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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).
Assessment of cytotoxic and genotoxic effects of conventional and whitening kinds of toothpaste on oral mucosa cells
Published in Acta Odontologica Scandinavica, 2018
Antonija Tadin, Lidia Gavic, Ana Zeravica, Klara Ugrin, Nada Galic, Davor Zeljezic
Nowadays, whitening types of toothpaste are commonly used in many households. Whitening kinds of toothpaste are based on formulations with enhanced physical (mechanical) and chemical cleaning abilities claiming to remove and prevent extrinsic stains effectively. However, in some dentifrices chemicals that provide a bleaching effect are added; thus there are two particular subclasses—whitening toothpaste and bleaching toothpaste [2]. The performance of this whitening toothpaste is based on their size and rigidity of molecules of the added abrasive substance, which are more resilient than the stain molecules themselves. Typically, silica dioxide, hydrated silica dioxide, calcium carbonate, calcium phosphate dihydrate, calcium pyrophosphate, alumina oxide, perlite (70-75% silica dioxide) and sodium bicarbonate are the abrasive agents used in whitening toothpaste [2,3]. Surface stains can be reduced by adding various chemicals to toothpaste. Most of the dye molecules which are included in the pellicle contain proteins. Therefore, enzymes such as protease and papain produce a whitening effect. Sodium pyrophosphate, sodium tripolyphosphate, and other pyrophosphates can bind with enamel, dentin on tartar and absorb the stain molecules, creating a whitening effect [2]. In contrast to whitening toothpaste, bleaching toothpaste contain chemicals, most commonly that of hydrogen peroxide or calcium peroxide (Calprox). When peroxides come into contact with the tooth’s surface or penetrate tooth tissue, they break down the stain molecule generating a bleaching effect. However, the concentration of peroxides added to toothpaste are low (usually 1% hydrogen peroxide or 0.5–0.7% calcium peroxide) [2,4]. Although in several studies whitening kinds of toothpaste that demonstrated to improve tooth color also exhibited adverse side effects. They can damage hard and soft tissue, which manifests either immediately or after prolonged exposure. Enamel and dentin abrasion are among the most severe side effects that can increase tooth sensitivity and gum irritation [2,4].
Methods for fabricating oxygen releasing biomaterials
Published in Journal of Drug Targeting, 2022
Ahmet Erdem, Reihaneh Haghniaz, Yavuz Nuri Ertas, Siva Koti Sangabathuni, Ali S. Nasr, Wojciech Swieszkowski, Nureddin Ashammakhi
Tissue engineering aims to develop products for the repair and regeneration of diseased or lost tissues [1]. Although substantial progress has been made in this area, difficulties still face the survival and unction of engineered constructs [2]. One of the biggest challenges is supplying the necessary oxygen (O2) to the newly formed tissue constructs, following their implantation in the body [3,4]. Because vascularisation takes some time [5], tissue constructs rely on diffusion with limited access to receiving sufficient O2 [6]. O2-generating materials have thus, been developed to overcome this problem by providing the O2 to implanted constructs [7]. There are various materials that can be used as a source for the generation of O2, among which most commonly used ones comprise calcium peroxide [8], magnesium peroxide [9] and hydrogen peroxide [10]. However, the common problem with the O2 delivery systems is the sudden or burst release of O2. Fast O2 generation of O2 results in the release of hydroxyl radicals which lead to the formation of hyperoxide conditions and cell injury [11]. One strategy to prevent this is to encapsulate O2 source into a polymeric material, such as poly(lactide-co-glycolide) (PLGA) [12], polycaprolactone (PCL) [13], and polyvinylpyrrolidone (PVP) [12] or into ceramics/polymer carrier materials [3,4] with varying degrees of success. When an O2 generating material is encapsulated in a carrier polymer, the polymer decomposes in aqueous environment leading to the exposure of O2 source material which reacts with water to produce H2O2, which dissociates then to water and O2 [5]. To have appropriate control over O2 release important factors include the use of appropriate method for the fabrication of O2-releasing products. These methods include emulsion [10], solvent casting [14], freeze-drying [15], electrospraying [12], gelation [16] and microfluidic [17] fabrication techniques. Each method has its advantages and limitations [7]. Therefore, we explain procedures in each of these methods, and compare and contrast them. The characterisation methods used to define the properties of resulting O2 releasing materials such as chemical, physical and biological investigations are also explained in this review.
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].