**2.2. Surgical methods**

**2. Methods of accelerated tooth movements**

and Prostaglandin E1

increase orthodontic tooth movement [2]. Animal studies have shown PGE2

). Prostaglandin E1

movement and facilitate bone resorption [3–6]. Camacho and Velásquez Cujar conducted a study that showed that it required repeated injections due to its short half-life [7]. Particular

Another prostaglandin that has been reported to speed up orthodontic tooth movement

mechanical stress and cause bone remodelling, Patil and his co-workers had shown that even

the hyperalgesia that accompanies with the local injection of PGE1, an analogue of it which is misoprostol was tried out. It was seen that it was effective in increasing orthodontic tooth

The parathyroid hormone (PTH) acts directly on osteoblasts and on osteoclasts indirectly by binding to the PTH type 1 receptor on osteoblasts. This causes the expression of insulin like growth factor 1. There is promotion of osteoblast survival, osteoblastogenesis and receptor activator for nuclear factor κ B ligand (RANKL) which induces osteoclast activation [2]. PTH facilitates bone remodelling in intermittent treatment by enhancing activities of osteoblasts

(PGE1

**A.** Pharmacological methods

**2.1. Pharmacological methods**

• 1,25-Dihydroxycholecalciferol

• Intravenous immunoglobulins

tion of the prostaglandins [8].

minimal amounts of PGE1

movement (**Figure 1**) [10].

and osteoclasts [11].

(PGE2

synthases that are required for the synthesis of PGE2

(PGE1

• Parathyroid hormones

**B.** Surgical methods **C.** Physical methods

24 Current Approaches in Orthodontics

biomodulators:

• Misoprostol

Prostaglandin E2

is Prostaglandin E1

• Prostaglandin E2

We can categorise the methods of accelerated tooth movement into the following categories:

Orthodontic forces cause a fluid movement in the periodontal ligament space and distortion of the matrix and cells. There is release of molecules which initiate bone remodelling for tooth movement [1]. There are a number of researches on pharmacological agents that act as biomodulators for increased orthodontic tooth movement. These are examples of such

) is an arachidonic acid metabolite is an often-tested substance to

injection had significant increase in tooth movement [9]. Due to

to increase tooth

could be targeted to control the produc-

) has also been seen to be induced by

Bichmalyr in 1931, put forward a surgical technique with orthodontic appliances for rapid correction of severe maxillary protrusion. First, wedges of bone were removed to reduce the volume for which the roots of the maxillary anterior teeth would require for retraction. Kӧle further looked into this technique in 1959 by including special movements like crossbite correction and space closure. He believed that he was able to move bony blocks using the crowns of teeth as handles as the blocks were connected by only less-dense medullary bone [16]. Currently there are few surgical methods being practiced, they are:


In 2001, Wilcko et al. had introduced a method which combines corticotomy surgery and alveolar bone grafting which is referred to as accelerated osteogenic orthodontics or recently 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 [17] and termed as regional acceleratory phenomenon (RAP).

Piezocision can be used as an adjunct to treat a number of malocclusions and aid in rapid orthodontic treatment in adults. Since it is much more minimally invasive than corticotomy, it is having high degree of patient acceptance, short surgical time and has less postoperative discomfort [25, 26]. Dibart and coworkers in 2013 showed that there was an increase in the rate of tooth movement in their animal study and preliminary human studies are being con-

Accelerated Orthodontics

27

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

To further reduce the amount of invasive nature of surgical intervention, a method called micro-osteoperforation (MOP). It is procedure in which small pinhole-sized perforations are created within the alveolar bone surrounding the dentition. This initiates cytokine release to call in osteoclasts to increase bone resorption. Thus, acceleration of tooth movement occurs during orthodontic treatment. The site of perforation is within the attached gingiva and close to the target teeth on the mesial and distal aspect of the roots of the teeth which will be moved. The most favourable place for placement of the perforation is the buccal cortical plate but lingual plate can also be approached with a contra-angled appliance. Two to four perforations

In 2013, Alikhani et al. showed that MOP increased expression of cytokines for osteoclast differentiation, increased canine retraction, reduced orthodontic treatment by 62% with mild discomfort in patients [29]. In an animal study, Alikhani and co-workers found that the expression of inflammatory markers and bone resorption was significant. Their human clini-

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

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

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

cal trial found distalisation was twice as much with MOP than the forces alone [30].

ducted to correlate with the animal studies [26, 27].

are ideal amounts with depths of 3–7 mm into the bone [28].

**2.3. Physical methods**

used in the present day are:

• Low level laser therapy

• Low-intensity pulsed ultrasound

RANKL in the periodontal ligament [32].

• Vibratory stimulus

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

**Figure 2.** Piezocision.

Piezocision can be used as an adjunct to treat a number of malocclusions and aid in rapid orthodontic treatment in adults. Since it is much more minimally invasive than corticotomy, it is having high degree of patient acceptance, short surgical time and has less postoperative discomfort [25, 26]. Dibart and coworkers in 2013 showed that there was an increase in the rate of tooth movement in their animal study and preliminary human studies are being conducted to correlate with the animal studies [26, 27].

To further reduce the amount of invasive nature of surgical intervention, a method called micro-osteoperforation (MOP). It is procedure in which small pinhole-sized perforations are created within the alveolar bone surrounding the dentition. This initiates cytokine release to call in osteoclasts to increase bone resorption. Thus, acceleration of tooth movement occurs during orthodontic treatment. The site of perforation is within the attached gingiva and close to the target teeth on the mesial and distal aspect of the roots of the teeth which will be moved. The most favourable place for placement of the perforation is the buccal cortical plate but lingual plate can also be approached with a contra-angled appliance. Two to four perforations are ideal amounts with depths of 3–7 mm into the bone [28].

In 2013, Alikhani et al. showed that MOP increased expression of cytokines for osteoclast differentiation, increased canine retraction, reduced orthodontic treatment by 62% with mild discomfort in patients [29]. In an animal study, Alikhani and co-workers found that the expression of inflammatory markers and bone resorption was significant. Their human clinical trial found distalisation was twice as much with MOP than the forces alone [30].
