The scientists from the Northwestern University are engaged in the analysis of the tooth decay processes. In their opinion, it can be directly related to the genetic characteristics of a person. For the first time they managed to crack one of the secrets of tooth decay. Studying enamel, they found a small amount of impurity atoms, that can contribute to both the enamel's strength and its rapid destruction.
Using these atoms, the researchers determine the spatial distribution of impurities in tissues. The scientists were able to detail the process down to nanoscale, in order to understand the characteristics of the caries and the genetic conditions that affect the strength and destruction of enamel.
A study leader Derk Joesther noted that enamel has limited self-healing capabilities. It has a complex structure, that has features at different scales of thickness. In some cases, it can reach several millimeters, representing a three-dimensional interweaving of molecular rods. Each has a width of about 5 microns, each consists of long and thin crystallites of hydroxylapatite. Their width is several tens of nanometers. These nanoscale crystallites are the main building blocks of the enamel.
The crystallites were susceptible to dissolution, that leads to the destruction of the enamel, and the scientists decided to find out why. Advanced methods have helped to study that crystallites of human enamel have a core-shell structure.
Each has a continuous crystalline structure with periodically arranged ions of calcium, phosphate and hydroxyl. But in the very center of the crystallite, a huge amount of these ions has been replaced by magnesium, sodium, carbonate and fluoride. The core also contains two layers, both rich in magnesium.
They surround sodium, fluoride and carbonate ions. The scientists, studying such a structure, compared it with the smallest sandwich in the world, that is only 6 billionths of a meter in diameter. The destructive processes of tooth enamel really depend on the genetic characteristics. They are associated with the behavior of dissolved crystallites, that are able to make enamel more durable, and also capable of rapidly destroying it.