Prognathism Research Articles

Effect of transcutaneous electrical nerve stimulation on maximum mouth opening after orthognathic surgery: a randomised controlled trial

Background: The present study aims to determine the effect of transcutaneous electrical nerve stimulation (TENS) on maximum mouth opening (MMO) after orthognathic surgery. Materials and methods: This study is a randomised clinical trial. The samples of this study were class III patients who are candidates for Le Fort I osteotomy surgery for maxillary advancement and bilateral sagittal split osteotomy (BSSO) for mandibular setback surgery due to the lack of maxilla growth and mandibular prognathism using the Dalpont method. On the day following surgery, the intervention group received TENS physiotherapy and instructions to take analgesics. In the control group, patients only received analgesics. MMO was measured in both groups using a digital caliper preoperatively, 1 month, and 6 months postoperatively. Results: A total of 82 patients participated in this study, who were divided into two groups of 41, intervention and control. The difference in the mean MMO in different periods after surgery of the intervention group (F=59733.350, P<0.001) and the control group (F=32.480, P<0.001) was significant. The pattern of MMO increase over time was not the same in the two groups. There was a steeper slope in the increase of MMO in the intervention group than in the control group. Conclusion: It can be concluded from the results of this study, that the use of TENS after orthognathic surgery can be effective along with analgesics in reducing pain intensity and, subsequently, recovery in MMO in the short term.

Dentofacial and skeletal effects of two orthodontic maxillary protraction protocols: bone anchors versus facemask

BackgroundMaxillary retrognathia and/or mandibular prognathia are resulting in class III malocclusion. Regarding orthodontic class III malocclusion treatment, the literature reports several treatment approaches. This comparative clinical study investigated two maxillary protraction protocols including bone anchors and Delaire type facemask.MethodsCephalometric radiographs of n = 31 patients were used for data acquisition. The patients were divided into two groups according to their treatment protocol: bone anchored protraction (n = 12, 8 female, 4 male; mean age 11.00 ± 1.76 years; average application: 13.50 ± 5.87 months) and facemask protraction (n = 19, 11 female, 8 male; mean age 6.74 ± 1.15 years; average application: 9.95 ± 4.17 months). The evaluation included established procedures for measurements of the maxilla, mandibula, incisor inclination and soft tissue. Statistics included Shapiro-Wilk- and T-Tests for the radiographs. The level of significance was set at p < 0.05.ResultsThe cephalometric analysis showed differences among the two groups. SNA angle showed significant improvements during protraction with bone anchors (2.30 ± 1.18°) with increase in the Wits appraisal of 2.01 ± 2.65 mm. SNA angle improved also during protraction with facemask (1.22 ± 2.28°) with increase in the Wits appraisal of 1.85 ± 4.09 mm. Proclination of maxillary incisors was larger in patients with facemask (3.35 ± 6.18°) and ML-SN angle increased more (1.05 ± 1.51°) than in patients with bone anchors. Loosening rate of bone anchors was 14.58%.ConclusionsBoth treatment protocols led to correction of a class III malocclusion. However, this study was obtained immediately after protraction treatment and longitudinal observations after growth spurt will be needed to verify the treatment effects over a longer period. The use of skeletal anchorage for maxillary protraction reduces unwanted side effects and increases skeletal effects needed for class III correction.

Miniscrew-assisted Rapid Palatal Expansion Before Orthognathic Surgery for a Patient With Laterognathia

In this case report, a 19-year-old male patient with maxillary transverse deficiency, concave profile, and facial asymmetry is presented. In the case of transversal insufficiency, nonsurgical maxillary expansion was performed with the miniscrew-assisted rapid palatal expansion (MARPE) appliance to reduce the number of surgeries and provide both dentoalveolar and skeletal expansion. The periodontal soundness and short-term stability of the maxillary expansion were confirmed both clinically and radiologically. Mandibular prognathism was later corrected with orthognathic surgery. MARPE is an effective approach to the treatment of maxillary transverse deficiencies in adult patients.

Biomechanical effects of mandibular deviation on the temporomandibular joint in patients with mandibular prognathism under incisal occlusion

PurposeThe aim of this study was to investigate the biomechanical effects of mandibular deviation on the TMJ in patients with mandibular prognathism before and after orthognathic surgery using three-dimensional finite element analysis. MethodsEight patients with mandibular prognathism without deviation, eight patients with mandibular prognathism with deviation and sixteen normal subjects were recruited. Three-dimensional models of the maxillofacial were reconstructed using MIMICS. Nine muscle forces were used to simulate incisal occlusion and contact was used to simulate fossa-disc-condyle interactions. ResultsBefore surgery, the stress in the TMJ was generally greater in the Pre-MD&MP group than in the Pre-MD group; it was much greater in both groups than in the control group, ranging from about 2 to 12 times as great in the Pre-MD group and from about 5 to 64 times as great in the Pre-MD&MP group. After orthognathic surgeries, the stresses in the Post-MP&MD were significantly reduced by approximately 21.7 % to 93.4 %. And in the Post-MP group, the stresses were reduced by approximately 1.4 % to 51.1 %. ConclusionMandibular deviation exacerbated the abnormal stress distribution in the TMJ of patients with mandibular prognathism. Orthognathic surgeries could improve the stress distribution in patients with mandibular prognathism (with and without deviation). TMD was closely related to the stress levels of the TMJ.

Association between mandibular prognathism and Matrilin-1, bone morphogenic protein, Tyr67Asn, homeobox protein hox-A2, Rho-GTPase activating protein, and Myosin 1H genes in the Indian population.

Mandibular prognathism (MP) patients present with aesthetic concerns and functional issues, including difficulties in mastication and pronunciation. Studies revealed that mandibular prognathism had definitive Mendelian inheritance patterns. This study aimed to ascertain distinct genetic markers associated with mandibular prognathism in individuals of Indian descent, focusing on exploring the prevalent genetic variations associated with certain genes. This study sought to identify the association of the following gene markers with mandibular prognathism: 1) Matrilin-1 (MATN1) (rs1065755), 2) Bone morphogenic protein 3 (BMP-3) (Tyr67Asn), 3) Homeobox protein hox-A2 (HOXA2) (Val327Ile), 4) Rho-GTPase activating protein (ARHGAP 21) (Gly1121Ser), 5) Myosin 1H (MYO1H) (rs10850110).

Effect of condylar rotation on the stress environment of the temporomandibular joint in patients with mandibular protrusion

PurposeThe study aims to analyse the effects of condylar rotation on the biomechanical environment of the TMJ after bilateral sagittal split ramus osteotomy (BSSRO) through the finite element method (FEM). MethodsThirteen patients with mandibular prognathism and twenty-three normal subjects were recruited. The three-dimensional (3D) models were reconstructed. 13 representative morphological parameters were measured for comparison. A patient was selected to perform virtual BSSRO surgery by rotating the condyles in MIMICS. The preoperative and postoperative 3D models of the patient were subsequently imported into ABAQUS for finite element analysis. The preoperative and postoperative stresses and joint spaces in the TMJs were investigated. ResultsThe maxillofacial morphologies of the patients with mandibular protrusion was significantly different from those of the asymptomatic subjects (P<.05). Stresses in the postoperative group were lower than those in the preoperative group. The rotation of the condyle could cause the variations in stress levels and joint spaces within the TMJs. Inward and upward rotation of the condyle was associated with higher stress in the TMJ, whereas the lowest stress was observed when the condyle remained stationary following surgical intervention. SignificanceLateral, medial and superior joint spaces were more related to the stresses in the TMJs. The condyle should be kept in place as much as possible to avoid disrupting the balance of the TMJ in patients with mandibular protrusion.

Evaluation of mandibular condyle position in Class III patients after bimaxillary orthognathic surgery: A cone-beam computed tomography study.

This retrospective study evaluated the mandibular condyle position before and after bimaxillary orthognathic surgery performed with the mandibular condyle positioned manually in patients with mandibular prognathism using cone-beam computed tomography. Overall, 88 mandibular condyles from 44 adult patients (20 female and 24 male) diagnosed with mandibular prognathism due to skeletal Class III malocclusion who underwent bilateral sagittal split ramus osteotomy (BSSRO) and Le Fort I performed using the manual condyle positioning method were included. Cone-beam computed tomography images obtained 1-2 weeks before (T0) and approximately 6 months after (T1) surgery were analyzed in three planes using 3D Slicer software. Statistical significance was set at P < 0.05 level. Significant inward rotation of the left mandibular condyle and significant outward rotation of the right mandibular condyle were observed in the axial and coronal planes (P < 0.05). The positions of the right and left condyles in the sagittal plane and the distance between the most medial points of the condyles in the coronal plane did not differ significantly (P > 0.05). While the change in the sagittal plane can be maintained as before surgery with manual positioning during the BSSRO procedure, significant inward and outward rotation was observed in the axial and coronal planes, respectively, even in the absence of concomitant temporomandibular joint disorder before or after the operation. Further long-term studies are needed to correlate these findings with possible clinical consequences.

MATN1 gene variant (rs1065755) and malocclusion risk: Evidence from Romanian population analysis

Malocclusion, characterized by its diverse phenotypic expression, significantly impacts patients’ quality of life. Over recent years, extensive attention has been directed towards the genetic basis of this condition, particularly focusing on various polymorphisms of the MATN1 gene. Among these, the rs1065755 polymorphism has emerged as particularly relevant, associated with an elevated risk of mandibular prognathism. In this study, employing DNA sequencing, we investigated the extent of association between the rs1065755 SNP and malocclusion risk within the Romanian population. Our approach concentrated on assessing continuous phenotypic variation through four cephalometric measurements, aiming for a comprehensive understanding beyond categorical phenotypes. The findings shed light on the relationship between the MATN1 rs1065755 SNP and the investigated dentofacial disorder, revealing a positive association between TT homozygous individuals and Class II skeletal malocclusion. However, further investigations employing larger sample sizes are necessary to validate these findings conclusively. Keywords: malocclusion, MATN1, rs1065755, cephalometric measurements.

Temporomandibular joint stress analysis of patients with different mandibular deformities during unilateral molar occlusion

Mandibular prognathism, retrusion and deviation are common mandibular deformities. They can lead to functional and aesthetic problems due to their important role in the oral system. Different from other occlusions, unilateral molar occlusion often occurs during mastication, which has a deep impact on the functions of temporomandibular joints (TMJs). Therefore, the study of unilateral molar occlusion is of great importance and significance to the daily life of patients with mandibular deformities. A total of 35 individuals were involved in this study, including 11 asymptomatic subjects, 10 patients with mandibular prognathism, 5 patients with mandibular retrusion and 9 patients with mandibular deviation. Finite element (FE) models corresponding to the unilateral molar occlusion were constructed. During unilateral molar occlusion, mandibular deformity increases the pressure on the condyle and articular disc. Compared with mandibular protrusion or retraction, facial asymmetry will significantly increase the stress of TMJ. Chewing on the non-deviated side also will lead to higher stress in the TMJ of patients with mandibular deviation. Therefore, patients with mandibular deviation have the highest risk of temporomandibular disorder (TMD), and it is recommended that patients with mandibular deviation chew bilaterally or with the deviated side.

Utilizing Artificial Neural Networks for Geometric Bone Model Reconstruction in Mandibular Prognathism Patients

Patient-specific 3D models of the human mandible are finding increasing utility in medical fields such as oral and maxillofacial surgery, orthodontics, dentistry, and forensic sciences. The efficient creation of personalized 3D bone models poses a key challenge in these applications. Existing solutions often rely on 3D statistical models of human bone, offering advantages in rapid bone geometry adaptation and flexibility by capturing a range of anatomical variations, but also a disadvantage in terms of reduced precision in representing specific shapes. Considering this, the proposed parametric model allows for precise manipulation using morphometric parameters acquired from medical images. This paper highlights the significance of employing the parametric model in the creation of a personalized bone model, exemplified through a case study targeting mandibular prognathism reconstruction. A personalized model is described as 3D point cloud determined through the utilization of series of parametric functions, determined by the application of geometrical morphometrics, morphology properties, and artificial neural networks in the input dataset of human mandible samples. With 95.05% of the personalized model’s surface area displaying deviations within −1.00–1.00 mm relative to the input polygonal model, and a maximum deviation of 2.52 mm, this research accentuates the benefits of the parametric approach, particularly in the preoperative planning of mandibular deformity surgeries.

Is Incisor Compensation Related to Skeletal Discrepancies in Skeletal Class III? A Retrospective Cephalometric Study.

This study investigated compensation in skeletal Class III subjects to compare various severities of abnormal jaws. A retrospective analysis of 137 skeletal Class III cephalograms (63 males and 74 females) was conducted, with cephalometric assessments determining skeletal and dental values. The results were compared with Class I cephalograms. Incisor compensation was examined by pairing normal jaws with varied abnormal jaws, classified by severity using one standard deviation (SD). Statistical analyses included Kruskal-Wallis tests, Bonferroni tests, Spearman's correlations, and multiple linear regression. Four skeletal Class III groups were identified: OMx+PMd, RMx+OMd, OMx+OMd, and PMx+PMd (P = prognathic; O = orthognathic; R = retrognathic; Mx = maxilla; Md = mandible.). The upper central incisor (U1) showed proclination, and the lower central incisor (L1) showed retroclination across all groups except for U1 in PMx+PMd and L1 in OMx+OMd, which exhibited normal inclination. U1 exhibited limited compensation even with progressive maxillary retrognathism, while L1 showed limited compensation after one SD of mandibular prognathism. Maxilla (SNA) and jaw discrepancy (ANB) were inversely related to the U1 degree, whereas only jaw discrepancy (ANB) was positively related to the L1 degree. U1 in PMx+PMd and L1 in OMx+OMd showed no incisor compensation. U1 had limited compensation even with progressive maxillary retrognathism while L1 showed limited compensation after one SD mandibular prognathism.

Appraising mandibular prognathism in class III malocclusion following orthognathic surgery: Patient-reported and cephalometry-based outcomes

Patients with class III malocclusion often exhibit mandibular prognathism and complain of “prognathic appearance”. The overall positive effects of orthognathic surgery on facial appearance have been demonstrated using patient-reported outcome measures (PROMs), but studies investigating the correlation between subjective PROMs results and objective measurements of imaging studies are sparse in the literature.This study recruited consecutive patients with skeletal class III malocclusion who underwent two-jaw orthognathic surgery between January 2016 and January 2021. The PROMs survey was conducted focusing on subjective perception of mandibular appearance. Lateral cephalometric images were measured to examine the correlation with the PROMs results.A total of 96 patients were eligible for this study. Of these, 74 patients (77.1%) reported complete correction of prognathic appearance postoperatively, whereas 22 patients (22.9%) perceived residual prognathic appearance. In a comparison of postoperative measurements between completely and incompletely satisfied patients, there were significant differences in SNB, ANB, convexity, facial angle, Nv-B, Nv-Pog, SN'B', soft tissue facial angle, lip–chin–throat angle, N'v-B′, and N'v-Pog’. The PROM results were significantly associated with the objective measurements of imaging studies.Investigating the correlation between PROMs and objective measurements enables integration of patients’ perception of the outcomes into future therapeutic strategy and surgical planning, contributing to the enhancement of patient satisfaction.

Tongue pressure and maxillofacial muscle activities during swallowing in patients with mandibular prognathism.

Coordination among lip, cheek and tongue movements during swallowing in patients with mandibular prognathism remains unclear. This study aimed to identify the temporal sequences of tongue pressure and maxillofacial muscle activities during swallowing in patients with mandibular prognathism and compared characteristics with those of healthy volunteers. Seven patients with mandibular prognathism (mandibular prognathism group) and 25 healthy volunteers with individual normal occlusion (control group) were recruited. Tongue pressures and masseter, orbicularis oris, mentalis and supra- and infrahyoid muscle activities while swallowing gel were measured simultaneously using a sensor sheet system with five measurement points and surface electromyography, respectively. Onset time, offset time and durations of tongue pressure and muscle activities were analysed. In the mandibular prognathism group, tongue pressure was often produced first in more peripheral parts of the palate. Offset of tongue pressure in the posteromedian and peripheral parts of the palate and maxillofacial muscle activities except for orbicularis oris were delayed. Duration of tongue pressure in the anteromedian part of the palate was significantly shorter and durations of masseter, mentalis and suprahyoid muscle activities were significantly longer. Times to onset of orbicularis oris and suprahyoid muscle activities based on first onset of tongue pressure were significantly shorter. These results suggest that patients with mandibular prognathism may exhibit specific patterns of tongue pressure production and maxillofacial muscle activities during swallowing.

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

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. 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. 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. 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.

Investigation of orthognathic surgery indicators-combination with index of orthognathic functional treatment needs (IOFTN) and maxillofacial morphometric analysis.

The aim of this retrospective study was to determine orthognathic surgery indicators for Japanese patients with jaw deformities using both Index of Orthognathic Functional Treatment Needs (IOFTN) and maxillofacial morphometric analysis. The subjects were 89 patients treated with orthognathic surgery and 92 patients treated with orthodontic treatment alone, and were classified as class I, II, or III according to the ANB angle. Based on the results for IOFTN and the results of cephalometric analysis, the indication criteria for orthognathic surgery were examined. In IOFTN analysis, none of patients in the orthognathic surgery group were classified as category 1 or 2, while 48% of the patients in the orthodontic treatment group were classified as category 4 or 5. The results of the cephalometric analysis of patients in classified categories 4 and 5 showed that the orthognathic surgery group had significantly greater lateral mandibular deviation in Class I cases, significantly more severe degree of mandibular retrusion in Class II cases, and significantly more severe degree of mandibular prognathism in Class III cases. The results of the logistic regression analysis showed that IOFTN was a common variable as an indication criterion for orthognathic surgery, and several different variables were also selected from the cephalometric measurements in each group. IOFTN is a highly sensitive and useful indicator as a criterion for orthognathic surgery. However, in the choice of treatment strategy, maxillofacial morphometric analyses and the patient's desired goal are important.

Case report – mesioclusion treated with Bimler C períod of 12 months

This study aims to present a clinical case and assess the efficacy of the Bimler C Elastic Modeler, a functional orthopedic appliance, in the early treatment of a patient diagnosed with mesiocclusion (mandibular prognathism) based on Bimler and McNamara Cephalometrics. Additionally, we aim to delineate the observed positive changes in facial expression during the course of treatment with this functional orthopedic appliance. The female patient, aged six years and nine months, manifested atypical swallowing, respiratory challenges, and allergic conditions such as rhinitis. Comprehensive examination further revealed facial asymmetry and a smile with lip asymmetry. Intra-oral examination exposed a rightward deviation of the mandible, crossbite, open bite, and mesiocclusion. The proposed intervention encompassed the application of the Bimler Elastic Modeler (BEM) functional orthopedic appliance. The documented treatment duration spanned 12 months, with ongoing monitoring every 2 or 3 months. The treatment, utilizing the BEM functional orthopedic appliance, coupled with exercises and adjustments, improved mandibular and tongue posture, enhancing overall chewing balance. The appliance effectively repositioned the mandible to a more balanced position approaching normocclusion, achieving this without causing pain or discomfort and without the necessity for elastic or constant forces. Given the crucial role of facial expression muscles in these activities, a pronounced enhancement in facial harmony was observed. These affirmative outcomes significantly contributed to heightened patient engagement throughout the treatment process and a concomitant enhancement in patient self-esteem, attributable to the documented aesthetic and functional ameliorations.

Highlights of orthognathic surgery in class II patients: a systematic review

Introduction: Orthognathic surgery is indicated to modify the position of the maxillomandibular structure, which may cause changes in the sagittal position of the mandibular condyle in individuals with retrognathism and mandibular prognathism. In the context of orthognathic surgery, anterior open bite (AOB) is an easily recognized malocclusion and presents only aesthetic and functional problems. Objective: Foi desenvolver uma revisão sistemática para apresentar as principais considerações da cirurgia ortognática em pacientes classe II. Methods: The PRISMA Platform systematic review rules were followed. The search was carried out from October to December 2023 in the Scopus, PubMed, Science Direct, Scielo, and Google Scholar databases. The quality of the studies was based on the GRADE instrument and the risk of bias was analyzed according to the Cochrane instrument. Results and Conclusion: A total of 88 articles were found, 40 articles were evaluated in full and 20 were included and developed in the present systematic review study. Considering the Cochrane tool for risk of bias, the overall assessment resulted in 21 studies with a high risk of bias and 21 studies that did not meet GRADE and AMSTAR-2. Most studies did not show homogeneity in their results, with X2=57.5%&gt;50%. The etiology of anterior open bite is multifactorial and may be caused by environmental and hereditary factors. Class II patients may have significantly greater amounts of lateral and inferior translation than class III patients. Two-jaw surgery for open bite correction led to different directions and amounts of condylar rotational displacement in patients with skeletal class II malocclusion. Treatment can be carried out through preventive, interceptive, corrective, or even surgical treatments. The differentiated bonding of brackets to the anterior teeth is also a very useful resource for the treatment of anterior open bite.

Prosthetic full mouth rehabilitation of patient with mandibular prognathism and asymmetry: a case report

Prosthetic full mouth rehabilitation of patient with mandibular prognathism and asymmetry: a case report

Cephalometric evaluation of skeletal stability and pharyngeal airway changes after mandibular setback surgery: Bioabsorbable versus titanium plate and screw fixation.

This study compared sequential changes in skeletal stability and the pharyngeal airway following mandibular setback surgery involving fixation with either a titanium or a bioabsorbable plate and screws. Twenty-eight patients with mandibular prognathism undergoing bilateral sagittal split osteotomy by titanium or bioabsorbable fixation were randomly selected in this study. Lateral cephalometric analysis was conducted preoperatively and at 1 week, 3-6 months, and 1 year postoperatively. Mandibular stability was assessed by examining horizontal (BX), vertical (BY), and angular measurements including the sella-nasion to point B angle and the mandibular plane angle (MPA). Pharyngeal airway changes were evaluated by analyzing the nasopharynx, uvula-pharynx, tongue-pharynx, and epiglottis-pharynx (EOP) distances. Mandibular and pharyngeal airway changes were examined sequentially. To evaluate postoperative changes within groups, the Wilcoxon signed-rank test was employed, while the Mann-Whitney U test was used for between-group comparisons. Immediate postoperative changes in the airway were correlated to surgical movements using the Spearman rank test. Significant changes in the MPA were observed in both the titanium and bioabsorbable groups at 3-6 months post-surgery, with significance persisting in the bioabsorbable group at 1 year postoperatively (2.29°±2.28°; P<0.05). The bioabsorbable group also exhibited significant EOP changes (-1.21±1.54 mm; P<0.05) at 3-6 months, which gradually returned to non-significant levels by 1 year postoperatively. Osteofixation using bioabsorbable plates and screws is comparable to that achieved with titanium in long-term skeletal stability and maintaining pharyngeal airway dimensions. However, a tendency for relapse exists, especially regarding the MPA.

Comparison of three-dimensional soft tissue changes according to the split pattern after sagittal split osteotomy in patients with skeletal class III malocclusion

ObjectivesThis study aimed to analyse the changes in soft tissue and hard tissue stability associated with the split pattern, i.e. long split (LS) or short split (SS), after sagittal split osteotomy.Materials and methodsPatients who underwent sagittal split ramus osteotomy were classified into LS or SS groups according to postoperative computed tomography images. They were examined via lateral cephalography and three-dimensional (3D) optical scanning before surgery (T0) and 1 (T1), 3 (T2), and 12 (T3) months after surgery. Six standard angles (SNA, SNB, ANB, FMA, FMIA, and IMPA) were used as measures of hard tissue change. The two sets of 3D data were superimposed, and the volumetric differences were calculated as the soft tissue change. The areas evaluated were delimited by 10 × 20-mm rectangles in the frontal aspect and a 25 × 25-mm square in the lateral aspect.ResultsA total of 42 sides (26 patients) were analysed, including 20 (16 patients) in the SS group and 22 (16 patients) in the LS group. We found no significant differences in cephalographic angle or soft tissue changes in the frontal aspect between the SS and LS groups. We found significant differences in the subauricular region from T0–T1 (p = 0.02), T0–T2 (p = 0.03), and T0–T3 (p = 0.037) in terms of soft tissue changes in the lateral aspect. The volume increase associated with posterior mandibular movement was greater in the LS group.ConclusionsWe found that LS patients with mandibular prognathism exhibited increased subauricular volumes following mandibular setback.Clinical relevanceIt is essential to predict the postoperative facial profile before surgery. The split pattern after sagittal split osteotomy affects the postoperative profile of patients with mandibular prognathism.