Effects Of Non-Invasive Low Level Laser Therapy, Low Intensity Pulsed Ultrasound Treatment And Their Combination On Orthodontic Tooth Movement
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Date
2015-12
Authors
Jawab Al-Azzawi, Mohammed Mahmood
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Orthodontic treatment is a process of achieving appropriate functions and esthetics
by the movement of a tooth through the application of an external physical force in
order to obtain physiological tissue reactions around a tooth, while avoiding the side
effects of an external force. However, long-term therapy for several years is required.
Accordingly, faster tooth movement without harmful effect on periodontal tissue and
alveolar bone has been an important issue of interest to orthodontists and patients.
Recently with the development of science, there is high attention among
orthodontists to investigate the non-invasive stimulating techniques to improve
orthodontic treatment. Many researchers have shown that proper use of low level
laser treatment (LLLT) in orthodontic clinic can accelerate treatment, reduce
appointments, and provide superior results, but there is no established regimen that
all LLLT users within orthodontics are agreeing to follow. The non-invasive lowintensity
pulsed ultrasound (LIPUS) has also been used to stimulate bone fracture
healing by improving osteogenesis, remodeling and angiogenesis. However, there are
limited numbers of studies on LIPUS stimulation for orthodontic tooth movement.
To the best of our knowledge, there is no other study comparing the effect of LLLT
with LIPUS for orthodontic tooth movement, or comparing the stimulatory effect of
the combination of LLLT with LIPUS for orthodontics. This research was aimed to
study in vitro and in vivo effect of different low level laser regimes, low intensity
pulsed ultrasound and the combination of both techniques on orthodontic tooth
movement. For in vitro, Human fetal osteoblast cell line (hFOB) was cultured and
divided into different groups; 1st group was treated with 940 nm LLLT (with power
ranging between 100-300mW), 2nd group was treated with LIPUS, 3rd group was
treated with combination of LLLT and LIPUS. The application of LLLT or LIPUS or
combination of them was once a day for 7 days. For cell proliferation, MTT assay
was used. Both alkaline phosphatase and osteocalcin activity assays were assessed
for cell differentiation. RT-PCR was also performed to elucidate the osteoblasts gene
expression for COL1A1, RUNX-2 and BSP. For in vivo, 6-week-old Sprague Dawley
male rats were used. Orthodontic appliances were inserted. A force of 10g was
applied to the molars to induce tooth movement. The rats were grouped into four
groups. The 1st group was irradiated with LLLT, 2nd group was treated with LIPUS
and a 3rd group was treated with combination of both LLLT and LIPUS. A 4th group
was a control group. The LLLT and LIPUS were used to treat the area around the
moving tooth once a day till 1, 3, 7, 14 and 21 days. To determine the amount of
tooth movement, plaster models of the maxillae were made. The models were
imaged and analysed. Histological examination was performed after staining with
(haematoxylin and eosin) and (Alizarin red and Alcian blue) stain. RT-PCR was also
performed to elucidate the gene expression of RANK, RANKL, OPG and RUNX-2 in
the area of treatment. The results of in vitro showed that all treatment groups
significantly increased rate in cell proliferation and differentiation compared to the
control group. The LIPUS group and the 300 mW LLLT group significantly
increased the amount of cell proliferation. By contrast, the combination groups
showed significantly greater amount of cell differentiation and gene expression. The
results of in vivo showed that the amount of tooth movement, the histological bone
remodelling and the RT-PCR was significantly greater in the treatment groups than
that in the control group. Among the treatment groups, the combination group was
the highest and the LIPUS group was the lowest. The findings of this study suggest
that LLLT and LIPUS can stimulate osteoblast cells for bone formation.
Additionally, they facilitate the velocity of tooth movement and improve the quality
of bone remodelling during orthodontic tooth movement especially when they are
combined together.
Description
Keywords
Orthodontic treatment , achieving appropriate functions.