**3. Accelerated tooth movement**

The methods which accelerate tooth movement can be classified in three groups:


#### **3.1. Chemical applications**

gingivitis, periodontitis, enamel demineralization, increased levels of dental caries, and open

However, a major challenge in orthodontics is to shorten treatment time by avoiding undesirable side effects without compromising treatment outcome. The rate of orthodontic tooth movement is primarily determined by the remodeling of tissues surrounding the roots; this in return is under the control of molecular mechanisms regulating cellular behaviors in the alveolar bone and periodontal ligament [3]. Assuming that the clinician optimized mechanics and cooperation for any patient, the main factor controlling the treatment time and rate will be the patient's biological response to the orthodontic forces [4, 5]. Therefore, identifying and controlling the cellular regulators are essential to shorten orthodontic treatment time safely. The concept of accelerating tooth movement has received increased attention recently [6] with the introduction of various clinical techniques; including local injection of cellular mediators [7], physical or mechanical stimuli [8] and surgically assisted orthodontics [9, 10]. Local or systemic pharmaceutical administration and physical or mechanical stimulation methods might not be applicable to daily clinical practice because of their possible side effects and their outcomes that await validation [11]. Over the past decade, the regional acceleratory phenomenon induced by surgical trauma has received emphasis for accelerating orthodontic tooth movement and reducing the treatment time [11]. However, many techniques which are surgically assisted involve considerably high surgical trauma limiting application of the technique currently.

A new method which uses micro-osteoperforations (MOPs) to stimulate alveolar bone remodeling without the disadvantages of surgery such as the requirement of corticotomies, cuts in cortical bone, raising split-thickness flap, and decorticating the bone has recently been identified [5, 12]. Animal studies revealed that micro-osteoperforations significantly stimulate expression of inflammatory markers and increase the number of osteoclasts and bone resorption. The increase in bone remodeling contributes to the rise in both rate and magnitude of tooth movement [4]. In addition to the requirement of additional studies, similar results are

In this chapter, we focused on the biologic basis of orthodontic tooth movement, accelerated tooth movement techniques and application methods, advantages, disadvantages, effects, and possible side effects of micro-osteoperforations as a new, reliable, repeatable and minimally

Application of mechanical forces to teeth causes orthodontic tooth movement as a result of the biological responses of the periodontal tissues. Alveolar bone remodeling includes selective resorption in some areas and apposition in others. The biologic response to orthodontic therapy includes not only the response of the periodontal ligament and alveolar bone but also the response of growing areas which are distant from the dentition. However, it can be stated that tooth movement is primarily a periodontal ligament phenomenon because the alveolar

invasive method for accelerating orthodontic tooth movement.

**2. Biologic basis of orthodontic tooth movement**

bone response is also mediated by the periodontal ligament [13].

reported in clinical trials [4, 5].

74 Current Approaches in Orthodontics

gingival embrasure spaces may occur during orthodontic treatment [2].

In this method, substances such as prostaglandins, corticosteroids, vitamin D, cytokines, neuropeptides, leukotrienes, nitric oxide, diazepam, and vasoactive medications, which are considered as physiological agents that transform mechanical forces into cellular response, are used to decrease the resistance to the strength applied during tooth movement that occurs within the cells and to change the environmental factors [15, 16].

Taking systemic effect rather than being limited to the applied area and affecting other target cells in the body are reported as a common side effect of using these hormones and medications [17]. Therefore, there is no medication treatment which safely accelerates tooth movement [18].
