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Device assisted approach :
1) Direct electric current effect on tooth movment:
| - It's a mechanism passed on applying electric current on different sites
during the orthodontic treatment to generate local response & accelerate
the bone remodeling.
- Pressure site --> anode is placed
- Tension site --> cathode is placed |
|
Disadvantages :
The bulkiness of the device and its irritation to the patient is the main drawback, so to overcome this --> Studies where made to invent a BIOCATALYTIC FUEL CELL to generate electricity intraorally using enzymes and glucose as fuel.
| -It's placed on the gingiva near the alveolar bone.
-Small in size / minimal tissue injury |
Disadvantages :
| - Short lifetime |
| - Poor power density |
2)Cyclic force device effect on tooth movement :
Nishimura et al in 2008, used a Ni-Ti expansion spring on the 1st molar of Wistar rats, and applied a vibration of 60 Hz, 1 m/s2. They stated that the rats that received the vibration
showed increased orthodontic tooth movement.
In the sectioned samples, they showed increased RANKL expression in the fibroblasts and osteoclasts of the periodontal ligament of the rats that received vibration.
Liu et al in 2009 conducted a study on thirty mice, in which they used an omega shaped NiTi expander to deliver a force of 20 g on the 1st molar. Mechanical vibration (4 Hz for 20
min/day) was applied perpendicular to the occlusal surface of the first molar.
This regimen was repeated seven times, every 3 days. Upon micro-CT examination of the jaws of the killed mice, it showed that the mice that received vibration showed 40% more tooth movement.
Bone Bending theory :
Bioelectrical potential develops. The concave site will be negatively charged attracting osteoblasts and the convex site will be positively charged attracting osteoclasts as detected by Zengo in his measurements on dog alveolar bone.
The bioelectrical potential is created when there is application of discontinuous forces, which leads to the idea of trying cyclic forces and vibrations.
It has been found that applying vibrations for different duration per day accelerated tooth movements between 15% and 30% in animal experiments.
A) Endogenous piezoelectric stimulation :
(OrthoAccel Technologies) AcceleDent Device
Electric potential can be created by applying force resulting in bending of bone and generation of piezoelectric charges.
The charges are created when stress is applied and released.
Vibration could be used to apply and release stress in a rapid rate.
This device should be used for 20 mins/ Day on 30 Hz frequency.
This device consists of an activator, which is the active part of the appliance that delivers the vibration impulses with a USB interface through which it can be connected to a computer to review the patient usage of the appliance.
A mouthpiece that contacts the teeth. It is a portable device that can be charged similar to any other electronic device.
Various case studies using this device have shown the treatment times to be reduced by up to 30-40%.
ACCELE DENT DEVICE
3)Low Level Laser Therapy
Photobiomodulation or low-level laser therapy (LLLT) is one of the most promising approaches today.
Laser has a biostimulatory effect on bone regeneration, which has been shown in the midpalatal suture during rapid palatal expansion and also stimulates bone regeneration after bone fractures and extraction site.
Gallium – Aluminium – Arsenide Irradiation (LLLT) :
| -Wavelength : 630-860nmJ
- Minimally invasive and safe to apply |
It has been found that laser light stimulates the proliferation of osteoclast, osteoblast, and fibroblasts, and thereby affects bone remodeling and accelerates tooth movement.
The mechanism involved in the acceleration of tooth movement is by the production of ATP and activation of cytochrome C, that low-energy laser irradiation enhanced the velocity of tooth movement via RANK/RANKL and the macrophage colony-stimulating factor and its receptor expression.
Low-Level Laser Therapy increase bone remodleing without the side effects on periodontium .
Laser wavelength of 800nm and output power of 0.25 mW have indicated significant stimulation of bone metabolism, rapid ossification and alsoacceleration of tooth movement to 1.5-fold in rat experiments.
- Light with wavelength : 800-860nm just above visible light spectrum
- 97% of light is lost , only 3% excite intracellular enzymes and increase cellular activity in PDL and bone.
- Increases blood flow and may enhance tooth movement,
- Can be adjusted to be directed at anterior teeth , posterior teeth or whole arch .
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