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Amorphous calcium phosphate/urethane methacrylate resin composites. I. Physicochemical characterization
William F Regnault1, Tonya B Icenogle, Joseph M Antonucci
1Center for Devices and Radiological Health, Food and Drug Administration, Rockville, MD, USA.
Journal of Materials Science. Materials in Medicine
|July 11, 2007
Summary
This study investigated dental composites made with urethane dimethacrylate (UDMA) and amorphous calcium phosphate (ACP). Composite ion release and strength varied with polymer type and pH, impacting dental material performance.
Area of Science:
- Materials Science
- Biomaterials Engineering
- Polymer Chemistry
Background:
- Dental composites require tailored polymer matrices and fillers for optimal performance.
- Understanding ion release and mechanical properties is crucial for material longevity and biocompatibility.
Purpose of the Study:
- To evaluate the mechanical strength and ion release profiles of experimental dental composites.
- To investigate the influence of polymer matrix composition (UDMA, PEG-U, UDMA/PEG-U) and aqueous environment pH on composite behavior.
- To analyze the degradation and ion release mechanisms of amorphous calcium phosphate (ACP) fillers.
Main Methods:
- Preparation of experimental composites using UDMA, PEG-U, UDMA/PEG-U resins and ACP filler.
- Polymerization of composite samples.
- Mechanical strength testing of composites.
- Evaluation of ion release kinetics in saline and lactic acid solutions.
- X-ray diffraction (XRD) analysis to assess filler phase changes.
Main Results:
- Composite strength decreased in saline (pH 7.4).
- Ion release kinetics were significantly influenced by polymer matrix and pH.
- UDMA/PEG-U composite exhibited sustained ion release (>350 h) in saline.
- PEG-U composites showed reduced ion release after 72h in saline, attributed to mineral re-deposition.
- ACP converted to poorly crystallized apatite in some conditions.
- In lactic acid (pH 5.1), ion release increased without observable ACP conversion, linked to altered ion stoichiometry.
Conclusions:
- Dental composite performance is highly dependent on both polymer matrix design and the surrounding aqueous environment.
- The UDMA/PEG-U matrix offers sustained ion release properties beneficial for dental applications.
- Environmental pH and filler-matrix interactions critically affect ion release and material stability.
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