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Can we accelerate the osteoporotic bone fracture healing response?
Published in Peter V. Giannoudis, Thomas A. Einhorn, Surgical and Medical Treatment of Osteoporosis, 2020
Martijn van Griensven, Elizabeth Rosado Balmayor
In order to administer PTH locally, loading onto tricalcium phosphate scaffolds has been investigated in in vivo models. Implantation of tricalcium phosphate loaded with 30 μg/kg or 60 μg/kg PTH in a critically sized femur defect in rats, resulted in bone regeneration with a good bone quality (25,26). In order to optimize the release of parathyroid hormone, the tricalcium phosphate can be combined with collagen. Thereby, bone regeneration could be achieved with a lower dose of PTH (27).
Chemistry of Mature Enamel
Published in Colin Robinson, Jennifer Kirkham, Roger Shore, Dental Enamel, 2017
Colin Robinson, Jennifer Kirkham, Steven J. Brookes, Roger C. Shore
OCP, for example, is structurally similar to hydroxyapatite and some workers consider this to be an apatite precursor.25 While it has not been definitively identified in mature enamel,28 imperfect hydrolysis to apatite might lead to a nonstoichiometric apatite at the crystal interior. This may perhaps be associated with planar or screw dislocations as described above. Brown29 argued that the flattened, bladelike shape of apatite crystals in mineralized tissues reflects its OCP origin. This was supported by the presence of two diffuse lines evident in X-ray diffraction patterns derived from developing tissue. While this is still questionable, more recent electron microscopic and fourier transform infrared data has suggested that the initial ribbonlike deposits in dental enamel that form the central portion of the mature crystals were not definitely apatitic but were OCP-like.30 The presence of pyrophosphate in enamel after heating31 also supports this concept. However, Herman and Dallemagne32 attributed the formation of pyrophosphate to hydrated tricalcium phosphate, possibly accompanied by a small amount of calcium carbonate. Indeed, Termine and Posner33 have suggested that hydrated tricalcium phosphate and not OCP is the first mineral deposited in the developing tissue. Alternatively, a brushitelike phase has also been suggested.34 Whatever their origins and situation in enamel apatite, the data certainly indicates the presence of some distortions in the structure involving the presence of acid phosphate groups in mature enamel.
Calcium Phosphate and Bioactive Glasses
Published in Vincenzo Guarino, Marco Antonio Alvarez-Pérez, Current Advances in Oral and Craniofacial Tissue Engineering, 2020
Osmar A. Chanes-Cuevas, José L. Barrera-Bernai, Iñigo Gaitán-S., David Masuoka
It has been known for more than 250 years that calcium phosphates are a component of the human body. Therefore, it was logical to assume that this material was thought of as a natural substitute for bone. Within calcium phosphates, one of the most used for this purpose is tricalcium phosphate (TCP). The first reported case of a tricalcium phosphate used as a graft dates back to 1920 by Albee who reported that a TCP graft promoted the formation of new bone tissue (Moed et al. 2003). Tricalcium phosphate is a bioceramics of formula Ca, (PO4)2, which is divided into two main groups, the form a and 13, both with the same Ca/P ratio of 1.5 but with different crystallographic, monoclinic and rhombohedral structures, respectively (Samavedi et al. 2013; Barrere et al. 2006; Jeong et al. 2019). This structure gives them different properties, since it depends on their stability, solubility, mechanical resistance and even their biological properties, and therefore their final applicability. The a form is generally obtained by two methods, the first is by means of a thermal transformation in which the temperature rises above 1125°C of some precursor with a Ca/P ratio of 1.5, such as hydroxyapatite deficient in calcium, amorphous calcium phosphate or the β-TCP form. The second method of obtaining it is by the so-called solid state reaction, in which precursors are mixed and the temperature is raised in the same way. Some authors recognize an α’ form that occurs only at temperatures greater than 1430°C and returns to the a form when cooled below its transition temperature, and therefore lacks clinical interest (Carrodeguas and De Aza 2011). In general, the α-TCP form is more soluble and less stable, and also has less mechanical resistance than the β-TCP form, so it is not used as a bone graft, but rather as cement, which can be accompanied by a polymer that functions as a vehicle for α-TCP particles. Colpo and collaborators developed an α-TCP cement using an acrylamide-based polymer as a vehicle, which was also used to release drugs in a controlled manner (Colpo et al. 2018). An and collaborators tested an α-TCP cement together with carboxymethylcellulose and hyaluronic acid, achieving values of up to 10 MPa, which shows that polymers also help improve their mechanical properties (An et al. 2016). The α-TCP cements set by a reaction in which three α-TCP molecules incorporate hydrogen from water to form an acidic phosphate, also adding a hydroxyl group to the resulting molecule (Gildenhaar et al. 2012).
Advances in pharmacotherapy for diabetic foot osteomyelitis
Published in Expert Opinion on Pharmacotherapy, 2021
Raju Ahluwalia, Jose Luiz Lázaro-Martínez, Ines Reichert, Nicola Maffulli
The principal types of biodegradable ceramics available for antibiotic delivery are based on either calcium sulfate or calcium phosphate (Tables 4 and 5). Within the calcium phosphate group, two main types exist: tricalcium phosphate and hydroxyapatite. Calcium sulfate has also been used as a bone graft material since 1892 [90], having a compressive strength equivalent to that of cancellous bone [91]. However, it is brittle and quickly loses its strength as it is hydrolyzed on its own and needs to be combined with another ceramic. Its use in DFO showed that 20 of 323 patients required further debridement before wound healing occurred [92], and another 20 patients required an amputation, 6 being below knee. Jogia et al. reported no recurrence or amputation following debridement of forefoot ulcers in 20 patients at 12-month follow-up with routine use of calcium sulfate impregnated with antibiotics [93]. Krause et al. found that 13 of 49 feet treated by trans-metatarsal amputation with calcium sulfate and tobramycin experienced a reduction in below knee amputation rates at an average follow-up of 28 months (8–52 months) [94].
Effect of dentifrice containing fTCP, CPP-ACP and fluoride in the prevention of enamel demineralization
Published in Acta Odontologica Scandinavica, 2018
Suzana Carvalho Teixeira Pinto de Souza, Kaline Cassiano de Araújo, Joseane Ribeiro Barbosa, Viviane Cancio, Anderson Araújo Rocha, Mônica Almeida Tostes
Tricalcium phosphate products (functionalized β-tricalcium phosphate; fTCP) are prepared with silica, which may provide linking opportunities with hard-tissue defects under acidic conditions. Silica can permeate throughout enamel without attacking the inter-prismatic organic material, which may encourage greater calcium, phosphate and fluoride uptake in demineralized lesions [12]. It is an agent that works in synergy with fluoride to create a stronger, more acid-resistant mineral relative to that achievable with fluoride, β-TCP or fTCP alone [12,13]. Some initial reports have shown that Clinpro™ 5000 tooth Crème anti-cavity toothpaste containing fTCP, is useful for reducing white spot lesions [14]. fTCP is produced by milling TCP with sodium lauryl sulphate. This process prevents undesirable interactions between calcium and fluoride, which could render both inactive.
Ultrasonic measurement of dentin remineralization effects of dentifrices and silver diamine fluoride
Published in Acta Odontologica Scandinavica, 2021
Kengo Wakamatsu, Hiroyasu Kurokawa, Taketo Okuwaki, Toshiki Takamizawa, Akimasa Tsujimoto, Koji Shiratsuchi, Ryo Ishii, Masashi Miyazaki
Dentifrices containing functionalized tricalcium phosphate (fTCP) provide and enhance bioavailable Ca and PO4 ions to teeth. These ions act synergistically with fluoride, enhancing their effect [9]. fTCP is ball milled with sodium lauryl sulphate to produce particles reported to exhibit remineralizing effects in both in vitro and in situ studies. Furthermore, fTCP products provide more fluoride and ions to the tooth surface while preventing Ca from prematurely interacting with F ions to form CaF [10]. Teeth naturally absorb the components released from fTCP, preventing the initiation and further progression of demineralization and allowing remineralization. However, limited information is available regarding the effect of fTCP on dentin in root caries.