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A review of the bioactivity of hydraulic calcium silicate cements.
Niu, LN, Jiao, K, Wang, TD, Zhang, W, Camilleri, J, Bergeron, BE, Feng, HL, Mao, J, Chen, JH, Pashley, DH, et al
Journal of dentistry. 2014;(5):517-33
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Abstract
OBJECTIVES In tissue regeneration research, the term "bioactivity" was initially used to describe the resistance to removal of a biomaterial from host tissues after intraosseous implantation. Hydraulic calcium silicate cements (HCSCs) are putatively accepted as bioactive materials, as exemplified by the increasing number of publications reporting that these cements produce an apatite-rich surface layer after they contact simulated body fluids. METHODS In this review, the same definitions employed for establishing in vitro and in vivo bioactivity in glass-ceramics, and the proposed mechanisms involved in these phenomena are used as blueprints for investigating whether HCSCs are bioactive. RESULTS The literature abounds with evidence that HCSCs exhibit in vitro bioactivity; however, there is a general lack of stringent methodologies for characterizing the calcium phosphate phases precipitated on HCSCs. Although in vivo bioactivity has been demonstrated for some HCSCs, a fibrous connective tissue layer is frequently identified along the bone-cement interface that is reminiscent of the responses observed in bioinert materials, without accompanying clarifications to account for such observations. CONCLUSIONS As bone-bonding is not predictably achieved, there is insufficient scientific evidence to substantiate that HCSCs are indeed bioactive. Objective appraisal criteria should be developed for more accurately defining the bioactivity profiles of HCSCs designed for clinical use.
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Kidney disease outcomes quality initiative guidelines for bone and mineral metabolism: emerging questions.
Patel, TV, Singh, AK
Seminars in nephrology. 2009;(2):105-12
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Abstract
Since their initial publication in 2003, the National Kidney Foundation Kidney Disease Outcomes Quality Initiative clinical practice guidelines for bone and mineral metabolism have transformed the clinical approach to the management of metabolic bone disease in both dialysis and nondialysis chronic kidney disease patients. These guidelines largely were based on expert opinion rather than evidence. In the past 5 years, with the publication of several randomized controlled trials, large observational studies, and smaller clinical series, significant progress has been made in our understanding of mineral metabolism, calcium and phosphorus management, and the use of activated vitamin D irrespective of parathyroid hormone level in chronic kidney disease. More recently, fibroblast growth factor-23 and serum alkaline phosphatase have been shown to predict mortality in dialysis patients, making these attractive markers to monitor. In the wake of this progress, the bone Kidney Disease Outcomes Quality Initiative guidelines will need to be revised. Here, we review some of the issues and controversies that likely will form the basis of these revised guidelines.