The effect of 12 weeks of mechanical vibration on root resorption: a micro-CT study

The aim was to investigate the effect of mechanical vibration on root resorption with or without orthodontic force application.

Twenty patients who required maxillary premolar extractions as part of orthodontic treatment were randomly divided into two groups of 10: no-force group and force group. Using a split-mouth procedure, each patient's maxillary first premolar teeth were randomly assigned as either vibration or control side for both groups. A buccally directed vibration of 50 Hz, with an Oral-B HummingBird device, was applied to the maxillary first premolar for 10 min/day for 12 weeks. After the force application period, the maxillary first premolars were extracted and scanned with micro-computed tomography. Fiji (ImageJ), performing slice-by-slice quantitative volumetric measurements, was used for resorption crater calculation. Total crater volumes were compared with the Wilcoxon and Mann-Whitney U tests.

The total crater volumes in the force and no-force groups were 0.476 mm³ and 0.017 mm³ on the vibration side and 0.462 mm³ and 0.031 mm³ on the control side, respectively. There was no statistical difference between the vibration and control sides (P > 0.05). There was more resorption by volume in the force group when compared to the no-force group (P < 0.05).

Mechanical vibration did not have a beneficial effect on reducing root resorption; however, force application caused significant root resorption.