OPG and RANKL levels around miniscrew implants during orthodontic tooth movement

Introduction: The aim of this study was to determine the peri-miniscrew implant crevicular fluid receptor
activator of nuclear factor-lB ligand (RANKL) and osteoprotegerin (OPG) levels around loaded and unloaded
miniscrew implants at different time intervals. Methods: Twenty loaded and 16 unloaded miniscrew implants
were included in this study. All miniscrew implants were placed bilaterally between the maxillary second premolars
and first molars as anchorage units for canine distalization. Peri-miniscrew implant crevicular fluid was taken
from the mesiobuccal aspects of the loaded and unloaded miniscrew implants before loading; at 24, 48, and 168
hours; and on day 30 after force application. Enzyme-linked immunosorbent assay kits were used to determine
RANKL and OPG levels in the peri-miniscrew implant crevicular fluid samples. Wilcoxon, Mann-Whitney U, and
Spearman correlation tests were used for statistical evaluations at the P\0.05 level. Results: Although the total
amount of OPG was not different between the groups, the total amount of RANKL was significantly elevated in
the loaded miniscrew implant group (P\0.05) at all time periods. Peri-miniscrew implant crevicular fluid volume
was the highest at 48 hours in the loaded group. Also, the OPG/RANKL ratio in the peri-miniscrew implant
crevicular fluid was significantly decreased in the loaded miniscrew implant group. Conclusions: The OPG
and RANKL levels vary around loaded and unloaded miniscrew implants as a result of force application.