Recovery Pattern of Mandibular Movement by Active Physical Therapy After Bilateral Transoral Vertical Ramus Osteotomy

Vertical Ramus Osteotomy, Is It Still a Valid Tool in Orthognathic Surgery?

The purpose of this study is to evaluate mandibular osteotomy procedures during orthognathic surgery, with an emphasis on the complications of the two leading procedures: intraoral vertical ramus osteotomy (IVRO) and sagittal split osteotomy (SSO). We conducted a retrospective cohort study by extracting the records of patients who underwent either IVRO or SSO procedures during orthognathic surgery in a single center between January 2010 and December 2019. A total of 144 patients were included (median age of 20.5 years, 52 males). The IVRO:SSO ratio was 118:26 procedures. When referring to all surgeries performed, IVRO procedures were associated with shorter hospitalization than the SSO procedures, while the overall durations of surgery and follow-up periods were comparable. In contrast, when referring only to bimaxillary procedures, the duration of the IVRO bimaxillary procedures was significantly shorter than the SSO bimaxillary procedures. There were 53 complications altogether. Postoperative complications consisting of skeletal relapse, temporomandibular joint dysfunction, sensory impairment, and surgical-site infection were significantly fewer in the IVRO group. Both types of osteotomies have acceptable rates of complications. IVRO appears to be a safer, simpler, though less acceptable procedure in terms of patient compliance.

Use of Transcutaneous Electrical Nerve Stimulation (TENS) for the Recovery of Oral Function after Orthognathic Surgery

The oral functions of patients are markedly diminished immediately after orthognathic surgery, and novel approaches are needed to accelerate their recovery. The aim of this study was to examine the usefulness of weekly applications of transcutaneous electrical nerve stimulation (TENS) for this purpose, based on the evidence of its effectiveness in other types of patients with muscle alterations. Maximum jaw opening, bite force, pain, and facial inflammation were compared between patients receiving TENS and those receiving sham-TENS for 30 min at baseline and weekly over a four-week period after orthognathic surgery and were also compared between the before and after of each procedure. TENS was applied at 220 Hz, applying the maximum intensity tolerated by each individual patient. The TENS procedure was identical for all patients, but the device was not turned on in the sham-TENS group. Patients were blinded to their group membership. Results were analyzed separately in skeletal class II and III patients. Improvements in jaw opening and inflammation were significantly greater in the TENS than in the sham-TENS group, attributable to the muscle relaxation achieved with the procedure. Research is warranted on the benefits of a more frequent application of TENS.

Reliability of Anterior Nasal Spine as a Reference Point After LeFort I Surgery Using Three-Dimensional Analysis

ABSTRACT

To evaluate the stability of maxilla following orthognathic surgery, it is necessary to consider the positional change of various landmarks according to bone remodeling of the maxilla. This study aimed to evaluate the stability of the anterior nasal spine (ANS) as a reliable landmark after orthognathic surgery. Forty-seven patients with skeletal class III malocclusion who underwent bimaxillary orthognathic surgery were included. Skeletal changes were measured using cone-beam computerized tomography at 3 time points: preoperative (T0), 1-month postoperative (T1), and 12-month postoperative (T2). Linear changes of the 6 landmark points of the maxilla were measured in 3 directions: anteroposterior, vertical, and transverse. The data were analyzed with paired t tests, independent t tests, and multiple regression analysis. At 12-month postoperatively, the ANS showed mean (standard deviation) 1.23 (1.07) mm posterior movement (P = 0.00), while other landmarks did not show positional changes, implying bony resorption of ANS. Multiple regression test showed surgical forward movements of ANS (T1-0) affect the postoperative backward changes (β = -.05, P < 0.05). There was a negative correlation between the surgical movement and postoperative change of ANS by Pearson correlation test (r = -0.38, P < 0.05). The ANS is not a reliable measurement point in three-dimensional superimposition after orthognathic surgery. Therefore, in studying the stability and positional change pattern after LeFort I surgery, it is not recommended to use ANS as a reference point, as changes can occur in the measurement point itself.

A New Approach to Set the Absolute Midsagittal Plane of the Mandible Using a Similarity Index in Skeletal Class III Patients with Facial Asymmetry

This study sought to test the feasibility of a newly developed plane called computed modified absolute mandibular midsagittal plane (cmAMP) based on the similarity index (SI) for evaluating the stereoscopical symmetry of the mandible by comparison with other proposed midsagittal planes. This study involved 29 adult patients (15 men, 14 women; average age, 23.1 ± 6.9 years) with skeletal Class III facial asymmetry who underwent bimaxillary orthognathic surgery. Using cone-beam computed tomography images taken before and 1 year after surgery, cmAMP with the highest SI value between the two anterior segments of the hemi-mandible was set by a computer algorithm. Results show that the SI using cmAMP had the highest value (0.83 ± 0.04) before surgery compared to the other midsagittal planes, and was not significantly different from the SI (0.80 ± 0.05) using a facial midsagittal plane (MSP) after surgery. The distance (1.15 ± 0.74 mm) and angle (2.02 ± 0.82°) between MSP and cmAMP after surgery were significantly smaller than those between MSP and other midsagittal planes. In conclusion, the cmAMP plane best matches the two anterior segments of hemi-mandible symmetrically and is the closest to MSP after orthognathic surgery in skeletal Class III patients with facial asymmetry.

The three-dimensional evaluation of positional change in mandibular condyle after intraoral vertical ramus osteotomy

OBJECTIVES

The purpose of this study was to compare the changes of the condylar axis, the anteroposterior condylar position relative to the glenoid fossa, after intraoral vertical ramus osteotomy (IVRO).

STUDY DESIGN

21 patients diagnosed as skeletal class III malocclusion underwent IVRO and were followed according to the authors' postoperative management regimen. The three-dimensional positions of the condyles were evaluated by cone-beam computerized tomography (CBCT) at pre-op, post-op, and at follow-up. CBCT images were referenced to assess the condylar axis change and the anteroposterior condylar position in the glenoid fossa. A repeated-measures analysis of variance (P<0.05) also was performed.

RESULTS

After surgery, both the axial condylar angles and the anteroposterior condylar position were significantly different (P<0.05). The coronal condylar axis rotated outwardly. The anteroposterior condylar position in the glenoid fossa had moved from the concentric to the anterior position. But the condyle changes between post-op and follow-up (P>0.05) were insignificant.

CONCLUSIONS

With postoperative intermaxillary elastic traction, the condyles changed their positions physiologically for newly established jaw movement after IVRO.

Positional changes in the mandibular proximal segment after intraoral vertical ramus osteotomy: Surgery-first approach versus conventional approach

Objective

To compare postoperative positional changes in the mandibular proximal segment between the conventional orthognathic surgery (CS) and the surgery-first approach (SF) using intraoral vertical ramus osteotomy (IVRO) in patients with Class III malocclusion.

Methods

Thirty-eight patients with skeletal Class III malocclusion who underwent bimaxillary surgery were divided into two groups according to the use of preoperative orthodontic treatment CS group (n = 18) and SF group (n = 20). Skeletal changes in both groups were measured using computed tomography before (T0), 2 days after (T1), and 1 year after (T2) the surgery. Three-dimensional (3D) angular changes in the mandibular proximal segment, condylar position, and maxillomandibular landmarks were assessed.

Results

The mean amounts of mandibular setback and maxillary posterior impaction were similar in both groups. At T2, the posterior portion of the mandible moved upward in both groups. In the SF group, the anterior portion of the mandible moved upward by a mean distance of 0.9 ± 1.0 mm, which was statistically significant (p < 0.001). There were significant between-group differences in occlusal changes (p < 0.001) as well as in overjet and overbite. However, there were no significant between-group differences in proximal segment variables.

Conclusions

Despite postoperative occlusal changes, positional changes in the mandibular proximal segment and the position of the condyles were similar between CS and SF, which suggested that SF using IVRO achieved satisfactory postoperative stability. If active physiotherapy is conducted, the proximal segment can be adapted in the physiological position regardless of the occlusal changes.

Changes in the temporomandibular joint position depending on the sagittal osteotomy technique and extent of mandibular movement

The bilateral sagittal split osteotomy (BSSO) and high oblique sagittal split osteotomy (HSSO) are common techniques for mandibular movement in orthognathic surgery. The aim of this study was to evaluate the influence of both techniques, as well as movement distances and directions, on the position of the temporomandibular joint (TMJ). A total of 80 mandibular movements were performed on 20 fresh human cadaver heads, four on each head. Pre- and postoperative cone beam computed tomography was used to plan the surgical procedure and analyse the TMJ. Reference measurements included the anterior, superior, and posterior joint spaces, intercondylar distances and angles in the axial and coronal planes, and the sagittal, coronal, and axial angulations of the proximal segment. Only minor differences were found between the BSSO and HSSO techniques, particularly in terms of the intercondylar angle in the axial plane (P <  0.03) and the condylar angle of the proximal segment in the sagittal plane (P <  0.011). Observed changes in the TMJ were mostly opposite when moving the mandible forwards and backwards and increased with increasing movement distance. BSSO and HSSO result in similar changes in TMJ position. The extent of the movement distance influences the position of the condyle more than the osteotomy technique.

Accuracy of modified CAD/CAM generated wafer for orthognathic surgery

The aim of this study was to investigate an accuracy of modified CAD/CAM generated wafers for orthognathic surgery. A total of 20 patients who had undergone bimaxillary orthognathic surgery were included and divided into two groups: A conventional CAD/CAM generated intermediate wafer and a modified CAD/CAM generated intermediate wafer. A series of CT images were taken to compare the virtual simulations with the actual postoperative outcomes(1 month after surgery). In conventional group, the mean difference of maxillary position between virtual simulation models and postoperative results was 0.78mm and overall average error within 1mm was observed in 66.4% of the repositioned maxilla. In modified group, the mean difference was 0.77mm and overall average error within 1mm was observed in 68.3%. There were no significant statistic differences between two groups in maxillary position. This study suggests that the CAD/CAM generated wafer provides excellent accuracy. The modified CAD/CAM wafer was only comparable to conventional design in accuracy and it cannot guarantee the superior precision. However, the modified design could be beneficial in cases with unstable condylar position or for inexperienced surgeons.

Changes in position of the hyoid bone and volume of the pharyngeal airway after mandibular setback: three-dimensional analysis

Important aspects of orthognathic surgery are the effects of skeletal movement and changes in the position of the hyoid bone, tongue, soft palate, and dimensions of the pharyngeal airway. Our aims were to evaluate the 3-dimensional changes in the pharyngeal airway and in the position of the hyoid bone after mandibular setback in 30 patients who were diagnosed with mandibular prognathism and were treated by intraoral vertical ramus osteotomy (IVRO). Three-dimensional cone-beam computed tomographic (CT) images were obtained preoperatively, one month postoperatively, and one year postoperatively. The total pharyngeal volume decreased between the preoperative state and one month and one year afterwards. The hyoid bone had moved 2.0mm posteriorly and 3.15mm superiorly by one month postoperatively. The position of the hyoid bone was affected by changes in posterior and superior movement of the B point at one month (r=0.44, p=0.015 and R=0.63, p=0.000, respectively) and also by superior movement of the B point at one year (r=0.57, p=-0.001). There was an advantageous relation between posterior positional changes in the B point (mandibular setback), and volumetric changes in the hypopharyngeal and total pharyngeal airway, so maxillofacial surgeons should consider the reduction in airway when planning excessive mandibular setback.

Three-Dimensional Analysis of Transverse Width of Hard Tissue and Soft Tissue After Mandibular Setback Surgery Using Intraoral Vertical Ramus Osteotomy: A Retrospective Study

PURPOSE

Some clinicians are concerned that if an intraoral vertical ramus osteotomy (IVRO) is used to position the mandible posteriorly, the proximal segments should be positioned laterally to the distal segment, which could increase the transverse mandibular width, leading to esthetically unfavorable results. This study investigated short- and long-term postoperative transverse mandibular width changes in the soft and hard tissue after IVRO for mandibular prognathism.

MATERIALS AND METHODS

The study comprised 44 patients who were treated with mandibular setback surgery using an IVRO. They were categorized into either the facial symmetry group or facial asymmetry group based on their preoperative levels of chin top deviation. Three-dimensional cone-beam computed tomography images were obtained at the preoperative, 1-month postoperative, and 12-month postoperative stages, designated as T1, T2, and T3, respectively. We set hard tissue width 1 (HW1) and hard tissue width 2 (HW2) as the sum of the distance at the bilateral ends of the angle and ramus, respectively, and set soft tissue width 1 (SW1) and soft tissue width 2 (SW2) as the sum of the distance at the bilateral ends of the soft tissue angle and ramus, respectively.

RESULTS

Compared with the value at T1, the HW1 value increased by 8.16% (P < .05) and HW2 increased by 4.39% (P > .05) at T2; HW1 increased by 4.35% (P < .05) and HW2 increased by 2.95% (P > .05) at T3. Compared with the value at T1, the SW1 value increased by 2.49% and SW2 increased by 2.50% at T2; however, SW1 decreased by 0.85% and SW2 increased by 0.37% at T3. The soft tissue variations between T1 and T2, as well as between T2 and T3, were statistically significant. However, no significant difference was found between T1 and T3 (P > .05). No difference between the facially symmetrical and asymmetrical groups was found over time for soft and hard tissues (P > .05).

CONCLUSIONS

Notably, IVRO does not seem to impact the transverse facial profile and enables reliable prediction of the esthetic results of surgery.

Safety and Stability of Postponed Maxillomandibular Fixation After Intraoral Vertical Ramus Osteotomy

The purpose of this study was to evaluate the postoperative safety and long-term stability of bimaxillary orthognathic patients with postponed maxillomandibular fixation (MMF) after intraoral vertical ramus osteotomy.A total of 61 patients (21 male and 40 female patients; average age [SD], 21.7 [4.7]) were enrolled. All patients underwent maxillary LeFort I osteotomy and bilateral intraoral vertical ramus osteotomy for mandibular prognathism. During the hospital stay, postoperative airway compromise was observed and patients underwent MMF with wire at the second postoperative day. Stability was evaluated by measuring the position at each period: preoperative (T0), 2-day postoperative (T1), and 1-year postoperative.Postoperative dyspnea and respiratory distress were absent in all patients. The mean number of refixations in physiotherapy was 0.62 (0.86) and the mean duration of physiotherapy was 11.6 (5.5) days. The mean amount of mandibular setback was 12.56 (5.76) mm and menton movement 0.98 (2.36) mm superiorly (T1). The mean mandibular relapse at Pog was 0.87 (1.96) mm anteriorly. Menton showed 1.11 (1.41) mm superiorly movement 1-year postoperatively (T2).Despite its many advantages, intraoral vertical ramus osteotomy requires a period of MMF which can lead to early discomfort and airway-related emergency. In this study, the physiotherapy procedure and postoperative long-term stability in the postponed MMF group were not different from those of an immediate MMF group studied previously. It therefore constitutes a viable option for oral breathers and other compromised patients.

Three-dimensional changes of proximal segments in facial asymmetry patients after bilateral vertical ramus osteotomy

The intraoral vertical ramus osteotomy (IVRO) is a useful technique for mandibular setback surgery. However, there is a tendency for lateral flaring of the proximal segments on the non-deviation side after the correction of mandibular asymmetry with this technique. The purpose of this retrospective study was to evaluate the positional changes of the proximal segments after IVRO setback in skeletal class III patients with asymmetry, using preoperative and postoperative computed tomography scan data, and to apply the results in clinical practice. A total of 28 skeletal class III patients with asymmetry who underwent bimaxillary orthognathic surgery were included. A three-dimensional cone beam computed tomography scan was obtained preoperative, at 1month postoperative, and at 1year postoperative. At 1month after the surgery, the proximal segments showed an outward rotation, lateral flaring, and anterior rotation of the condylar head. All postsurgical directional changes had returned to the preoperative state at 1year postoperative, and there was no statistically significant difference in postoperative angulation changes between the two sides. The results showed no statistical differences in the positional changes of the proximal segments between the deviation and non-deviation sides. This study reaffirms the benefits of the IVRO for a minimal bony interference between the proximal and distal segments in three dimensions, including mandibular asymmetry cases.

Immunohistochemical Analysis on Cortex-to-Cortex Healing After Mandibular Vertical Ramus Osteotomy: A Preliminary Study

PURPOSE

The present study analyzed the expression of specific cytokines in the transforming growth factor (TGF)-β superfamily postoperatively after mandibular vertical ramus osteotomy (VRO).

MATERIALS AND METHODS

Four beagle dogs were enrolled and euthanized at 1, 2, 4, and 8 weeks postoperatively for immunohistochemical analysis using 6 specific antibodies (bone morphogenetic protein [BMP]-2/4, BMP-7, TGF-β2, TGF-β3, matrix metalloproteinase-3, and vascular endothelial growth factor [VEGF]). The results from the surgical site and control (adjacent area) were compared.

RESULTS

Generalized upregulation of BMP-2/4 was observed in all healing periods, and the strongest expression of BMP-7 was observed at 1 week postoperatively. The strongest expression of TGF-β2 was observed at 8 weeks with increasing pattern. The strong expression of TGF-β3 was observed at 1 and 4 weeks, with the strongest expression of VEGF at 1 week, with a decreasing pattern. No notable uptake was detected with the 6 specific antibodies in the adjacent bone (control).

CONCLUSIONS

The absence of internal fixation after VRO led to dynamic healing with a specific expression pattern of BMP-7 and TGF-β2. The anatomic factors, including sufficient preexisting vascularity, led to the earlier expression pattern of VEGF.

Complications associated with orthognathic surgery

While most patients undergo orthognathic surgery for aesthetic purposes, aesthetic improvements are most often followed by postoperative functional complications. Therefore, patients must carefully decide whether their purpose of undergoing orthognathic surgery lies on the aesthetic side or the functional side. There is a wide variety of complications associated with orthognathic surgery. There should be a clear distinction between malpractice and complications. Complications can be resolved without any serious problems if the cause is detected early and adequate treatment provided. Oral and maxillofacial surgeons must have a full understanding of the types, causes, and treatment of complications, and should deliver this information to patients who develop these complications.

Is There a Difference in Stability After Intraoral Vertical Ramus Osteotomy Between Vertically High-Angle and Normal-Angle Patients?

PURPOSE

Few studies have evaluated the relapse pattern of intraoral vertical ramus osteotomy (IVRO) for the correction of mandibular prognathism with a high angle. The aim of this study was to measure the association between vertical facial types (high and normal mandibular plane angle) and relapse after IVRO for the management of mandibular prognathism.

MATERIALS AND METHODS

The retrospective cohort study sample (skeletal Class III patients) was divided into 2 groups according to the angle of the sella-nasion plane relative to the mandibular plane (SN-MP) at the initial examination. Lateral cephalograms were analyzed for the predictor (facial type) and outcome (cephalometric changes over time) variables before surgery, 7 days after surgery, and 12 months after surgery. The 2 groups were matched for sample size (n = 20 in each). Data were analyzed using repeated-measures analysis of variance with Bonferroni correction.

RESULTS

The normal-angle group (group N, SN-MP from 27° to 37°) and high-angle group (group H, SN-MP >37°) were not significantly different in terms of gender and age at the initial examination. Seven days after surgery, the mandibles in group H moved 2.5 mm more superiorly than those in group N (P = .013); consequently, the amount of overbite correction in group H was approximately 2 mm greater than that in group N (P = .002). Nevertheless, 12 months after surgery, there was no statistically significant difference in relapse of the maxilla and mandible between the 2 groups. In the 2 groups, the mandible moved approximately 0.7 mm superiorly during retention.

CONCLUSIONS

These findings suggest that IVRO is a clinically acceptable and stable treatment modality for mandibular prognathism with a high angle.

Intermaxillary Fixation Screw Morbidity in Treatment of Mandibular Fractures-A Retrospective Study

PURPOSE

The aim of the present retrospective study was to investigate the morbidity of screws used for intermaxillary fixation (IMF) in the treatment of mandibular fractures. A review of the published data was also performed for a comparison of outcomes. Our hypothesis was that the use of screws for IMF of mandibular fractures would result in minimal morbidity.

MATERIALS AND METHODS

Patients treated for mandibular fractures from 2007 to 2013, using screws for IMF, using the international diagnosis code for mandibular fracture, DS026, were anonymously selected (Department of Oral and Maxillofacial Surgery, Rigshospitalet, University Hospital of Copenhagen, Copenhagen, Denmark). The fracture type, radiographic findings, treatment modality, screw type and number, and root damage were recorded. For the outcome comparison, a review of the published data regarding iatrogenic dental root damage caused by screw fixation was performed in May 2015.

RESULTS

A total of 156 patients had undergone IMF with screws. The total number of screws was 793. The incidence of root lesions was 0.25% centrally and 0.88% peripherally. The incidence of screw loss was 0.13% and that of screw loosening was 1.89%. In the review, 737 related reports were identified in a search of PubMed and the Cochrane Library. Of these, 25 were considered suitable for inclusion. A lack of valid evidence resulted in a descriptive analysis, because a meta-analysis of the data was not possible.

CONCLUSIONS

The results of the present retrospective study have shown that the use of screws is a valid choice for IMF in mandibular fracture treatment with minimal morbidity. The 793 screws used for IMF resulted in a negligible amount of central and peripheral tooth root trauma.

Major factors contributing to anterior and posterior relapse after intraoral vertical ramus osteotomy

The aim of this retrospective cohort study was to investigate the factors contributing to mandibular relapse after intraoral vertical ramus osteotomy (IVRO) while controlling for possible confounders. Forty-seven patients who underwent bimaxillary surgery were divided into three groups according to the direction of horizontal mandibular relapse: a stable group (group S), a posterior relapse group (group P), and an anterior relapse group (group A). Lateral cephalograms were analysed 1 month before and at 7 days and 12 months after surgery. One month before surgery, the pogonion in group A was positioned about 13 mm more anteriorly than in group P (P < 0.05). Immediately after surgery, the mandibles in groups A and S had moved about 6 mm more posteriorly than in group P. At 12 months, both the mandibles (point B) and the maxillae (point A) had moved posteriorly in group P (P < 0.05). A multivariate linear regression analysis showed that the amount of setback was the one key factor predicting postoperative mandibular changes 12 months after IVRO. As the amount of setback decreased, mandibular posterior horizontal relapse increased after IVRO. These findings suggest that the amount of setback can be a key factor predicting postoperative mandibular relapse.

Stability of Pre-Orthodontic Orthognathic Surgery Using Intraoral Vertical Ramus Osteotomy Versus Conventional Treatment

PURPOSE

Postoperative skeletal and dental changes were evaluated in patients with mandibular prognathism who underwent mandibular setback surgery using an intraoral vertical ramus osteotomy (IVRO) with and without presurgical orthodontic treatment.

MATERIAL AND METHODS

This retrospective cohort study included consecutive patients with skeletal Class III malocclusions who underwent IVRO. Patients treated with pre-orthodontic orthognathic surgery (POGS) were compared with patients treated with conventional surgery (CS) with presurgical orthodontics (control) using lateral cephalograms (taken preoperatively, 7 days postoperatively, and 12 months postoperatively). Predictor (group and timing), outcome (cephalometric measurements over time), and other (ie, baseline characteristics) variables were evaluated to determine the differences in postoperative horizontal and vertical positional changes of the mandible, such as point B. Baseline demographics were similar between the groups (N = 37; CS group, n = 17; POGS group, n = 20). The data were analyzed with an independent t test, the Mann-Whitney U test, the Fisher exact t test, Pearson correlation analysis, and simple linear regression analysis.

RESULTS

The mean setback of the mandible at point B was similar, but the mandible of the POGS group, particularly the distal segment, moved superiorly during the postoperative period in conjunction with the removal of premature occlusal contacts (P < .001). In the CS group, the mandible had significantly more backward movement 12 months after surgery compared with the POGS group (P < .01). In the POGS group, horizontal and vertical postsurgical changes were linearly correlated with the amount of setback and vertical movement of the mandible.

CONCLUSIONS

Mandibular setback surgery using IVRO without presurgical orthodontics leads to considerably different postoperative skeletal and dental changes compared with conventional treatment, with more superior movement being observed at point B during the 1-year postoperative period.

Orthognathic surgery and temporomandibular joint symptoms

The aim of this article is to review temporomandibular joint symptoms as well as the effects of orthognathic surgery(OGS) on temporomandibular joint(TMJ). The causes of temporomandibular joint disease(TMD) are multifactorial, and the symptoms of TMD manifest as a limited range of motion of mandible, pain in masticatory muscles and TMJ, Joint noise (clicking, popping, or crepitus), myofascial pain, and other functional limitations. Treatment must be started based on the proper diagnosis, and almost symptoms could be subsided by reversible options. Minimally invasive options and open arthroplasty are also available following reversible treatment when indicated.

TMD manifesting in a variety of symptoms, also can apply abnormal stress to mandibular condyles and affect its growth pattern of mandible. Thus, adaptive developmental changes on mandibular condyles and post-developmental degenerative changes of mandibular condyles can create alteration on facial skeleton and occlusion. The changes of facial skeleton in DFD patients following OGS have an impact on TMJ, masticatory musculature, and surrounding soft tissues, and the changes of TMJ symptoms. Maxillofacial surgeons must remind that any surgical procedures involving mandibular osteotomy can directly affect TMJ symptoms, thus pre-existing TMJ symptoms and diagnoses should be considered prior to treatment planning and OGS.