Evaluation of specific activity of acid phosphatase in gingival crevicular fluid during orthodontic tooth movements

Analysis of gingival crevicular fluid (GCF) may be a good means of examining the biochemical processes associated with bone turnover. The aim of this study was to evaluate the specific activity of acid phosphatase (ACP) in GCF during canine retraction with sliding technique. In this clinical trial 5 subjects (aged 12–20 years) with bimaxillary dentoalveolar protrusion were selected. After extraction of four first premolars, the sliding technique was used to retract canines in each subject. GCF samples were collected from the distal aspect of each canine by using sterile paper points (#15) at four time intervals: immediately after the appliances were fitted, at the time of initial activation, and 15 and 30 days afterwards. Acid phosphatase and microprotein levels were assayed by means of quantitative colorimetric technique. Tooth movement at each sampling interval was measured. Data was analyzed with non-parametric tests of Freeman, Mann-Whitney, and Pearson’s correlation coefficient (α=0.05). After activation of the appliances, average specific activity of acid phosphatase in GCF significantly increased (p value < 0.001). In addition, the specific activity of ACP at sampling intervals showed significant differences (p value < 0.001). No significant relation was noted between changes in specific activity of ACP and tooth movement (p value = 0.215). It is possible to measure specific activity of acid phosphatase in the GCF during orthodontic tooth movements. It is elevated in the pressure side during orthodontic tooth movement.