Fibrae dentini

Fibrae dentini is a long protrusion from the apical pole of odontoblasts. It contains microtubules, microfilaments, mitochondria, microvesicles, but is devoid of ribosomes and endoplasmic reticulum. At the transition between enamel and dentin, it branches into several terminal branches that can extend into enamel. These fibers run in canals - canaliculi dentis.