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Glove Selection for Work with Acrylates Including Those Cured by Ultraviolet, Visible Light, or Electron Beam
Published in Robert N. Phalen, Howard I. Maibach, 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).
Injectable Scaffolds for Bone Tissue Repair and Augmentation
Published in Naznin Sultana, Sanchita Bandyopadhyay-Ghosh, Chin Fhong Soon, Tissue Engineering Strategies for Organ Regeneration, 2020
Subrata Bandhu Ghosh, Kapender Phogat, Sanchita Bandyopadhyay-Ghosh
Reinforcing bone by injecting a cementitious bone substitute such as poly (methyl methacrylate) (PMMA) is a common technique and is found to be effective for vertebral fractures. However, during the setting process, PMMA based cement has been reported to generate monomer toxicity and excessive heat that may lead to bone necrosis (Schoenfeld et al. 1979, Karlsson et al. 1995, Galibert et al. 1987, Deramond et al. 1997, Bohner et al. 2006). An alternative to PMMA is calcium phosphate cements (CPC) which are made of calcium phosphate particles dispersed in an aqueous solution. They are usually considered to be injectable, although their injectability is often found to be poor. Self-setting of calcium phosphate cements can happen in vivo assisted by the aqueous medium present at the biological target site (Hou et al. 2004, Bohner et al. 2006).
Pelvic fractures
Published in Charles M Court-Brown, Margaret M McQueen, Marc F Swiontkowski, David Ring, Susan M Friedman, Andrew D Duckworth, Musculoskeletal Trauma in the Elderly, 2016
Some authors have recommended interventions in selected patients. Tosounidis et al.40 reported the use of external fixation in patients with pubic ramus fractures with associated sacral fractures if pain persisted for longer than 2 weeks. Percutaneous fixation with retrograde medullary ramus screws and iliosacral screws is also an option. Winkelhagen et al.41 reported on a series of six patients with persistent pain following isolated pubic ramus fractures treated by medullary ramus screws. They noted significant improvement in pain which facilitated mobilization and discharge. The technique had the advantage of being minimally invasive, and biomechanically is equivalent to plating.42 Injection of methyl methacrylate cement into ramus fractures to relieve pain has also been reported.38 These techniques have only been reported in small numbers of patients and are probably only applicable to a subset of patients with these fractures where there is a posterior lesion and pain control is a significant problem.
Biological aspects of modern dental composites
Published in Biomaterial Investigations in Dentistry, 2023
Jan Tore Samuelsen, Jon E. Dahl
Only a limited number of studies have addressed patient exposure to monomers from resin-based materials. Most studies have addressed methacrylate exposure from removable prostheses. The maximum concentration of monomer released into saliva peaked 1 day after the insertion of complete dentures. The methyl methacrylate (MMA) content was 0.4 ± 0.1 µM 1 h after insertion, 3 ± 1 µM, and 0.5 ± 0.1 µM on the first- and third-days post insertion, respectively. Although the released MMA was not at toxic levels, it could potentially sensitize the patient or elicit an allergic reaction [10]. In another study, healthy human dentate subjects wore recently made auto-polymerized or heat-polymerized poly methyl methacrylate palatal appliances for 5 min. MMA is released into saliva from auto-polymerized appliances, with a maximum concentration of 0.45 mM in whole saliva and 1.8 mM in the salivary film on the fitting surface. Monomer was not found in saliva from subjects wearing properly heat-polymerized MMA appliances, whereas the maximum MMA concentration in saliva was 63 mM when the polymerization time was shorter than recommended. MMA was not detected in blood or urine [11].
Influence of sequential opening/closing of interface gaps and texture density on bone growth over macro-textured implant surfaces using FE based mechanoregulatory algorithm
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2022
Rajdeep Ghosh, Souptick Chanda, Debabrata Chakraborty
Intramedullary implant fixation is a standard surgical procedure which is extensively used in re-establishing fractured bones and joints, further aiding to the treatment of various joint diseases such as osteoarthritis (OA), rheumatoid arthritis (RA), femoral fractures etc. Contributing to the sedentary lifestyle among youth, increase in road accidents and ageing population in developed nations, there is a tremendous increase in need for joint replacements globally (Holzwarth and Cotogno 2012; Cilla et al. 2017; Sánchez, Schilling, Grupp, Giurea, Wyers, et al. 2021). There are primarily two types of intramedullary implantation widely used presently. Cemented fixation, in which bone cement, commercially known as poly (methyl methacrylate) or PMMA, is used to adhere the implant to the host bone by drilling a canal of required diameter into the healthy bone. On the other hand, in uncemented fixation, the implant is forced (press-fit or interference-fit) into the healthy bone canal without the use of bone cement. Primary fixation of such implants is achieved by the interference-fit and frictional conditions of the surface, which further aids to the enhancement of biologic fixation of bone to the implant, also referred to as secondary stability (Ghosh et al. 2020; Sánchez, Schilling, Grupp, Giurea, Wyers, et al. 2021). A proper combination of both primary stability and secondary fixation is crucial for long-term success of such intramedullary fixation devices (Ghosh et al. 2020).
Release behavior, mechanical properties, and antibacterial activity of ciprofloxacin-loaded acrylic bone cement: a mechanistic study
Published in Drug Development and Industrial Pharmacy, 2020
Marzieh Gandomkarzadeh, Arash Mahboubi, Hamid Reza Moghimi
Nowadays the use of ultraclean air theaters, perioperative antibiotics and antibiotic-loaded bone cement (ALBC) leads to a significant reduction in risk of infections [4]. Addition of antibiotics in poly(methyl methacrylate) (PMMA) bone cements is appropriate to treat and prevent orthopedics infections, for decades. In fact, acrylic bone cement, in addition to its role as a biomaterial used in total hip and knee arthroplasty surgeries, could act as a drug carrier to decrease the rate of infections at the site of action. The United States Food and Drug Administration (FDA) has approved ALBC products for second-stage of two-stage total joint replacement surgery due to infection. This drug delivery system is an alternative for systemic drug delivery systems with low efficacy in bone infections. The antibiotic impregnated bone cement provides higher concentration of drug at the infection site and effectively inhibits infections with much less side effects in comparison to systemic administration [5–7]. Novel antimicrobial agents like silver and gold nanoparticles have also been developed for the improvement of bone cement antibacterial features against resistant strains [8–10]. PMMA bone cement, are also designed as beads or spacers for treatment of musculoskeletal infections in the revision surgery [11].