Spectroscopic Imaging of Mineral Maturation in Bovine Dentin

Abstract

Dentin is a useful model for the study of mineral maturation. Using Fourier Transform Infrared Imaging (FTIRI), we characterized distinct regions in developing dentin at 7- micro m spatial resolution. Mineral-to-matrix ratio and crystallinity in bovine dentin from cervical and incisal parts of 3rd-trimester fetal compared with one-year-old incisor crowns showed that virtually all maturation stages in dentin could be spectroscopically isolated and analyzed. In the fetal incisors, mantle and circumpulpal dentin presented distinct patterns of mineral maturation. Gradients in both mineral properties examined were observed at the mineralization front and at the dentino-enamel junction.

Maturational changes in dentin mineral properties

“…The width of the mantle dentin zone (based here on its distinct mineral properties relative to the rest of dentin) has been a subject of controversy in addition to debate about its relative mineral and matrix content [7,[25][26]. In our results, mantle dentin in bovine incisors was represented by an 80-100μm wide strip, in agreement with earlier data [5]. The fluctuations in the increase in mineral density along the crown may be explained by the wavy distribution of dentinal tubules within the crown, or masses of hypomineralized interglobular dentin appearing periodically in the section.…”

“…In dentin such studies are limited [2][3][4][5], due to the lack of an appropriate model. The extensive anatomical variability [6][7] and a location-dependent variability in mineral properties, shown by spectroscopic, x-ray and biomechanical methods [7][8][9][10][11] also make interpretation of dentin mineral maturation data difficult.…”

“…The extensive anatomical variability [6][7] and a location-dependent variability in mineral properties, shown by spectroscopic, x-ray and biomechanical methods [7][8][9][10][11] also make interpretation of dentin mineral maturation data difficult. The combination of a high resolution spectroscopic imaging method and a fetal developing calf incisor model has been previously shown to be suitable [5]. Using this methodology, it is possible to identify and analyze dentin areas which are histologically comparable and have a continuous range of successive tissue ages.…”

“…Despite the fact that a region of distinct properties adjacent to DEJ is commonly recognized, the dimensions of this region is controversial and varies depending on the analyzed properties (histological, biochemical, mechanical). For the purposes of the present study, we examined a dentin zone next to DEJ that in a previous study in fetal developing incisors [5] was characterized by a different mineral maturation pattern than the rest of dentin and presented a consistent width throughout maturation, as well as the part of the dentin bulk immediately adjacent to that zone. These zones will be referred to as mantle and circumpulpal dentin, respectively.…”

“…The previous qualitative analyses of changes in mineral properties of developing dentin [4][5] are thus complemented with quantitative results.…”