**1. Introduction**

The treatment of skeletal discrepancies requires orthognathic surgery in combination with orthodontic treatment to improve malocclusion, function, facial, and smile esthetics.

In the 1960s, the surgeons performed orthognathic surgery without orthodontic treatment [1–3]. But it was clearly understood that mandibular or maxillary movement was limited without tooth movement. For example, amount of mandibular setback was limited by the overjet in Class III cases. To achieve a proper setback and to have a good the occlusal and facial esthetics results, orthodontic alignment of malaligned teeth and solving the compensation of teeth to the malposed jaws are required before surgery [4–6]. After the 1970s, orthognathic surgery in combination with orthodontic treatment began to have good standards and showed popularity [7–11].

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

In conventional orthognathic surgery approach, the surgery follows the orthodontic treatment (orthodontic-first approach). Teeth are tended to compensate for skeletal discrepancies to have functional occlusion. The presurgical orthodontic treatment is needed to solve the dental decompensation that reveals the true extent of the skeletal deformity to align the teeth and to fit the maxilla and mandible into a good occlusion after surgery [11, 12]. Following the orthodontic treatment, orthognathic surgery corrects the skeletal discrepancy to obtain a good jaw alignment with good facial proportions. As the direction of presurgical orthodontic treatment is opposite to that of natural dental compensation forces, the orthodontic treatment time is said to require time to overcome the natural compensation forces [13]. The presurgical orthodontic treatment period which includes aligning dental occlusion, reversing incisor decompensation, correcting tooth rotation, and arch coordination lasts for 12–36 months depending on the complexity of case and also for a period after the surgery [13].

One of the reasons for the shorter duration of treatment in SFA is the regional accelerated phenomenon (RAP) which is the increase of the osteoclastic and metabolic activities due to the surgery. Selective bone injury activates stimulus for anabolic and catabolic responses in the periodontium adjacent to the osteotomies performed during orthognathic surgery and increases bone reorganization [32, 36–45]. It was reported that RAP in humans began in a few days after surgery and peaked at 1–2 months and took 6 months to more than 24 months to subside [39]. Liou et al. also studied the causes of rapid postoperative orthodontic treatment time in SFA cases, and they found that the levels of serum alkaline phosphatase and C-terminal telopeptide of type I collagen (ICTP) increased, which supported the postoperative accelerated orthodontic tooth movement caused the orthognathic surgery [15]. Zingler et al. found that crevicular fluids in SFA cases were higher levels of bone remodeling factors

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The other reason for the shorter duration of treatment in SFA than in the conventional approach may be improvement of function. Choi and Bradley reported that teeth tended

Figure 1. a-d: Facial asymmetry case. Passive arch wires were inserted the day before surgery.

for fracture healing [32].

In last 10 years, surgery first approach (SFA) has begun to be implemented in some centers [14] and created broader interest [15–20].

The surgery first approach (SFA) is the orthognathic surgery approach that the orthognathic surgery precedes the orthodontic treatment. In the beginning of the treatment, surgery is performed without orthodontic preparation, and the orthodontic treatment is done after the surgery.

Historically, the SFA was presented by some researchers in earlier years [2, 21–24], but SFA in a combined treatment, which was introduced officially by Brachvogel et al. [25] and by Nagasaka et al., has gained attention in the past 10 years [26].

Among the published studies about SFA regarding the type of malocclusion, Class III is the most prevalent. Class III with openbite and asymmetry cases with SFA are the other published studies. SFA in Class II cases and in some deformities like TMJ disorders or condylar hyperplasia is rare [27–29].
