Total treatment timeDurationDuration of the orthodontic treatment
Whenever I present our surgery-first orthognathic approach or surgery-first approach (SFA) at symposia, many surgeons and orthodontists ask me about the possibility of reducing the total treatment time for managing dentofacial deformities. Given that the total treatment time required for completing treatment, including the presurgical orthodontics, orthognathic surgery, and postsurgical orthodontics, I understand why this issue is a hot topic for SFA. Compared to the management of diseases or deformities in other medical fields, the treatment of the dentofacial deformities takes much longer to complete (Fig. 15.1). Since orthognathic surgery was developed in the 1950s and 1960s, I feel that now is the time to progress this issue.
A traditional orthognathic approach generally requires a presurgical orthodontic treatment that takes an average of 17 months , followed by surgery and postsurgical orthodontic treatment for approximately 6–12 months. Therefore, the total treatment time required for a conventional orthognathic approach takes about 18–36 months (Fig. 15.1) [2–4]. Because traditional orthognathic surgery requires 2–3 years to complete, the procedure is quite rare among surgical procedures. Shortening the total treatment time would greatly benefit patients. Previously, presurgical orthodontic treatment has been argued to be the key time-consuming element in the orthognathic surgical process [2, 5–7]. However, we wondered whether presurgical orthodontic treatment was mandatory for all cases (Fig. 15.2).
Human teeth naturally adapt to their locoregional environment. For example, in patient with a Class III dentofacial deformity, the lower teeth tend to incline lingually and the upper teeth tend to evert labially to produce functional occlusion (Fig. 15.2). Most patients with Class III dentofacial deformities are able to bite as a result of these adaptative mechanisms. As a result, most of these patients display abnormal teeth positions, as well as malpositioned maxillas and mandibles, before orthognathic surgery [5, 8–11]. This is one reason for the presurgical orthodontic treatment; without this procedure, the occlusion after the orthognathic surgery would be unstable. For these reasons, presurgical orthodontic treatment is believed to be required for dental decompensation, arch alignment, maxilla and mandibular arch coordination, and correction of aggravated curves of Spee [9, 12] (Fig. 15.3).
Nevertheless, the direction of presurgical orthodontic treatment is opposite that of natural dental compensation. Therefore, the orthodontic movement required for dental decompensation needs time to overcome the natural compensation forces. Although presurgical orthodontic treatment has been an inevitable process for stable, preoperative orthognathic correction, recent advances in the application of miniscrews and presurgical orthodontic management simulations on dental models suggest that a surgery-first orthognathic approach, without presurgical orthodontic treatment, may be possible  (Fig. 15.4).
A surgery-first orthognathic approach, without presurgical orthodontic treatment, has been applied in our practice since 2006; only postsurgical orthodontic treatment has been performed in these cases . Surprisingly, we have observed that most cases have achieved normal occlusion, without any major complications.
Two possibilities exist regarding the total treatment time. Skipping the presurgical orthodontic treatment process might lengthen the total treatment time due to unstable postoperative occlusion or it might shorten the treatment duration due to a rapid dental natural adaptation process, regional accelerated phenomenon, or compensation in the direction of the natural compensation process during postsurgical orthodontic treatment. Therefore, we compared various treatment aspects, including the total treatment time, for patients undergoing SFA versus those undergoing the traditional orthognathic approach (Figs. 15.5, 15.6, 15.7 and 15.8).
I will introduce my research into the total SFA treatment time by comparing it to the traditional approach; this provides a more objective understanding of this issue . This prospective study investigated the surgical outcomes of 45 patients who underwent SFA (SFA group) and 52 patients who underwent the traditional orthodontic-first approach (traditional group). The patients included in this study had skeletal Class III deformities and underwent orthognathic surgery between December 2007 and December 2014, completing their orthognathic treatment within that interval. The inclusion/exclusion criteria identified patients for SFA. The indications were based on presurgical simulations involving the dental model and we predicted the SFA outcomes using this preoperative simulation model. After the simulated surgery, patients whose dental structures were predicted to remain stable, without preoperative orthodontics, were included in the SFA group. Patients with cleft-related or syndromic deformities, as well as those who required orthognathic surgeries due to facial asymmetry, Class II deformities, or open bites were excluded.
In SFA, presurgical orthodontic treatments are not performed. However, a simulated surgery, using a dental model, is performed prior to surgery to create the appropriate occlusal splints. This presurgical procedure is the most important step in SFA. The presurgical simulation on the dental model allows for dental alignment, incisor decompensation, and arch coordination . The model provides information regarding the amount of surgical movement of the maxilla and mandible, appropriate wafers, and an estimate of the extent of postsurgical orthodontic treatment. This presurgical procedure is a critical step, as previously reported . The overall procedure is carried out through a series of steps. (1) A standard model mount is used to analyze the occlusion state. (2) In the model setup, teeth that are adapted to the skeletal discrepancy are simulated and reorganized into their predicted location, as in a real presurgical orthodontic treatment. (3) Simulation of the actual orthognathic surgery is performed, including maxillary impaction or advancement and mandibular setback processes, for cases with Class III deformities. These indicate the possible occlusion outcomes, as in the traditional approach. (4) If the teeth are reverted to their presurgical orthodontic treatment positions, the model reflects the orthognathic surgery conditions without presurgical orthodontics. (5) Based on the final dental model, the intermediate and final wafers for the SFA orthognathic surgery can be made.
A bonding procedure for maxillomandibular fixation (MMF) is performed before the orthognathic surgery. The SFA surgical process is quite similar to the traditional approach. The surgery involves a LeFort I osteotomy followed by mandibular setback using a sagittal split ramus osteotomy (SSRO) [15–18]. Fixation of the proximal and distal mandibular segments is performed using the semi-rigid fixation method and a miniplate.
The SFA group included 45 patients (10 males) and the traditional group included 52 patients (10 males) with Class III deformities. All of the patients, in both groups, were Asians with average ages of 23.7 years (SFA group) and 29.7 years (traditional group). The follow-up period ranged from 4 to 36 months (average, 15.13 months). The timing of treatment cessation, including debanding, was determined by the orthodontist. The total treatment times were compared in terms of patients requiring extraction or not. In addition, to identify the factors that influenced the total treatment time, cephalometric landmark locations were determined, for both groups, preoperatively and in the immediate and later postoperative periods [19–21]. Spearman’s correlation analyses were used to compare the groups. All statistical analyses were performed using SPSS 17.0 (SPSS, Chicago, IL USA).
The total treatment times required to complete the orthognathic processes were investigated and compared based on the data. Various factors related to the total treatment time, including patient age, sex, and various preoperative cephalometric values, were investigated in the SFA group . We statistically compared the results of the SFA and traditional approaches in terms of total treatment times.
Satisfactory results were achieved in all 97 patients, in this study (Figs. 15.5 and 15.6), and none of the patients required additional surgeries to resolve occlusal instability or other complications. There were no major complications, such as serious infections, malocclusions, or fixation failures. One patient experienced a mild wound infection, which resolved after 10 days of antibiotic treatment. The baseline cephalometric landmarks are shown in table. The treatment duration in the SFA group ranged from 4 to 36 months. By contrast, the treatment duration in the traditional treatment group ranged from 11 to 40 months. Overall, the analysis revealed that the total treatment time in the SFA group averaged 14.6 months compared to 22.0 months in the traditional group. Among the SFA cases, 6 required tooth extractions, resulting in an average treatment period of 24.8 months (range, 18–31 months), whereas the average treatment time for patients not requiring tooth extractions was 13.6 months (range, 4–36 months; p < 0.001). Nine of the traditional group patients required tooth extractions, and their average treatment period was 21.6 months (range, 13–38 months); the average treatment period of patients not requiring tooth extractions was 21.7 months (range, 11–40 months) (Figs. 15.11 and 15.12) .