- The basic structural unit of enamel is the enamel prism/rod. The prism usually consist of several million hydroxyapatite crystallites packed into a long thin rod 4-6 um in diameter and up to 2.5 mm in length.
- The typical distance between x-striations is about 4-5 um; however, in the middle portion of enamel they may be as much as 25-30 um apart. Finally, in cervical enamel, where enamel is formed more slowly, they may only be 2 um apart.
- The formation of enamel rods is due to the orientation of the crystals in rod and inter-rod regions of mature enamel that were established during the formation of enamel matrix. This is because the crystals in the newly formed enamel matrix lie roughly perpendicular to the ameloblast membrane; the direction of crystals within these regions is explained through their process of formation. It is the inclination of the distal portion of Tomes’ process, in relation to the proximal portion, that gives the variations of crystal directions in the rod and inter-rod enamel. Furthermore, it is also necessary to note that in the head of the prism the crystals run parallel to the long axis of the prism; whereas in the tail the crystals gradually diverge from this to become angled at approximately 70 degrees. This leads to the production of interprismatic appearance in histological sections. Finally, the cross striations associated with enamel rods may be particularly important for strength in relation to stress forces.)
What is an Enamel Pearl?
Enamel pearls are small isolated spheres of enamel that are sometimes found on the root surface towards the cervical margin. Furthermore, they are particularly common in the root bifurcation area. The process of enamel pearl formation is due to that fact that if the epithelial root sheath remains adherent to the dentin, during development, in the cervical area near the furcation area, these inner cells of the root sheath may differentiate into ameloblasts and produce enamel (“enamel pearls”).
If you would like more information regarding Enamel please do not hesitate to contact Skygate Dental today on (07) 3114 1199 or 0406 579 197.