The pulpal effect of freezing temperatures applied to monkey teeth

When temperatures below -80 degrees C, are applied to intact monkey teeth via a liquid nitrogen probe for 1, 2, or 3 minutes, an increasing degree of pulpal damage occurs, but all pulps remain vital. The lesion appears to be predictable and is characterized by a distinct layer of coronal secondary dentin with cellular inclusions, odontoblast destruction, and microvascular injury. The root pulp remains essentially healthy and uninflamed. Periodontal and root tissue damage was also observed.