Novel self-healing dental resin with microcapsules of polymerizable triethylene glycol dimethacrylate and N,N-dihydroxyethyl-p-toluidine (original) (raw)
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Effects of Self-healing Microcapsules on Dental Resin Composites
2020
Dental restorations of resin-based composites mainly fail due to secondary caries and bulk fracture. Self-healing strategies in polymeric materials have been shown to enhance the mechanical properties with the ability of self-repair and crack inhibition, suggesting a prolonged life for dental composite restorations. The systematic review on self-healing dental composites (SHDCs) concluded that a healing performance of 25-80 % recovery rate of the virgin fracture toughness can been achieved based on current literature. The selfhealing systems used were PUF microcapsules of DCPD and TEGDMA-DHEPT or silica microcapsules of water/polyacid healing agent. TEGDMA-DHEPT microcapsules were synthesised as they have been proven previously to be biocompatible for dental materials. Microcapsules were prepared by in situ emulsion polymerisation of PUF shells (average diameter 150-300 μm). The experimental SHDC included: Bis-GMA:TEGDMA (1:1), 1 wt% BAPO, 0.5 wt% BPO catalyst, 20 wt% SiO2 (15 nm), and (0, 2.5, 5, 7.5, 10 wt%) of microcapsules. SEM imaging of the capsular shell revealed a smooth outer surface with deposits of PUF nanoparticles which offers a rough surface that may improve resin matrix retention. FT-IR showed that microcapsules crushed with BPO catalyst had DC of up to 60.3 %. The DC of SHDC after 24 h polymerisation was 73-76 % (P>0.05), micro-hardness 22-26 VHN (P>0.05), however, the flexural strength was reduced significantly from 80 to 55 MPa with increasing microcapsules to 10 wt% in composites (P<0.05). Microencapsulation parameters that can affect the microcapsule properties in the material performance were explored. Stirring speed and ratio of core:shell materials influenced: size/polydispersity of microcapsules 130-300 µm; microcapsule fill content 90-98 %; encapsulation efficiency 37-78 %; encapsulation yield 33-59 %; capsule permeability 6-25 % (leaking in 28 days). Composites containing 10 wt% microcapsules showed self-healing performance reached up to 36 % (recovery rate) in dental composite. The model SHDC may have the capability for crack-repair and prevention of catastrophic failure of dental restorations.
Al-Azhar Dental Journal for Girls, 2018
Purpose: The present study aimed to investigate the effect of incorporation of the new Triethylene glycoldimethacrylate and N,N-Bis(2-hydroxyethyl)-p-toluidine (TEGDMA)-(DHEPT) in polyurea formaldehyde (PUF) micro-capsules into an experimental dental resin composite on the flexural strength and fracture toughness and the evaluation of its self-healing efficacy. Materials and Methods: Polyurea formaldehyde microcapsules were synthesized by insitu polymerization technique, encapsulating a triethylene glycol dimethacrylate and dihydroxy ethyl para toluidine (TEGDMA-DHEPT) as a healing liquid, then experimental composite resin is prepared. Microcapsules are incorporated in the resin composite with concentrations 0%, 2.5%, 5%, 7.5% and 10%, then experimental resin composite specimens were fabricated. Fracture toughness and flexural strength were examined by three point loading using universal testing machine till fracture. The fracture toughness was evaluated by using single edge V-notched beam method, self healing efficacy is evaluated as the ratio between the healed fracture toughness and the virgin fracture toughness. Results: Regarding flexural strength results, it was found that the 0% group has the highest flexural strength while the 10% group had the lowest flexural strength. On the other hand, on evaluating the results, of 7.5% group it was found that this concentration did not affect the flexural strength remarkably. Regarding the virgin fracture toughness results, 0% group has the highest flexural strength, while the 10% group the lowest flexural strength, specimens were fractured and healed, then fractured again to measure the healed fracture toughness, on examining the results of the healed fracture toughness, it was found that no significant difference between 0% and 2.5% as no healing occur at such specimen, Also the results showed that the highest healed fracture toughness was in 5%, followed by 7.5%, followed by 10%. The self-healing efficacy increased to Codex : 66/1810
Novel self-healing dental luting cements with microcapsules for indirect restorations
Journal of dentistry, 2017
Dental luting cements are widely used to bond indirect restorations to teeth. Microcracks often lead to cement failures. The objectives of this study were to develop the first self-healing luting cement, and investigate dentin bond strength, mechanical properties, crack-healing, and self-healing durability in water-aging for 6 months. Microcapsules of poly(urea-formaldehyde) (PUF) shells with triethylene glycol dimethacrylate (TEGDMA) as healing liquid were synthesized. Cement contained bisphenol A glycidyl dimethacrylate, TEGDMA, 4-methacryloyloxyethyl trimellitic and glass fillers. Microcapsules were added at 0%, 2.5%, 5%, 7.5%, 8.5%, 9.5% and 10%. Dentin shear bond strength was measured using extracted human teeth. Flexural strength and elastic modulus were measured. Single edge V-notched beams were used to measure fracture toughness (KIC) and self-healing. Specimens were water-aged at 37°C for 6 months and then tested for self-healing durability. Adding 7.5% microcapsules into c...
Journal of Functional Biomaterials, 2022
Aim: The purpose of this study was to evaluate the mechanical properties of an experimental self-healing dental composite model (SHDC) composed of SiO2 nanoparticles with varying percentages of triethylene glycol dimethacrylate (TEGDMA) monomer and N,N-dihydroxyethyl-p-toluidine (DHEPT) amine microcapsules. Materials and methods: Microcapsules were prepared by in-situ polymerisation of PUF shells, as explained in our previous work. The model SHDC included bisphenol A glycidyl dimethacrylate (Bis-GMA:TEGDMA) (1:1), 1 wt% phenyl bis(2,4,6-trimethylbenzoyl) phosphine oxide (BAPO), 0.5 wt% benzoyl peroxide (BPO) catalyst, 20 wt% silanised silica dioxide (SiO2) (15 nm) and (0, 2.5, 5, 7.5, 10 wt%) of microcapsules (120 ± 45 μm). Light transmission, hardness, degree of conversion (DC), flexural strength and elastic modulus of the SHDC model were measured. Results: The degree of conversion of the SHDC ranged from 73 to 76% 24 h after polymerisation. Hardness measurements ranged from 22 to ...
Self-healing polymeric materials for potential dental application / Sonja Then
2011
Poly(urea-formaldehyde) (PUF) microcapsules that enclose dicyclopentadiene (DCPD) were successfully prepared by in situ polymerization. The effect of diverse process parameters and concentrations of ingredients on the product yield and quality was investigated. After optimizing the procedure high yields of microcapsules were obtained (up to 89%) which appeared in the form of a free-flowing white powder. The morphology of the microcapsules was observed by digital microscopy, optical microscopy (OM), and field emission gun scanning electron microscopy (FESEM). FTIR and 1 H-NMR were employed to analyze the chemical structure and content of the core material. The thermal properties were characterized utilizing DSC and TGA. The microcapsules could be incorporated into another polymeric host material. In the 3.
Robust synthesis of epoxy resin-filled microcapsules for application to self-healing materials
Philosophical transactions. Series A, Mathematical, physical, and engineering sciences, 2016
Mechanically and thermally robust microcapsules containing diglycidyl ether bisphenol A-based epoxy resin and a high-boiling-point organic solvent were synthesized in high yield using in situ polymerization of urea and formaldehyde in an oil-in-water emulsion. Microcapsules were characterized in terms of their size and size distribution, shell surface morphology and thermal resistance to the curing cycles of commercially used epoxy polymers. The size distribution of the capsules and characteristics such as shell thickness can be controlled by the specific parameters of microencapsulation, including concentrations of reagents, stirrer speed and sonication. Selected microcapsules, and separated core and shell materials, were analysed using thermogravimetric analysis and differential scanning calorimetry. It is demonstrated that capsules lose minimal 2.5 wt% at temperatures no higher than 120°C. These microcapsules can be applied to self-healing carbon fibre composite structural materi...
High performance dental resin composites with hydrolytically stable monomers
Objective. The objectives of this project were to: 1) develop strong and durable dental resin composites by employing new monomers that are hydrolytically stable, and 2) demonstrate that resin composites based on these monomers perform superiorly to the traditional bisphenol A glycidyl dimethacrylate/triethylene glycol dimethacrylate (Bis-GMA/TEGDMA) composites under testing conditions relevant to clinical applications. Methods. New resins comprising hydrolytically stable, ether-based monomer, i.e., triethylene glycol divinylbenzyl ether (TEG-DVBE), and urethane dimethacrylate (UDMA) were produced via composition-controlled photo-polymerization. Their composites contained 67.5 wt% of micro and 7.5 wt% of nano-sized filler. The performances of both copolymers and composites were evaluated by a battery of clinically-relevant assessments: degree of vinyl conversion (DC: FTIR and NIR spectroscopy); refractive index (n: optical microscopy); elastic modulus (E), flexural strength (F) and fracture toughness (KIC) (universal mechanical testing); Knoop hardness (HK; indentation); water sorption (Wsp) and solubility (Wsu) (gravimetry); polymerization shrinkage (Sv; mercury dilatometry) and polymerization stress (tensometer). The experimental UDMA/TEG-DVBE composites were compared with the BisGMA/TEGDMA composites containing the identical filler contents, and with the commercial micro hybrid flowable composite. Results. UDMA/TEG-DBVE composites exhibited n, E, Wsp, Wsu and Sv equivalent to the controls. They outperformed the controls with respect to F (up to 26.8% increase), KIC (up to 27.7% increase), modulus recovery upon water sorption (full recovery vs. 91.9% recovery), and stress formation (up to 52.7% reduction). In addition, new composites showed up to 27.7% increase in attainable DC compared to the traditional composites. Bis-GMA/TEGDMA controls exceeded the experimental composites with respect to only one property, the composite hardness. Significantly, up to 18.1% lower HK values in the experimental series (0.458 GPa) were still above the clinically required threshold of approx. 0.4 GPa
Applications of Microcapsules in Self-Healing Polymeric Materials
Microencapsulation - Processes, Technologies and Industrial Applications [Working Title]
Self-healing polymeric materials have a great potential to be explored and utilized in many applications such as engineering and surface coating. Various smart materials with self-healing ability and unique self-healing mechanisms have been reported in recent publications. Currently, the most widely employed technique is by embedding microcapsules that contain a healing agent into the bulk polymer matrix. When cracks develop in the polymer matrix, the curing agent is released from the microcapsules to cross-link and repair the cracks. Microencapsulation of the healing agent in the core can be achieved by in situ polymerizing of shell material. This chapter presents a general review on self-healing materials, and particularly, self-healing of epoxy matrices that includes epoxy composite and epoxy coating by microencapsulation technique. Microencapsulation processes, including types of resin used, processing parameters such as core/shell ratio, concentration of emulsifiers, viscosities of aqueous and organic phases and stirring rate are discussed.
Optimization of Microencapsulation Process for Self-Healing Polymeric Material
Sains Malaysiana, 2011
A series of poly(urea-formaldehyde) (PUF) microcapsules filled with dicyclopentadiene (DCPD) was successfully prepared by in situ polymerization. The effect of diverse process parameters and ingredients on the morphology of the microcapsules was observed by SEM, optical microscopy (OM) and digital microscopy. Different techniques for the characterization of the chemical structure and the core content were considered such as FT-IR and (1)H-NMR as well as the characterization of thermal properties by DSC. High yields of free flowing powder of spherical microcapsules were produced. The synthesized microcapsules can be incorporated into another polymeric host material. In the event the host material cracks due to excessive stress or strong impact, the microcapsules would rupture to release the DCPD, which could polymerize to repair the crack.