Dentin

Dentin (Latin dentinum) is a hard, calcified tissue that constitutes the main volume of the tooth. It is located beneath the enamel in the crown region and under the cementum in the root area, surrounding the pulp chamber and root canals. In terms of its physical properties, dentin is stronger than bone but more elastic than enamel.

Etiology and Pathophysiology

Dentin is permeated by millions of microscopic dentinal tubules containing processes of odontoblast cells and dentinal fluid. The presence of these tubules makes dentin a permeable tissue capable of transmitting stimuli and bacterial toxins to the pulp’s nerve endings.

Throughout the tooth’s life, odontoblasts continue to slowly produce secondary dentin, reducing the volume of the pulp chamber. In response to irritants at the enamel-dentin junction, the formation of tertiary (reparative or reactionary) dentin is activated.

Clinical significance

Dentin and pulp function as a unified complex. Exposure of dentin due to caries, injury, or pathological wear causes fluid movement in the tubules, which irritates the pulp receptors and leads to tooth sensitivity (hyperesthesia). In caries treatment, preserving a healthy layer of dentin over the pulp is a priority for maintaining the tooth’s vitality.