Cystatins and cathepsin B during orthodontic tooth movement

IntroductionThe lysosomal cysteine protease cathepsin B is known to play an important role in the resolution of organic matrix, a final step in bone resorption. Cystatins function as an inhibitor of cathepsin B. Determining the correlation between cathepsin B and cystatin levels in gingival crevicular fluid at various times might provide a better understanding of both the dynamics and the metabolic stages of orthodontic tooth movement.MethodsHuman gingival crevicular fluid was collected at the distal sulcus from the canines of persons not in orthodontic treatment, in retention, and in retraction at various times (initial, 1 day, 1 week, and 1 month postretraction). Cathepsin B and its inhibitor, cystatin, were found with fluorometry.ResultsThe level of cathepsin B was varied in the retraction group; this was different from the retention and the nonorthodontic groups. Significant initial decreases after force application and subsequent increases by 1 month posttreatment were observed in the retraction group. The variations and differences among groups were negatively correlated with cystatin.ConclusionsThe balance between enzyme and inhibitor might reflect the clinical status of orthodontic tooth movement and provide valuable information for the assessment of recall intervals and retention procedures.