Circulatory MicroRNA-27, -146, and -214 in Gingival Crevicular Fluid During Orthodontic Tooth Movement

Introduction: MicroRNAs (miRNAs) play important roles in tissue/bone remodeling processes during tooth movement. Recently, circulatory miRNAs have been found in gingival crevicular fluid (GCF). This study aims to evaluate the expression of specific circulatory miRNAs – miRNA-27a/b, miRNA-146a/b and miRNA-214 – in GCF during tooth movement and any correlation between miRNA profile change and the rate tooth movement. Hypotheses: 1. Expressions of miRNA-27a/b, miRNA-146/,b, and miRNA-214 in GCF are dynamic during tooth movement. 2. There exists a correlation between these miRNA expression profiles and the rate of tooth movement. Methods: Twelve healthy UIC orthodontic patients aged 11-21 years old requiring upper first premolar extraction were recruited. Maxillary canine retraction protocols with 150-cN force and maximum anchorage were utilized. GCF samples were collected at five time-points (initial, day of retraction, week-2, -5, and -7) throughout a 7-week retraction period and stored at -80°C. Full maxillary arch intraoral scans were taken at each time-point and superimposed to evaluate canine movement using 3D Geomagic program. Real-time PCR analyzed miRNA expression profiles. Non-parametric statistical analysis evaluated and correlated miRNA expression profiles with the rate of tooth movement (P=0.05). Results: Significant tooth movement was found at a rate of 0.2mm/week during the 7-weeks. No significant profile expression change of these miRNAs over the course of the study period was noted. Mild positive correlations were noted between the distance of tooth movement from T1 to T2 and profile expression changes at T2 for miRNA-27a/b and miRNA-214. A mild positive correlation was noted between the distance of tooth movement from T1 to T3 and profile expression changes at T3 for miRNA-27b. Conclusions: No significant expression profile changes of miRNA-27a/b, miRNA-146a/b, and miRNA-214 were found during tooth movement, but mild correlations between certain miRNA expressions and tooth movement were noted. Funding: Biomedical Research Award (AAOF) and DE024531. IRB Protocol: 2013-0183.