Autoradiographic analysis of odontoblast replacement following pulp exposure in primate teeth.
Cell migration and replication associated with odontoblast replacement occurring soon after pulp exposure in primate teeth were studied. Class 5 cavity preparations resulting in pulp exposures were restored with a calcium hydroxide-containing capping agent and amalgam. Eighty-four and 96 h after this the animals were injected with 0.5 microCi/g body wt tritiated thymidine (sp. act. 6.7 Ci/mM). Teeth were extracted 6, 8, 10 and 12 days after treatment. The number of labelled cells as well as the number of grains per labelled cell were counted for odontoblast-like, fibroblast-like and perivascular cells in three 60 x 260 microns zones. These zones represented the odontoblast and cell-free (zone 1), cell-rich (zone 2) and deep pulp (zone 3) areas of normal pulp tissue. Ten sections centred around the mid-point of the exposure were counted for each tooth. Matrix formation and labelled odontoblast-like cells were observed at the interface between the capping agent and the pulp as early as day 8. Other significant findings were: (1) an increase in labelled odontoblast-like cells in zone 1 over time, suggesting a continual influx of differentiating cells; (2) an increase in labelled cells in zone 1 over time with a concurrent decrease in zone 3, suggesting that the influx of cells in zone 1 was from the deeper pulp; and (3) differences in grain counts between zones, treatment times and cell types, indicating that at least two DNA replications had occurred between initial treatment and final odontoblast-like cell differentiation.
Fitzgerald
M
M
Department of Cariology and General Dentistry, University of Michigan, School of Dentistry, Ann Arbor 48109-1078.
Chiego
D J
DJ
Heys
D R
DR
D000818:Animals; D001345:Autoradiography; D002126:Calcium Hydroxide / Q000627:therapeutic use; D002452:Cell Count; D002455:Cell Division; D002465:Cell Movement; D003782:Dental Pulp / Q000293:injuries* / Q000378:metabolism / Q000473:pathology; D003785:Dental Pulp Capping; D005347:Fibroblasts / Q000378:metabolism / Q000473:pathology; D008253:Macaca mulatta; D009804:Odontoblasts / Q000378:metabolism / Q000473:pathology*; D013936:Thymidine / Q000378:metabolism; D013997:Time Factors; D014316:Tritium; D014945:Wound Healing
D014316:Tritium; D002126:Calcium Hydroxide; D013936:Thymidine