**2.3. Physical methods**

termed as periodontally accelerated osteogenic orthodontics (PAOO) [16]. This procedure which enables rapid tooth movement is due to a healing event that was described by Frost

RAP is the acceleration of the normal regional healing process from the original injury. It usually occurs after osteotomy, bone-grafting procedure, arthrodesis and fractures and there might be involvement and activation of precursor cells required for healing at the injury site. RAP can increase both soft and hard tissue healing processes by two- to tenfold [17]. It usually starts in the first few days of injury, peaks at the first or second month and may last for 3–4 months [16]. Orthodontic treatment can be started 1 week before or within 2 weeks after the surgery. Surgery begins with flap reflection and decortication with low-speed round burs. Bone graft is then laid over these areas of corticotomies. The flaps are then closed and sutured [18]. Several studies have been done related to corticotomies, an example is one by Uzuner and her co-workers where they showed that canine retraction assisted by corticotomy had reduced duration of retraction by 20% ratio [19]. PAOO has shown to have reduced treatment time, produce lower cortical bone resistance leading to reduced root resorption, enhancement of post-orthodontic stability, increased bone support since there is supplementation of the bone graft. However, PAOO still has risks since it is an invasive procedure and is expensive [20–24]. Since the corticotomy procedure is still invasive, Dibart et al. introduced a new minimally invasive method called piezocision. Piezocision involves microincisions which are confined to the buccal side that allows the use of piezoelectric knife and selective tunnelling which enables hard and soft tissue grafting [25]. Piezocision is usually done a week after orthodontic appliance placement. The procedure involves vertical incisions made buccally and interproximally. The mid portion of the incision between the roots enables the piezoelectric knife to be inserted. A piezotome is then inserted in the gingival openings that were made and piezoelectrical corticotomy of 3 mm is made. Hard or soft tissue grafts can then be added via

[17] and termed as regional acceleratory phenomenon (RAP).

26 Current Approaches in Orthodontics

a tunnelling procedure (**Figure 2**) [26].

**Figure 2.** Piezocision.

Despite all the attempts in making surgical methods being minimally invasive, they still remain as an invasive procedure. This had led to discoveries in other tools that can accelerate tooth movement during orthodontic treatment. The two most common physical methods used in the present day are:


Bone has the ability to respond to the mechanical stimuli that is applied to it as a mechanism to withstand functional activity. Rubin et al. showed the rate of remodelling in mechanically loaded long bones have been increased following vibrations or low level mechanical oscillatory signals [31]. In 2008, Nishimura et al. did an animal study which gave an insight on how resonance vibration could be able to accelerate tooth movement through the expression of RANKL in the periodontal ligament [32].

A novel device that was introduced by OrthoAccel Technologies is the AcceleDent device. The device has an activator and a mouthpiece. The patient bites on the mouthpiece component when in use. The activator which is extraorally positioned generates and transmits vibrations to the teeth. It can provide 0.2 N of vibration at 30 Hz for 20 minutes. It was fabricated to work in tandem with existing bracket systems and not replace them. The device produces cyclic forces to move teeth within the alveolus via accelerated bone remodelling [33]. Pavlin and co-workers in 2015 showed low-level cyclic loading with AcceleDent increased the rate of orthodontic movement (**Figure 3**) [34].

Another treatment modality to speed up orthodontic tooth movement is by the use of low-level laser therapy (LLLT). Laser irradiation on tissues has a biostimulating effect with not more than 1°C rise in local temperature. Biostimulation potency of laser irradiation utilised by treatment are called low-level laser therapy [35]. Other than accelerating tooth movement, LLLT can enhance stability of orthodontic mini-implants [36], reduce post-adjustment pain [37], and induce bone growth in midpalatal suture area following rapid maxillary expansion [38].

Studies done by Fujita et al. and Yamaguchi et al. showed that LLLT enhances osteoclastogenesis on the compressed side of teeth being moved. There was stimulation of RANKL and macrophage colony-stimulating factor [39, 40]. Coordination of bone remodelling had been facilitated by RANKL and osteoprotegerin following orthodontic force with LLLT. LLLT stimulates bone formation on the tension side [41]. Kim et al. observed osteopontin localisation in the periodontal tissue in their study subjects, indicating LLLT may stimulate osteogenesis as well in orthodontic treatment [42]. Although much findings show LLLT stimulates osteoblast and osteoclast function, further studies are still required to optimise the effect of LLLT on tooth movement (**Figure 4**) [43].

Apart from physical agents, low-intensity pulsed ultrasound (LIPUS) has also been suggested. It uses mechanical energy which passes through the tissues as acoustic pressure waves [44]. This leads to biochemical changes at molecular and cellular levels. It can increase the healing of both soft tissue and hard tissue [45]. LIPUS is usually used at frequency pulses of 1.5 MHz with 200 μs pulse width, which is repeated at 1KHz a for 20 minutes a day with an intensity

Accelerated Orthodontics

29

http://dx.doi.org/10.5772/intechopen.80915

Recent studies on LIPUS using animal models by Xue et al. showed that there is induction of alveolar bone remodelling. The remodelling occurred due to an increase in the gene expression of HGF/Runx2/BMP-2 signalling pathway with LIPUS. This led to an increase in the velocity of tooth movement during orthodontic treatment [47]. El-Bialy et al. observed that LIPUS may reduce the root resorption that was orthodontically-induced by deposition of den-

Over the years, the methods of reducing treatment time has risen along with its' demand. The options that are available on the orthodontist's plate are numerous ranging from surgical means to photostimulation. Much studies will still need to be done for newer methods to emerge and obtaining a clearer understanding on the methods that already exist. At present, the clinician should use all the knowledge obtained for deciding which treatment option is best for the patient to meet the healthcare needs of the patient and achieving an optimum

tin and cementum to create a preventive layer from root resorption [48].

of 30 mW/cm2

**3. Conclusion**

treatment outcome.

[46].

**Figure 4.** Low-level laser therapy.

**Figure 3.** AcceleDent device.

**Figure 4.** Low-level laser therapy.

to the teeth. It can provide 0.2 N of vibration at 30 Hz for 20 minutes. It was fabricated to work in tandem with existing bracket systems and not replace them. The device produces cyclic forces to move teeth within the alveolus via accelerated bone remodelling [33]. Pavlin and co-workers in 2015 showed low-level cyclic loading with AcceleDent increased the rate of

Another treatment modality to speed up orthodontic tooth movement is by the use of low-level laser therapy (LLLT). Laser irradiation on tissues has a biostimulating effect with not more than 1°C rise in local temperature. Biostimulation potency of laser irradiation utilised by treatment are called low-level laser therapy [35]. Other than accelerating tooth movement, LLLT can enhance stability of orthodontic mini-implants [36], reduce post-adjustment pain [37], and induce bone growth in midpalatal suture area following rapid maxillary expansion [38].

Studies done by Fujita et al. and Yamaguchi et al. showed that LLLT enhances osteoclastogenesis on the compressed side of teeth being moved. There was stimulation of RANKL and macrophage colony-stimulating factor [39, 40]. Coordination of bone remodelling had been facilitated by RANKL and osteoprotegerin following orthodontic force with LLLT. LLLT stimulates bone formation on the tension side [41]. Kim et al. observed osteopontin localisation in the periodontal tissue in their study subjects, indicating LLLT may stimulate osteogenesis as well in orthodontic treatment [42]. Although much findings show LLLT stimulates osteoblast and osteoclast function, further studies are still required to optimise the effect of LLLT on

orthodontic movement (**Figure 3**) [34].

28 Current Approaches in Orthodontics

tooth movement (**Figure 4**) [43].

**Figure 3.** AcceleDent device.

Apart from physical agents, low-intensity pulsed ultrasound (LIPUS) has also been suggested. It uses mechanical energy which passes through the tissues as acoustic pressure waves [44]. This leads to biochemical changes at molecular and cellular levels. It can increase the healing of both soft tissue and hard tissue [45]. LIPUS is usually used at frequency pulses of 1.5 MHz with 200 μs pulse width, which is repeated at 1KHz a for 20 minutes a day with an intensity of 30 mW/cm2 [46].

Recent studies on LIPUS using animal models by Xue et al. showed that there is induction of alveolar bone remodelling. The remodelling occurred due to an increase in the gene expression of HGF/Runx2/BMP-2 signalling pathway with LIPUS. This led to an increase in the velocity of tooth movement during orthodontic treatment [47]. El-Bialy et al. observed that LIPUS may reduce the root resorption that was orthodontically-induced by deposition of dentin and cementum to create a preventive layer from root resorption [48].
