[Age-related changes of the pulpal dentin wall in human front teeth]

A total of 55 extracted, vital human teeth (i.e. central and lateral incisors of the maxillary [n = 17] and the mandibular [n = 38]jaws) of patients between 40 and 97 years of age has been used to study the age-related restriction of the pulp chamber, in particular the root canal, and the structure of the inorganic dentinal wall of the pulp chamber by means of X rays and scanning electron microscopy. In addition, the density of the openings of the dentinal tubules was, under standardized conditions, determined at the coronal pulp chamber, in the middle of the root canal and apically on each of the four aspects of the pulp chamber, i.e. vestibular, mesial, oral and distal. The results demonstrated that the pulp chamber, in particular the root canal, with increasing age of the patient becomes restricted in the mesio-distal, but not or much later in the vestibulo-oral direction. This is because a network of tubule-free fibrodentin or more regular secondary dentin with or without tubules is deposited at these pulp chamber walls. The density of the tubules was at vestibular and oral aspects of the dentinal walls and also in upper incisors higher than at mesial and distal walls and in lower incisors. It also decreased mainly from the middle of the root canal towards the apex. However, because of the very heterogeneous structures at the pulp chamber walls, the tubule density was enormously variable.