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Electron spin resonance in silicon substituted apatite and tricalcium phosphate

Paper ID Volume ID Publish Year Pages File Format Full-Text
12484 794 2005 12 PDF Available
Title
Electron spin resonance in silicon substituted apatite and tricalcium phosphate
Abstract

Impurity centers associated with silicon have been observed in the phase mixture of silicon substituted apatite (Si-Ap) and silicon stabilized tricalcium phosphate (Si-TCP) using electron spin resonance (ESR). Two unique centers occur upon addition of SiO2 to the calcium phosphate system: an orthorhombic center with g-values 2.0072±0.0001, 2.0024±0.0001 and 2.0003±0.0001 (Si-h1) and a center with tetrahedral symmetry having g-values components 2.0054±0.0001 and 1.9992±0.0003 (Si-h2). Both centers are hypothesized to be characteristic of defects associated with silicon in the Si-Ap phase. Through comparison of the intensity of F-OH centers in undoped calcium hydroxyapatite (HA) prepared with various levels of OH occupancy, a relationship is demonstrated between the ESR intensity of an F-center signal with g=2.0019+0.0004 (F-OH) and the OH occupation of HA. Relative changes in the intensity of ESR signals Si-h1 and F-OH are consistent with a chemical model describing the substitution of SiO44− for PO43− in HA with the creation of OH− vacancies as charge compensation, resulting in a mixed phase composition of Si-Ap and Si-TCP that results when a hydroxyapatite precipitate (HA) is heated in the presence of added SiO2.

Keywords
Calcium phosphate bioceramic; Silica; Ceramic structure; Electron spin resonance
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Electron spin resonance in silicon substituted apatite and tricalcium phosphate
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Publisher
Database: Elsevier - ScienceDirect
Journal: Biomaterials - Volume 26, Issue 18, June 2005, Pages 3819–3830
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
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Price was $35.95
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