Age changes in juxtaodontoblastic capillaries of rat molars

ABSTRACT – To Study the location and structure of juxtaodontoblastic capillaries during dentin formation, molars from 15 d, 1, 3 and 8‐month‐old rats were processed for eleetron microscopy. Seetions eomprising the enamel‐covered approximal walls of the pulp and subjacent pulpal tissue were examined. During early dentin formation (15 d) the capillaries were situated at the proximal end of the odontoblasts. In 1‐month‐old rats the capillaries were found between the odontoblasts, only 4–6 μm from the predentin. At 3 months they were again located in the subodontoblastic region. The number of cross‐sectioned capillaiies per 100 μm length of dentin decreased from 5–6 in 1‐month‐old rats to 2–3 in 3‐month‐oId rats. In 8‐month‐old rats no juxtaodontoblastic capillary plexus was found. The ultrastrueture of the capillaries was similar in all age groups except for a marked increase in the number of endothelial fenestrations when the capillaries were located close to the mineralizing zone. The findings indieate that eapillaries play an active role in dentin formation.