Effect of high-frequency vibration on orthodontic tooth movement and bone density

Abstract

Objectives: Previous reports have shown that high-frequency vibration can increase bone remodeling and accelerate tooth movement. The aim of this study was to evaluate the effects of high-frequency vibration on treatment phase tooth movement, and post-treatment bone density at initiation of retention, with cone-beam computed tomography (CBCT).

Materials and methods: Thirty patients with initial Class I skeletal relationships, initial minimum-moderate crowding (3-5 mm), treated to completion with clear aligners and adjunctive high-frequency vibration, (HFV group) or no vibration, (Control group) were evaluated. The patients were instructed to change aligners as soon as they become loose. Changes in bone density associated with orthodontic treatment were evaluated using i-CAT cone-beam computed tomography (CBCT) and InVivo Anatomage^® software to quantify density using Hounsfield units (HU) between treated teeth in 10 different regions. HU values were averaged and compared against baseline (T1) and between the groups at initiation of retention (T2).

Results: The average time for aligner change was 5.2 days in the HFV group, and 8.7 days in the control group (P = 0.0001). There was significant T1 to T2 increase of HU values in the upper arch (P = 0.0001) and the lower arch (P = 0.008) in the HFV group. There was no significant change in average HU values in the upper (P = 0.83) or lower arches (P = 0.33) in the control group. The intergroup comparison revealed a significant difference in the upper, (P = 0.0001) and lower arches (P = 0.007).

Conclusion: High-frequency vibration adjunctive to clear aligners, allowed early aligner changes that led to shorter treatment time in minimum-moderate crowded cases. At initiation of retention, the HFV group demonstrated statistically significant increase as compared with pre-treatment bone density, whereas control subjects showed no significant change from pre-treatment bone density.

Keywords: Clear aligners; high-frequency vibration; orthodontic retention; tooth movement.

Figure 1

Sagittal section through the palate showing posterior rim of the incisive foramen and the posterior nasal spine were on the same slice

Figure 2

Reference lines for measuring the maxillary alveolar bone density passing through the posterior rim of the incisive foramen (a). The corresponding axial view of the maxilla (b)

Figure 3

Reference lines for measuring the mandibular alveolar bone density passing through the posterior inferior point of the second cervical vertebra (a). The corresponding axial view of the mandible (b)

Figure 4

Measuring the bone density at five different locations; between the right canine and lateral, right lateral and central, left central and lateral, left lateral and canine and at the midline. HFV (a), Control (b)

Figure 5

A patient from the HFV group with class I malocclusion (a) before and (b) after treatment with Invisalign clear aligners. Total treatment with 34 aligners was 175 days. (Average aligner change of 5.14 days)

Figure 6

A patient from the control group with class I malocclusion (a) before and (b) after treatment with Invisalign clear aligners. Total treatment with 23 aligners was 203 days. (Average aligner change of 8.83 days)

Figure 7

Bone density of the alveolar bone before and after HFV application, Upper arch (a) lower arch (b)

Figure 8

Graph showing the average pre-and post-treatment bone density changes in HU value in the HFV group. (*= statistically significant P < 0.05)

Figure 9

Graph showing the average pre-and post-treatment bone density changes in HU value in the Control group. (*= statistically significant P < 0.05)