China
Africa
Explore chapters and articles related to this topic
Tooth Whitening Materials
Published in Linda Greenwall, Tooth Whitening Techniques, 2017
This type of toothpaste may contain hydrogen peroxide, calcium peroxide, sodium percarbonate or carbamide peroxide as an active ingredient to lighten teeth. Some of the toothpastes contain the same concentration of peroxide as the home whitening agents, whereas other toothpastes contain hydrogen peroxide in very low concentration (a 1.5% concentration may be too low to exert a whitening effect). The mechanism of application does not seem sufficient to warrant a significant amount of tooth lightening. However, long-term use of peroxide-containing toothpastes has the potential to make some changes, but there is a question about their safety (Haywood 1996). They act to remove the discoloration of surface staining and possibly also have some chemical effects (Lynch et al. 1998).
Protocol with non-toxic chemicals to control biofilm in dental unit waterlines: physical, chemical, mechanical and biological perspective
Published in Biofouling, 2022
Rachel Maciel Monteiro, Viviane de Cassia Oliveira, Rodrigo Galo, Denise de Andrade, Ana Maria Razaboni, Evandro Watanabe
To face the presence of biofilm on dental unit waterlines, different chemical products have been applied in vitro and in situ. Peracetic acid, sodium bicarbonate, chlorine dioxide, silver nanoparticles, sodium percarbonate, hydrogen peroxide and ammonium quaternaries are among the most widely chemical products used (Gawande et al. 2008; Patel et al. 2016; Tuvo et al. 2020; Cheng et al. 2021). Sodium bicarbonate and citric acid in the presence of water react releasing carbon dioxide (CO2), which is responsible for the effervescence of the reaction. Different authors have proposed that effervescence release can promote a mechanical action disrupting biofilms and favoring removal of deposits on surfaces (Abelson 1981; Denture cleansers, 1983; Srinivasan and Gulabani 2010). Here, it has been hypothesized that the combined application of NaCl, C6H8O7 and NaHCO3 could expand the anti-biofilm activity of the protocol by increasing the external osmotic pressure and by the generation of effervescence that would cause a mechanical action. The results of the anti-biofilm activity do not support the assumption as the treatment with Product AB or Product A + B + AB did not promote broad elimination or reduce the viability of biofilms.
Using hydrogen peroxide to prevent antibody disulfide bond reduction during manufacturing process
Published in mAbs, 2018
Cheng Du, Yunping Huang, Ameya Borwankar, Zhijun Tan, Anthony Cura, Joon Chong Yee, Nripen Singh, Richard Ludwig, Michael Borys, Sanchayita Ghose, Nesredin Mussa, Zheng Jian Li
Two inorganic chemicals containing hydrogen peroxide, sodium percarbonate (Sigma-Aldrich, Cat. 371432, 2Na2CO3 3H2O2) and sodium perborate (Sigma-Aldrich, Cat. 372862, NaBO3 H2O) were also tested. Both sodium percarbonate and sodium perborate undergo hydrolysis upon contact with water, producing hydrogen peroxide, and carbonate or borate, respectively.
Promoting vascularization for tissue engineering constructs: current strategies focusing on HIF-regulating scaffolds
Published in Expert Opinion on Biological Therapy, 2019
Tilman U. Esser, Kaveh Roshanbinfar, Felix B. Engel
An alternative way to bridge the time for endogenous vascularization is the use of oxygen releasing materials (Figure 1(e)). Perfluorocarbons (PFC) have the characteristic to dissolve oxygen (O2) in large quantities. PFC emulsions have been utilized as mixtures with culture medium or incorporated into hydrogels or microparticles seeded with cells [51–53]. Engineered cardiac constructs have been perfused with such PFC emulsions for three days and were found to contain higher amounts of DNA, suggesting a greater number of remaining cells (45% vs. 25% of initial cell numbers for PFC-perfused vs. control) [51]. Furthermore, PFC microparticles could increase the survival of osteoblast in a hypoxic environment in vitro [52]. Osteoblasts continued to proliferate for five days, where control cells did not. Although cell numbers declined after day 5, they only dropped to initial (day 0) values by day 10 [52]. PFC incorporated into methacrylated chitosan hydrogels were also found to improve healing in a rat skin wound model, as indicated by increased epithelial wound coverage and collagen production [53]. In another study, core/shell microparticles with a polymeric poly lactic-co-glycolic acid (PLGA) shell, containing size-controlled nanopores and a PFC core, were charged with oxygen [54]. The contained oxygen was released only in contact with desaturated blood. This system showed five times higher oxygen delivery per gram of material in comparison to human red blood cells; however, oxygen release occurred within minutes [54]. Furthermore, sodium percarbonate (SPO), which decomposes in contact to water to yield O2, has been incorporated into PLGA films [55]. The effect of SPO-PLGA films on the survival of skin tissue flaps, which had been partially disconnected from their supporting vasculature, was investigated. Oxygen was released from SPO-PLGA films over the course of 70 h (~110 ml O2 per gram of SPO), with approximately 70% being released within the first 24 h. This translated to a significantly reduced skin flap necrosis after 3 days, compared to SPO-free controls (15% vs. 40%), although this difference equalized by day 7 [55]. Similarly, the oxygen generating calcium peroxide (CaO2) was incorporated into 3D PLGA-scaffolds, which sustained elevated O2 concentrations under hypoxic culture conditions (approximately 6.5 mmHg vs. 5.0 mmHg at Day 10) and allowed for continued proliferation of fibroblasts for at least 10 days, where controls stopped proliferating after day 3 [56].