Separation of human tooth enamel microstructures by density fractionation

Brudevold, F.; Srinivasan, B. N.; Skobe, Ziedonis

doi:10.1016/0003-9969(77)90071-1

Cited by 3 publications

(2 citation statements)

References 9 publications

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“…These outer and inner types of enamel might contribute to high-and low-density enamel structures. 64 The thickness of the outer layer from the demineralized MV cusp match roughly to that of the 'wall' in the demineralized DV cusp and, respectively, of the surface layer in the normal enamel of the DL cusp. Thus, the periodic structure of tilted 'hills' and 'valleys' immediately near the surface and down to the above depth in the MV cusp is a differentiated enamel layer with higher Ca concentration, which appears to represent the acid-resistant surface layer.…”

Section: Angled Periodic Structure and The Intercusp Differences In Dmentioning

confidence: 75%

Broad‐beam PIXE and µ‐PIXE analysis of normal and in vitro demineralized dental enamel

Preoteasa

Preoteasa²,

Kuczumow

et al. 2008

X-Ray Spectrometry

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Dental enamel has been widely studied by particle-induced x-ray emission (PIXE), but less attention was paid to its demineralization, which leads to caries formation. Using broad-beam PIXE and m-PIXE, we investigated normal enamel and the in vitro formation of pre-carious lesion in lactic acid solution, aiming also to evaluate intercusp differences within the same tooth. Broad-beam PIXE was performed using 3.0 MeV protons, and m-PIXE maps of Ca, Fe and Zn were collected with 3.1 MeV protons at ∼4 µm resolution. In normal enamel a differentiated Ca-rich surface layer was observed, where Fe and Zn reached their highest levels. In deeper layers, Fe and Zn evidenced quasiperiodic patterns of maxima, possibly due to coupled diffusion-reaction catalytic processes involved in the enamel growth. Both Fe and Zn appeared to be located in a few distinct types of pools. Near the surface, demineralization induced an increase of Fe, Cu, Zn, Sr and Pb with respect to Ca, attributed to partial hydroxyapatite dissolution and/or to chelate extraction and concentration of trace metals. Ca maps revealed limited changes in the surface layer and a massive loss in the inner enamel; here, Fe was almost depleted and Zn partially removed. The maps of Ca, Fe and Zn demonstrated major intercusp variations in both normal and altered enamel. Thus, broad-beam PIXE and m-PIXE, which do not require (semi)thin sectioning of the tooth as the conventional methods, provide compositional and structural insight of normal dental enamel, of its intercusp variability and of the alterations produced by in vitro demineralization, largely not accessible to the current techniques, and highly relevant for understanding the incipient caries formation.experimental setups and were aimed, among others, at the analysis of trace elements in sound human enamel and dentine, 1,2 the identification of an ancient tooth inlay, 9 the characterization of changes in elemental distribution in enamel after CO 2 -laser irradiation, 12 and in the studies on diffusion of metallic components from amalgam restorations in the surrounding hard dental tissue. 10,15 Dental caries studies included various approaches, such as the establishing of trace elements correlations with the caries promotion or inhibition, age and gender of subjects, 3 -5 and the analysis of alterations of dominant and trace elements in naturally decayed enamel and dentin 13 and in the surface profiles across naturally occurring pre-carious lesions in teeth. 11 However, in the above studies, only teeth with natural carious-type lesions already expressed clinically were included, a procedure which does not allow a detailed understanding of the early stage of caries formation. The importance of this stage cannot be underestimated, because the microscopic alteration of the enamel surface layer which initiates the caries formation precedes the bacterial invasion ending in a gross dental cavity and eventually in the loss of the tooth. 21 Treatment of enamel in solution of organic acids such as lactic acid provides a s...

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Section: Angled Periodic Structure and The Intercusp Differences In Dmentioning

confidence: 75%

Broad‐beam PIXE and µ‐PIXE analysis of normal and in vitro demineralized dental enamel

Preoteasa

Preoteasa²,

Kuczumow

et al. 2008

X-Ray Spectrometry

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“…Enamel is an imperfect semi-permeable membrane, which acts as a molecular sieve (Borggreven et al, 1980;Borggreven et al, 1977;Shellis and Dibdin, 2000), and is permeable to water, ions and small organic molecules (Shellis and Dibdin, 2000). Most diffusion occurs at the prism boundaries (Brudevold et al, 1977;Lindén, 1968) where the largest pores are found (Shellis and Dibdin, 2000), but it has also been observed to a more limited extent within the prisms between crystallites in modern teeth (Lindén, 1968). suggest diffusion may also be possible through the hydrated Mg-ACP phase at room temperature and pressure, although further work is needed to clarify this.…”

Section: Enamel Diagenesis and The Addition Of Carbonatementioning

confidence: 99%

The effect of grain size on carbonate contaminant removal from tooth enamel: Towards an improved pretreatment for radiocarbon dating

Wood

Duval

Hương³

et al. 2016

Quaternary Geochronology

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It is rarely possible to directly radiocarbon date skeletal remains from hot environments as collagen rapidly degrades. Although able to survive in the majority of burial environments for longer, unburnt biological apatites frequently produce inaccurate radiocarbon dates due to contamination from carbonate in the groundwater. The location of this contamination within the skeletal material is rarely investigated, hampering development of improved methods. This paper focuses on tooth enamel and aims to test whether carbonate contaminants are sitting at the crystallite boundaries, and from this to test a pretreatment to produce more accurate radiocarbon age estimates. Although the porosity of enamel is low, trace elements are known to diffuse between enamel prisms and crystallites. Gordon et al. (2015, Science, 347 (6223), 746-750) identified magnesium substituted amorphous calcium phosphate between the apatite crystallites. This phase contains the majority of magnesium within modern rodent enamel, providing an opportunity to monitor its removal, and thus carbonate contaminants sitting between or on the surface of the crystallites. Modern Sus scrofa enamel and four ancient Sus scrofa teeth have been used to demonstrate that the more finely ground the enamel, the more magnesium can be removed with an acetic acid leach, and the more accurate the radiocarbon dates. After leaching in acetic acid, teeth dating to beyond the limit of the radiocarbon method (c.50 ka) produce ages of c.20 kBP when hand ground, and c.30 kBP when mechanically ground. This suggests that some contaminants are sitting at the crystallite boundaries. However,

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Scanning electron microscope study of cat and dog enamel structure

Skobe

Prostak

Trombly

1985

Journal of Morphology

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Scanning electron microscopy revealed several similarities as well as significant differences in the enamel structure between cat and dog teeth. Three enamel layers were present in both species; a surface rodless (aprismatic) layer, an outer layer of parallel rods (only at some sites), and an inner layer with prominent Hunter-Schreger bands. In the inner layer of both carnivores, the diameter of individual rods varied significantly and frequently their course changed abruptly with respect to neighboring rods. In dog teeth the cross-sectional shape of inner enamel rods was pleomorphic, but hexagonal in outer enamel. In contrast, cat enamel rods were rounded in both inner and outer enamel layers. Hunter-Schreger bands of cats circumscribed the teeth in relatively straight segments, but these bands showed pronounced waviness in dog teeth. In cats and dogs the surface rodless layer was structurally continuous with subjacent interrod enamel and covered all tooth surfaces with the exception of the cervical areas. The data show that the structure of inner and outer enamel layers differ between these two carnivore species and that the enamel structure of the cat was most similar to that described in humans. One principal difference between carnivore and human teeth is that the growth lines of carnivores do not terminate at perikymata on the tooth surface.

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Separation of human tooth enamel microstructures by density fractionation

Cited by 3 publications

References 9 publications

Broad‐beam PIXE and µ‐PIXE analysis of normal and in vitro demineralized dental enamel

Broad‐beam PIXE and µ‐PIXE analysis of normal and in vitro demineralized dental enamel

The effect of grain size on carbonate contaminant removal from tooth enamel: Towards an improved pretreatment for radiocarbon dating

Scanning electron microscope study of cat and dog enamel structure

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