Search results for " resin"

Improving PMMA resin using graphene oxide for a definitive prosthodontic rehabilitation - A clinical report

2019

The use of acrylic resins as a definitive material has shown some advantages comparing to other definitive materials. However, their poor mechanical properties remain a major drawback. In this case report, graphene oxide (GO) was incorporated into polymethyl methacrylate (PMMA) resin for a definitive maxillary rehabilitation, combined with an intraoral digital impression and a three-dimensional facial scan. After 8 months of the placement of the definitive prosthesis, no mechanical, aesthetic, or biologic complications were reported, and the soft tissues showed excellent health and stability. The incorporation of GO in PMMA resins seems to be a suitable option for prosthetic rehabilitation.…

Improved method of manufacturing carbon nanotube infused multifunctional 3D woven composites

2021

This research work aimed to develop smart multifunctional composites via a process for uniformly dispersing carbon nanotubes (CNT) on an orthogonal three-dimensional (3D) woven glass fabric with minimised filtering effect. These smart composites could detect strain under tensile and flexural loading by the piezoresistive response of the infused CNT network. Conventional vacuum assisted resin transfer moulding was modified to control the infusion of 0.25 wt% CNT on the 3D woven glass fabric by varying the vacuum pressure. Results showed that at 101.3 kPa vacuum pressure, the CNT percolated through the thickness of the orthogonal 3D woven glass fabric while being marginally filtered by the f…

Preparation of Polymer-Supported Polyazamacrocycles. The Role of the Polymeric Matrix in the Preparation of Polymer-Supported Polyazamacrocycles

2000

Different approaches have been studied for the preparation of resins containing different polyazamacrocycles. Preparation of monolithic resins by polymerization of vinylic derivatives of the corresponding macrocycles is shown to be a more versatile strategy for this purpose. The use of energy-dispersive analysis by X-ray has revealed to be a very useful tool for the rapid evaluation of the interaction of those materials with both anions and cations and has allowed the corresponding selectivity trends to be obtained in a fast and simple way. Important effects of the polymeric matrix are observed in some cases.

Citotoxicity of four types of resins used for removable denture bases: in vitro comparative analysis

2009

Objective: To compare the cytotoxicity of four types of resins used for manufacturing denture bases. Method and Materials: 9 disk-shaped samples of four resin (two heat-polymerized, one auto-polymerized, and one light-polymerized), 9 samples of glass (negative control) and 9 samples of lead (positive control) were made according to the manufacturer instructions. The materials were tested by contact with BALB/C 3T3 fibroblast cells. Each sample was tested after 24, 48 and 72 hours. The cellular vitality was verified through spectrophotometric analysis of the solution where the colour is directly related to the amount of metabolically active and living cells. The results were analyzed through…

Remineralization effects of conventional and experimental ion-releasing materials in chemically or bacterially-induced dentin caries lesions

2019

Abstract Objectives The aim of this study was to evaluate the remineralization effects of conventional and experimental ion-releasing materials on different artificial dentin carious lesions. Methods Forty human dentin discs were submitted to different demineralization protocols for simulated caries lesion: (D1) Shallow chemically-induced caries, (D2) deep chemically-induced caries, (D3) deep bacterially-induced caries. Each disc was divided in five parts; one of those served as baseline control. The remaining parts of each disc (n = 12–16/group) were treated using the following materials: EXP, an experimental resin-based bioactive material consisting of a self-etch primer and an adhesive c…

A laboratory comparison of Individual Targis/Vectris posts with standard fiberglass posts

2007

This article presents an in vitro analysis of a specific occlusal loading test on endodontically treated teeth restored with 2 different composite post materials. Individual, customized posts (IFPs) were compared to standard fiberglass posts (SFPs). The selected IFPs (standard cylindric Targis/Vectris posts) were compared to SFPs (Conic 6% Post, Ghimas). The posts were first subjected to a 3-point bending test to compare their flexural elastic properties. They were then used to restore 22 endodontically treated artificial maxillary central incisors and subjected to a specific occlusal loading simulation test. The loading test showed that IFP restorations performed better than SFP restoratio…

Fracture Resistance of New Metal-Free Materials Used for CAD-CAM Fabrication of Partial Posterior Restorations

2020

Background and Objectives: To evaluate in vitro the fracture resistance and fracture type of computer-aided design and computer-aided manufacturing (CAD-CAM) materials. Materials and Methods: Discs were fabricated (10 &times

Reduction of Polymerization Shrinkage Stress and Marginal Microleakage Using Soft-Start Polymerization

2003

Purpose: This study evaluated the influence of a soft-start light-curing exposure on polymerization shrinkage stress and marginal integrity of adhesive restorations. Materials and Methods: Six resin-based composites (Pertac II, Tetric Ceram, Definite, Surefil, Solitaire, and Visio-Molar) were adhesively bonded to a cylindrical cavity (n = 9 per material/light) in a photoelastic material. Visible light-curing was applied using either the standard polymerization mode (800 mW/cm2 exposure duration 40 s) of the curing light (Elipar TriLight, 3M ESPE) or the exponential mode from the same device (ramp-curing: 150 mW/cm2 to 800 mW/cm2 within the first 15 s of a total curing time of 40 s). Polymer…

Solid state NMR applications in the field of cultural heritage

2009

Preparazione e caratterizzazione di compositi polimerici funzionali a base di nanostrutture carboniose

Obiettivo di questo lavoro è la realizzazione di materiali nanocompositi polimerici utilizzando come matrice la resina epossidica commerciale Epikote828 e come filler nanotubi di carbonio (CNT) e nanoplacchette di grafene (GNP) e la caratterizzazione funzionale per applicarli come schermi per interferenze elettromagnetiche. Per correlare le proprietà funzionali alle proprietà morfologico-strutturali, i materiali sono stati analizzati mediante microscopia acustica a scansione (SAM) per valutare la dispersione del filler, spettroscopia Raman e per verificare risonanza magnetica nucleare in stato solido (ss-NMR) per studiare le interazioni filler-matrice e test di nanoindentazione per studiare…