Relation between the presence of supragingival calculus and protease activity in dental plaque.

Protease activity was measured in dental plaque collected from patients with or without supragingival calculus. Plaque specimens from the calculus group showed significantly greater protease activity in the presence of 0.05% sodium thioglycollate than did those from the non-calculus group. No significant difference between the two groups was observed in the protease activity without sodium thioglycollate. There was no significant correlation between the age of the patients and the protease activity.