the relationship between PUR microstructure and its energy absorption capabilities, the mechanical and dynamic performance of PURs containing various macrodiol structural units were compared using material characterization techniques and molecular dynamic simulation. The results showed that the PUR polycarbonate diols formed as energy absorbing materials showed high tensile strength, high toughness, and excellent loss factor distribution based on the comparison of stress-strain tensile curves, glass transition temperatures, phase images, and dynamic storage loss modulus.
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