The amazing odontoblast: activity, autophagy, and aging.

Odontoblasts are dentin-secreting cells that survive for the whole life of a healthy tooth. Once teeth are completely erupted, odontoblasts transform into a mature stage that allows for their functional conservation for decades, while maintaining the capacity for secondary and reactionary dentin secretion. Odontoblasts are also critically involved in the transmission of sensory stimuli from the dentin-pulp complex and in the cellular defense against pathogens. Their longevity is sustained by an elaborate autophagic-lysosomal system that ensures organelle and protein renewal. However, progressive dysfunction of this system, in part caused by lipofuscin accumulation, reduces the fitness of odontoblasts and eventually impairs their dentin maintenance capacity. Here we review the functional activities assumed by mature odontoblasts throughout life. Understanding the biological basis of age-related changes in human odontoblasts is crucial to improving tooth preservation in the elderly.