Evaluation of soft tissue profile changes around the nose and upper lip following maxillary anterior alveolar osteotomy with Wassmund and Wunderer technique in Japanese.

PURPOSE: The extent to which maxillary anterior alveolar osteotomy alters the facial profile remains unclear. The present study retrospectively analyzed and evaluated changes in maxillary anterior fragments and soft tissue from the nose to upper lip from pre- to postoperatively in patients who underwent the Wassmund and Wunderer (WW) technique. METHODS: Thirty-seven Japanese patients with maxillary prognathism underwent orthognathic surgery with the WW technique were retrospectively included in the present study. Changes in both hard- and soft-tissue landmarks and correlations between both tissues were evaluated using lateral cephalograms taken immediately before and ≥6 months after orthognathic surgery. RESULTS: The maxillary anterior segment showed predominantly posterior movement, with only slight upward movement. Posterior shift and lingual inclination of the maxillary anterior teeth were prominent. As for soft tissues, the change in the nasal tip was small and posterior change was large in the subnasal and upper lip areas. Nasolabial angle, nasal height, and inclination of nasal tip increased, while upper lip protrusion, nasal tip angle, and philtrum length decreased. Correlations were found between posterior changes in hard tissues and posterior changes in soft tissues. Among these, posterior changes and lingual inclination of the maxillary anterior teeth strongly correlate with posterior changes of the upper lip. CONCLUSION: Posterior shift of the maxillary anterior segment using the WW technique is useful because it can greatly improve the protrusion of the upper lip while minimizing nasal morphological changes, and the positioning of the maxillary anterior teeth may be an important key factor.

Screening of Sensorial and Inflammatory Changes in Patients Submitted to Orthognathic Surgery.

BACKGROUND: Despite the high levels of success after orthognathic surgery, the immediate postoperative pain and edema, besides the neurosensorial deficits, are common complications. OBJECTIVE: This study aimed to evaluate the pattern of sensory and inflammatory responses in patients undergoing orthognathic surgery. METHODS: This prospective observational study included 20 patients undergoing bimaxillary orthognathic surgery, who were evaluated in the preoperative period and on Days 1, 2, 3, 4, 5, 6, 7, and 30 after surgery, using a battery of tests to assess sensorial and inflammatory changes. RESULTS: Subjective and objective evaluations of edema indicated a trend toward edema resolution within 30 days, with a significant decrease in mouth opening on days 1, 7, and 30 after surgery. Regarding nasal obstruction, a significant increase in Nasal Obstruction Symptom Evaluation (NOSE) scores was demonstrated on the first, second, and third days, returning to preoperative levels after 30 days. There was a significant increase in visual analogic scale (VAS) scores from the first to the seventh day after surgery, with a reduction within 30 days. For mechanical and thermal sensitivity tests, the lower lip and chin regions had poorer results, without recovery after 30 days. Positive correlations were observed between painful and inflammatory parameters, as well as between subjective and objective evaluations. Analysis of saliva biomarkers did not show significant differences for pre- and postoperative CCL3 or CCL4 levels. CONCLUSION: Data provide new evidence about the early inflammatory and sensorial complications after orthognathic surgery.

Honoring Professor Hugo Lorenz Obwegeser: A Visionary in Maxillofacial Surgery and Orthodontics.

Hugo Lorenz Obwegeser was a pioneering Austrian surgeon whose contributions profoundly transformed the field of maxillofacial surgery. His groundbreaking work marked a pivotal turning point, enabling more sophisticated and effective corrections of facial deformities. Obwegeser revolutionized his area of expertise by introducing innovative osteotomies of the mandible and maxilla, which became foundational techniques for addressing facial asymmetries. In addition to his surgical advancements, Obwegeser was a key figure in establishing the European Association for Cranio-Maxillo-Facial Surgery, helping to define the modern scope of the specialty. His legacy in maxillofacial surgery is distinguished by his unwavering commitment to innovation, mentorship, and the continuous advancement of surgical practices. This article aims to honor the extraordinary achievements of Hugo Lorenz Obwegeser and his lasting impact on the field of maxillofacial surgery.

Mandible-First and Maxilla-First Sequencing in Virtual Surgical Planning for Orthognathic Surgery: Comparison of Planned and Actual Outcomes.

Background: Recent studies have shown that virtual planning for orthognathic surgery is an accurate and repeatable method. It is also a fact that surgical sequence can affect the results in terms of accuracy. Various studies stated that both approaches offer comparable results when properly planned and implemented; however, further clinical studies are still needed. This study aims to evaluate the effect of virtual surgical planning (VSP) on surgical outcomes and whether it is affected by mandible-first or maxilla-first approaches. Methods: This study analyzed data from 45 patients who underwent orthognathic surgery due to dentofacial deformity. Six of these patients underwent single-jaw orthognathic surgery, and 39 underwent bimaxillary orthognathic surgery (Maxilla-first group: 21, mandible-first group: 18). The displacements of specific landmarks were assessed by comparing preoperative and postoperative conventional computed tomographies with VSP data. Results: This study showed a statistically significant relationship between the measurements made with the 2 methods (r = .944; P = .0001). The fact that the intra-class correlation coefficient value is statistically significant and relatively high and that most of the differences in the Bland-Altman chart fall between the limits of compliance indicates a correlation between the virtual plan and surgical outcomes. In addition, in vertical measurements, the absolute mean difference of the B point and the Pogonion in the Maxilla-first group were statistically significantly higher than in the Mandible-first group (P = .038, P = .011). Conclusions: Our findings corroborate the high accuracy of the VSP reported in previous studies and also demonstrate that VSP with both maxilla-first and mandible-first sequencing achieves high accuracy in the sagittal and coronal planes. Although virtual planning significantly influences accurate surgical outcomes, it is not the sole determinant. Factors like condylar positioning and fixation methods can also impact the final results.

Variations of the Lingula and Mandibular Ramus in the Context of Sagittal Split Ramus Osteotomy: A Cone Beam Computed Tomography Study Supporting an Ethnic-Centric Approach to Orthognathic Surgery.

OBJECTIVES: To investigate the ethnic variations concerning the lingula and ramus of the mandible, with particular emphasis on sagittal split ramus osteotomy (SSRO) in orthognathic surgery. MATERIALS AND METHODS: This study examined Cone beam computed tomography (CBCT) scans from the Kenyan and Malay populations. Lingula morphology was classified into four categories. Morphometric measurements included lingula size, height above the occlusal plane, distance to the second mandibular molar, and distance from its apex to all four mandible borders. Regarding the ramus of the mandible, the thickness of each cortical plate, trabecular bone, and overall thickness were determined at two points. Furthermore, points of fusion of cortical plates were determined in both the vertical and horizontal planes. RESULTS: Among Kenyans, the triangular shape was most common (46.5%, n = 80 sides), while truncated was most common among Malays (34.4%, n = 57 sides). The overall mean size of lingula differed significantly between Kenyan (7.37 ± 2.19 mm) and Malay (4.14 ± 2.50 mm) populations (p<0.001). The lingula was more located postero-superiorly in Kenyans compared to Malays (p < 0.001). The mean distance from the distal aspect of the second mandibular molar to the lingula was 38.37 ± 4.98 mm among Kenyans, in contrast to 31.95 ± 0.03 mm among Malays (p < 0.001). The Malays exhibited a thicker mandible with a larger trabecular distance (5.99 ± 1.41 mm and 3.41 ± 1.29 mm, respectively) than Kenyans (5.28 ± 1.39 mm and 1.98 ± 0.98 mm, respectively) (p < 0.001). The points of fusion of the cortical plates differed significantly between Kenyans and Malays. CONCLUSION: This study focuses on two ethnic groups, Kenyans and Malays, and brings to light the ethnic-based differences in the position of the lingula and the dimensions of the mandibular ramus, both of which are essential considerations in orthognathic surgery. Preoperative consideration of such variations is warranted, potentially mitigating iatrogenic injuries and enhancing successful patient outcomes.

Changes in facial appearance alter one's sensitivity not only to the self but also to the outside world.

Introduction: Changes in facial appearance due to orthognathic surgery are known to improve a patient's postoperative quality of life, however, potential changes in cognitive function are unknown. This study examined the effects of changes in facial appearance due to orthognathic surgery on the sensitivity to self and to outside objects in patients with jaw deformities. Methods: Patients with jaw deformities (n = 22) and healthy controls (n = 30) were tested at 3 months preoperatively, at 1 month preoperatively, and at 1 month postoperatively to assess their impression of objects (positive, negative, and neutral pictures) and their evaluation of their own face and body. Results: The results showed that changes in facial appearance improved self-evaluation and increased their sensitivity to emotional objects even when the objects were identical. Furthermore, the improving rating for own face was associated with the sensitivity for objects. Discussion: The changes in facial appearance in patients may have helped to clear the sensitivity to these emotional objects. These findings may provide a new indicator of efficacy in orthognathic surgery.

Establishment of Cephalometric Hard Tissue Profile among Bengali and Caucasian Populations for Orthognathic Surgery.

The study aimed to compare cephalometric hard tissue profile values and analysis between Bengali and Caucasian populations. The study included 100 individuals (50 males, 50 females) aged 18-35. Subjects having class I molar occlusions and well-balanced facial profiles were included in the study. Lateral cephalograms were taken with consent, and a prestructured proforma recorded relevant information and cephalometric measurements. Our study found increased posterior cranial base length in Bengali males and increased anterior cranial base length in both sexes. Bengali males had a less convex profile, while females had a more convex profile compared to Caucasians with similar mandibular features. Increased maxillary and mandibular incisor proclination was observed. Our findings indicate the necessity for separate norms for orthognathic surgery in normal ethnic Bengali adults.

Maxillofacial bone movements-aware dual graph convolution approach for postoperative facial appearance prediction.

Postoperative facial appearance prediction is vital for surgeons to make orthognathic surgical plans and communicate with patients. Conventional biomechanical prediction methods require heavy computations and time-consuming manual operations which hamper their clinical practice. Deep learning based methods have shown the potential to improve computational efficiency and achieve comparable accuracy. However, existing deep learning based methods only learn facial features from facial point clouds and process regional points independently, which has constrains in perceiving facial surface details and topology. In addition, they predict postoperative displacements for all facial points in one step, which is vulnerable to weakly supervised training and easy to produce distorted predictions. To alleviate these limitations, we propose a novel dual graph convolution based postoperative facial appearance prediction model which considers the surface geometry by learning on two graphs constructed from the facial mesh in the Euclidean and geodesic spaces, and transfers the bone movements to facial movements in dual spaces. We further adopt a coarse-to-fine strategy which performs coarse predictions for facial meshes with fewer vertices and then adds more to obtain more robust fine predictions. Experiments on real clinical data demonstrate that our method outperforms state-of-the-art deep learning based methods qualitatively and quantitatively.

Harmonizing soft tissue subnasale and chin position in a forehead-based framework: interracial commonalities and differences between Asian and Caucasian females.

OBJECTIVES: To establish a reference system for assessing the anteroposterior (A-P) position of the subnasal and lower-facial soft tissues for whole facial harmony. MATERIALS AND METHODS: Forty Asian and 40 Caucasian females with attractive profiles were selected as the "attractive" samples, with "ordinary" samples for comparison. Each profile was analyzed, and comparisons were made to reveal the interracial commonalities and differences. Esthetically essential parameters were established. An averaged attractive profile for each race was created by digital morphing and then modified into 30 variations based on combined variations of the esthetically essential parameters. Assessments were performed to investigate the esthetic ranges. RESULTS: A-P position of the subnasal and lower-facial landmarks harmonized with the forehead for female profile esthetics. In addition to balanced soft tissue subnasale (sSn)- and soft titssue pogonion (Pos)-to-forehead A-P relations, harmonizing lower-facial soft tissues to sSn was indispensable for profile attractiveness. sSn-to-glabella, Pos-to-glabella, and Pos-to-sSn A-P relations were esthetically essential. Perceived by orthodontists, the attractive Asian female profiles had sSn-to-glabella A-P relations ranging from 0.5 mm to 4.5 mm, Pos-to-sSn from -9.0 mm to -5.5 mm, and Pos-to-glabella from -8.5 mm to -1.0 mm. Compared with Asians, the attractive Caucasian female profiles had more anteriorly and widely distributed sSn relative to the forehead, wider ranges of Pos-to-sSn A-P relations, and more prominent chins. CONCLUSIONS: A reference system comprising sSn-glabella, Pos-sSn, and Pos-glabella horizontal distances was constructed for facial profile analysis. This system could aid treatment planning for surgical or orthopedic repositioning of the maxilla and chin.

Enhancing surgical occlusion setting in orthognathic surgery planning using mixed reality technology: a comparative study.

OBJECTIVES: Orthognathic surgery necessitates precise occlusal alignment during surgical planning, traditionally achieved through manual alignment of physical dental models as the recognized gold standard. This study aims to evaluate the efficacy of mixed reality technology in enhancing surgical occlusion setting compared to traditional physical alignment and an established virtual method, addressing the research question: Can mixed reality technology improve the accuracy and efficiency of occlusion setting in orthognathic surgery planning? MATERIALS & METHODS: This experimental study compared the surgical occlusion settings of 30 orthognathic cases using three methods: a new virtual method with mixed reality technology, the traditional gold standard of physical alignment, and an established virtual occlusion method using the IPS Case Designer (KLS Martin SE & Co. KG, Tuttlingen, Germany). RESULTS: Results indicated that surgical occlusions set with mixed reality technology were comparable to the conventional method in terms of maxillary movement and occlusal relationship. Differences observed were within the inter-observer variability of the gold standard. Both virtual methods tended to position the maxilla more anteriorly, resulting in fewer occlusal contacts. However, virtual occlusion demonstrated clinical applicability, achieving an average of 11 occlusal contacts with a bilaterally symmetrical distribution along the dental arch. CONCLUSIONS: The mixed reality environment provides an intuitive and flexible experience for setting surgical occlusion, eliminating the need for costly 3D-printed physical models or the automatic calculations required by other virtual occlusion methods, thereby offering maximum freedom. CLINICAL RELEVANCE: As a novel form of virtual occlusion, it presents a comprehensive tool that contributes to a timely and cost-effective full digital workflow of orthognathic surgery planning.

Effectiveness of tranexamic acid on intra- and postoperative bleeding in Bimaxillary osteotomies: a retrospective study.

PURPOSE: Perioperative bleeding is a serious concern during orthognathic surgery. Tranexamic acid (TXA), a synthetic lysine analog with antifibrinolytic properties, reduces blood loss across various surgical fields. This study aimed to investigate the effectiveness of preoperative TXA administration in reducing intraoperative and postoperative blood loss following combined Le Fort I and sagittal split ramus osteotomies at our hospital. METHODS: This single-center, retrospective cohort study included patients who underwent combined Le Fort I and sagittal split ramus osteotomies between November 2017 and October 2022. The primary outcome was the volume of intraoperative blood loss. RESULTS: Among 1,329 eligible patients, 87 were included in the analysis (32 in the TXA group and 55 in the control group, where no TXA was administered). The median (interquartile range) intraoperative blood loss was 200.0 (157.5-237.5) mL in the TXA group and 260.0 (180.0-350.0) mL in the control group, showing a significant difference between the groups (p = 0.0365). However, postoperative blood drainage within 24 h and 24-48 h did not differ significantly between the two groups. CONCLUSION: A single intravenous administration of TXA was associated with a decrease in intraoperative bleeding without severe adverse events during combined Le Fort I and sagittal split ramus osteotomies. However, postoperative blood loss, nausea, vomiting, and autologous blood transfusion were not significantly associated with this administration.

Correlation between oral cavity volume and upper airway changes in skeletal Class III patients undergoing bimaxillary orthognathic surgery: a pilot cone-beam computed tomography study.

OBJECTIVES: To evaluate changes of the upper airway and oral cavity volumes in patients with skeletal Class III malocclusion undergoing bimaxillary orthognathic surgery, and to analyze the correlation between postoperative upper airway decrease and the amount of jaw movement and oral cavity volume reduction. MATERIALS AND METHODS: Thirty patients (16 males and 14 females) undergoing bimaxillary surgery were included. Three-dimensional reconstruction of the upper airway and oral cavity were performed using preoperative (T0) and postoperative (T1) (6 months) cone-beam computed tomography scans. RESULTS: The volume, sagittal area and minimum cross-sectional area of the upper airway were diminished (P < .001). The decrease in volume and minimum cross-sectional area in the oropharyngeal region of the upper airway were weakly correlated with B-point posterior movement (P < .05). Total oral cavity volume was decreased, with maxillary oral volume increasing and mandibular oral volume decreasing (P < .001). Upper airway decrease was highly correlated with total oral volume reduction and mandibular oral volume reduction, with the most significant correlation being with total oral volume reduction (P < .001). CONCLUSIONS: Class III bimaxillary surgery reduced the volume, sagittal area, and minimum cross-sectional area of the upper airway as well as oral cavity volume. Upper airway changes were weakly correlated with anterior-posterior mandibular movement but significantly correlated with oral cavity volume changes. Thus, oral cavity volume reduction is a crucial factor of upper airway decrease in patients with skeletal Class III malocclusion undergoing bimaxillary orthognathic surgery.

Changes in the upper airway and its surrounding structures after bimaxillary surgery in patients with cleft-related Class III deformity.

OBJECTIVES: To compare upper airway changes following bimaxillary surgery for correction of Class III deformity between patients with unilateral cleft lip and palate (UCLP) and bilateral cleft lip and palate (BCLP) and to compare the preoperative and postoperative upper airway among patients with UCLP and BCLP to healthy controls. MATERIALS AND METHODS: Sixty adults with CLP-related skeletal Class III deformity (30 UCLP and 30 BCLP) who consecutively underwent bimaxillary surgery were studied retrospectively. Cone-beam computed tomography (CBCT) was performed before and after surgery to measure upper airway and movements of facial skeletal and surrounding structures. CBCT images from 30 noncleft skeletal Class I adults, matched by age, gender, and body mass index and without surgical intervention, served as controls. RESULTS: After surgery, the volume of the nasopharynx increased in patients with CLP (both P < .001). Patients with CLP did not differ from controls in postoperative volume of the nasopharynx or oropharynx. However, the nasal cavity differed significantly between patients with CLP and controls (P < .001). CONCLUSIONS: After bimaxillary surgery, the nasal cavity of patients with CLP differed significantly compared with the controls. Volumes of the nasopharynx and oropharynx did not differ between patients with CLP after surgery and controls.

Lower incisor position in skeletal Class III malocclusion patients: a comparative study of orthodontic camouflage and orthognathic surgery.

OBJECTIVES: To determine the difference between orthodontic camouflage and orthodontic-orthognathic surgery using the traditional cephalometric measurement IMPA and the newly proposed IA/PAMD, the angle between the long axis of the lower incisor (IA) and the principal axis of the mandibular alveolus (PAMD). MATERIALS AND METHODS: This study included 40 cases each in the orthodontic camouflage group (OG) and orthodontic-orthognathic surgery group (SG). The differences between the IMPA and IA/PAMD before and after treatment were compared between the two groups. T0 lateral cephalometric images of the 10 cases with the highest and lowest increase in the IA/PAMD were analyzed to identify characteristics associated with a higher risk of overdecompensation of the lower incisors during presurgical orthodontic treatment. RESULTS: Both the OG and SG showed a significant improvement in hard- and soft-tissue measurements. However, in the OG, there was significant lingual inclination of the lower incisor but only a small change in the IA/PAMD. In the surgical group, the IMPA was close to 90° after treatment, but the IA/PAMD significantly increased. CONCLUSIONS: In orthodontic camouflage, the lower anterior teeth were significantly moved lingually with a better root-bone relationship. However, this relationship deteriorated in some surgical patients. Therefore, it is important to conduct cephalometric or cone-beam computed tomography examinations during preoperative orthodontics to identify and prevent possible periodontal risks.

Comprehensive analysis of alar base inclination and lip line cant following orthognathic correction of maxillomandibular asymmetry: A retrospective study.

This paper examines the relationship between roll rotation of the jaws and changes in alar base or lip line asymmetry in the coronal plane following orthognathic correction. The study involved patients with preoperative frontal alar base and lip line asymmetries greater than 0.5° (because it corresponds to the minimum asymmetry perception threshold) and underwent bimaxillary orthognathic surgery without (Group I) or with (Group II) genioplasty. The alar base angle (ABA), lip line cant angle (LLCA), maxillary cant angle (MxCA), and mandibular cant angle (MnCA) were measured using preoperative and 12 months postoperative cone beam computed tomography (CBCT) images. Thirty-four patients were included in the study. Significant correlations were found between changes in MxCA and ABA besides between changes in MnCA and LCA in Groups I (P = 0.016, P˂0.001, respectively) and II (P = 0.002, P˂0.001, respectively). The mean of the change in ABA/the change in MxCA and the change in LLCA/the change in MnCA ratios for Group I were 0.59 ± 1.57 and 0.73 ± 0.94, respectively, while those for Group II were 0.46 ± 3.70 and 0.39 ± 2.00, respectively. Angular measurements from jugular and mental foramina points, aligned with the bony midline, offer a convenient tool for predicting alar base and lip symmetry during bimaxillary orthognathic surgery planning.

Improved stability of open bite deformities: taking control of the transverse width using digital technology and robotic archwire bending.

Many factors need to be considered when selecting treatment protocol for surgical correction of skeletal open bite deformities. In order to achieve stable long-term results, it is essential to explore the origin of the open bite, including dysfunction of the temporomandibular joint, tongue and compromised nasal breathing, in addition to the skeletal deformity. Recurrence of skeletal open bite is associated with relapse of the expanded transverse width. Three-dimensional virtual planning allows different treatment options to be explored and final decisions to be made together with the orthodontist. This study presents a treatment protocol for predictable and stable widening of the maxillary transverse width over the long term, involving premolar extraction and rounding and shortening of the upper dental arch by advancing the molar segments. The stability of inter-canine, inter-premolar, and inter-molar distances, as well as overjet and overbite, were measured in 16 patients treated with this technique; measurements were obtained pre- and post-surgery, and the mean follow-up was 43 months. Orthodontic treatment was designed digitally and finished with robotically bent wires (SureSmile), which allowed exact planning of the overall treatment, thus making orthognathic surgery more predictable for the patient. The changes in transverse width were significant and stable over time.

3-Dimensional accuracy of navigation-guided bimaxillary orthognathic surgery: A systematic review and meta-analysis.

The transfer of a virtual orthognathic surgical plan to the patient still relies on the use of occlusal splints, which have limitations for vertical positioning of the maxilla. The use of real-time navigation has been proposed to enhance surgical accuracy. This systematic review (PROSPERO CRD42024497588) aimed to investigate if surgical navigation can improve the three-dimensional accuracy of orthognathic surgery. The inclusion criteria were orthognathic surgery, use of intra-operative navigation and quantitative assessment of surgical accuracy. The exclusion criteria were non-bimaxillary orthognathic surgeries, non-clinical studies, studies without post-operative 3D analysis and publications not in the English language. A search of PubMed, Embase and Cochrane Library generated 940 records, of which 12 were found relevant. Risk of bias was assessed done using the Joanna Briggs Institute Critical Appraisal Checklist Tool. Among the included studies, there were nine of observational character and three randomized control studies (RCTs). All studies demonstrated promising outcomes with reported good surgical accuracy within a 2 mm difference between the planned and post-surgical result. Meta-analysis of two RCTs was carried out and results were in favor of surgical navigation with a total odds ratio of 4.44 [2.11, 9.37] and an overall effect outcome of Z = 3.92 (p < 0.0001). Navigation was up to 0.60 mm more accurate than occlusal wafers only (p < 0.001). However, there were variations in the application of surgical navigation and methods of analysis, leading to a heterogenous data set. Future studies should focus on standardized protocols and analysis methods to further validate the use of surgical navigation in orthognathic surgery. Despite some limitations, surgical navigation shows potential as a valuable tool in improving the accuracy of orthognathic surgery.

Does mandible ramus height asymmetry affect postoperative skeletal stability in orthognathic surgery patients?

BACKGROUND: Relapses following orthognathic surgery have been reported to exceed 2% to 50%, depending on multiple factors. This study aimed to analyze the stability after orthognathic surgery in patients with mandibular ramus height asymmetry through 3D reconstruction using Cone-beam CT. METHODS: This retrospective cohort study investigated patients who underwent mandibular setback surgery using bilateral sagittal split ramus osteotomy. Three-dimensional CT scans were taken at three different time points. Evaluation of the postoperative stability involved measuring changes in the x, y, and z axes as well as roll and yaw rotations of the mandible at specific landmarks (B point, mental foramen) on 3D CT scans obtained immediately after surgery and 6-12 months postoperatively. They were categorized into four groups based on bilateral mandibular height asymmetry through Asymmetry index (AI). The one-way ANOVA was implemented to compare the intergroup differences and Tukey's post hoc test was employed. Additionally, the Pearson correlation coefficient was also calculated. RESULTS: A total of 24 patients were included in this study. The corresponding AI, representing the degree of asymmetry in both mandibles, were calculated as Group 1 was 1.25 ± 0.64%, Group 2 was 2.89 ± 0.47%, Group 3 was 5.03 ± 0.51%, and Group 4 was 9.40 ± 1.99%. The x-axis change in Group 4 was significantly larger at 1.71 mm compared to Group 1 at 0.64 mm. The mandibular roll, Group 4 showed a statistically significant increase at 1.33° compared to Group 1 at 0.35°. And there was a significant positive correlation observed between x-axis change and AI (p = 0.019), as well as between mandibular roll and AI (p = 0.025). CONCLUSION: After orthognathic surgery, stability was influenced by numerous factors, with the findings of this study suggesting that the degree of ramus height asymmetry in the mandible can be considered one contributing factor.

A simple and free software-based inferior alveolar nerve protector surgical guide in bilateral sagittal split osteotomy.

OBJECTIVES: This technical note introduces a novel concept of a alveolar inferior nerve protector guide during orthognathic surgery based on a free-software creation and printing. TECHNICAL NOTE: Orthognathic surgery using Virtual Surgical Planning software like Dolphin Imaging ® v 11.9 facilitated a bimaxillary procedure with mandible advancement and occlusal plane correction, later followed by 3D printing of splints. The process involved importing a composite skull with osteotomies into Blender ® software, where solids were added and edited to match Dolphin's osteotomies, ensuring bone contact without distortion. The guide creation was performed adhering to bilateral sagittal split osteotomy principles, maintaining precision, resulting in preserved inferior alveolar nerve and faster operation times compared to non-guided procedures, as demonstrated by postoperative CT scans. CONCLUSIONS: Integrating advanced tools like Blender software into maxillofacial surgery represents a significant advancement. Despite challenges like the absence of specific manuals for this purpose in Blender, using such software offers innovative and cost-effective solutions. Developing user-friendly resources tailored to surgical applications such as a protector guide within Blender can enhance its usability and improve surgical outcomes and patient care, leading to groundbreaking advancements in maxillofacial surgery.

Three dimensional assessment of root changes after multi-segments Le Fort I osteotomy.

The primary purpose of this study was to accurately assess linear, volumetric and morphological changes of maxillary teeth roots following multi-segments Le Fort I osteotomy. A secondary objective was to assess whether patient- and/or treatment-related factors might influence root remodeling. A total of 60 patients (590 teeth) who underwent combined orthodontic and orthognathic surgery were studied retrospectively. The multi-segments group included 30 patients who had either 2-segments or 3-segments Le Fort I osteotomy. The other 30 patients underwent one-segment Le Fort I osteotomy. Preoperative, 1 year, and 2 years postoperative cone beam computed tomography (CBCT) scans were obtained. A validated and fully automated method for evaluating root changes in three dimensions (3D) was applied. No statistical significant differences were found between multi-segments and one-segment Le Fort I for linear, volumetric and morphological measurements. The Spearman correlation coefficient revealed a positive relationship between maxillary advancement and root remodeling, with more advancement leading to more root remodeling. This research may allow surgeons to properly assess root remodeling after combined treatment of orthodontics and the different Le Fort I osteotomies.