Comparative analysis of 3D tomography based soft tissue rendering and Proface facial scanning systems in orthognathic surgery.

PURPOSE: This study aimed to investigate the linear and angular differences in the nasolabial soft tissue in patients who underwent bimaxillary orthognathic surgery using two different three-dimensional imaging methods. Furthermore, the advantages, disadvantages, and limitations of these methods were determined after comparing the data obtained from the imaging methods used in the study. MATERIALS AND METHODS: Preoperative (T0) and 6-months postoperative (T1) cone-beam computed tomography (CBCT) and three-dimensional facial scanning (3DFS) data from 22 patients who underwent maxillary advancement surgery were examined. The DICOM (Digital Imaging and Communications in Medicine) data (CBCT group) and ".obj" format images (3DFS group) of the patients were analyzed using Dolphin software (Dolphin Imaging®, Version 12, Chatsworth, CA, USA). The linear and angular soft tissue measurements were calculated after determining the reference anatomical landmarks for both groups. RESULTS: Measurements with CBCT and 3DFS imaging methods were compared at T0, T1, and all measurements (T0+T1). No statistically significant difference was observed between the CBCT and 3DFS groups for five measurements performed at T0 and T0+T1, but statistically significant differences were observed between the groups for the other seven measurements. There was no statistically significant difference between the CBCT and 3DFS groups for six measurements at T1, but there were statistically significant differences between the groups for the other six measurements. After reviewing the postoperative differences in the nasolabial soft tissue, a statistically significant increase in four linear and one angular measurement in the 3DFS group was observed, and there was a statistically significant increase in two linear and two angular measurements in the CBCT group. Upon comparison of postoperative differences in soft tissue alterations, no statistically significant difference between the 3DFS group and the CBCT group were observed in any of the soft tissue measurements. CONCLUSION: Orthognathic surgery has significant effects on nose width and upper lip morphology. Although both 3DFS and CBCT methods can be used to evaluate such effects, the results of the present study revealed differences in sensitivity and limitations between the two methods. Thus, surgical outcomes should be evaluated in consideration of the abovementioned parameters.

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.

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.

Effect of transcutaneous electrical nerve stimulation on neuro-sensory disturbance after orthognathic surgery: a randomized clinical trial.

Background: The present study aims to determine the effect of Transcutaneous Electrical Nerve Stimulation (TENS) on neuro-sensory disturbance after orthognathic surgery. Materials and methods: In a randomized clinical trial, the participants via split-mouth sampling were randomly divided into two intervention (n=27) and control (n=27) groups. In the intervention group, participants received TENS physiotherapy. TENS physiotherapy was performed on the day after surgery, 1, 2, 3, and 4 weeks after surgery, along with prescriptions for the use of painkillers. On the control group, no physical therapy was performed and the patients only used painkillers (immediately after the operation). Paresthesia was evaluated using the 2-point discrimination (TPD) test and the semi-quantitative sensory-neural disorders test called brush stroke 6 months after the surgical procedures. Self-reported sensory-neural disorders were measured and reported for each patient before and 6 months after surgery using the visual analog scale (VAS). Results: A total of 54 patients participated in this study. The mean TPD score in the TENS group and the control group 6 months after the operation were 5.76 (SD=0.73) and 6.14 (SD=0.54), respectively (P=0.003). The mean VAS score in the TENS group and the control group 6 months after the operation was 6.48 (SD=0.50) and 5.80 (SD=0.63), respectively (P=0.005). Also, 66.7 and 38.9% in the TENS and control groups, respectively, performed the brush stroke test correctly (P=0.007). Conclusion: In sum, the benefits of TENS physiotherapy can be effective in reducing complications such as pain in dental surgery treatments or orthognathic surgeries.

Evaluation of occlusal force changes in orthognathic surgery using force-sensing sensors in 3 years of follow-up.

Purpose: The aim of this study was to test a prototype device called occlusal force diagnostic system in relation to occlusal force adaptation following orthognathic surgery. Methods: Retrospective study of 10 patients scheduled for a bimaxillary osteotomy involving a combination of maxillary Le Fort I impaction procedure coupled with a sagittal split advancement of the mandible; in a 3 years follow-up period. Results: The selection of examiner is not a variable that affects the occlusal force (N) measured by FSS sensors in any of the experimental conditions tested. The sensor position and the surgery recovery time affect the occlusal force irrespective of the examiner selection and/or the surgery recovery time. Conclusion: The piezoelectric sensors used in the present study have shown high reliability and validity of measurement. The surgery recovery time impacts the occlusal force (N), with a 50% increase in occlusal force (N) measured after 6 months post-surgery, with the value keeping stable at 36 months. This suggests that the patient is only fully recovered from the functional point-of-view at 6 months, having from that point on an improved and stable masticatory function.

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.

Impact of the orofacial muscular rehabilitation exercise on facial expression recovery post-orthognathic surgery.

OBJECTIVE: This study aimed to evaluate the impact of myofunctional rehabilitation of the orofacial muscles through specific exercises on the recovery of facial expression in patients following orthognathic surgery. MATERIAL AND METHODS: The study included 62 patients who underwent Le Fort I and sagittal split ramus osteotomy (SSRO). Patients were divided into two groups: the first group started immediate post-operative myofunctional rehabilitation of the orofacial muscles through specific exercises. In contrast, patients in Group II did not undergo any myofunctional rehabilitation post-operative exercises. The recovery of facial expressions postoperatively was evaluated in both calm and smiling states by comparing the differences between 3D facial scanning data of chosen facial anatomical structures collected at five key time points: pre-surgery (D0), 2 days (D2), 14 days (D14), 1 month (D30), and 3 months (D90) postoperatively. RESULTS: The analysis revealed that characteristic angles and lengths experienced significant changes post-surgery, with ∠chRnchL and ∠chRsnchL decreasing at D2 and normalizing by D30 in the experimental group, while the control group showed a slower recovery, normalizing by D90. The ChL-R length decreased at D2, returning to normal by D30 in the experimental group and D90 in the control group. The height Li-Ls increased at D2 and normalized by D30 in calm and smiling expressions across single and double jaw surgery patients. These findings underscore the more rapid recovery in the experimental group compared to the control group (P < 0.05; P < 0.005; P < 0.0001). CONCLUSION: Initiating myofunctional rehabilitation immediately following orthognathic surgery enhances facial muscle function recovery, improves patient confidence, and expedites social reintegration. This approach is crucial for functional and psychological benefits.

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.

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.

Empowering surgeons: will artificial intelligence change oral and maxillofacial surgery?

Artificial Intelligence (AI) can enhance the precision and efficiency of diagnostics and treatments in oral and maxillofacial surgery (OMS), leveraging advanced computational technologies to mimic intelligent human behaviors. The study aimed to examine the current state of AI in the OMS literature and highlight the urgent need for further research to optimize AI integration in clinical practice and enhance patient outcomes. A scoping review of journals related to OMS focused on OMS-related applications. PubMed was searched using terms "artificial intelligence", "convolutional networks", "neural networks", "machine learning", "deep learning", and "automation". Ninety articles were analyzed and classified into the following subcategories: pathology, orthognathic surgery, facial trauma, temporomandibular joint disorders, dentoalveolar surgery, dental implants, craniofacial deformities, reconstructive surgery, aesthetic surgery, and complications. There was a significant increase in AI-related studies published after 2019, 95.6% of the total reviewed. This surge in research reflects growing interest in AI and its potential in OMS. Among the studies, the primary uses of AI in OMS were in pathology (e.g., lesion detection, lymph node metastasis detection) and orthognathic surgery (e.g., surgical planning through facial bone segmentation). The studies predominantly employed convolutional neural networks (CNNs) and artificial neural networks (ANNs) for classification tasks, potentially improving clinical outcomes.

Postoperative maxillary stability after Le Fort I osteotomy using a u-HA/PLLA system: three-dimensional analysis by surface superimposition based on virtual Le Fort I osteotomy.

The postoperative stability achieved with Le Fort I osteotomy (LFI) using bioabsorbable systems remains controversial. A new method - multipoint measurement method - was devised for detailed three-dimensional examination of postoperative stability following LFI, and the stability after LFI when using SuperFIXSORB-MX made of u-HA/PLLA was investigated. Thirty-one patients who underwent LFI using SuperFIXSORB-MX were evaluated retrospectively. The patients were divided into four malocclusion types: open bite, mandibular retrognathia, mandibular protrusion, and facial asymmetry. Seven maxillary reference points were measured three-dimensionally using computed tomography scans obtained preoperatively (T0), 4 days post-surgery (T1), and 1 year post-surgery (T2). Surgical changes (T1-T0) and the postoperative discrepancy (T2-T1) of the maxilla were analysed to evaluate postoperative stability by surface superimposition of the virtual LFI segments. Postoperative discrepancy was the largest for the facial asymmetry type, ranging from 0.75 ± 0.45 mm to 0.98 ± 0.52 mm in three-dimensional distance (minimum to maximum mean ± standard deviation values for the individual reference points). The relapse at U1 was 16% in the transverse axis, and the anterior nasal spine moved further upward by 17% of the amount of movement of the maxilla. Fixation with SuperFIXSORB-MX was considered to be within clinically acceptable limits.

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.

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.

Maxillary advancement surgery with vertical component: Impact on the nasolabial aesthetics.

The aim of this study is to evaluate the changes in nasolabial soft tissues following Le Fort I osteotomies, focusing on the impact of maxillary vertical repositioning. This retrospective study included 39 patients with a history of Le Fort 1 osteotomy between 2013 and 2021. Patients were grouped based on their maxillary movement into three categories: pure advancement (group A), advancement with impaction (group B), and advancement with downward repositioning (group C). Preoperative and postoperative CBCT (Cone Beam Computed Tomography) data were analyzed to measure the changes in nasolabial soft tissues. The current study utilized Mimics Suite 20.0 for measuring linear and angular variables. The evaluated variables included intercanthal distance, nasal dorsal length, tip protrusion, mouth width, alar width, upper lip height, nostril dimensions, and angles of nasolabial, alar base, and upper lip. Among them intercanthal distance, nasal dorsal length, or tip protrusion showed no statistical difference (p > 0,05). Mouth width, alar width, alar base angle were increased and upper lip angle was decreased significantly (p < 0.001). Changes in upper lip height and nasolabial angle differed among the groups of the study. While upper lip height increased significantly in groups A and C (p < 0.05), there was a slight decrease in Group B with no significance (p > 0.05). Nasolabial angle decrased significantly on Groups A and B (p < 0.05). The results of this study revealed changes in several soft tissue parameters, some of which occurred regardless of vertical repositioning of the maxilla. Within the limitations of the study, maxillary advancement surgery can affect the aesthetics of the nasolabial region and cause specific changes in related soft tissues. Understanding these changes is essential to establish realistic patient expectations and achieve optimal functional and aesthetic outcomes.

Analysis of Three-Dimensional Tooth Movement: A Comparative Study Between Digital Dental Models and Craniofacial Models.

OBJECTIVE: This study aims to validate the efficacy of using a digital dental model (DM) with reference to the palatal region of interest (PROI) for assessing orthodontic tooth movement (TM) by comparing it with the analysis of a computed tomography (CT) model with reference to the cranial region of interest (CROI). MATERIALS AND METHODS: Thirty-four patients (mean age: 21 years and 11 months) with jaw deformities underwent DM and CT scans before and after presurgical orthognathic treatment. Linear and angular measurements during TM were conducted in three dimensions using both DM and CT to assess reliability. RESULTS: DM analysis with PROI registration exhibited high levels of reproducibility, with minimal standard errors in X, Y, and Z displacements (<0.15 mm) and 0.43 degrees in angular change. CT analysis with CROI registration demonstrates similarly high reproducibility, with standard errors inferior to DM analysis (<0.20 mm). Bland-Altman analysis indicated agreement in linear changes of each X, Y, and Z displacement between DM and CT measurements, with limits of agreement (LOA) below 0.91 mm. CONCLUSIONS: The results of this study suggest that the PROI, focusing on the third palatal rugae and the horizontal part of the palatal vault, serves as a reliable reference region for evaluating three-dimensional (3D) tooth movement. CLINICAL SIGNIFICANCE: Digital dental models offer distinct advantages including the absence of X-ray exposure, no metal artifacts, and the ability to generate high-resolution 3D models. The methodology demonstrated high precision and reproducibility, supporting its potential clinical utility in orthodontic treatment planning and assessment.

Accuracy and clinical fit of milled versus rapid prototyped orthognathic surgical splints.

Three-dimensional (3D) printing has slowly become an integral part of orthognathic surgery. However, there is a lack of studies evaluating accuracy of orthognathic surgical splints fabricated from subtractive milling versus additive 3D printing. The primary aim of this in vitro study was to compare the differences in trueness between milled and 3D-printed splints, while the secondary aim was to compare the differences in clinical fit of these splints. A sample of eight patients was selected, and STL files of the final orthognathic surgical splint were used to fabricate three splints for each of the eight cases. The first splint was fabricated by subtractive milling (SM), whereas the second and third splints were 3D printed with Digital Light Processing (DLP) and Laser Stereolithography (SLA), respectively. Paired superimposition of scans was performed using a reference model. The clinical fit of the splints to the printed models was also assessed. The mean root mean square (RMS) deviations for the SM, SLA, and DLP were 0.11 ± 0.02, 0.16 ± 0.02 and 0.14 ± 0.02 respectively. The post-hoc analysis showed that the SM splints had the highest accuracy (p<0.01). However, DLP splints showed the best clinical fit, followed by SM and SLA. In conclusion, splints fabricated by SM were more accurate than those fabricated by 3D printing, although this difference may not be clinically significant. The site, rather than the magnitude of the errors, may have a greater effect on the clinical usability of splints. In general, SM and DLP splints demonstrated a good clinical fit and were suitable for the fabrication of surgical splints.

Comparative analysis of postoperative complications and outcomes in outpatient versus inpatient orthognathic surgery: A retrospective cohort study.

The purpose of this study was to assess and compare the complication rates of single-jaw orthognathic surgery between outpatients and inpatients, and to examine their impact on the outcome of care setting. A retrospective cohort study was performed of patients who underwent single-jaw orthognathic procedures. Outpatients between 2008 and 2023 were selected as the study group, while inpatients between 1997 and 2023 were enrolled as the control group. The predictor variable was the patient care setting. The primary outcome variable was the occurrence of overall complications. Secondary outcomes included surgery-, anesthesia-, and patient-related complications. Other study variables included age, sex, surgery, and anesthetic procedures. Descriptive, bivariate, and multiple logistic regression statistics were computed and the significance level was set at p ≤ 0.05. The sample included 307 patients with a mean age of 23.1 years ±9.5 years, of whom 55% were female. The outpatient and inpatient groups consisted of 123 (40.1%) and 184 (59.9%) patients, respectively. Of the 123 outpatients, 104 (85.5%) were discharged on the day of surgery. Age (p = 0.012) and ketamine administration (p = 0.022) were significantly associated with complications among outpatients. Outpatient setting and age were significantly associated with overall complications (OR 2.48; 95% confidence interval [CI] 1.34-4.66, p = 0.003 and OR 0.94, 95% CI 0.88-0.98, p = 0.021, respectively) and anesthetic-related complications (OR 4.43, 95% CI 2.03-10.5, p = 0.0003 and OR 0.92, 95% CI 0.83-0.98, p = 0.041, respectively). The study demonstrated that outpatient orthognathic surgery had a high success rate but also identified a higher rate of anesthetic-related complications among outpatients, particularly in younger patients and in those receiving ketamine.