Glove Selection for Work with Acrylates Including Those Cured by Ultraviolet, Visible Light, or Electron Beam
Robert N. Phalen, Howard I. Maibach in Protective Gloves for Occupational Use, 2023
Common UV or light-cured composites for dental fillings and sealants include bisphenol A-diglycidyl methacrylate (BIS-GMA), triethyleneglycol dimethacrylate (TREGDMA), 2-HEMA, TMPTA, and sometimes methyl methacrylate (MMA; Figure 23.2).66,67 The most common ACD reactions are to 2-HEMA and TREGDMA;62,65 however, reactions to 2-HPMA, THFMA, EMA, butanediol dimethacrylate (BUDMA), and urethane dimethacrylate (UDMA) are common among dental workers.62 In the latter, cross-allergy to other methacrylates is suspected.Methyl methacrylate (MMA).The figure shows the chemical structure for methyl methacrylate (MMA) with a carboxylic acid group (–COOH), bound to a carbon-carbon double bond (C=C), and bound to a methyl group (–CH3).
An Introduction to Bioactivity via Restorative Dental Materials
Mary Anne S. Melo in Designing Bioactive Polymeric Materials for Restorative Dentistry, 2020
Concerning polymeric restorative materials, here, referred to as methacrylate resin-based materials that have preventive and dental restorative applications has extended the concept of bioactivity (Pratap et al. 2019). Currently, bioactive materials generally refer to biomaterials that can induce a response to the biological system upon interacting. They could have the following bioactivities as illustrated in Figure 1.1: A surface that may nucleate the formation of biological-like calcium phosphates or released components involved in the induction of the bioapatite-like material when in contact with saliva or tissue fluids.The release of key ions, such as calcium ions to assist in the chemical equilibrium of the mineral net into the hard dental tissues, such as enamel and dentin.The release or contact of components of agents that can modulate or suppress bacterial metabolism, consequentially reducing biofilm growth.
OSL point dosimeters for in vivo patient dosimetry
Sam Beddar, Luc Beaulieu in Scintillation Dosimetry, 2018
Figure 18.6 Response of nanoDot as a function of orientation of detector with respect to incident beam. At , the beam was incident on the face with the serial number (see Figure 18.1). At , the beam was incident on the edge containing the paper label. Angular dependence was evaluated using (a) a mammography unit, (b) from a general radiography unit, (c) from a general radiography unit, (d) from a CT scanner, and (e) from a CT scanner. PMMA, polymethyl methacrylate. (Reproduced from Al-Senan R, Hatab M., Medical Physics, 38, 4396-405, 2011, Figure 8. With permission.)
Antibacterial activity and physicochemical properties of a sealer containing copaiba oil
Published in Biofouling, 2023
Lara Rodrigues Schneider, Andressa da Silva Barboza, Juliana Silva Ribeiro de Andrade, Daniela Coelho dos Santos, Carlos Enrique Cuevas-Suárez, Evandro Piva, Angela Diniz Campos, Rafael Guerra Lund
Dimensional change is an important property that shows, in percentages, the shrinkage or expansion of the material after adjustments. The ANSI/ADA (2000) states that the maximum limit is 1% for linear reduction and 0.1% for expansion (Carvalho-Junior et al. 2007) The dimensional change of all sealers tested was higher than the values considered acceptable by the ANSI/ADA (2000), which indicates hydrophilicity of the materials evaluated (Reiznautt et al. 2021). The structure of methacrylate monomers used as an organic matrix in the formulation of experimental materials has a considerable amount of hydrophilic groups. These hydrophilic groups can form hydrogen bonds with water molecules, justifying the expansion of the materials (Carvalho-Junior et al. 2007). The increase in dimensional change could improve the sealing ability of endodontic sealers (dos Santos et al. 2021).
Critical design parameters to develop biomimetic organ-on-a-chip models for the evaluation of the safety and efficacy of nanoparticles
Published in Expert Opinion on Drug Delivery, 2023
Mahmoud Abdelkarim, Luis Perez-Davalos, Yasmin Abdelkader, Amr Abostait, Hagar I. Labouta
Materials that were often used are silicon and glass, which enable cell adhesion but with a lower stability [132]. Thermoplastics such as poly(methyl methacrylate) (PMMA), cyclic olefin copolymer (COC), polystyrene, and poly(ethylene terephthalate) have high mechanical strength but with greater hydrophobicity [133]. Two procedures of surface treatment were applied to decrease the hydrophobicity of thermoplastics; the first is dynamic coating with ionic or nonionic small molecules, and the second is permanent chemical modification [134]. Polymers have higher biocompatibility with lower toxicity. Of which, polydimethylsiloxane (PDMS) is the most commonly used material for microfluidic device fabrication [135]. PDMS provides greater flexibility for different dynamic flows, enhances more oxygen supply to cells due to their gas permeability as well as they have high optical clarity that allows immunostaining and imaging [136]. Plasma treatment was found to lower the hydrophobicity of PDMS, but the effect is short due to the hydrophobic recovery [137]. Surface coating with other biomaterials such as collagen, gelatin, and hydrogels act as an extracellular matrix that induces cell adhesion, proliferation, and better cell growth. It allows cells to communicate, organize and provide the required mechanical stress on the cells with low antigenicity, in addition to chitosan, which is more flexible and porous to cells [138,139].
The most promising microneedle device: present and future of hyaluronic acid microneedle patch
Published in Drug Delivery, 2022
Huizhi Kang, Zhuo Zuo, Ru Lin, Muzi Yao, Yang Han, Jing Han
MeHA is highly hydrophilic and can swell rapidly within minutes. A swelling rate of approximately 600% can be achieved in vitro in 30 seconds (Park et al., 2022). Therefore, in addition to transdermal drug delivery, it can also be applied to the immediate extraction of biomolecules from tissue fluids for analysis, such as glucose and cholesterol (Chang et al., 2017). The swelling rate can be adjusted by adding a suitable photo-initiator to control the UV exposure time. Cross-linking time was inversely proportional to swelling rate and drug-carrying capacity (Chew et al., 2020). MeHA not only enhances the mechanical strength of MNP and extends the duration of skin microchannels, but also produces a longer peak time of drug action Tmax and a higher peak concentration of drug Cmax. The degree of methacrylate can be adjusted according to treatment needs. The degree of cross-linking has a great impact on the mechanical strength of MNP. MNP varies greatly in morphology and properties depending on the concentration of MeHA (Yao et al., 2021), and this review lists several different MeHA-prepared HA MNP. HA MNP prepared with MeHA can be used for diagnostic extraction and transdermal delivery (Table 5).
Related Knowledge Centers
- Methacrylic Acid
- Methyl Methacrylate
- Poly(Methyl Methacrylate)
- Ethyl Methacrylate
- Butyl Methacrylate
- (Hydroxyethyl)Methacrylate
- Glycidyl Methacrylate