3D evaluation model of facial aesthetics based on multi-input 3D convolution neural networks for orthognathic surgery.

BACKGROUND: Quantitative evaluation of facial aesthetics is an important but also time-consuming procedure in orthognathic surgery, while existing 2D beauty-scoring models are mainly used for entertainment with less clinical impact. METHODS: A deep-learning-based 3D evaluation model DeepBeauty3D was designed and trained using 133 patients' CT images. The customised image preprocessing module extracted the skeleton, soft tissue, and personal physical information from raw DICOM data, and the predicting network module employed 3-input-2-output convolution neural networks (CNN) to receive the aforementioned data and output aesthetic scores automatically. RESULTS: Experiment results showed that this model predicted the skeleton and soft tissue score with 0.231 ± 0.218 (4.62%) and 0.100 ± 0.344 (2.00%) accuracy in 11.203 ± 2.824 s from raw CT images. CONCLUSION: This study provided an end-to-end solution using real clinical data based on 3D CNN to quantitatively evaluate facial aesthetics by considering three anatomical factors simultaneously, showing promising potential in reducing workload and bridging the surgeon-patient aesthetics perspective gap.

A clinical presentation of markerless augmented reality assisted surgery for resection of a dentigerous cyst in the maxillary sinus.

Dentigerous cysts (DC) in the maxillary sinus are rare and pose challenges for effective treatment. Despite various available surgical techniques, a definitive approach remains debated. This study introduces a markerless Augmented Reality Assisted Surgery (ARAS) system that utilizes tooth image recognition and surgical simulation to enhance the precision of maxillary sinus DC extractions. Using advanced technology, such as 3-dimensional (3D) intraoral scanning and CT imaging for accurate data capture, the system aligns virtual models with patient anatomy without external markers, demonstrating a minimally invasive surgical solution. The ARAS system enabled precise surgical planning and realization of a DC extraction in the maxillary sinus by creating a bone window in direct contact with the cyst, assisting in complete removal with minimal risk to adjacent structures. The ARAS system may aid surgeons in visualizing patient anatomy during surgery, with overlays of relevant medical images, aiding in precise localization and minimizing tissue damage.

Computer-Assisted Preoperative Simulation and Augmented Reality for Extraction of Impacted Supernumerary Teeth: A Clinical Case Report of Two Cases.

Delayed eruption, malocclusion, poor oral hygiene, and formation of follicular cysts are some complications associated with an impacted supernumerary tooth (ST). Although surgical extraction is one of the methods to prevent these complications, it can also lead to fractured roots or has a risk of permanent injury to young teeth and gingiva. Recently, computer-assisted preoperative simulation has been helpful in planning the surgery for precise extraction of impacted ST guided with 3-dimensional images. Herein, we present 2 cases of extraction of severely impacted ST guided by preoperative computer-assisted simulation and intraoperative augmented reality. While being minimally invasive, the augmented reality-guided system can precisely highlight the tooth position. The therapeutic aspects of these procedures have also been discussed.

Machine-learning-based approach for predicting postoperative skeletal changes for orthognathic surgical planning.

BACKGROUND: Manually surgical planning becomes an increasing workload of surgeons because of the fast-growing patient population. This study introduced a machine-learning-based approach to assist surgical planning in orthognathic surgery. METHODS: Both preoperative and one-year-later postoperative computerised tomography images of 56 patients were collected. A 12-layers cascaded deep neural network structure with two successive models was proposed to yield an end-to-end solution, where the first model extracts landmarks from 2D patches of 3D volume and the second model predicts postoperative skeletal changes. RESULTS: The experimental results showed that the model obtained a prediction accuracy of 5.4 mm at the landmark level in 42.9 s. It also represented 74.4% of 3D regions at volume level when compared with the ground truth of human surgeons. CONCLUSIONS: This study demonstrated the feasibility of predicting postoperative skeletal changes for orthognathic surgical planning by using machine learning, showing great potential for reducing the workload of surgeons.

Automatic 3D landmarking model using patch-based deep neural networks for CT image of oral and maxillofacial surgery.

BACKGROUND: Manual landmarking is a time consuming and highly professional work. Although some algorithm-based landmarking methods have been proposed, they lack flexibility and may be susceptible to data diversity. METHODS: The CT images from 66 patients who underwent oral and maxillofacial surgery (OMS) were landmarked manually in MIMICS. Then the CT slices were exported as images for recreating the 3D volume. The coordinate data of landmarks were further processed in Matlab using a principal component analysis (PCA) method. A patch-based deep neural network model with a three-layer convolutional neural network (CNN) was trained to obtain landmarks from CT images. RESULTS: The evaluating experiment showed that this CNN model could automatically finish landmarking in an average processing time of 37.871 seconds with an average accuracy of 5.785 mm. CONCLUSION: This study shows a promising potential to relieve the workload of the surgeon and reduces the dependence on human experience for OMS landmarking.

Investigating the Efficacy of Intraoral Wet Sheets.

OBJECTIVE: It is important that oral care is effective, efficient, and economical. Herein, we investigated the efficacy of intraoral wet sheets for oral care in comparison with sponge brushes. METHODS: We completed a Plaque Control Record (PCR) after observing intraoral plaque using a plaque disclosure test in healthy volunteers. After the teeth were cleaned for 3 minutes using a wet sheet, the test was repeated and the PCR was completed. The same method was performed using a sponge brush on the same subject under the same conditions 1 week later. The t test was used to analyze PCR findings. RESULTS: Ten healthy subjects were enrolled (mean age, 28.6 years). The PCR values improved from 44.0% before to 30.9% after use of the wet sheet. The post-cleaning PCR was significantly lower. The PCR values improved from 55.0% before to 50.2% after use of the sponge brush. CONCLUSIONS: The PCR improvement was greater when using the wet sheet. In all cases, the wet sheet was highly effective at smoothing tooth surfaces. Intraoral wet sheets may be an option for oral care performed by nurses and caregivers. Compared to the sponge brush, the intraoral wet sheet can save time and reduce costs.

Development and preliminary evaluation of an autonomous surgical system for oral and maxillofacial surgery.

BACKGROUND: Human-related factors affect the accuracy and safety of the oral and maxillofacial surgery (OMS). This study proposed an autonomous surgical system aiming to conduct the OMS under the assistance and surveillance of the surgeon. METHODS: A markerless navigation module and a compact OMS robot were seamlessly integrated into this system. The specifications of each module and the working concept of the system were elaborated in this paper. A drilling experiment was conducted on five 3D-printed mandible models to test the pose detecting capability and evaluate the operational performance. RESULTS: The experiment showed that this system could successfully guide the robot finishing the operation regardless of the mandible pose. The accuracy of software and hardware are acceptable and potential performance improvement can be achieved in positioning accuracy. CONCLUSION: This system proposed a novel concept and a practical solution to decrease the human-related factors on the OMS, which may change the role of the surgeon in the future operating room and finally benefit the outcomes of OMS.

A Case of Systemic Infection Caused by Streptococcus pyogenes Oral Infection in an Edentulous Patient.

BACKGROUND: Infections in the oral and maxillofacial region can sometimes extend beyond the oral cavity, with serious consequences. Most oral infections are odontogenic, occurring through the root apex of the tooth or the periodontal pocket. It thus makes sense that edentulous patients have a much lower risk of oral bacterial infection. For this reason, while there are many reports on systemic infections caused by oral infections, few of these describe such infections in edentulous patients. CASE PRESENTATION: We present a case of oral and maxillofacial cellulitis followed by sepsis due to Streptococcus pyogenes infection in an 89-year-old Japanese edentulous woman. S. pyogenes was detected in the wound of left maxilla and the blood sample. S. pyogenes has been reported to be one of the most common and influential aerobic bacteria associated with deep neck infection and subsequent systemic infection. Left maxillary sinusitis was observed, and this could be the origin of the S. pyogenes infection. S. pyogenes derived from the sinusitis and leaked to the oral cavity might have caused systemic infection through wounding of the oral mucosa. Fortunately, intensive antibiotic therapy was effective, and the patient recovered without any surgical procedures. CONCLUSIONS: We experienced a rare case of oral and maxillofacial cellulitis followed by sepsis due to a Streptococcus pyogenes infection in an old edentulous woman. This result indicated that, while edentulous patients are considered to have no risk of odontogenic infection, they still carry a risk of bacterial infection.

Three-dimensional changes of noses after transplantation of implant-type tissue-engineered cartilage for secondary correction of cleft lip-nose patients.

INTRODUCTION: We have developed an implant-type tissue-engineered cartilage using a poly-l-lactide scaffold. In a clinical study, it was inserted into subcutaneous areas of nasal dorsum in three patients, to correct cleft lip-nose deformity. The aim of this study was to helping evaluation on the efficacy of the regenerative cartilage. METHODS: 3D data of nasal shapes were compared between before and after surgery in computed tomography (CT) images. Morphological and qualitative changes of transplants in the body were also evaluated on MRI, for one year. RESULTS: The 3D data from CT images showed effective augmentation (>2 mm) of nasal dorsum in almost whole length, observed on the medial line of faces. It was maintained by 1 year post-surgery in all patients, while affected curves of nasal dorsum was not detected throughout the observation period. In magnetic resonance imaging (MRI), the images of transplanted cartilage had been observed until 1 year post-surgery. Those images were seemingly not straight when viewed from the longitudinal plain, and may have shown gentle adaptation to the surrounding nasal bones and alar cartilage tissues. CONCLUSION: Those findings suggested the potential efficacy of this cartilage on improvement of cleft lip-nose deformity. A clinical trial is now being performed for industrialization.

Video see-through augmented reality for oral and maxillofacial surgery.

BACKGROUND: Oral and maxillofacial surgery has not been benefitting from image guidance techniques owing to the limitations in image registration. METHODS: A real-time markerless image registration method is proposed by integrating a shape matching method into a 2D tracking framework. The image registration is performed by matching the patient's teeth model with intraoperative video to obtain its pose. The resulting pose is used to overlay relevant models from the same CT space on the camera video for augmented reality. RESULTS: The proposed system was evaluated on mandible/maxilla phantoms, a volunteer and clinical data. Experimental results show that the target overlay error is about 1 mm, and the frame rate of registration update yields 3-5 frames per second with a 4 K camera. CONCLUSIONS: The significance of this work lies in its simplicity in clinical setting and the seamless integration into the current medical procedure with satisfactory response time and overlay accuracy. Copyright © 2016 John Wiley & Sons, Ltd.

Computer-assisted preoperative simulation for positioning and fixation of plate in 2-stage procedure combining maxillary advancement by distraction technique and mandibular setback surgery.

INTRODUCTION: Computer-assisted preoperative simulation surgery is employed to plan and interact with the 3D images during the orthognathic procedure. It is useful for positioning and fixation of maxilla by a plate. We report a case of maxillary retrusion by a bilateral cleft lip and palate, in which a 2-stage orthognathic procedure (maxillary advancement by distraction technique and mandibular setback surgery) was performed following a computer-assisted preoperative simulation planning to achieve the positioning and fixation of the plate. A high accuracy was achieved in the present case. PRESENTATION OF CASE: A 21-year-old male patient presented to our department with a complaint of maxillary retrusion following bilateral cleft lip and palate. Computer-assisted preoperative simulation with 2-stage orthognathic procedure using distraction technique and mandibular setback surgery was planned. DISCUSSION: The preoperative planning of the procedure resulted in good aesthetic outcomes. The error of the maxillary position was less than 1mm. CONCLUSION: The implementation of the computer-assisted preoperative simulation for the positioning and fixation of plate in 2-stage orthognathic procedure using distraction technique and mandibular setback surgery yielded good results.

Computer-assisted preoperative simulation for positioning of plate fixation in Lefort I osteotomy: A case report.

Computed tomography images are used for three-dimensional planning in orthognathic surgery. This facilitates the actual surgery by simulating the surgical scenario. We performed a computer-assisted virtual orthognathic surgical procedure using optically scanned three-dimensional (3D) data and real computed tomography data on a personal computer. It helped maxillary bone movement and positioning and the titanium plate temporary fixation and positioning. This simulated the surgical procedure, which made the procedure easy, and we could perform precise actual surgery and could forecast the postsurgery outcome. This simulation method promises great potential in orthognathic surgery to help surgeons plan and perform operative procedures more precisely.

Vision-based markerless registration using stereo vision and an augmented reality surgical navigation system: a pilot study.

BACKGROUND: This study evaluated the use of an augmented reality navigation system that provides a markerless registration system using stereo vision in oral and maxillofacial surgery. METHOD: A feasibility study was performed on a subject, wherein a stereo camera was used for tracking and markerless registration. The computed tomography data obtained from the volunteer was used to create an integral videography image and a 3-dimensional rapid prototype model of the jaw. The overlay of the subject's anatomic site and its 3D-IV image were displayed in real space using a 3D-AR display. Extraction of characteristic points and teeth matching were done using parallax images from two stereo cameras for patient-image registration. RESULTS: Accurate registration of the volunteer's anatomy with IV stereoscopic images via image matching was done using the fully automated markerless system, which recognized the incisal edges of the teeth and captured information pertaining to their position with an average target registration error of < 1 mm. These 3D-CT images were then displayed in real space with high accuracy using AR. Even when the viewing position was changed, the 3D images could be observed as if they were floating in real space without using special glasses. CONCLUSION: Teeth were successfully used for registration via 3D image (contour) matching. This system, without using references or fiducial markers, displayed 3D-CT images in real space with high accuracy. The system provided real-time markerless registration and 3D image matching via stereo vision, which, combined with AR, could have significant clinical applications.

Bone regeneration in calvarial defects in a rat model by implantation of human bone marrow-derived mesenchymal stromal cell spheroids.

Mesenchymal stem cell (MSC) condensation contributes to membrane ossification by enhancing their osteodifferentiation. We investigated bone regeneration in rats using the human bone marrow-derived MSC-spheroids prepared by rotation culture, without synthetic or exogenous biomaterials. Bilateral calvarial defects (8 mm) were created in nude male rats; the left-sided defects were implanted with MSC-spheroids, ß-tricalcium phosphate (ß-TCP) granules, or ß-TCP granules + MSC-spheroids, while the right-sided defects served as internal controls. Micro-computed tomography and immunohistochemical staining for osteocalcin/osteopontin indicated formation of new, full-thickness bones at the implantation sites, but not at the control sites in the MSC-spheroid group. Raman spectroscopy revealed similarity in the spectral properties of the repaired bone and native calvarial bone. Mechanical performance of the bones in the MSC-implanted group was good (50 and 60% those of native bones, respectively). All tests showed poor bone regeneration in the ß-TCP and ß-TCP + MSC-spheroid groups. Thus, significant bone regeneration was achieved with MSC-spheroid implantation into bone defects, justifying further investigation.

Rare case of external dental fistula of the submental region misdiagnosed as inverted follicular keratosis and thyroglossal duct cyst.

INTRODUCTION: Odontogenic cutaneous sinus tract is a relatively rare occurrence that can be complicated to diagnose. The presence of a cutaneous lesion is often not even partly associated with a dental etiology because of the less frequency of occurrence in the case of dental symptoms. Consequently, the underlying dental cause is often missed leading to inappropriate diagnosis and treatment. CASE PRESENTATION: Here, we report the case of a 45-year-old man who presented with a persistent lesion of the cervical region. At the time of presentation, the lesion had been present for approximately one year with a gradual increase in size but no specific symptoms. The patient had previously undergone punch resection under local anesthesia, which resulted in a histopathological diagnosis of inverted follicular keratosis. A diagnosis was made of an odontogenic cutaneous sinus tract secondary to chronic apical periodontitis of the left mandibular second molar. DISCUSSION: Cutaneous sinus tract in the face and neck is most likely to develop intraorally. Root canal treatment or surgical extractions are the common treatment choices. A previously reported review of 137 cases found that 106 (77%) were treated by extraction and 27 (20%) were treated by surgical or conservative nonsurgical endodontic therapy. CONCLUSION: Early diagnosis of cutaneous sinus tract using proper aid is responsible for shortening the treatment duration and avoiding unnecessary treatment.

Real-time computer-generated integral imaging and 3D image calibration for augmented reality surgical navigation.

Autostereoscopic 3D image overlay for augmented reality (AR) based surgical navigation has been studied and reported many times. For the purpose of surgical overlay, the 3D image is expected to have the same geometric shape as the original organ, and can be transformed to a specified location for image overlay. However, how to generate a 3D image with high geometric fidelity and quantitative evaluation of 3D image's geometric accuracy have not been addressed. This paper proposes a graphics processing unit (GPU) based computer-generated integral imaging pipeline for real-time autostereoscopic 3D display, and an automatic closed-loop 3D image calibration paradigm for displaying undistorted 3D images. Based on the proposed methods, a novel AR device for 3D image surgical overlay is presented, which mainly consists of a 3D display, an AR window, a stereo camera for 3D measurement, and a workstation for information processing. The evaluation on the 3D image rendering performance with 2560×1600 elemental image resolution shows the rendering speeds of 50-60 frames per second (fps) for surface models, and 5-8 fps for large medical volumes. The evaluation of the undistorted 3D image after the calibration yields sub-millimeter geometric accuracy. A phantom experiment simulating oral and maxillofacial surgery was also performed to evaluate the proposed AR overlay device in terms of the image registration accuracy, 3D image overlay accuracy, and the visual effects of the overlay. The experimental results show satisfactory image registration and image overlay accuracy, and confirm the system usability.

Augmented reality navigation with automatic marker-free image registration using 3-D image overlay for dental surgery.

Computer-assisted oral and maxillofacial surgery (OMS) has been rapidly evolving since the last decade. State-of-the-art surgical navigation in OMS still suffers from bulky tracking sensors, troublesome image registration procedures, patient movement, loss of depth perception in visual guidance, and low navigation accuracy. We present an augmented reality navigation system with automatic marker-free image registration using 3-D image overlay and stereo tracking for dental surgery. A customized stereo camera is designed to track both the patient and instrument. Image registration is performed by patient tracking and real-time 3-D contour matching, without requiring any fiducial and reference markers. Real-time autostereoscopic 3-D imaging is implemented with the help of a consumer-level graphics processing unit. The resulting 3-D image of the patient's anatomy is overlaid on the surgical site by a half-silvered mirror using image registration and IP-camera registration to guide the surgeon by exposing hidden critical structures. The 3-D image of the surgical instrument is also overlaid over the real one for an augmented display. The 3-D images present both stereo and motion parallax from which depth perception can be obtained. Experiments were performed to evaluate various aspects of the system; the overall image overlay error of the proposed system was 0.71 mm.

Clinical presentation of epignathus teratoma with cleft palate; and duplication of cranial base, tongue, mandible, and pituitary gland.

A 2-day-old girl was diagnosed with an oral epignathus teratoma and an uncommon combination of orofacial malformations including cleft palate; tongue, mandible, cranial base, cervical vertebrae, lower lip, and pituitary gland duplications; and fistula of the glabella and lower lip. Computed tomography revealed that the mass within the nasal cavity had tooth-like calcifications and protruded into the nasopharynx and oral cavity. It was implanted on the anterior wall of the body of the sphenoid bone and was accompanied with mandibular duplication. Magnetic resonance imaging detected duplication of the pituitary gland and confirmed the absence of intracranial communication of the nasopharyngeal mass. The teratoma did not cause respiratory obstruction; however, the patient required continuous nasogastric tube feeding. Usually, an epignathus teratoma is associated with few midline defects and can be corrected with multiple interventions at different time points. The current study describes the surgical procedure comprising excision of the tumor along with reconstructive surgeries of the mandible, tongue, and fistulae undertaken when the infant reached 7 months of age. The cleft palate was repaired at 18 months of age using the Kaplan buccal flap method. Histopathologic examination confirmed a grade 0 teratoma covered with keratinized skin and containing pilosebaceous and sweat glands, adipose tissue, and smooth muscle. The long-term success of this intervention was determined at the follow-up examination conducted at 3 years of age, with no signs of the teratoma recurrence observed.

Real-time in situ three-dimensional integral videography and surgical navigation using augmented reality: a pilot study.

To evaluate the feasibility and accuracy of a three-dimensional augmented reality system incorporating integral videography for imaging oral and maxillofacial regions, based on preoperative computed tomography data. Three-dimensional surface models of the jawbones, based on the computed tomography data, were used to create the integral videography images of a subject's maxillofacial area. The three-dimensional augmented reality system (integral videography display, computed tomography, a position tracker and a computer) was used to generate a three-dimensional overlay that was projected on the surgical site via a half-silvered mirror. Thereafter, a feasibility study was performed on a volunteer. The accuracy of this system was verified on a solid model while simulating bone resection. Positional registration was attained by identifying and tracking the patient/surgical instrument's position. Thus, integral videography images of jawbones, teeth and the surgical tool were superimposed in the correct position. Stereoscopic images viewed from various angles were accurately displayed. Change in the viewing angle did not negatively affect the surgeon's ability to simultaneously observe the three-dimensional images and the patient, without special glasses. The difference in three-dimensional position of each measuring point on the solid model and augmented reality navigation was almost negligible (<1 mm); this indicates that the system was highly accurate. This augmented reality system was highly accurate and effective for surgical navigation and for overlaying a three-dimensional computed tomography image on a patient's surgical area, enabling the surgeon to understand the positional relationship between the preoperative image and the actual surgical site, with the naked eye.

Augmented reality system for oral surgery using 3D auto stereoscopic visualization.

We present an augmented reality system for oral and maxillofacial surgery in this paper. Instead of being displayed on a separated screen, three-dimensional (3D) virtual presentations of osseous structures and soft tissues are projected onto the patient's body, providing surgeons with exact knowledge of depth information of high risk tissues inside the bone. We employ a 3D integral imaging technique which produce motion parallax in both horizontal and vertical direction over a wide viewing area in this study. In addition, surgeons are able to check the progress of the operation in real-time through an intuitive 3D based interface which is content-rich, hardware accelerated. These features prevent surgeons from penetrating into high risk areas and thus help improve the quality of the operation. Operational tasks such as hole drilling, screw fixation were performed using our system and showed an overall positional error of less than 1 mm. Feasibility of our system was also verified with a human volunteer experiment.