Two-jaw Surgery Research Articles

Comparison between one-jaw and two-jaw designs in virtual surgery planning for patients with class III malocclusion

Orthognathic surgery is highly effective for treating maxillomandibular discrepancies in patients with class III malocclusion. However, whether one- or two-jaw surgery should be selected remains controversial. Our study aimed to evaluate quantitative differences between one-jaw and two-jaw surgical designs.In total, 100 consecutive patients with skeletal class III malocclusion who underwent orthognathic surgery with preoperative three-dimensional simulation between August 2016 and November 2021 were recruited. Based on the same final occlusal setup, a two-jaw surgery design and two types of one-jaw design were created. In total, 400 image sets, including preoperative images and three types of surgical simulation, were measured and compared.The one-jaw mandibular setback design led to improvement in most cephalometric measurements and facial symmetry. Although the one-jaw maxillary advancement design improved the ANB angle and facial convexity, it induced maxillary protrusion and reduced facial symmetry. Compared with the other designs, the two-jaw design provided significantly closer cephalometric measurements to the normative values, better symmetry, and less occlusal cant.Overall, the two-jaw design provided a quantitatively better facial appearance in terms of symmetry, proportion, and profile. Although an optimal surgical design necessitates thorough preoperative evaluation and a shared decision-making process, two-jaw surgery can be considered for improving overall facial esthetics and harmony.

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%>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.

Surgical occlusion setup and skeletal stability of correcting cleft-associated class III deformity using surgery-first bimaxillary surgery.

This study aimed to assess the three-dimensional (3D) quantitative characteristics of the surgical occlusion setup in surgery-first cleft orthognathic surgery, and to evaluate its influence on post-surgical skeletal stability. This prospective study was comprised of 35 patients with unilateral cleft lip and palate and class III deformity who consecutively underwent two-jaw surgery with surgery-first approach. Digitized dental models were analyzed to quantify the 3D characteristics of the final surgical occlusion setup. Cone-beam computed tomography was used to measure the 3D surgical skeletal movement and post-surgical skeletal stability. The correlation between skeletal stability and surgical occlusal contact or surgical skeletal movement was also evaluated. The surgical occlusion setup had a large incisor overjet and positive overbite, and buccal cross bite and open bite on second molars. Occlusal contact on three segments was present in 51.4% of the patients, and the average number for tooth contact was 4.3 teeth. No correlation was found between maxillary or mandibular stability and surgical occlusal contact. However, a significant correlation was found between maxillary and mandibular stability and the surgical skeletal movement. The surgical occlusion for correction of cleft-associated class III deformity using the surgery-first approach was characterized with large overjet and positive overbite, and posterior cross bite and open bite. On average, there was occlusal contact on four to five teeth; half of surgical occlusion setups had contact on three segments. The post-surgical skeletal stability was not related to the surgical occlusal contact but to the surgical skeletal movement.

The prediction of sagittal chin point relapse following two-jaw surgery using machine learning

The study aimed to identify critical factors associated with the surgical stability of pogonion (Pog) by applying machine learning (ML) to predict relapse following two-jaw orthognathic surgery (2 J-OGJ). The sample set comprised 227 patients (110 males and 117 females, 207 training and 20 test sets). Using lateral cephalograms taken at the initial evaluation (T0), pretreatment (T1), after (T2) 2 J-OGS, and post treatment (T3), 55 linear and angular skeletal and dental surgical movements (T2-T1) were measured. Six ML modes were utilized, including classification and regression trees (CART), conditional inference tree (CTREE), and random forest (RF). The training samples were classified into three groups; highly significant (HS) (≥ 4), significant (S) (≥ 2 and < 4), and insignificant (N), depending on Pog relapse. RF indicated that the most important variable that affected relapse rank prediction was ramus inclination (RI), CTREE and CART revealed that a clockwise rotation of more than 3.7 and 1.8 degrees of RI was a risk factor for HS and S groups, respectively. RF, CTREE, and CART were practical tools for predicting surgical stability. More than 1.8 degrees of CW rotation of the ramus during surgery would lead to significant Pog relapse.

Orthognathic surgical planning using graph CNN with dual embedding module: External validations with multi-hospital datasets

Background and objectiveDespite recent development of AI, prediction of the surgical movement in the maxilla and mandible by OGS might be more difficult than that of tooth movement by orthodontic treatment. To evaluate the prediction accuracy of the surgical movement using pairs of pre-(T0) and post-surgical (T1) lateral cephalograms (lat-ceph) of orthognathic surgery (OGS) patients and dual embedding module-graph convolution neural network (DEM-GCNN) model. Methods599 pairs from 3 institutions were used as training, internal validation, and internal test sets and 201 pairs from other 6 institutions were used as external test set. DEM-GCNN model (IEM, learning the lat-ceph images; LTEM, learning the landmarks) was developed to predict the amount and direction of surgical movement of ANS and PNS in the maxilla and B-point and Md1crown in the mandible. The distance between T1 landmark coordinates actually moved by OGS (ground truth) and predicted by DEM-GCNN model and pre-existed CNN-based Model-C (learning the lat-ceph images) was compared. ResultsIn both internal and external tests, DEM-GCNN did not exhibit significant difference from ground truth in all landmarks (ANS, PNS, B-point, Md1crown, all P > 0.05). When the accumulated successful detection rate for each landmark was compared, DEM-GCNN showed higher values than Model-C in both the internal and external tests. In violin plots exhibiting the error distribution of the prediction results, both internal and external tests showed that DEM-GCNN had significant performance improvement in PNS, ANS, B-point, Md1crown than Model-C. DEM-GCNN showed significantly lower prediction error values than Model-C (one-jaw surgery, B-point, Md1crown, all P < 0.005; two-jaw surgery, PNS, ANS, all P < 0.05; B point, Md1crown, all P < 0.005). ConclusionWe developed a robust OGS planning model with maximized generalizability despite diverse qualities of lat-cephs from 9 institutions.

Evaluation of accuracy of maxillary repositioning surgery using an observer-independent method

ObjectiveTo evaluate the accuracy of maxillary repositioning in two-jaw surgery using computer-aided surgical simulation (CASS) and computer-aided design/manufacturing (CAD/CAM) splints by using a highly accurate observer-independent method. MethodsA retrospective evaluation was conducted of 30 consecutive adults who underwent Le Fort I osteotomy by a single surgeon. Surgical planning and fabrication of occlusal splints were performed using custom-developed CASS software. Preoperative images with landmarks were superimposed on postoperative images to evaluate discrepancies between the planned and actual position of the maxilla following surgery. Translational and rotational differences were expressed as the root mean square deviation (RMSD). The number of cases that exceeded the clinically acceptable limits (2 mm for the translational difference at the centroid, 4° for the rotational difference, and 1 mm for the mediolateral difference at the dental midline) were also evaluated. ResultsPostoperative anteroposterior translation and pitch values were significantly different to and negatively correlated with the planned values, respectively. The largest translational RMSDs at the centroid and the dental midline were 1.04 mm and 1.03 mm, respectively, in the anteroposterior direction. The largest rotational RMSD was 1.86° in pitch. The percentage of discrepancies exceeding the clinically acceptable limit was 3.3% for the centroid, 3.3% for rotation, 20.0% for the midline, and 26.7% for any one criterion. ConclusionWhile maxillary repositioning using CASS and CAD/CAM splints was accurate on a population level, there remains potential for clinically significant errors to occur on an individual level, particularly in controlling the dental midline position and occlusal plane angle.

Long-term stability of surgical orthodontic treatment for patients with asymmetric mandibular prognathism: a retrospective comparison study on surgical methods

ABSTRACT Purpose To consider long-term postoperative stability, and its contributing factors in surgical orthodontic treatment for asymmetric mandibular prognathism by comparing a sagittal split ramus osteotomy (SSRO) and a combination of Le Fort I osteotomy and SSRO. Materials and Methods Patients with asymmetric mandibular prognathism had undergone SSRO (14 patients; one-jaw surgery group) or a combination of Le Fort I osteotomy and SSRO (15 patients; two-jaw surgery group) were enrolled. Cephalometric analyses were performed at five time points: initial visit (T0), pre-surgery (T1), several months after surgery (T2), start of retention (T3) and more than 5 years after surgery (T4). Factors were evaluated by measuring two groups at each time point, comparing changes in measurements during each time period, correlating mandibular changes between each period, and correlating changes in lower first molar and ramus inclination with T2-T4 measurements. Results The two-jaw surgery group had significantly smaller transverse changes of menton (Me) at T3–T4 and T2–T4 compared to the one-jaw surgery group. In the one-jaw surgery group, transverse changes in Me at T2–T4 were positively correlated with changes in transverse inclination of mandibular ramus at the deviated side observed at T1–T2. Vertical change of pogonion at T2–T4 was positively correlated with change in bucco-lingual inclination of lower first molar at T0–T1. Conclusions Two-jaw surgery is suggested to be more effective than one-jaw surgery in achieving long-term stability of mandibular position in the transverse and anteroposterior dimensions after surgical orthodontic treatment for asymmetric mandibular prognathism. Long-term follow-up is necessary to monitor potential mandibular relapse.

Effectiveness of individualized 3D titanium-printed Orthognathic osteotomy guides and custom plates

BackgroundComputer-aided design/manufacturing (CAD/CAM) technology was developed to improve surgical accuracy and minimize errors in surgical planning and orthognathic surgery. However, its accurate implementation during surgery remains a challenge. Hence, we compared the accuracy and stability of conventional orthognathic surgery and the novel modalities, such as virtual simulation and three-dimensional (3D) titanium-printed customized surgical osteotomy guides and plates.MethodsThis prospective study included 12 patients who were willing to undergo orthognathic surgery. The study group consisted of patients who underwent orthognathic two-jaw surgery using 3D-printed patient-specific plates processed by selective laser melting and an osteotomy guide; orthognathic surgery was also performed by the surgeon directly bending the ready-made plate in the control group. Based on the preoperative computed tomography images and intraoral 3D scan data, a 3D virtual surgery plan was implemented in the virtual simulation module, and the surgical guide and bone fixation plate were fabricated. The accuracy and stability were evaluated by comparing the results of the preoperative virtual simulation (T0) to those at 7 days (T1) and 6 months (T2) post-surgery.ResultThe accuracy (ΔT1‒T0) and stability (ΔT2‒T1) measurements, using 11 anatomical references, both demonstrated more accurate results in the study group. The mean difference of accuracy for the study group (0.485 ± 0.280 mm) was significantly lower than in the control group (1.213 ± 0.716 mm) (P < 0.01). The mean operation time (6.83 ± 0.72 h) in the control group was longer than in the study group (5.76 ± 0.43 h) (P < 0.05).ConclusionThis prospective clinical study demonstrated the accuracy, stability, and effectiveness of using virtual preoperative simulation and patient-customized osteotomy guides and plates for orthognathic surgery.

Soft-Tissue Response following Genioplasty Combined with Anterior Segmental Osteotomy.

The authors' main aim was to analyze soft-tissue response of the chin following genioplasty with anterior segmental osteotomy, which enables optimal surgical planning of genioplasty. Sixty-two patients who underwent genioplasty with concomitant anterior segmental osteotomy were divided into three groups depending on the direction of pogonion (Pog) movement: G1 (without sagittal change), G2 (advancement genioplasty), and G3 (setback genioplasty). All genioplasties included height reduction. Hard- and soft-tissue measurements with cephalometry were performed at T1 (before surgery), T2 (after surgery), and T3 (after orthodontic treatment) for the analysis of sagittal and vertical changes. Correlation and regression analyses were conducted to analyze soft- to hard -tissue movement and soft-tissue thickness changes. During the T1 to T2 period, the horizontal soft- to hard-tissue ratio at Pog was 0.85 in G2 and 0.80 in G3, and the vertical ratio at menton (Me) was 0.9 for all groups. The correlation coefficients were 0.64 (G2) and 0.83 (G3) at Pog and 0.9 (all), 0.85 (G1), 0.95 (G3) at Me. There was no significant correlation between initial soft-tissue thickness and soft-tissue response ratio. During the T2 to T3 period, no significant relapses were observed, which demonstrates the stability of anterior segmental osteotomy combined genioplasty. Clinically and statistically significant soft-tissue responses were demonstrated at Pog and Me. The higher values in G3 in particular suggest that setback genioplasty with anterior segmental osteotomy is an effective treatment alternative to conventional two-jaw surgery in some patients with bimaxillary prognathism with macrogenia. Therapeutic, IV.

Three-Dimensional Change of Lip after Two-Jaw Surgery in Facial Asymmetry Using Facial Scanner

A facial scanner and three-dimensional computed tomography (CT) were used to evaluate the three-dimensional change in lip asymmetry before and after two-jaw surgery for 22 patients with facial asymmetry (menton deviation &gt; 3 mm). We used the labrale superius (Ls), deviated/non-deviated-side cheilions (Ch-D/Ch-ND), and labrale inferius (Li) to construct the upper and lower lip planes to evaluate the lip asymmetry. A correlation analysis was performed to determine the factors related to the vertical change in the cheilions (ΔChZ-D/ND). In the transverse axis, Ch-D and Li moved to improve the asymmetry after surgery. All landmarks, except the Ls, moved backward in the anteroposterior axis. In the vertical axis, significant upward movement was observed in all hard tissue landmarks; however, there were no significant changes in the soft tissue. In the lip plane, the difference in the height of Ch-D and Ch-ND was significantly reduced (1.38 mm vs. 0.72 mm). In the anteroposterior axis, the ΔChZ-D/ND showed significant correlations with the mandibular setback. In the vertical axis, the ΔCh-ND showed significant correlations with the maxillary impaction of the non-deviated side. The improvement in lip asymmetry post-surgery was mainly achieved by the movement of the lower lip and Ch-D rather than the upper lip and Ch-ND.

Changes in a facial recognition algorithm following different types of orthognathic surgery: a comparative study.

ObjectivesContemporary biometric technologies have been gaining traction in both public and private security sectors. Facial recognition is the most commonly used biometric technology for this purpose. We aimed to evaluate the ability of a publicly available facial recognition application program interface to calculate similarity scores of presurgical and postsurgical photographs of patients who had orthognathic surgery.Materials and MethodsPresurgical and postsurgical photographs of 75 patients who had orthognathic surgery between January 2018 and November 2020 in our department were used. Frontal photographs of patients in relaxed and smiling states were taken. The patients were classified into three groups Group 2 had one-jaw surgery, Group 3 had two-jaw surgery to correct mandibular prognathism, and Group 4 had two-jaw surgery to correct facial asymmetry. For comparison, photographs of 10 participants were used as controls (Group 1). Two facial recognition application programs (Face X and Azure) were used to assess similarity scores.ResultsThe similarity scores in the two programs showed significant results. The similarity score of the control group, which did not undergo orthognathic surgery, was the highest. The results for Group 2, Group 3, and Group 4 were higher in the order of Group 2, Group 3, and Group 4.ConclusionIn this study, all orthodontic patients were recognized as the same person using the face recognition program before and after surgery. A significant difference in similarity results was obtained between the groups with both Face X and Azure and in both relaxed and smiling states.

Postoperative stability following orthognathic surgery and final skeletal morphology in class III patients with cleft lip and palate

Orthognathic surgery has become useful procedures for patients with cleft lip and palate (CLP) to improve the inharmonious relationship between the maxilla and mandible. The purpose of this study is to assess the postoperative stability and skeletal morphology following orthognathic surgeries for patients with skeletal class III deformity with CLP. This study retrospectively evaluated the long-term stability of orthognathic surgery and the final profile of skeletal morphology in 30 patients using lateral cephalometric imaging. Sagittal split ramus osteotomy was performed for 10 patients (CLP-S), Le Fort I osteotomy was performed for 5 patients (CLP-L) and two-jaw surgery was performed for 15 patients (CLP-T). As a control, we included 5 patients treated by two-jaw surgery, 7 patients treated by SSRO without CLP and 20 CLP patients with orthodontic treatment alone. In the CLP group at 2 years postoperatively, the mean relapse in SNA was 19.8% (CLP-T) and 18.1% (CLP-L), and the mean relapse in SNB was 17.6% (CLP-S) and 26.9% (CLP-T). No significant differences were observed in the relapse ratio of the same operation between with and without CLP. In comparison of surgical and non-operative patients with CLP, there were significant differences in preoperative skeletal factors, but the profiles were similar at the end of treatment. Our orthognathic surgeries provided the same level of stability for patients with skeletal class III deformity with or without CLP, creating harmonious intermaxillary relationship.

One-Jaw versus Two-Jaw Orthognathic Surgery for Patients with Cleft: A Comparative Study Using 3D Imaging Virtual Surgical Planning

Whether a one-jaw or two-jaw design is used in orthognathic surgery for patients with cleft remains varied and controversial. This study aimed to compare the two approaches using 3-dimensional imaging surgical simulation. This study was conducted on 41 consecutive patients with complete unilateral cleft lip and palate treated in the craniofacial center. All patients had original two-jaw virtual planning and orthognathic surgery. Simulation of one-jaw LeFort I surgery was performed using the same final dental occlusion on 3-dimensional images. Cephalometric data and asymmetry index were collected and compared among the designs. Average advancement of the maxilla was 7.46 mm in one-jaw and 4.80 mm in two-jaw design. SNA, SNB, and A-N perpendicular were significantly greater and close to normative data in the one-jaw design. ANB angles were similar in both designs. The anterior and posterior occlusal plane cants, the deviation of midline landmarks, and the asymmetry index were more improved in the two-jaw approach. It is concluded that the two-jaw cleft orthognathic surgery could significantly improve facial midline and symmetry compared with the one-jaw approach. However, the two-jaw surgery with mandibular setback produced less protrusive facial contour although a harmonious relationship between the maxilla and mandible was achieved.

Long-term Management of a Patient with Apert Syndrome

To present an Apert syndrome patient with midfacial growth deficiency treated with Le Fort III distraction osteogenesis and subsequent two-jaw surgery. Apert syndrome is expressed as a severe and irregular craniosynostosis, midfacial hypoplasia, and symmetric syndactyly in the fingers and toes. For craniosynostosis syndromes, treatment planning is complex due to the disharmony between facial profile and occlusion. A 4-year-and-5-month-old boy, diagnosed with Apert syndrome, showed a concave profile accompanied with midfacial hypoplasia, moderate exorbitism, a reversed occlusion of -10.0 mm, an anterior open bite of -5.0 mm, and skeletal class III jaw-base relationship. The patient, aged 15 years and 4 months, underwent a Le Fort III osteotomy, and subsequent osteodistraction was performed via a rigid external distraction (RED) device. His midfacial bone was advanced by approximately 7.0 mm. One year after the distraction, preoperative treatment with 0.018-in preadjusted edgewise appliances was initiated. Two-jaw surgery with a Le Fort I osteotomy and bilateral sagittal split ramus osteotomy was performed after 42 months of preoperative orthodontic treatment. At the age of 20 years and 9 months, his facial profile dramatically changed to a straight profile, and an acceptable occlusion with an adequate interincisal relationship was obtained. A functional occlusion with an excellent facial profile was maintained throughout the 2-year retention period, although the upper dental arch width was slightly decreased, resulting in the recurrence of the left posterior crossbite. Our report indicates the necessity of long-term follow-up in patients with craniosynostosis because of syndrome-specific growth and methodologically induced relapse. The two-stage operation combining early distraction osteogenesis and postgrowth orthognathic surgery proves to be an effective therapy for correcting midfacial hypoplasia and skeletal mandibular protrusion caused by Apert syndrome.

A severe skeletal Class III malocclusion treated with Le Fort I combined with sagittal split ramus osteotomy, mandibular body ostectomy and tongue reduction surgery. A case report

This case report describes the orthodontic-orthognathic management of a 17-year-old male patient with extremely severe skeletal Class III malocclusion due to a marked mandibular protrusion with a small and narrowed upper jaw which increased the remarkable concave facial profile. Dental articulation was entirely lacking, resulting in great difficulty in masticating food. A two-jaw surgery combined with mandibular body ostectomy was performed to correct mandibular asymmetry and the severe sagittal skeletal discrepancy (Wits appraisal –36.5 mm and ANB angle –14.3°). Bi-maxillary surgery was performed in two-stages; the first surgery consisted of maxillary advancement with Le Fort I osteotomy followed by a second surgery where a combination of sagittal split ramus osteotomy (SSRO) and mandibular body ostectomy was performed to correct the severe mandibular prognathism. A partial glossectomy was also carried out to address macroglossia. After a total treatment time of 32 months, a Class I occlusion with a favorable facial profile and lip competence were obtained. The occlusion was made approximately ideal, and mastication improved remarkably. Three years after retention, the occlusion was stable and no relapse was observed. The patient’s complaints and orthodontic problems were completely resolved. Therefore, a combination of two-jaw surgeries with Le Fort I maxillary osteotomy, mandibular SSRO, mandibular ostectomy, and glossectomy may be a viable option in the correction of extremely severe anteroposterior skeletal discrepancy.

Early Orthosurgical Treatment of a Skeletal Class III: Can the Self-Esteem Be Improved?

Young patients with a skeletal Class III malocclusion with a strong psychological and appearance impact may require surgical correction during their growth. This case report describes the orthosurgical treatment of a 11-year-old boy with history of bullying, presenting severe Class III skeletal malocclusion, anterior cross-bite and mandibular prognathism. He also had significant vertical and anteroposterior discrepancies and a concave profile with prominent lips. The treatment plan included extraction of the first premolars, a maxillary LeFort I osteotomy and a mandibular bilateral sagittal split osteotomy. The orthodontic treatment combined with the two-jaw surgery improved his jaws alignment, occlusal function, and the most important: his self-esteem and quality of life.

Treatment of a Class II Hyperdivergent Case with Progressive Condylar Resorption

Condylar resorption can be challenging to orthodontist when encountered during treatment. The clinical characteristics and cephalometric findings of a patient who experienced postoperative skeletal relapse caused by progressive condylar resorption (CR) are presented in this case report. The predisposing factors and treatment protocols of condylar resorption are also discussed. A 17-year-old female patient came to our hospital with chief complaint of no contact of anterior teeth. Cephalometric analysis shows that she is a patient with skeletal Class II hyper-divergent pattern caused by mandibular retrognathism. Flattened left condylar head was found on panoramic film suggesting possible condylar erosion in the past. Before starting her treatment, the superimposition of serial cephalometric films was done, and no active resorption of condyles were found. After four months of pre-surgical orthodontic treatment, a two-jaw surgery was performed. However, an increase in overjet was noticed nine months after that. Cephalometric superimposition revealed a decrease in ramus height indicating a skeletal relapse due to CR. Inter-arch elastics was stopped to eliminate the loading on temporomandibular joint (TMJ), and vitamin D plus calcium supplementation was prescribed. Condyle remained stable throughout the rest of the treatment. Total treatment time is 36 months, and satisfactory facial profile and occlusion have been achieved. CR is attributable to young female, Class II hyperdivergent skeletal pattern, posteriorly inclined condylar neck, estrogen deficiency, and pre-existing TMJ disorder. Mandibular advancement over 10 mm, posteriorly displaced condyles, and counterclockwise rotation of the proximal and distal segment are high-risk surgical factors. Impact of CR can be minimized by making the correct diagnosis, optimal orthodontic or orthodontic-surgical planning, and periodic check up on condylar condition.

Three-dimensional analysis of lip soft tissue changes and related jaw changes in patients with skeletal class III malocclusion and facial asymmetry.

To investigate three-dimensional soft tissue changes of lips and related jaw changes in patients with skeletal class III malocclusion and facial asymmetry using cone-beam computerized tomography (CBCT). This study included 46 CBCT scans of patients with aforementioned character before (T1) and 6-12 months after orthognathic surgery (T2). Subjects were divided into 2 groups according to two types of orthognathic surgery namely, the one-jaw surgery group who underwent bilateral sagittal splint ramus osteotomy (BSSRO) and the two-jaw surgery group who underwent Le Fort I osteotomy and BSSRO. Mimics 19.0 software are used for model reconstruction, landmark location and three-dimensional cephalometric analysis. Descriptive statistics and correlation analyses are used to investigate jaw hard tissue and lip soft tissue changes. In one-jaw group, the mandible shows changes in contour and position (p < 0.05), and the surgery causes changes of lip structure on the deviated side. While in two-jaw group, jaws only show changes in spatial position, and surgery changes contour of bilateral lips and nasolabial angle (p < 0.05). At the same time, lip symmetry increases significantly in both groups postoperatively. Orthognathic surgery can improve lip aesthetics in patients with skeletal class III malocclusion and facial asymmetry. However, changes induced by two surgical approaches are different. Surgeons should have a clear acquaintance with this difference to deal with different situations.

Skeletal Stability of Two-Jaw Surgery Without Bone Grafting in Patients With Cleft Lip and Palate.

The purpose of this study was to evaluate the postoperative skeletal stability of orthognathic surgery performed without a bone graft in cleft lip and palate patients. Nineteen cleft lip and palate patients that underwent orthognathic surgery from July 2008 to August 2019 at the Department of Oral and Maxillofacial Surgery of Pusan National University Dental Hospital were selected. None of these patients underwent bone grafting during orthognathic surgery. Lateral cephalograms were taken 1 month before surgery (T0), immediately after surgery (T1), and 6 months after surgery (T2). Lateral cephalograms were analyzed using the V-Ceph program. The analysis was performed using SPSS for Windows version 26.0. The analysis was conducted by repeated-measures analysis of variance. A total of 19 patients were included in this retrospective study (9 males/10 females of overall mean age 22 ± 4.89 years). Mean maxillary depth values at the 3-time points were 85.37° ± 2.62° (T0), 90.13° ± 2.77° (T1), and 89.29° ± 2.91° (T2). Mean McNamara-N Perpend values were -5.52 ± 3.19 mm (T0), 0.09 ± 3.10 mm (T1), and -0.83 ± 3.14 mm (T2). Mean sella nasion point A (SNA) values were 75.42° ± 2.98° (T0), 79.19° ± 2.94° (T1), and 78.45° ± 2.84° (T2). Mean relapse rates were maxillary depth 20.15%, McNamara-N Perpend 17.95%, and SNA 18.74%. Mean horizontal advancement was 5.61 ± 2.32 mm based on McNamara vertical to A point, mean horizontal relapse was -0.92 ± 0.56 mm, and the mean horizontal relapse rate was 17.95%. Favorable skeletal stability can be obtained without bone graft when the amount of maxillary advancement is less than 6 mm in cleft patients.

Outcome of full digital workflow for orthognathic surgery planning in the treatment of asymmetric skeletal class III deformity

Studies have reported the advantages of digital imaging-assisted orthognathic surgery planning, but there is scarce information about a full digital planning modality. This study evaluated the 3D cephalometric-based and patient-reported outcomes of a full digital workflow for orthognathic surgery planning in the treatment of asymmetric maxillomandibular disharmony. A postoperative 3D image dataset of 30 Taiwanese Chinese patients with asymmetric skeletal Class III deformities who underwent full digital planning for two-jaw surgery were retrieved from the authors' database. The 3D cephalometric data (dental, skeletal, and soft tissue evaluations) were compared to the ethnicity-matched 3D cephalometric normative values. Patient-reported outcome measure tools regarding postoperative overall appearance and satisfaction with facial areas (ranging from 0 to 100 and 0 to 10, respectively) were administered. The number of needed or requested revisionary surgery was collected. No difference (all p>0.05) was observed between the orthognathic-surgery-treated patients and the normative value for most of the tested 3D cephalometric parameters, with the exception (p<0.05) of three mandible and occlusal-plane-related parameters. Both patient-reported outcome measure tools showed that patients' satisfaction with their postoperative appearance was high for overall face (89.7±4.5) and specific facial regions (nose, 7.1±1.3; lip, 8.3±1.6; upper gum, 8.5±1.2; cheek, 8.8±1.1; chin, 9.2±1.2; and teeth, 9.3±0.8), with no need for revisionary surgery. The patients treated with a full 3D digital planning-assisted two-jaw surgery had a similar 3D dental relation, facial convexity, and symmetry compared to healthy ethnicity-matched individuals, and they reported higher satisfaction levels with their postoperative facial appearance results.