2D mapping of texture and lattice parameters of dental enamel

Al-Jawad, Maisoon; Steuwer, A.; Kilcoyne, S.H.; Shore, R.C.; Cywiński, R.; Wood, David

doi:10.1016/j.biomaterials.2007.02.019

Cited by 99 publications

(89 citation statements)

References 18 publications

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“…2. In contrast to the bucco-lingual slice evaluated previously [5], it appears that in this tooth section the preferred orientation in the 002 direction does not consistently follow the contour of the EDJ. Instead it is perpendicular to the EDJ along the sides of the tooth in the cervical enamel and in the central part of the tooth crown, while on either side of the tooth cusps the 002 texture direction is parallel to the EDJ.…”

Section: Resultscontrasting

confidence: 99%

Three Dimensional Mapping of Texture in Dental Enamel

Al-Jawad

Simmons

Steuwer³

et al. 2007

KEM

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Abstract. We have used synchrotron x-ray diffraction to study the crystal orientation in human dental enamel as a function of position within intact tooth sections. Keeping tooth sections intact has allowed us to construct 2D and 3D spatial distribution maps of the magnitude and orientation of texture in dental enamel. We have found that the enamel crystallites are most highly aligned at the expected occlusal points for a maxillary first premolar, and that the texture direction varies spatially in a three dimensional curling arrangement. Our results provide a model for texture in enamel which can aid researchers in developing dental composite materials for fillings and crowns with optimal characteristics for longevity, and will guide clinicians to the best method for drilling into enamel, in order to minimize weakening of remaining tooth structure, during dental restoration procedures. IntroductionThe hydroxyapatite structure of human dental enamel has been determined using powder x-ray diffraction, and is well established as space group P63/m and lattice parameters a=9.441(2)Å and c=6.878(1)Å [1-3]. However, these values were obtained from measurements of powdered enamel collected from several teeth, and as a result any information on the spatial variation of the texture relating to the growth of the HA crystallites was lost. Hirota examined the tilting of the enamelprism orientation in a human canine using laboratory two-dimensional x-ray diffraction [4]. However, only 12 points within the tooth were measured and therefore the information obtained about the prism orientation does not relate to the whole tooth. Understanding the spatial texture distribution and orientation arrangement in the dental enamel of a tooth is extremely valuable in order to improve dental restorative materials and techniques and ultimately will need to be more fully understood if functional, synthetic, biomimetic enamel is to be developed. Recently, we have shown for the first time how synchrotron x-ray diffraction can be used to determine the basic crystallographic parameters of the HA phase across a whole intact tooth section, allowing us to explore composition and texture on the sub-millimetre length-scale. We found that the orientation of the enamel crystallites in a bucco-lingual section of a lower second premolar (LR5) followed the shape of the enamel-dentine-junction (EDJ) with their long axes approximately at right-angles to the EDJ, and that areas of high crystallite alignment on the tooth cusps matched the expected biting surfaces [5]. We now present detailed results of the texture direction and magnitude in an intact mesio-distal section, and we show the change in texture direction in three dimensions by studying several sequential mesio-distal sections through the same tooth.

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Section: Resultscontrasting

confidence: 99%

Three Dimensional Mapping of Texture in Dental Enamel

Al-Jawad

Simmons

Steuwer³

et al. 2007

KEM

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“…Maximum and minimum radii differ by up to 1 pixel, and 1/440.2 is indistinguishable from 1/439.8. For extreme variations of c, 0.3% in enamel (Al-Jawad et al, 2007), deviatoric strain changes less than 10 À 5 . Finally, dentin and enamel deviatoric strains are positionally invariant at 0 MPa (Fig.…”

Section: Deviatoric Strain Measurement Lattice Parameter Variation mentioning

confidence: 92%

“…The X-ray scattering has mapped texture and crystallinity in enamel and dentin (Low, 2004;Al-Jawad et al, 2007), but scatteringbased strain quantification is limited to bone (Borsato and Sasaki, 1997;Almer and Stock, 2005Gupta et al, 2005Gupta et al, , 2006Fujisaki et al, 2006;Fujisaki and Tadano, 2007;Akhtar et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

High energy X-ray scattering quantification of in situ-loading-related strain gradients spanning the dentinoenamel junction (DEJ) in bovine tooth specimens

Almer

Stock

2010

Journal of Biomechanics

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“…These spatially distributed strain gages are ''read'' nondestructively with wide angle X-ray scattering (WAXS or diffraction) and small angle X-ray scattering (SAXS), respectively. Most studying bone (and tooth) think of X-ray scattering in terms of composition measurements (Smith and Smith, 1976;Baig et al, 1999) or preferred (crystallographic) orientation (Ascenzi et al, 1998;Wenk and Heidelbach, 1999;Al-Jawad et al, 2007); engineering and materials science approaches for residual stress analysis with X-ray diffraction (Noyan and Cohen, 1987;He and Smith, 1998;Cullity and Stock, 2001) open a new window for analyzing bone's response to applied stress. Previous WAXS (and SAXS)-based internal strain quantification focused primarily on uniformly loaded specimens Stock, 2005, 2007) although recently the gradient of strains across the bovine dentinoenamel junction (DEJ) was studied with these techniques (Almer and Stock, in press).…”

Section: Introductionmentioning

confidence: 99%