Dentin formation in formocresol pulpotomized primary monkey teeth studied by tetracycline and 3H-proline incorporation.

The influence of formocresol treatment on the pulp tissue of 24 primary monkey teeth was studied using tetracycline and 3H-proline labeling techniques. Six untreated monkey teeth served as controls. The tetracycline labeled teeth were examined between 352 and 600 d, following treatment. The 3H-proline labeled teeth were observed over a period of 22-607 d, the isotope being administered 15 d before extraction. The labeling was evaluated in the coronal, middle and apical area of the roots. Dentin formation as indicated by tetracycline labeling was observed in both control teeth and successfully treated teeth, as well as in some of the unsuccessfully treated teeth. The average dentin formation rate per day varied from 1 micrometer in the control teeth to 0.14 micrometer in the pulpotomized teeth (P less than 0.01). Success of treatment was of significant importance for the amount of dentin formation (P less than 0.001). Labeling with 3H-proline, indicating collagen synthesis, could be observed in the pulp and predentin of the majority of areas judged to be normal, degenerated or inflamed. Labeling was not observed in fixed or necrotic tissue. In degenerated pulp tissue the proline labeling was clearly reduced. The findings indicate that dentin formation and collagen synthesis may take place in formaldehyde influenced pulp tissue although at a decreased rate.