Ceramics Research Today is a free monthly online journal that collates and summarizes the latest research about Ceramics, including details on dentistry, restoration, benefits.

In situ SAXRD study of sol-gel induced well-ordered mesoporous bioglasses for drug delivery.

Zhao YF, Loo SC, Chen YZ, Boey FY, Ma J

School of Materials Science and Engineering, Nanyang Technological University, Nanyang Avenue 50, Singapore 639798.

In this work, two systems of mesoporous bioglasses (MBGs) were sol-gel derived using block copolymer pluronic F127 and P123, respectively, as templates. A two-dimensional hexagonal (P6mm) mesoporous structure was obtained for the two systems, with d-spacing in (100) reflection of 8.49 nm for P123-templated MBG (P123-MBG) and 10.26 nm for F127-templated MBG (F127-MBG). The phase transformation behavior for the systems was elucidated using an in situ synchrotron small angle X-ray diffraction approach, with the corresponding mechanisms proposed. It was indicated that both systems go through a complicated phase transformation, from a disordered to a finely ordered hexagonal structure during the self-evaporation process. The surfactants not only acted as templates for the ordered structure, but also enhanced the rigidity of Si-O network, which prevented disruption to the ordered Si-O arrangement by the Ca(2+) and P-O group. In vitro bioactivity study showed similar bioactivity for both the P123-MBG and F127-MBG systems. Drug loading and release studies using a model metoclopramide drug showed that both MBGs presented better loading and release compared to normal bioglass (BG). The significantly higher loading and better sustained release for P123-MBG, compared to F127-MBG, is attributed to its higher pore volume and surface area.

Published 12 May 2008 in J Biomed Mater Res A, 85(4): 1032-42.
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Articles on Ceramics published 2 April 2008:

Microbial response to environmental gradients in a ceramic-based diffusion system.   Biotechnol Bioeng, 100(1): 141-9.

A solid, porous matrix was used to establish steady-state concentration profiles upon which microbial responses to concentration gradients of nutrients or antimicrobial agents could be quantified. This technique relies on the development of spatially defined concentration gradients across a ceramic plate resulting from the diffusion of solutes through the porous ceramic matrix. A two-dimensional, finite-element numerical transport model was used to predict the establishment of concentration ... [Abstract] [Full-text]

Articles on Ceramics published 26 March 2008:

Development of carbon coatings for cordierite foams: an alternative to cordierite honeycombs.   Langmuir, 24(7): 3267-73.

Cordierite foams were prepared by replication of polyurethane foams and were coated with three types of carbon xerogels. The dip coating and synthesis conditions were optimized, and the coated foams were characterized exhaustively. The composition of the starting solution, coat loading, and carbonization temperature are the most important parameters determining both textural and mechanical properties. Carbon xerogel coatings obtained from aqueous solutions of resorcinol (R) and formaldehyde (F) ... [Abstract] [Full-text]

Articles on Ceramics published 12 March 2008:

Light-activation of resin cement through ceramic: relationship between irradiance intensity and bond strength to dentin.   J Biomed Mater Res B Appl Biomater, 85(1): 160-5.

This study investigated the relationship between the irradiance transmitted through ceramic and the bond strength of a resin cement to dentin. After application of an adhesive system, elastomer molds with cylindrical orifices (1.2 mm in diameter) were placed onto bovine dentin surfaces and filled with a photoactivated luting agent (Enforce; Dentsply Caulk). Light-activation was performed through a 0.6-mm-thick ceramic disc using different intensities: 250, 400, 550, 700, or 850 mW/cm(2). ... [Abstract] [Full-text]

Finite element analysis of subsurface damage of ceramic prostheses in simulated intraoral dental resurfacing.   J Biomed Mater Res B Appl Biomater, 85(1): 50-9.

Finite element analysis (FEA) was used to investigate the stress fields and the degrees of subsurface damage of ceramic prostheses in simulated intraoral dental resurfacing operations using clinical diamond burs. A two-dimensional finite element model was established with the dental operational parameters and the material properties as input variables. This model enabled to predict the stress fields and to evaluate the depths of subsurface damage in ceramic prostheses as functions of the dental ... [Abstract] [Full-text]

Articles on Ceramics published 25 December 2007:

CD200: a putative therapeutic target in cancer.   Biochem Biophys Res Commun, 366(1): 117-22.

CD200 was recently described as a new prognosis factor in multiple myeloma and acute myeloid leukemia. CD200 is a membrane glycoprotein that imparts an immunoregulatory signal through CD200R, leading to the suppression of T-cell-mediated immune responses. We investigated the expression of CD200 in cancer using publicly available gene expression data. CD200 gene expression in normal or malignant human tissues or cell lines was obtained from the Oncomine Cancer Microarray database, Amazonia ... [Abstract] [Full-text]

Articles on Ceramics published 24 December 2007:

Osteoconduction and osteoinduction of low-temperature 3D printed bioceramic implants.   Biomaterials, 29(7): 944-53.

Rapid prototyping is a valuable implant production tool that enables the investigation of individual geometric parameters, such as shape, porosity, pore size and permeability, on the biological performance of synthetic bone graft substitutes. In the present study, we have employed low-temperature direct 3D printing to produce brushite and monetite implants with different geometries. Blocks predominantly consisting of brushite with channels either open or closed to the exterior were implanted on ... [Abstract] [Full-text]

Articles on Ceramics published 16 November 2007:

Effects of different debonding techniques on the debonding forces and failure modes of ceramic brackets in simulated clinical set-ups.   Am J Orthod Dentofacial Orthop, 132(5): 680-6.

INTRODUCTION: The objectives of this study were to evaluate the effects of different debonding techniques on the in-vitro mean debonding forces and failure modes of ceramic brackets bonded to enamel with clinically simulated setups. METHODS: Three kinds of ceramic brackets (Clarity; 3M Unitek, Monrovia, Calif; Inspire and Inspire Ice; Ormco, Orange, Calif) were bonded to extracted premolars with the same bonding system. Thirty ceramic brackets, 10 of each type, were removed by hand; 60 ceramic ... [Abstract] [Full-text]

Flexural vibration analyses of piezoelectric ceramic tubes with mass loads in ultrasonic actuators.   Ultrasonics, 47(1): 82-9.

Based on Timoshenko beam model, a theoretical model of radially polarized piezoelectric ceramic tubes is investigated. In the model, the piezoelectric effects are considered, and the shear correction factor is introduced which reveals effects of the size of the cross-section and Poisson's ratio. Based on the model, the particular attentions are devoted to effects of the boundary conditions at two ends on flexural resonance frequencies of the piezoelectric ceramic tubes. Changing the sizes of ... [Abstract] [Full-text]

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