Site and severity of facial asymmetry after bimaxillary surgery for class III deformity: a case-control study.

OBJECTIVES: The study aimed (1) to evaluate the site and severity of facial asymmetry in Class III patients before and after bimaxillary surgery, and (2) to identify the influence of initial severity and positional jaw asymmetry on residual facial asymmetry. MATERIALS AND METHODS: Preoperative and postoperative cone-beam computed tomography of 65 patients with Class III facial asymmetry who underwent bimaxillary surgery were evaluated. Five midline and 14 paramedian facial soft tissue landmarks were identified to assess facial asymmetry. The outcomes were compared to a control group consisting of 30 age- and gender-matched Class I subjects. The postoperative positional jaw asymmetry (i.e., shift, roll, yaw) of each osteotomy segment (maxilla, mandible, chin, ramus) was also measured. RESULTS: Before surgery, the asymmetry was more severe at the chin, middle and lower contour. Bimaxillary surgery effectively corrected facial asymmetry, particularly in achieving normalization of chin deviation. However, significant asymmetry persisted postoperatively in the middle and lower contour (p < 0.001 and p < 0.01, respectively), which was affected by the positional ramus asymmetry in the roll and shift. CONCLUSIONS: Deviation of the chin, middle and lower contour contributed significantly to overall facial asymmetry in Class III asymmetry. Despite normalization of the chin deviation after bimaxillary surgery, asymmetry persisted at the middle and lower contour, primarily as the result of insufficient correction of the positional ramus asymmetry. CLINICAL RELEVANCE: Understanding the residual asymmetry after bimaxillary surgery is important for minimizing deviation and optimizing the surgical planning for its correction.

[Growth disturbances of the temporomandibular joint: causes, diagnosis and treatment]. / Groeistoornissen van het kaakgewricht: oorzaken, diagnose en behandeling.

Growth disturbances of the temporomandibular Joint are characterized by mandibular asymmetry, sometimes with secondary maxillar disturbances. Although the clinical symptoms are sometimes quite severe, patients usually have no pain. There are several growth disturbances, but in this article we discuss three particular causes of facial asymmetry, namely hemimandibular growth defects; overdevelopment, underdevelopment and neoplasms of the mandibular joint. Hemimandibular overdevelopment (hyperplasia) is a growth disorder characterized by progressive asymmetry of the mandibula. Hemimandibular hypoplasia, on the other hand, is a growth disorder involving underdevelopment of the condyle mandibulae due to impingement of the growth center and ankylosing. A pronounced asymmetrical face can cause aesthetic problems and always requires diagnostics, because in addition to the hyperplasia and hypoplasia mentioned above, other causes can explain the asymmetry such as, for example, an osteoarthritis or even a tumor emanating from the base of the skull, mandibula or soft tissues.

Facial Asymmetry Caused by Mandibular Condylar Hyperplasia: A Two Center Study.

BACKGROUND: Condylar hyperplasia is a non-neoplastic overgrowth of the mandibular condyle. The disorder is progressive and causes gradual jaw deviation, facial asymmetry, and dental malocclusion. The only treatment capable of stopping hyperplastic growth is surgical condylectomy to remove the upper portion of the condyle containing the deranged growth center. When this procedure is conducted in proportion to the length of the healthy side it may also correct the jaw deviation and facial asymmetry. OBJECTIVES: To assess the degree to which condylectomy corrects the asymmetry and to determine the proportion of patients after condylectomy who were satisfied with the esthetic result and did not desire further corrective surgery. METHODS: We conducted a retrospective analysis of medical records of patients who underwent condylectomy that was not followed by corrective orthognathic surgery for at least 1 year to determine the degree of correction of chin deviation and lip cant. Patient satisfaction from treatment or desire and undergo further corrective surgery was reported. RESULTS: Chin deviation decreased after condylectomy from a mean of 4.8° to a mean of 1.8° (P < 0.001). Lip cant decreased after condylectomy from a mean of 3.5° to a mean of 1.5° (P < 0.001). Most patients (72%) were satisfied with the results and did not consider further corrective orthognathic surgery. CONCLUSIONS: Proportional condylectomy could be a viable treatment to both arrest the condylar overgrowth and achieve some correction of the facial asymmetry.

The Asymmetry Within: A Renewed Look at Cupids Bow in Unilateral Cleft Lip.

The purpose of this study is to analyze the angular variations within Cupid's bow in patients with unoperated unilateral cleft lip (UCL). Angular features of Cupid's bow were quantified in standardized presurgical photographs of children with UCL by 5 medical professionals specializing in craniofacial anomalies. The peaks and valley of Cupid's bow were identified. A cleft side (CSA) and a noncleft side angle (NCSA) were delineated and measured by each expert. The data was pooled, and the angles were analyzed for symmetry. Cupid's bow asymmetry was defined as a difference between NCSA and CSA ≥3°. Of the 37 patients studied, 29 were found to have asymmetry of Cupid's bow with an average angle difference of 8.0° (95% CI: 6.6°-9.5°). Within this group,15 patients were found with acute asymmetry and 14 with obtuse asymmetry. Geometric analysis was performed on an example of a patient with acute asymmetry to demonstrate how correction of asymmetry can be considered during surgical repair. There is an asymmetry that exists in the Cupid's bow of a significant number of patients with unoperated UCL. This finding not only adds to our understanding of UCL but may also have important implications when selecting the method/technique of surgical repair.

Assessment of Masseter Volume and Postoperative Stability After Orthognathic Surgery in Patients With Skeletal Class III Malocclusion With Facial Asymmetry.

OBJECTIVE: This study aimed to evaluate the effect of orthognathic surgery on masseter volume in patients with skeletal Class III malocclusion with facial asymmetry and the effect of masseter volume on stability in orthognathic surgery. METHODS: This research studied 16 patients with Class III malocclusion with facial asymmetry who received combined orthodontic-orthognathic treatment and underwent craniofacial computed tomography (CT) before (T0), 2 weeks after (T1), and 6 months after (T2) surgery. Three-dimensional (3D) CT images were retrospectively analyzed, using 3D volume reconstruction to obtain the masseter volume and examine the impact of the masseter volume on stability in orthognathic surgery. RESULTS: A statistically significant difference ( P < 0.05) in the volume of the masseter was found up to 6 months after orthognathic surgery compared with the preoperative period, and the reduction in the masticatory muscle volume on the lengthened side is greater than on the shortened side ( P < 0.05). The volume of both masseters differed according to facial asymmetry, and the difference was significantly reduced after orthognathic surgery ( P < 0.05). During the period time (T1-T2), cephalometric maxillary marker points were not significantly different ( P > 0.05), and mandibular marker points were significantly anteriorly shifted ( P < 0.05). There was an association between the masseter volume and anterior shift of point B (R > 0.5, P < 0.05), the upward and anterior shifts of the gonion point differed between the lengthened and shortened sides ( P < 0.05). CONCLUSION: The size of the masseter becomes smaller 6 months after orthognathic surgery, and orthognathic surgery improves both bone and soft tissue symmetry. A larger sagittal relapse of mandibular setback occurred in patients with greater masseter volume. Considering these alterations may be helpful in planning orthognathic surgery.

Establishment of the mid-sagittal reference plane for three-dimensional assessment of facial asymmetry: a systematic review : Establishment of the mid-sagittal reference plane: a systematic review.

OBJECTIVE: To systematically review the literature for mid-sagittal plane establishment approaches to identify the most effective method for constructing the mid-sagittal plane for the evaluation of facial asymmetry. MATERIALS AND METHODS: Six electronic databases (PubMed, Medline (via Ovid), EMBASE (via Ovid), Cochrane Library, Web of Science, and Scopus) and grey literature were searched for the studies that computed the mid-sagittal reference plane three-dimensionally, using a combination of MeSH terms and keywords. The methodological quality and the level of evidence for the included studies were analyzed using QUADAS-2 and GRADE, respectively. RESULTS: The preliminary search yielded 6746 records, of which 42 articles that met the predefined inclusion criteria were included in the final analysis. All the included articles reported the construction of the mid-sagittal reference plane (MSP) using varied methods. The risk of bias and concerns regarding the applicability of the included studies were judged to be 'low'. The level of evidence was determined to be 'low' for the effectiveness of the technique and 'moderate' for the ease of clinical applicability. CONCLUSION: Despite methodological heterogeneity, this review substantiates the comparable efficacy of cephalometric and morphometric MSP construction methods. A fully automated morphometric MSP holds promise as a viable option for routine clinical use. Nevertheless, future prospective studies with an emphasis on the impact, accuracy, and clinical applicability of MSP construction techniques in cases of facial asymmetry are required. CLINICAL RELEVANCE: The present review will assist clinicians in selecting the most suitable method for MSP construction, leading to improved treatment planning and ultimately more favorable treatment outcomes.

The Evaluation of Condylar Position Change in the Asymmetric Mandible Following Sagittal Split Osteotomy.

BACKGROUND: The change of condyle position following orthognathic surgery affects the stability of treatments. This study aims to assess the correlation between the amount of condyles' position change and the severity of mandibular asymmetry following BSSO. MATERIALS AND METHODS: This is a cross-sectional study. Subjects with asymmetric mandibular prognathism following BSSO were studied. Subjects were classified into 2 groups: group 1, subjects had mandibular asymmetry without occlusal cant and underwent BSSO. Group 2, subjects had mandibular asymmetry with occlusal cant and underwent BSSO+ Lefort I osteotomy. The condyle position was evaluated using cone-beam computer tomography (CBCT). Pearson's correlation test was used to assess any correlation between the condyle changes and the change in the mandible in sagittal and anterior-posterior directions. RESULTS: A total of 44 subjects were studied. In group 1, the condyle tilted outward in the deviated condyle and inward in the non-deviated condyle immediately after osteotomy. After 12 months, both condyles showed a rotation relative to the original position. In group 2, the condyles of the deviated sides and non-deviated sides moved inferiorly after surgery (condylar sagging), which was more significant in the non-deviated sides. The condyle rotation was similar to group 1. The severity of asymmetry and occlusal cant correlate with the condylar position change in the two groups. CONCLUSION: The severity of mandibular asymmetry correlates with the amount of condyles' position change immediately after BSSO. However, the condyles tend to return to their original position 12 months later.

Symmetry recovery in zygomaticomaxillary complex fractures compared to normal unfractured population: A new reliable 3D evaluation.

OBJECTIVE: This study aims to quantify the facial symmetry of surgically treated zygomaticomaxillary complex (ZMC) fractures through a new reliable three-dimensional evaluation method, which is crucial for improving post-operative aesthetic and functional outcomes. MATERIAL AND METHODS: Healthy patients and patients with surgically treated ZMC fractures were retrospectively reviewed. Using Brainlab Elements® the zygomatic bone and the orbit of each patient was segmented and mirrored. Subsequently, the mirrored side was matched with the other side via volume-based registration, using the segmented orbit as reference. Volumetric asymmetry was measured using 3-matic software, and a surface-based matching technique was used to calculate the mean absolute differences (MAD) between the surfaces of the two sides of the ZMC. The reliability of this novel method using volume-based registration was tested, and the intra-class correlation coefficient was assessed. RESULTS: The MAD between the surfaces of the left and right sides in the control group was 0.51 mm (±0.09). As for the ZMC fracture group, MAD was 0.78 mm (±0.20) and 0.72 mm (±0.15) pre- and post-operatively, respectively. The MAD showed statistically significant differences between pre- and post-operative groups (p = 0.005) and between control and post-operative groups (p < 0.001). The intra-class correlation coefficient was high (≥0.99). CONCLUSIONS: This evaluation method using mirroring and volume-based registration to determine the symmetrical position of the ZMC is reliable. The surface-based measurements revealed an improved symmetry after surgery. However, the symmetry of the treated patients remained lower than the control group.

Changes in masseter muscle morphology after surgical-orthodontic treatment in patients with skeletal Class III malocclusion with mandibular asymmetry: The automatic masseter muscle segmentation model.

INTRODUCTION: This study evaluated the masseter muscle changes after surgical-orthodontic treatment in patients with a skeletal Class III malocclusion using automatic segmentation. METHODS: Images of 120 patients with skeletal Class III malocclusion were obtained and reconstructed at T0 (pretreatment), T1 (presurgery), and T2 (6-12-month postsurgery). The patients were divided into symmetrical and asymmetrical groups. The volume, major axis length, maximum cross-sectional area, horizontal cross-sectional area 5 mm above the mandibular foramen (CSAF), and orientation were calculated automatically. RESULTS: In the asymmetrical group, the volume and major axis length on the deviated side were lower than on the nondeviated side at T0, T1, and T2 (P <0.05). There were no significant differences in maximum cross-sectional area and CSAF bilaterally. The orientation was coronally more vertical and sagittally more forward on the deviated side (both P <0.001). In the symmetrical group, there were no significant bilateral differences at T0, T1, and T2. The volume, major axis length, and CSAF decreased, and the coronal orientation was more vertical on the nondeviated side at T2 than at T0 in both groups (P <0.05). The coronal plane orientation was more inclined on the deviated side at T2 than at T0 in the asymmetrical group (P <0.05). CONCLUSIONS: The smaller volume on the deviated side at T2 indicates the need for myofunctional training after surgery. The masseter muscle volume and the cross-sectional area did not recover to the preorthodontic levels. Studies with longer follow-up durations are needed to confirm these findings.

Mandibular condyle volumes are associated with facial asymmetry in patients with cleft lip and palate: A retrospective cohort study.

This study compares condylar volumetric asymmetry and facial asymmetry in patients with cleft lip and/or palate (CLP) and controls. The mandibular condyle is important to facial growth, but its role in facial asymmetry for those with CLP has not been described. Condylar volumes and mandibular asymmetry were retrospectively calculated using Mimics Version 23.0 (Materialise, Leuven, Belgium) from patients with CLP undergoing computed tomography (CT) imaging and a cohort of controls. A total of 101 participants, 60 with CLP and 41 controls, had mean condylar volumetric asymmetry of 16.4 ± 17.4 % (CLP) and 6.0 ± 4.0 % (controls) (p = 0.0002). Patients with CLP who had clinically significant chin deviation (>4 mm) had more asymmetric condyles than those without significant chin deviation (p = 0.003). The chin deviated toward the smaller condyle in patients with facial asymmetry more often than in patients without facial asymmetry (81 % vs. 62 %, p = 0.033). While controls had some degree of condylar asymmetry, it tended to be milder and not associated with facial asymmetry. There is a greater degree of condylar volumetric asymmetry in patients with CLP compared to individuals in the general population. Clinically significant facial asymmetry in CLP is associated with a higher degree of condylar asymmetry, with the facial midline deviating toward the smaller condyle.

Mandibular Distraction Osteogenesis in Children and Adolescents: A Clinical and Radiographic Research Using Cone-Beam Computed Tomography.

AIM: The aim of this cross-sectional study was to evaluate, via cone-beam computed tomography, the long-term postoperative outcome in children treated with mandibular distraction osteogenesis. MATERIALS AND METHODS: All young patients treated with mandibular distraction osteogenesis (MDO), during a 16-year period, at the University Department of Oral and Maxillofacial Surgery of a Pediatric Hospital, were recalled, and various clinical and radiographic parameters were recorded. RESULTS: Eleven patients were included: 5 with hemifacial microsomia (HFM) and 6 with mandibular micrognathia. In all cases, MDO had been successful in regular follow-up and decannulation, soon after MDO, was achieved in all tracheostomy cases. The long-term result in cases of HFM was found stable, functionally and esthetically accepted, although less satisfactory than in regular follow-up; in micrognathia patients, relapse of different degrees was registered in 4 of 6 cases, without any need for tracheostomy though. Detailed and accurate information was obtained by cone-beam computed tomography (CBCT). The shape of the regenerated bone was irregular in HFM cases and relatively normal in the micrognathia cases. Quality of the regenerated bone was normal in all patients. The irregular shape registered in HFM cases did not compromise a safe orthognathic operation. CONCLUSIONS: Distraction osteogenesis remains an early treatment choice in cases of mandibular deformities. Long-term findings showed that there is a degree of relapse with growth, which was more obvious in mandibular micrognathia cases. Computed tomography contributes to detailed evaluation of changes at the distraction site.

Children's Visual Perception of Facial Scarring and Cleft Lip Deformity Using Eye Tracking Data.

OBJECTIVE: The purpose of this study is to determine children's perception of secondary cleft lip deformity (SCLD) using objective eye tracking technology and subjective responses on a survey to understand pediatric perceptions of facial scarring. DESIGN: Cross-sectional study of participants aged 5-17 years old. METHODS: Participants viewed images of children's faces with an eye tracking device. Sixteen images were displayed, 12 with unilateral SCLD and four with no facial scarring. Eye tracking data were obtained. Gaze samples were analyzed for areas of interest (AOIs). Immediately after viewing each image, participants answered two survey questions relating to facial asymmetry attitude toward the child pictured. For analysis, participants were divided into age groups. RESULTS: A total of 259 participants were enrolled (42.5% female). Mean age was 10.5 years and 78% identified as White. In all age groups, total fixation time was greater for SCLD compared to control images. Early elementary age children spent significantly less time assessing the nose AOI compared to other groups, and also spent the least total fixation time and had the lowest visit count on all AOIs. Subjective survey questions showed similar trends with elementary age not noticing facial asymmetry compared to older age groups. CONCLUSION: This study demonstrates the successful use of eye tracking technology in children as young as 5 years old. This study suggests that SCLD is perceived as less noticeable in elementary age children and becomes more noticeable to older groups. Understanding peer perception on SCLD from this study may impact decision on revision surgery for SCLD. LEVEL OF EVIDENCE: IV Laryngoscope, 134:2726-2733, 2024.

A proposed protocol for correlation between bone density in hemimandibular hyperplasia radiography and histopathological findings - A retrospective study.

The role of low-dose computed tomography (LDCT) in surgical planning can be assessed based on the correlation among bone density (BD/HU), radiographic values, and the histopathological appearance of hyperplastic overgrowth in mandibular condyles (hemimandibular hyperplasia/osteochondroma). The aim of this study was to evaluate the correlation between LDCT indices of bone-density measurements in surgical planning and histopathological specimens. The patients incuded in this study underwent detailed radiological evaluation as preparation for further clinical procedures. Excised condyles were evaluated in terms of bone density index using LDCT, and then histopathologically to investigate the accuracy of surgical procedures and set the basis for future surgical planning. An index value between both condyles' bone densities represented the relative difference between the healthy condyle and the side with hemimandibular hyperplasia (HH). Patients with unilateral condylar hyperplasia (UCH) showed a statistical correlation between condyle heads with increased bone density (BD) and scintigraphic (SCI) values (p < 0.001). On the other hand, correlation between BD and histopathological studies alone was significant (p < 0.001). With the increase in BD measured in HU in UCH condyles, the overall value of fibrous cartilage layer thickness decreased (p < 0.001). Furthermore, histopathological evaluation indicated that increased bone density on the UCH side resulted in increased total thickness (p > 0.001). The proposed index measurements in the mandibular condyles based on LDCT/BD can be used to estimate the degree of required surgical resection. Results from LDCT radiographic studies correlate with histopathological specimens more than scintigraphy.

Esthetic Surgery of the Chin in Cis- and Transgender Patients-Application of T-Genioplasty vs. Single-Piece Segment Lateralization.

Background and Objectives: Correction of lower face asymmetry still remains challenging in maxillofacial surgery. This report describes techniques for the lateral transposition of the symphyseal segment to restore lower face symmetry while maintaining gender-related features in cis- and transgender patients. Materials and Methods: A retrospective review of medical records of 31 patients who attended for esthetic corrective surgery after orthodontic camouflage or orthognathic treatment, or during facial feminization of the lower face between June 2021 and June 2023 was performed. Result: All patients underwent lateralization genioplasty (with or without advancement or setback), either with or without narrowing T-osteotomy supplemented with necessary procedures in order to obtain proper facial balance and desired esthetical effects, such as bichectomy, liposuction, and face and neck lift. The mean asymmetry of the chin was 5.15 mm and was surgically corrected either by single segment lateralization or T-shape narrowing genioplasty depending on the gender and esthetical requirements. No complications were reported. Conclusions: Lateral shift genioplasty serves as a powerful tool in primary and secondary corrective surgery for lower face asymmetry that maintains gender-specific facial features. It may serve either as an additive to orthodontic camouflage or a way to correct previous orthognathic surgery pitfalls. The surgeon performing esthetic genioplasty associated with gender-specific expectations must be trained in facelift and facial liposculpting techniques in order to provide the best results and properly choose the right procedures for the right patients.

Three-dimensional Analysis of the Temporal Bone Morphology in Patients with Craniofacial Microsomia.

OBJECTIVE: To characterise the morphology of temporal bone in patients with craniofacial microsomia (CFM). DESIGN: A retrospective study. SETTING: A craniofacial centre. PATIENTS: Ninety-four patients with unilateral craniofacial microsomia. INTERVENTIONS: Mimics 21.0 (Materialise Inc., Belgium) was used to locate temporal bone landmarks on preoperative computed tomography data. The spatial Cartesian coordinate system was established in 3-matic 13.0 (Materialise Inc., Belgium). The coordinates of each landmark and the distances and angles between the landmarks were calculated. A classification system was used to quantify the severity of the zygomatic arch deformity. MAIN OUTCOME MEASURE(S): The bilateral differences in coordinates, linear and angular measurements, and the severity of temporal bone deformity (TTL δ, Psag δ, Paxiδ, and Tsag δ) among the groups were compared using the paired t-test and Kruskal-Wallis test, respectively. RESULTS: Compared to those of the unaffected side, the landmarks of the inner ear and petrous part on the affected side showed a decrease in the Z-coordinate or an increase in the X-coordinate. A superolateral rotation tendency of the temporal bone on the affected side was found. There were no significant differences in the linear and angular measurements between the groups. The degree of zygomatic arch deformation was lower in the mild group; however, no significant difference was found between the moderate and severe groups. CONCLUSIONS: In patients with CFM, asymmetry of the temporal bone and its inner organs (vestibulocochlear organ, facial nerve, and vessels) exists in multiple dimensions; its severity is not completely consistent with the degree of mandibular involvement.

Deep Learning-based Assessment of Facial Asymmetry Using U-Net Deep Convolutional Neural Network Algorithm.

OBJECTIVES: This study aimed to evaluate the diagnostic performance of a deep convolutional neural network (DCNN)-based computer-assisted diagnosis (CAD) system to detect facial asymmetry on posteroanterior (PA) cephalograms and compare the results of the DCNN with those made by the orthodontist. MATERIALS AND METHODS: PA cephalograms of 1020 patients with orthodontics were used to train the DCNN-based CAD systems for autoassessment of facial asymmetry, the degree of menton deviation, and the coordinates of its regarding landmarks. Twenty-five PA cephalograms were used to test the performance of the DCNN in analyzing facial asymmetry. The diagnostic performance of the DCNN-based CAD system was assessed using independent t -tests and Bland-Altman plots. RESULTS: Comparison between the DCNN-based CAD system and conventional analysis confirmed no significant differences. Bland-Altman plots showed good agreement for all the measurements. CONCLUSIONS: The DCNN-based CAD system might offer a clinically acceptable diagnostic evaluation of facial asymmetry on PA cephalograms.

Helical distraction is superior to linear and circular distraction in mandibular distraction osteogenesis: an in silico study.

Helical mandibular distraction is theoretically better than linear or circular distraction. However, it is not known whether this more complex treatment will result in unquestionably better outcomes. Therefore, the best attainable outcomes of mandibular distraction osteogenesis were evaluated in silico, given the constraints of linear, circular, and helical motion. This cross-sectional kinematic study included 30 patients with mandibular hypoplasia who had been treated with distraction, or to whom this treatment had been recommended. Demographic information and the computed tomography (CT) scans showing the baseline deformity were collected. The CT scans of each patient were segmented and three-dimensional models of the face created. Then, the ideal distraction outcomes were simulated. Next, the most favorable helical, circular, and linear distraction movements were calculated. Finally, errors were measured: misalignment of key mandibular landmarks, misalignment of the occlusion, and changes in intercondylar distance. Helical distraction produced trivial errors. In contrast, circular and linear distractions resulted in errors that were statistically and clinically significant. Helical distraction also preserved the planned intercondylar distance, while circular and linear distractions led to unwanted changes in the intercondylar distance. It is now evident that helical distraction offers a new strategy to improve the outcomes of mandibular distraction osteogenesis.

Intraoral volume changes in relation to the hard tissue shape changes in asymmetric patients before and after orthognathic surgery - A retrospective CT study.

OBJECTIVES: To evaluate Intraoral volume changes in relation to the hard tissue shape changes in asymmetric patients before and after orthognathic surgery and establish a correlation between them. MATERIALS AND METHODS: A retrospective study which evaluated 12 asymmetric patients' pre and post-surgical CT records satisfying the inclusion criteria. Borders were defined for the measurement of extraoral, intraoral and tongue volume. The volume assessment was carried out using software from 3D SYSTEMS, Colorado, US, Version 1.0.2.2055. RESULTS: Predicting changes in volume between extra-oral, intra-oral spaces and tongue, Linear regression modeling of the data revealed that for every mm3 change in post-surgical extra-oral volume the post-surgical intra-oral volume decreased by 0.684 mm3 and for every mm3 change in post-surgical intra-oral volume, the post-surgical tongue volume increased by 0.728 mm3. CONCLUSIONS: Significant decrease in the extra-oral volume, Intra-oral volume and tongue volume was evident after orthognathic surgery in patients with facial asymmetry. This volumetric approach sheds insight into achieving a muscular equilibrium between intraoral and extraoral structures, which would improve orofacial function and enhance facial aesthetics.