Long-term Stability Over 2 Years After Isolated Maxillary Orthognathic Surgery Combined With Mandibular Autorotation in Risk Patients for Condylar Resorption.

OBJECTIVE: Counterclockwise rotation of mandible can cause condylar resorption and condylar displacement posteroinferiorly after maxillary orthognathic surgery with mandibular in patients with high-angle mandibular retrognathism. This study was aimed to evaluate long-term stability >2 years and postoperative changes of condylar displacement. MATERIALS AND METHODS: In 15 patients who underwent Le Fort I osteotomy with mandibular autorotation, postoperative stability was cephalometrically investigated until 2 years. Condylar changes were analyzed with transcranial temporomandibular joint projection. Correlation between condylar displacement and surgical movement was analyzed. RESULTS: Significant clockwise relapse of mandible ( P <0.01 for SNB reduction and backward movement of point B) was observed between 6 months and >2 years after surgery, even though the values were small (0.5±0.1 degrees and 1.14±0.13 mm, respectively). The condyle was displaced posteroinferiorly immediately after surgery; however, it achieved a stable position at postoperative 6 weeks. The amount of vertical condylar displacement was significantly correlated with surgical change in mandibular posterior border sagittal angle, palatal plane angle, facial height ratio, and point B in the horizontal dimension. Greater mandibular rotation prompted more vertical condylar displacement. CONCLUSIONS: Small mandibular relapse in long term should be considered after maxillary orthognathic surgery with mandibular autorotation, although it is regarded as a surgical maneuver to minimize mandibular instability in patients susceptible to postoperative condylar resorption.

Remote Real-Time Training for Sustainable Cleft Operation in Rural Region of West Africa: Effective Webinar in the COVID-19 Pandemic.

INTRODUCTION: The surgical requirement for cleft lip and palate repair remains unmet in many developing areas of the world, including remote regions of Ghana. This article reviews the utilization of Internet education and online consultation for cleft lip and palate surgical training in Sunyani Regional Hospital (SRH), Ghana. METHODS: The cleft lip and palate treatment was promoted to patients in remote areas of Sunyani, Ghana region, through a charitable outreach program. These basic designs and settings were managed by local participants such as doctors, residents, nurses, and staff in SRH, Ghana. RESULTS: From November 2014 to December 2020, the authors collaborated in surgical treatment for 84 cases that were diagnosed with unilateral cleft lip, bilateral cleft lip, hard and soft palate cleft, and microstomia. The type of surgery has varied and has included cheiloplasty, palatoplasty, and others. The average scores of esthetic outcome evaluation were nasal form=2.4, symmetry of the nose=2.9, and vermillion border=2.9. Through the program, the surgeons and residents became significantly more proficient at cleft lip and palate surgery. The seminar topics have covered essential and sustainable topics based on SRH's current needs and showed the effectiveness in the current coronavirus disease-19 pandemic situation. CONCLUSIONS: The shortage of orofacial cleft surgeons working in rural areas like Sunyani, Ghana, remains an obstacle that poses a challenge to any effort to improve health care quality in these rural communities. Sustainable remote education is essential for the training of local cleft surgeons to fill this local need; our collaborative and charitable program could be a recommended education design for cleft surgeons and institutes for their sustainable education.

Anterior Dental Implant in Grafted Cleft Alveolus: A Clinical Comparison Between Intramembranous and Endochondral Bone Graft.

BACKGROUND: Alveolar bone graft is usually performed during the early mixed dentition phase, at the chronological age of 6 to 8 years old, to reconstruct the cleft alveolus. As the appropriate time for implant placement is after completion of full growth, it can result in a likelihood of resorption. The aim of this study is to compare the clinical outcomes of anterior dental implants with delayed bone grafting using iliac crest (endochondral) and mandibular ramus or symphysis (intramembranous) bone in adolescents to adulthood patients with cleft alveolus. MATERIALS AND METHODS: This study included 10 patients with cleft alveolus who underwent delayed bone grafting with autogenous block bone and particulate cancellous bone and marrow (PCBM) from the mandibular ramus and symphysis with dental implant placement, and iliac crest. The success of the treatment was evaluated through clinical and radiographic examination including marginal bone loss measurement of the implants. RESULTS: All patients underwent delayed bone grafting between the ages of 11 and 21.1 years (mean age: 15.1±4.3 y). The implant diameters ranged from 3.8 to 4.5 mm and the lengths ranged from 8.0 to 11.5 mm. All of the implants were integrated successfully and survived during the 3-year follow-up period. CONCLUSIONS: Delayed bone grafting followed by implant placement showed long-term stability with satisfactory esthetic and functional rehabilitation. One of the main advantages of delayed bone grafting is to achieve adequate bone support for future dental implant placements with less bone resorption compared with those of primary, early secondary, and secondary bone grafting.

Reconstruction of Mandibular Contour Defect Using Patient-Specific Titanium Implant Manufactured by Selective Laser Melting Method.

ABSTRACT: The purpose of this study was to evaluate the surgical accuracy and postoperative stability of patient-specific titanium implants (PSTIs) manufactured by the selective laser melting method and applied for mandibular contour reconstruction. For 2 patients who showed asymmetry of the mandibular angle after mandibuloplasty, including angle reduction, reconstructive surgeries of the mandibular contour defects were performed using PSTI. Patient-specific titanium implant was three-dimensional designed using a mirror image similar to the shape of the contralateral side, and 3 screw holes were formed, avoiding the inferior alveolar nerve. Patient-specific titanium implant was applied intraorally, and screw fixation was performed via a transbuccal approach. Surgical accuracy and postoperative stability were evaluated by comparing preoperative three-dimensional design with immediate postoperative computed tomography (CT), and immediate postoperative CT with postoperative 6-month CT, respectively. Both patients were satisfied with the surgical results, and no complications were observed. Surgical accuracy was defined as a mean Hausdorff distance <0.4mm, and postoperative stability was defined as a mean Hausdorff distance <0.3mm. Our results suggest that PSTI by the selective laser melting method for augmentation of the mandibular border is useful as an additional cosmetic surgery.

Legal Liability of a Dentist: Inferior Alveolar Nerve Damage After Calcium Hydroxide Extrusion.

ABSTRACT: During root canal treatments, calcium hydroxide can extrude through the apex causing chemical, mechanical, and/or thermal injuries to the inferior alveolar nerve, which can lead to neurological disorders. unfortunately, dental practitioner negligence can produce this potentially life-changing injury that can compromise the patient's life. The aim of this study is present a case of dental negligence by calcium hydroxide extrusion causing inferior alveolar nerve damage, discuss the methods of prevention, and characterize the medico-legal aspects of complication.

Accurate Mandible Reconstruction by Mixed Reality, 3D Printing, and Robotic-Assisted Navigation Integration.

ABSTRACT: Mandibular reconstruction is one of the most complex procedures concerning the patient's postoperative facial shape and occlusion condition. In this study, the authors integrated mixed reality, three-dimensional (3D) printing, and robotic-assisted navigation technology to complete the mandibular reconstruction in a novel and more accurate way. Mixed reality can visualize the significant anatomical structures of the operative area, but only be used in simulated operation by now. Three-dimensional printing surgical guide plate makes it easy to separate tissue, while imprecision often occurs due to the potential of displacement and deformation. In recent years, most robotic-assisted navigation surgery technology can only achieve precise position by 2D view on the screen but not realistic 3D navigation. in this study, the integrated 3 technologies were used in mandibular reconstruction. Preoperative imaging examination was performed, and the data were imported into the digital workstation before operation. First, the original data was edited and optimized to reconstruct the digital model and formulate the surgical plan. Then MR was used to output the visualized project and matched the 3D reconstruction model in reality. The 3D plate was printed for surgical guidance. Last, robotic-assisted navigation was used to guide and position the vascularized fibula autograft and the immediate dental implantation. In conclusion, the authors integrated the 3 technologies and constructed a new digital surgical procedure to improve surgical accuracy and simplify the procedure comparing with traditional surgery.

Effects of 17ß-Estradiol Deficiency and Mechanical Overload on Osseous Changes in the Rat Temporomandibular Joint.

PURPOSE: To deduce the contributing factors to idiopathic condylar resorption in young female patients, we hypothesized that 17ß-estradiol (E2) deficiency would cause arthritic changes in the mandibular condyle under mechanical overloading in a rat model. We also hypothesized that osseous changes in the microstructure by the combination of E2 deficiency and mechanical overloading would be different depending on the region of the condyle. MATERIALS AND METHODS: The mandibular condyles of female Sprague-Dawley rats were mechanically overloaded (50g) 8 weeks after an ovariectomy (OVX). Changes in the condyles were analyzed with micro-computed tomography and histochemical and immunohistochemical staining. RESULTS: The size of the mandibular condyle decreased significantly with OVX or mechanical loading. The incidence of arthritic changes, including osteophyte formation, bone erosion, and flattening, was significantly different between the sham and OVX groups. The posterior parts of the condyles showed poor bone quality before OVX, and their condition significantly worsened with reduced bone mineral density and bone volume/tissue volume, as well as a sparse trabecular pattern. CONCLUSIONS: E2 deficiency and mechanical overloading of the temporomandibular joint cause morphologic changes in the mandibular condyle and changes in the osseous microstructure, which are more apparent in areas of poor bone quality.

Quantitative Augmented Reality-Assisted Free-Hand Orthognathic Surgery Using Electromagnetic Tracking and Skin-Attached Dynamic Reference.

The purpose of this study was to develop a quantitative AR-assisted free-hand orthognathic surgery method using electromagnetic (EM) tracking and skin-attached dynamic reference. The authors proposed a novel, simplified, and convenient workflow for augmented reality (AR)-assisted orthognathic surgery based on optical marker-less tracking, a comfortable display, and a non-invasive, skin-attached dynamic reference frame. The 2 registrations between the physical (EM tracking) and CT image spaces and between the physical and AR camera spaces, essential processes in AR-assisted surgery, were pre-operatively performed using the registration body complex and 3D depth camera. The intraoperative model of the maxillary bone segment (MBS) was superimposed on the real patient image with the simulated goal model on a flat-panel display, and the MBS was freely handled for repositioning with respect to the skin-attached dynamic reference tool (SRT) with quantitative visualization of landmarks of interest using only EM tracking. To evaluate the accuracy of AR-assisted Le Fort I surgery, the MBS of the phantom was simulated and repositioned by 6 translational and three rotational movements. The mean absolute deviations (MADs) between the simulation and post-operative positions of MBS landmarks by the SRT were 0.20, 0.34, 0.29, and 0.55 mm in x- (left lateral, right lateral), y- (setback, advance), and z- (impaction, elongation) directions, and RMS, respectively, while those by the BRT were 0.23, 0.37, 0.30, and 0.60 mm. There were no significant differences between the translation and rotation surgeries or among surgeries in the x-, y-, and z-axes for the SRT. The MADs in the x-, y-, and z-axes exhibited no significant differences between the SRT and BRT. The developed method showed high accuracy and reliability in free-hand orthognathic surgery using EM tracking and skin-attached dynamic reference.

Effects of Chewing Exerciser on the Recovery of Masticatory Function Recovery after Orthognathic Surgery: A Single-Center Randomized Clinical Trial, a Preliminary Study.

Background and Objectives: The aim of this study was to evaluate the effects of the chewing exerciser (CE) on the functional recovery of the masticatory muscles after orthognathic surgery. Material and Methods: This randomized clinical trial was conducted in patients undergoing bimaxillary orthognathic surgery including bilateral sagittal split ramus osteotomy. Postoperative physiotherapy (PT) was performed for 3 weeks starting 3 weeks after the surgery. The patients were randomly divided into two groups: control (Con) (conventional PT) group and CE group (use of CE in addition to conventional PT). The masticatory function was evaluated based on three standards: bite force (BF), amount of mouth opening (MO), and surface electromyography (sEMG) of the anterior temporal muscle (TA), masseter muscle (MM), sternocleidomastoid muscle, and anterior belly of digastric muscle before, 3 weeks (before PT) and 6 weeks after the surgery (after PT). Results: Finally, 22 subjects participated in this study: 10 patients for Con group and 12 patients for CE group. In both groups, the BF, which was reduced significantly after the surgery, recovered after the PT similar to that before the surgery. In both groups, the MO was also significantly reduced by the surgery. However, it did not recover as much, as it was before the surgery after applying the PT. There was no difference in BF and MO between the two groups. All muscles did not show significant changes in sEMG by surgery and PT at both resting and clenching states. Conclusion: Applying CE as a PT after orthognathic surgery did not cause any harmful side effects. In both groups, the weakened muscle activity after orthognathic surgery (OGS) was adequately restored 6 weeks after the surgery. However, CE did not offer a statistically significant benefit to the masticatory function in the recovery process after OGS.

Repositioning of the Maxillomandibular Complex Using Maxillary Template Adjusted Only by Maxillary Surface Configuration Without an Intermediate Splint in Orthognathic Surgery.

Accurate repositioning of the maxillary and mandibular segment is essential to improve esthetics and function in orthognathic surgery. With the improvement of three-dimensional imaging technology and computer-aided design and manufacturing techniques, various computer-aided design and manufacturing templates have been developed as alternatives to the traditional error-prone and time-consuming intermediate splint. However, the majority of previously developed templates still use an intermediate splint or the structures connected to occlusal surface and transferred the preoperative virtual plan to the real operation field indirectly.Here, the authors introduce a technical note regarding maxillary surgical templates adjusted only by the maxillary surface configuration. These templates consist of osteotomy and repositioning guide templates that provide information about the osteotomy line, bony interference, and planned position and eliminate the need for an intermediate splint. Using these templates, the maxillomandibular complex can be successfully repositioned without using an intermediate splint. Further studies are needed to determine the accuracy and stability of maxillary templates.

Adaptation of soft tissue following bilateral sagittal split ramus osteotomy in skeletal class III patients with facial asymmetry: A retrospective study.

PURPOSE: This retrospective study aimed to evaluate sequential changes in soft tissue thickness after bilateral sagittal split ramus osteotomy (BSSRO) in skeletal class III patients with facial asymmetry and to explore their correlation with surgical movements for optimal postoperative facial symmetry and esthetic outcomes. MATERIAL AND METHODS: This study included 37 patients with class III malocclusion and > 4 mm Menton (Me) deviation who underwent BSSRO. Posteroanterior cephalograms were captured at preoperative (T0), 6 weeks (T1), 6 months (T2), and 1 year (T3) postoperative intervals to analyze changes in Me deviation, fronto-ramal inclination (FRI), and soft tissue thickness. Statistical analysis was conducted to assess the changes in soft tissue thickness over time and the effects of surgical correction. RESULTS: Significant improvements in facial asymmetry were noted after surgery, with reductions in Me deviation and FRI on both the deviated side (DS) and non-deviated side (NDS). An increase in soft tissue thickness was observed on both the DS and NDS after surgery, with the NDS showing a continued increase between 6 months and 1 year, indicating an ongoing compensation for symmetry restoration. The study also identified a positive correlation between the surgical movement of the FRI and the increase in soft tissue width on the NDS after 6 months. CONCLUSION: This study established that soft tissue thickness continues to adapt and change up to 1 year after BSSRO, underscoring the need for a long-term evaluative approach in orthognathic surgery for patients with facial asymmetry.

Growth characteristics and classification systems of hemifacial microsomia: a literature review.

BACKGROUND: Hemifacial microsomia is characterized by the hypoplasia of the mandible and temporomandibular joint, involving a variety of abnormalities of the craniofacial area. Since it gradually worsens as patients grow, it is necessary to understand the characteristics of facial bone growth and facial deformity in hemifacial microsomia patients in order to determine appropriate treatment timing and treatment methods. MAIN BODY: Appropriate classification of hemifacial microsomia would facilitate accurate diagnosis, selection of treatment methods, and prognosis prediction. Therefore, in this article, we review previously published hemifacial microsomia classification and provide an overview of the growth of the facial skeleton and the characteristics of hemifacial microsomia-related facial deformities. The OMENS system is the most comprehensive classification method based on the characteristics of hemifacial microsomia deformity, but it needs to be improved to include malar/midface abnormalities and nerve involvement. In hemifacial microsomia, growth is progressing on the affected side, but to a lesser degree than the unaffected side. Therefore, surgical intervention in growing patients should be performed selectively according to the severity of deformity. CONCLUSION: Understanding growth patterns is important to develop appropriate treatment protocols for correcting asymmetry in adult patients and to minimize secondary anomalies in growing patients.

Comparison of whole blood collection and double-unit erythrocytapheresis in preoperative autologous blood donation.

INTRODUCTION: We compared preoperative autologous blood donation (PABD) using serial manual whole blood (WB) and PABD using a single session, double-unit erythrocytapheresis in terms of the hemodynamic recovery and clinical outcomes. MATERIALS AND METHODS: This study included 56 donors in the WB PABD group and 117 donors in the double-unit erythrocytapheresis PABD group. All subjects were men with body weight >70 kg, Hb level >13.3g/dL, Hct >40%, and who were scheduled for oral and maxillofacial surgery. Three cycles of manual WB collection for PABD or a single session, double-unit erythrocytapheresis using the Alyx was performed. RESULTS: There were no significant differences in donor demographic variables including age, height, weight, Hb, Hct, or red cell mass between the 2 groups. The double-unit erythrocytapheresis was completed earlier than the last manual WB PABD (at 15.3 ± 4.7 days and 6.5 ± 3.2 days before surgery, p<0.001). Hct values before surgery were higher in the double-unit erythrocytapheresis PABD group than in the manual WB PABD group (39.7 ± 3.2 vs. 38.6 ± 2.7, p=0.024). ΔHct and %ΔHct before the first PABD and before surgery were lower in the double-unit erythrocytapheresis PABD group than in the manual WB PABD group (-5.6 ± 2.8 vs. -6.8 ± 2.7, p=0.010 and -12.3 ± 5.9 vs. -14.8 ± 5.6, p=0.008, respectively). The incidence of additional allogeneic blood transfusions during or after surgery and the post-operative Hb and Hct values were similar in the 2 groups. The length of hospital stay after surgery was significantly longer in the manual WB PABD group than in the double-unit erythrocytapheresis group (6.1 ± 2.5 vs. 5.4 ± 1.9, p=0.043). Of the 33 donors in the double-unit erythrocytapheresis PABD group, 7 (21.2%) reported discomforts related to the procedure, and 6 graded the discomforts (hypocalcemia, perioral tingling sense, paresthesia, dizziness, stuffiness, pain on the intravenous site, and muscle tension) as mild. CONCLUSION: The single session, double-unit erythrocytapheresis prolonged the time interval between PABD and surgery and led to better hemodynamic recovery than the serial manual WB PABD, and hypocalcemic symptoms were mild.

V2-Net: An Attention-guided Volumetric Regression Network for Tooth Landmark Localization on CT Images with Metal Artifacts.

For virtual surgical planning in orthognathic surgery, marking tooth landmarks on CT images is an important procedure. However, the manual localization procedure of tooth landmarks is time-consuming, labor-intensive, and requires expert knowledge. Also, direct and automatic tooth landmark localization on CT images is difficult because of the lower resolution and metal artifacts of dental images. The purpose of this study was to propose an attention-guided volumetric regression network (V2-Net) for accurate tooth landmark localization on CT images with metal artifacts and lower resolution. V2-Net has an attention-guided network architecture using a coarse-to-fine-attention mechanism that guided the 3D probability distribution of tooth landmark locations within anatomical structures from the coarse V-Net to the fine V-Net for more focus on tooth landmarks. In addition, we combined attention-guided learning and a 3D attention module with optimal Pseudo Huber loss to improve the localization accuracy. Our results show that the proposed method achieves state-of-the-art accuracy of 0.85 ± 0.40 mm in terms of mean radial error, outperforming previous studies. In ablation studies, we observed that the proposed attention-guided learning and a 3D attention module improved the accuracy of tooth landmark localization in CT images of lower resolution and metal artifacts. Furthermore, our method achieved 97.92% in terms of the success detection rate within the clinically accepted accuracy range of 2.0 mm.

Enhanced Bone Regeneration by Bone Morphogenetic Protein-2 after Pretreatment with Low-Intensity Pulsed Ultrasound in Distraction Osteogenesis.

BACKGROUND: Bone morphogenetic protein 2 (BMP-2) and low-intensity pulsed ultrasound (LIPUS) have been used to enhance bone healing in distraction osteogenesis (DO). The aim of this study was to assess the synergistic effect of BMP-2 and LIPUS on bone regeneration in DO and to determine the optimal treatment strategy for enhanced bone regeneration. METHODS: Rat mesenchymal stromal cells were treated with various application protocols of BMP-2 and LIPUS, and cell proliferation, alkaline phosphatase activity, and osteogenesis-related marker expression were evaluated. In vivo experiments were performed in a rabbit DO model according to the application protocols with different timings of BMP-2 and LIPUS application. RESULTS: Application of BMP-2 after LIPUS pretreatment (BMP-2 after LIPUS) showed greater cell proliferation than LIPUS treatment alone, and higher ALP activity than all other treatment protocols. BMP-2 after LIPUS also exhibited increased gene expression levels of ALP, Cbfa1, and Osterix compared with LIPUS treatment alone. In vivo experiments revealed no significant differences in bone healing based on the timing of LIPUS treatment in DO. The combination of BMP-2 and LIPUS resulted in increased bone volume and bone mineral density compared with BMP-2 or LIPUS. Regarding the timing of BMP-2 application, the application of BMP-2 after LIPUS pretreatment led to greater bone volume than the application of BMP-2 before LIPUS. CONCLUSION: The results of this study suggest that the combined treatment of BMP-2 and LIPUS can lead to enhanced bone healing in DO and that effective bone healing can be achieved through the application of LIPUS before BMP-2.

Clinical and radiographic outcomes of dental implant after maxillary sinus floor augmentation with rhBMP-2/hydroxyapatite compared to deproteinized bovine bone.

OBJECTIVES: This study aimed to evaluate the clinical and radiographic outcomes of early implant placement and functional loading in maxillary sinus floor augmentation (MSFA) using recombinant human bone morphogenetic protein 2/hydroxyapatite (rhBMP-2/HA) and to compare these outcomes with those of the conventional protocol in MSFA using deproteinized bovine bone (DBB). MATERIALS AND METHODS: The rhBMP-2/HA and DBB groups consisted of 14 and 13 patients who underwent MSFA with BMP and DBB, respectively. After placement of 22 implants and 21 implants in the rhBMP-2/HA and DBB groups, respectively, abutment connections were performed 3 months after implant placement for the rhBMP-2/HA group and 6 months after implant placement for the DBB group. Changes in grafted sinus height (GSH), marginal bone loss (MBL), and implant stability were evaluated up to one year after functional loading. RESULTS: Survival rates for the rhBMP-2/HA and DBB groups after one year of functional loading were 90.9% and 90.5%, respectively. Both groups exhibited no significant time-course changes in GSH until one year of functional loading (rhBMP-2/HA, p = 0.124; DBB, p = 0.075). Although significant MBL occurred after one year of functional loading for both groups (rhBMP-2/HA, p < 0.001; DBB, p < 0.001), there were no significant differences in time-course changes in MBL between the two groups (p = 0.450). The mean implant stability quotient values in the rhBMP-2/HA and DBB groups were 75.3 and 75.4 after one year of functional loading, respectively, and there were no significant differences between the two groups (p = 0.557). CONCLUSIONS: MSFA using rhBMP-2/HA allowed implant rehabilitation with early implant placement and functional loading and led to a comparable survival rate and implant stability after 1 year of functional loading with acceptable MBL and stable maintenance of GSH compared to the MSFA using DBB with 6 months of healing after implant placement.

Automatic and quantitative measurement of alveolar bone level in OCT images using deep learning.

We propose a method to automatically segment the periodontal structures of the tooth enamel and the alveolar bone using convolutional neural network (CNN) and to measure quantitatively and automatically the alveolar bone level (ABL) by detecting the cemento-enamel junction and the alveolar bone crest in optical coherence tomography (OCT) images. The tooth enamel and the alveolar bone regions were automatically segmented using U-Net, Dense-UNet, and U2-Net, and the ABL was quantitatively measured as the distance between the cemento-enamel junction and the alveolar bone crest using image processing. The mean distance difference (MDD) measured by our suggested method ranged from 0.19 to 0.22 mm for the alveolar bone crest (ABC) and from 0.18 to 0.32 mm for the cemento-enamel junction (CEJ). All CNN models showed the mean absolute error (MAE) of less than 0.25 mm in the x and y coordinates and greater than 90% successful detection rate (SDR) at 0.5 mm for both the ABC and the CEJ. The CNN models showed high segmentation accuracies in the tooth enamel and the alveolar bone regions, and the ABL measurements at the incisors by detected results from CNN predictions demonstrated high correlation and reliability with the ground truth in OCT images.

Decompression effects on bone healing in rat mandible osteomyelitis.

Osteomyelitis (OM) of the jaw is usually caused by a chronic odontogenic infection. Decompression is the release the intraluminal pressure in the cystic cavity allowing gradual bone growth from the periphery. The aim of this study was to analyze the effectiveness of decompression in an OM jaw model. A 4-mm-diameter defect was made on mandibles of fourteen Sprague-Dawley rats and inoculated with S. aureus (20 µl of 1 × 107 CFU/ml) injection. Two weeks later, four groups were made as non-treatment (C1), only curettage (C2), curettage and decompression (E1), and curettage and decompression with normal saline irrigation (E2). After four weeks, each group was analyzed. Most micro-CT parameters, including bone mineral density [0.87 (± 0.08) g/cm3] with bone volume [0.73 (± 0.08) mm3] was higher in E2 group than that of C1 group (p = 0.04, p = 0.05, respectively). E2 group in histology showed the highest number of osteocytes than those of control groups, 91.00 (± 9.90) (p = 0.002). OPN were expressed strongly in the E1 ("5": 76-100%) that those of other groups. Decompression drains induced advanced bone healing compared to that of curettage alone. Therefore, it could be recommended to use decompressive drain for enhancing the jaw OM management.

A Complete Digital Workflow for Planning, Simulation, and Evaluation in Orthognathic Surgery.

The purpose of this study was to develop a complete digital workflow for planning, simulation, and evaluation for orthognathic surgery based on 3D digital natural head position reproduction, a cloud-based collaboration platform, and 3D landmark-based evaluation. We included 24 patients who underwent bimaxillary orthognathic surgery. Surgeons and engineers could share the massive image data immediately and conveniently and collaborate closely in surgical planning and simulation using a cloud-based platform. The digital surgical splint could be optimized for a specific patient before or after the physical fabrication of 3D printing splints through close collaboration. The surgical accuracy was evaluated comprehensively via the translational (linear) and rotational (angular) discrepancies between identical 3D landmarks on the simulation and postoperative computed tomography (CT) models. The means of the absolute linear discrepancy at eight tooth landmarks were 0.61 ± 0.55, 0.86 ± 0.68, and 1.00 ± 0.79 mm in left-right, advance-setback, and impaction-elongation directions, respectively, and 1.67 mm in the root mean square direction. The linear discrepancy in the left-right direction was significantly different from the other two directions as shown by analysis of variance (ANOVA, p < 0.05). The means of the absolute angular discrepancies were 1.43 ± 1.06°, 0.50 ± 0.31°, and 0.58 ± 0.41° in the pitch, roll, and yaw orientations, respectively. The angular discrepancy in the pitch orientation was significantly different from the other two orientations (ANOVA, p < 0.05). The complete digital workflow that we developed for orthognathic patients provides efficient and streamlined procedures for orthognathic surgery and shows high surgical accuracy with efficient image data sharing and close collaboration.

Implantable electrical stimulation bioreactor with liquid crystal polymer-based electrodes for enhanced bone regeneration at mandibular large defects in rabbit.

The osseous regeneration of large bone defects is still a major clinical challenge in maxillofacial and orthopedic surgery. Previous studies demonstrated that biphasic electrical stimulation (ES) stimulates bone formation; however, polyimide electrode should be removed after regeneration. This study presents an implantable electrical stimulation bioreactor with electrodes based on liquid crystal polymer (LCP), which can be permanently implanted due to excellent biocompatibility to bone tissue. The bioreactor was implanted into a critical-sized bone defect and subjected to ES for one week, where bone regeneration was evaluated four weeks after surgery using micro-CT. The effect of ES via the bioreactor was compared with a sham control group and a positive control group that received recombinant human bone morphogenetic protein (rhBMP)-2 (20 µg). New bone volume per tissue volume (BV/TV) in the ES and rhBMP-2 groups increased to 132% (p < 0.05) and 174% (p < 0.01), respectively, compared to that in the sham control group. In the histological evaluation, there was no inflammation within the bone defects and adjacent to LCP in all the groups. This study showed that the ES bioreactor with LCP electrodes could enhance bone regeneration at large bone defects, where LCP can act as a mechanically resistant outer box without inflammation. Graphical abstract To enhance bone regeneration, a bioreactor comprising collagen sponge and liquid crystal polymer-based electrode was implanted in the bone defect. Within the defect, electrical current pulses having biphasic waveform were applied from the implanted bioreactor.