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Recovery of crystallographic texture in remineralized dental enamel.

Siddiqui S, Anderson P, Al-Jawad M - PLoS ONE (2014)

Bottom Line: Little is known about the crystallographic effects of demineralization and remineralization.Remineralization restores the texture to the original level seen in healthy enamel and restores mineral density.The results also showed that remineralization promotes ordered formation of new crystallites and growth of pre-existing crystallites which match the preferred orientation of healthy enamel.

View Article: PubMed Central - PubMed

Affiliation: Institute of Dentistry, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom.

ABSTRACT
Dental caries is the most prevalent disease encountered by people of all ages around the world. Chemical changes occurring in the oral environment during the caries process alter the crystallography and microstructure of dental enamel resulting in loss of mechanical function. Little is known about the crystallographic effects of demineralization and remineralization. The motivation for this study was to develop understanding of the caries process at the crystallographic level in order to contribute towards a long term solution. In this study synchrotron X-ray diffraction combined with scanning electron microscopy and scanning microradiography have been used to correlate enamel crystallography, microstructure and mineral concentration respectively in enamel affected by natural caries and following artificial demineralization and remineralization regimes. In particular, the extent of destruction and re-formation of this complex structure has been measured. 2D diffraction patterns collected at the European Synchrotron Radiation Facility were used to quantify changes in the preferred orientation (crystallographic texture) and position of the (002) Bragg reflection within selected regions of interest in each tooth slice, and then correlated with the microstructure and local mineral mass. The results revealed that caries and artificial demineralization cause a large reduction in crystallographic texture which is coupled with the loss of mineral mass. Remineralization restores the texture to the original level seen in healthy enamel and restores mineral density. The results also showed that remineralization promotes ordered formation of new crystallites and growth of pre-existing crystallites which match the preferred orientation of healthy enamel. Combining microstructural and crystallographic characterization aids the understanding of caries and erosion processes and assists in the progress towards developing therapeutic treatments to allow affected enamel to regain structural integrity.

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Intensity versus azimuthal angle taken from a typical (002) Bragg reflection of an enamel diffraction pattern.Pronounced peaks highlight a high degree of texture in this sample. Both peaks have been fitted to a Gaussian plus baseline (red and green lines respectively).
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pone-0108879-g002: Intensity versus azimuthal angle taken from a typical (002) Bragg reflection of an enamel diffraction pattern.Pronounced peaks highlight a high degree of texture in this sample. Both peaks have been fitted to a Gaussian plus baseline (red and green lines respectively).

Mentions: The (002) Miller index is orthogonal to the c axis of the hexagonal crystallite structure in hydroxyapatite. Since this is the long axis of the needle-like enamel crystallites, evidence of preferred orientation is most strongly seen as variations in the intensity around the Debye-ring of (002) Bragg reflection [32]. A typical plot of intensity versus azimuthal angle, fitted with a Gaussian peak shape to fit the FWHM, is shown in Fig. 2. Sharp intense peaks show the presence of strong preferred orientation (low values of FWHM), whereas broad peaks (high values of FWHM) would have indicated a more randomly distributed orientation of crystallites [36]. This analysis was applied to every diffraction image from each tooth slice across a track from the enamel surface to EDJ.


Recovery of crystallographic texture in remineralized dental enamel.

Siddiqui S, Anderson P, Al-Jawad M - PLoS ONE (2014)

Intensity versus azimuthal angle taken from a typical (002) Bragg reflection of an enamel diffraction pattern.Pronounced peaks highlight a high degree of texture in this sample. Both peaks have been fitted to a Gaussian plus baseline (red and green lines respectively).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4215832&req=5

pone-0108879-g002: Intensity versus azimuthal angle taken from a typical (002) Bragg reflection of an enamel diffraction pattern.Pronounced peaks highlight a high degree of texture in this sample. Both peaks have been fitted to a Gaussian plus baseline (red and green lines respectively).
Mentions: The (002) Miller index is orthogonal to the c axis of the hexagonal crystallite structure in hydroxyapatite. Since this is the long axis of the needle-like enamel crystallites, evidence of preferred orientation is most strongly seen as variations in the intensity around the Debye-ring of (002) Bragg reflection [32]. A typical plot of intensity versus azimuthal angle, fitted with a Gaussian peak shape to fit the FWHM, is shown in Fig. 2. Sharp intense peaks show the presence of strong preferred orientation (low values of FWHM), whereas broad peaks (high values of FWHM) would have indicated a more randomly distributed orientation of crystallites [36]. This analysis was applied to every diffraction image from each tooth slice across a track from the enamel surface to EDJ.

Bottom Line: Little is known about the crystallographic effects of demineralization and remineralization.Remineralization restores the texture to the original level seen in healthy enamel and restores mineral density.The results also showed that remineralization promotes ordered formation of new crystallites and growth of pre-existing crystallites which match the preferred orientation of healthy enamel.

View Article: PubMed Central - PubMed

Affiliation: Institute of Dentistry, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom.

ABSTRACT
Dental caries is the most prevalent disease encountered by people of all ages around the world. Chemical changes occurring in the oral environment during the caries process alter the crystallography and microstructure of dental enamel resulting in loss of mechanical function. Little is known about the crystallographic effects of demineralization and remineralization. The motivation for this study was to develop understanding of the caries process at the crystallographic level in order to contribute towards a long term solution. In this study synchrotron X-ray diffraction combined with scanning electron microscopy and scanning microradiography have been used to correlate enamel crystallography, microstructure and mineral concentration respectively in enamel affected by natural caries and following artificial demineralization and remineralization regimes. In particular, the extent of destruction and re-formation of this complex structure has been measured. 2D diffraction patterns collected at the European Synchrotron Radiation Facility were used to quantify changes in the preferred orientation (crystallographic texture) and position of the (002) Bragg reflection within selected regions of interest in each tooth slice, and then correlated with the microstructure and local mineral mass. The results revealed that caries and artificial demineralization cause a large reduction in crystallographic texture which is coupled with the loss of mineral mass. Remineralization restores the texture to the original level seen in healthy enamel and restores mineral density. The results also showed that remineralization promotes ordered formation of new crystallites and growth of pre-existing crystallites which match the preferred orientation of healthy enamel. Combining microstructural and crystallographic characterization aids the understanding of caries and erosion processes and assists in the progress towards developing therapeutic treatments to allow affected enamel to regain structural integrity.

Show MeSH
Related in: MedlinePlus