The Effects of Various Frequencies of Low-Level Mechanical Vibration on Retention in an Orthodontic Relapse Model in Mice

ABSTRACT Objectives: The aim of this study is to study the effect of mechanical vibration on retention following orthodontic tooth movement (OTM) in a mouse orthodontic relapse model. We applied various frequencies of vibration to the maxillary right first molar during relapse, and monitored changes to the alveolar bone and molar root. Materials and Methods: Thirty-four male CD1 mice were placed in 4 groups. The Control Group underwent OTM for 7 days. The other three groups received OTM for 7 days, followed by a relapse phase of 7 days. OTM was performed with a 10g Ni-Ti spring. The Relapse Group did not receive vibration during relapse, while Relapse + 10 Hz and Relapse + 30 Hz Groups received intermittent vibration throughout their relapse phases. Micro-CT imaging was performed for bone volume fraction (BVF), tissue density (TD), first molar movement (M1-M2 Distance), and mesial root volume (MRV). Results: Differences in M1-M2 Distance were statistically significant between control and experimental groups. No significant findings were observed between controls and experimental groups for BVF, TD, and MRV. No significant differences were observed between relapse and relapse with vibration groups for BVD, TD, M1-M2 Distance, and MRV. Non-significant measurements demonstrated Relapse + 10 Hz vibration increased relapse while Relapse + 30 Hz vibration decreased relapse. Conclusion: Our findings demonstrate that 10 Hz and 30 Hz mechanical vibration have no statistically significant effects on retention based on a mouse relapse model. Further research is necessary to understand the effects of mechanical vibration on retention