Tooth organic content

The reason to extend the experiments to tooth material was the idea that the matrix would have a less porous structure compared to human haversian bone and be less exposed to diagenetic alteration. While the porosity in human bone is mainly determined by a complicated network between the Haversian system and the Volk-mann canals that are perpendicular to it, especially enamel is a far denser material than human bone and its organic content is significantly less (2% of organic material only). But in contrast to the enamel, dentine has a similar composition of the organic and the inorganic matrix compared to bone, and it has a high microporosity due to nerve canals that start from the pulpa and stop close to the enamel-dentine junction (edj). However, these nerve canals have a smaller diameter than a haversian pore (70 pm) and the canals are orientated parallel and are not connected with each other. So a fluorine ion cannot percolate from one pore to another, as it is the case in a human bone, but it has to overcome the distance from one canal to the next one by diffusion. So the permeability is low and this results in a smaller diffusion rate D. 

Dental enamel, p = 2.9-3.0 glan , which is harder and more rigid than the tooth interior of dentine (Figure 11.3), contains about 96% hydroxyapatite (HA) (Chapter 5.3). The organic content is much lower (-0.1%) than that of dentine (-25%). Traces of Fe, Zn, Sr, Cu and so on are found in tooth enamel. 

---