Biomedical subjects

D Tadic

Publications and source records attributed to D Tadic.

At least 19 recordsLinked to original sources

PubMed2004

A novel method to produce hydroxyapatite objects with interconnecting porosity that avoids sintering.

Porous objects of carbonated apatite were prepared by mixing polyvinyl alcohol fibres (PVA) and sodium chloride as porogens with nanocrystalline carbonated apatite powder. After cold isostatic pressing (CIP) and dissolving the porogens, the bioceramic showed an interconnecting porosity with pore diameters in the range of 250-400 microm. The method can be transposed to any material that is insoluble in water (like many polymers). Such objects are promising for bone regeneration because the interconnecting porosity in carbonated apatite provides a good environment for bone attachment and ingrowth.

Biocompatible Materials↗

PubMed2004

A thorough physicochemical characterisation of 14 calcium phosphate-based bone substitution materials in comparison to natural bone.

Fourteen different synthetic or biological bone substitution materials were characterised by high-resolution X-ray diffractometry, infrared spectroscopy, thermogravimetry, and scanning electron microscopy. Thus, the main parameters chemical composition, crystallinity, and morphology were determined. The results are compared with natural bone samples. The materials fall into different classes: Chemically treated bone, calcined bovine bone, algae-derived hydroxyapatite, synthetic hydroxyapatite, peptide-loaded hydroxyapatite, and synthetic beta-TCP ceramics.

Animals↗

PubMed2003

An optimized synthetic substrate for orthodontic bond strength testing.

OBJECTIVE: The purpose of this study was to investigate the suitability of different synthetic calcium phosphate based substrates as a biomimetic enamel surface model for orthodontic bond strength testing. METHODS: Carbonated apatite, amorphous calcium phosphate and commercial hydroxyapatite specimens were prepared as substrates for orthodontic bond strength testing. Carbonated apatite specimens were prepared by pressing, sintering and treatment with NaF. The shear bond strength was measured with a universal testing machine. RESULTS: Hydroxyapatite, amorphous and cold pressed carbonated hydroxyapatite exhibited fractures within the substrate after debonding. Mean bond strength values for carbonated hydroxyapatite were 7.38 (1.75) MPa for specimens pressed at 300 degrees C and 9.55 (2.23) MPa for specimens pressed at 300 degrees C and then sintered at 600 degrees C. An additional NaF treatment after sintering resulted in lower bond strength measurements of on average 6.52 (1.03) MPa. SIGNIFICANCE: Hot pressed and sintered carbonated hydroxyapatite showed acceptable shear bond strength values and may represent a suitable biomimetic model for orthodontic bond strength testing.

Apatites↗

PubMed2003

Mechanically stable implants of synthetic bone mineral by cold isostatic pressing.

A calcium phosphate phase that is equivalent in composition (carbonate content) and crystallinity (nanocrystals) to the mineral phase of bone was prepared by a continuous precipitation method. The powder was compacted by cold isostatic pressing into desired shapes with high compressive strength (range of 20-50 MPa, depending on the geometry). It is concluded that such implant materials can be prepared with a fine-tuned biodegradability in combination with a high mechanical strength. The high mechanical strength of the objects also permits further mechanical shaping procedures like drilling or cutting.

Biocompatible Materials↗

PubMed2002

Continuous synthesis of amorphous carbonated apatites.

Amorphous carbonated hydroxyapatite was prepared by rapid mixing of aqueous solutions of a continuous computer-controlled reactor. The variation of the carbonate content in the solid product is possible by adjustment of the ratios of phosphate to carbonate in the initial solution. The principal reaction parameters (temperature, pH, stirrer speed, solution composition and supersaturation) are controlled and monitored. By controlling these processing parameters, a non-stoichiometric hydroxyapatite with fine-tuned crystallinity, morphology, and carbonate content can be reproducibly prepared. The higher solubility under the conditions of osteoclastic resorption was tested in vitro at constant pH (4.4).

Apatites↗

PubMed1995