Levels of t-PA and PAI-2 in gingival crevicular fluid during orthodontic tooth movement in adults

Abstract

Background: The regulation of plasminogen activation is a key element in controlling proteolytic events in the extracellular matrix.

Objective: The aim of this study was to investigate gingival crevicular fluid (GCF) levels of tissue plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI -2) during orthodontic tooth movement in adults.

Methods: Five male subjects (Mean age: 22.5 ± 2.8 years) and five female subjects (Mean age: 23.4 ± 3.9 years) were used. Each subject had one upper canine retracted into an extraction space. The contralateral and opposing canines, which were not moved, served as controls. GCF was collected at the distal cervical margins of the experimental and control teeth 0, 1, 24, and 168 hours after a retracting force was placed. GCF levels of t-PA and PAI-2 were determined by commercially available ELISA kits.

Results: After 24 hours of tooth movement the levels of t-PA and PAI-2 in the GCF were significantly higher from the experimental canines compared with the control teeth. There were no significant experimental - control differences at 0, 1, and 168 hours. There were no differences in the total protein levels up to 168 hours after orthodontic tooth movement.

Conclusions: These results indicate that the amounts of t-PA and PAI-2 in the GCF increase with orthodontic tooth movement, and suggest that such increases may be involved in extracellular matrix degradation in response to mechanical stress. Failure to detect elevated levels of t-PA and PAI-2 at 168 hours was attributed to decay of the force retracting the canines.