Acid Phosphatase Activity in Gingival Crevicular Fluid During Human Orthodontic Tooth Movement

The purpose of this longitudinal study was to investigate whether acid phosphatase level changes in Gingival Crevicular Fluid (GCF) could be used to monitor bone turnover changes during human orthodontic tooth movement. Seven patients (2 males and 5 females; mean age, 23 years) were selected. Pre-Adjusted Edgewise Appliance (MBT 0.022 X 0.028-inch slot) was strapped up and aligning and leveling was completed prior to distalization of maxillary canines. The contralateral canine (CC) was not subjected to distal force and was used as the control tooth whereas the maxillary canine on the right side was used as the experimental tooth and was considered to be the distalized canine (DC). From the mesial and distal tooth sites of the DC and the CC, one μL of GCF was harvested with a (HirschmannR microcapillary pipette, Sigma AldrichR), before appliance activation, 1 hour after, and every week thereafter for a period of 28 days. The results were expressed as total ACP activity (U/L) determined spectrophotometrically at 300 C at 405 nm. One way Analysis of Variance (ANOVA) and Independent Samples t-test and MannWhitney U-test was done for comparison of enzyme activity among the pre-determined intervals and the SPSS computer program version 21 was used to carry out the statistical evaluation. The ACP activity in GCF was elevated in DC as compared with CC in the first week (3.964+0.940 U/ L) and third week (6.643+0.802 U/L), confirming the fact that the enzyme activity in DCs was greater than in the CCs, more so in the distal (compression) than in the mesial (tension) sites. The increased ACP activity in the GCF in the distal sites of DCs reflects the biologic activity in the periodontium during orthodontic tooth movement (OTM) and could therefore serve to monitor bone turnover changes during OTM in clinical practice.