abstract—Odontoblasts isolated from rat incisors were incubatedin vitroin the presence of tritiated leucine or fucose, and the amount of precursor incorporated into TCA‐precipitated proteins was determined. The effect on precursor incorporation of varying the total precursor concentration was examined. The incorporation of leucine and fucose into TCA‐precipitated proteins was found to be linear with time for at least 90 min. Inhibition studies with puromycin, cycloheximide and chloramphenicol demonstrated the presence of odontoblastic protein synthesis. One hour afterin vivoadministration of tritiated leucine the highest specific activity of odontoblast‐predentin protein material was noted the corresponding maximum for pulp proteins was found to occur after 30 min. Thein vivoincorporation of tritiated fucose was maximal after 4 h in both odontoblasts and pulp tissue.