Dental Asia September/October 2021

Clinical Feature
Although root resorption has caused
concerns for prolonged tooth
movement, a study done by Pavlin et
al. suggested that while there was a
significant enhancement in retraction
velocity, there was no canine root
resorption after patients received
vibration treatment 11 .
The popular brands of vibrator include
AcceleDent (Fig. 12) and VPro (Fig. 13)
from the United States (US).
MICROVIBRATION
The common brand of orthodontic
vibrator used in the US with FDA
approval are AcceleDent and VPro. The
patient utilises the device by biting
lightly on to the plastic plate for about
20 minutes per day. It will deliver a
light force of 0.25N with a vibrating
frequency of 30Hz.
Alihani et al. studied the vibrators with
a controlled group, and they found
that the mechanical vibrations could
affect tooth movement time due to the
induction of anabolic and catabolic
effects on bone around the teeth 1 .
Liao founded that the periodontal
ligament responses were amplified due
to the vibrations applied. The responses
were recorded by computational
stimulation, the volume-average
hydrostatic stress in the periodontal
ligament was found at higher level
with vibration when compared with the
control group 6 .
Proffit studied the principles of vibrators.
They were used in traditional fixed
orthodontic appliances and in removable
Invisalign aligners. The treatment time
was 20 minutes per day, with a vibration
of 30Hz and has force of 20g 12 .
They could neither confirm nor fully
understand the exact mechanism of
alveolar remodelling at that time but
he had proposed two hypotheses: the
first one referred to piezoelectricity
that could generate within the alveolar
bone, the second one is related to the
pressure‐tension established within the
periodontal ligament 12 .
Grimm, stated: “Piezoelectricity is
generated by orthodontic forces
bending alveolar bone to produce an
electrical charge which, in turn, induces
an osteogenic response’’ 3 .
This is agreed by Shapiro and he
recommended “that orthodontic
forces should not be continuous as the
piezoelectric charges are only created
when stress is applied and released” 13 .
Kau, concluded: “mechanical vibrational
appliance may be suitable for initiating
these stress‐induced charges as forces
could be applied and released at a rapid
rate”.
A number of cases were reported which
support the use of microvibration to
accelerate tooth movement 4 .
Leethanakul reported an increase in
movement for patients using vibratingelectric
toothbrush head (125Hz) on one
side when compared with the control side.
Gingival crevicular fluid was collected and
measured at the mesial and distal aspects
of each canine at monthly intervals.
Interleukin-1β levels were analysed using
an enzyme-linked immunosorbent assay.
The exact movement of canine was
measured monthly revealing accelerated
movement 5 .
Pavlin et al. found that AcceleDent could
shorten the time of tooth movement
when the technique was used during
orthodontic treatment, and noted
increasing reports on the use of the
vibrating devices.
However, Woodhouse and Miles et al.,
did not agree with Pavlin and pointed
out that there was not enough data that
vibration is accelerating tooth movement
significantly 7,14 .
Fig. 12: AcceleDent vibrator
Fig. 13: VPro vibrator
Woodhouse compared the time for lower
arch teeth alignment to the insertion of
the correction wire in orthodontics for
extraction cases. They concluded that
there was no evidence supporting that
additional vibrational force can increase
the rate of tooth alignment significantly
or aid in the reduction of total treatment
period 7,14 .
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DENTAL ASIA SEPTEMBER / OCTOBER 2021