A comparative study of different vibratory stimuli frequencies during orthodontic tooth movement on the secretion of receptor activator of nuclear kappa-b ligand (RANKL)/osteoprotegerin (OPG) ratio

Abstract

The accelerated orthodontic tooth movement had several methods. The vibration is one method that is used to accelerate tooth movement. However, previous studies showed controversy results because of several factors. The one factor had also affected which was frequency. In addition, there were a few studies that investigated the effect of vibration to tooth movement and cytokine secretion in clinical setting. Objectives: To investigate the effect of vibratory stimuli frequencies at 30 Hz and 60 Hz on the rate of maxillary canine distalization and secretion of RANKL and OPG. Methods: 60 subjects (age 21.5 ± 2.0 years) who received orthodontic treatment plan which was upper first premolar extraction and canine distalization by 60 grams force on 0.022" pre-adjusted edgewise appliance with 0.016" x 0.022" SS archwire after completed leveling and aligning. All participants were randomly selected to 3 groups 1. Canine distalization + vibration 30 Hz. 2. Canine distalization + vibration 60 Hz 3. Canine distalization only. For seven days after started, canine distalization was analysis with per-protocol analysis. Examiner applied vibration for 20 minutes/day at the same time. Gingival crevicular fluid was collected to analysis RANKL and OPG on before distalization (T1) and 24 h (T2), 48 h (T3), and 7 days (T4) after canine distalization. After seven days, participants applied vibration with themselves at home following the recommendation. The rate of maxillary canine distalization was calculated with digital models T1 to 3 months after canine distalization (T5). The data was analyzed with (intention-to-treat). All parameters were non - normal distribution, the changes parameter and different time-point among 3 groups were examine by Kruskal-Wallis test at significant level 0.05. Results: The maxillary canine distalization rate did not statistically significant different between group (p>0.05). RANKL, OPG and RANKL/OPG ratio were not statistically significant different between groups and intragroup at each time-points (p>0.05) Nevertheless, RANKL on the compression side was statistically significantly higher at T2, T3 and T4 than T1 in the control group (p<0.001). Conclusions: The effect of vibratory stimuli frequencies at 30 Hz and 60 Hz combined with light orthodontic force (60 grams) for 3 months did not significantly accelerate the rate of canine distalization when compared to 60 grams of orthodontic force alone. In addition, the RANKL and OPG or the RANKL/OPG ratio expression did not statistically significant for 7 days vibratory stimuli application.