Comprehensive repair of the alveolar cleft using cortical and cancellous bone layers: A retrospective study.

To retrospectively review the clinical effect of comprehensive treatment of alveolar cleft (CTAC) using the mandible as the bone source. Patients with alveolar clefts who met the inclusion criteria were subjected to a CTAC protocol that included the following: (1) preoperative orthodontic treatment for creating good soft-tissue conditions; (2) 'area-like grafting' with subperiosteal osteogenic chin bone instead of cartilaginous osteogenic iliac bone; (3) simulation of normal bone anatomy via a sandwich-like bone graft consisting of 'cortical bone + cancellous bone + cortical bone'; and (4) strong internal fixation to ensure initial bone block stability. At 6 months postoperatively, the titanium plate was removed and cone-beam computed tomography was performed to evaluate the surgical results. A total of 54 patients underwent treatment with the CTAC protocol. The average age at the initial operation was 10.3 ± 2.1 years, and the average hospital stay was 2.8 ± 0.6 days. At 6 months postoperatively, 49 patients (90.7%) showed good clinical results. The transplanted bone block formed a 'cortical bone + cancellous bone + cortical bone' structure similar to that of the normal jawbone. A mature bone bridge formed, and the impacted permanent teeth continued to erupt and enter the bone graft area. CTAC is a comprehensive restorative solution for alveolar cleft repair that integrates multiple concepts, including orthodontics, embryology, anatomy, and improvements to surgical methods. The method is easy to perform, causes little surgical trauma, and shows a stable success rate, and is thus worth promoting.

Automatic localization of cephalometric landmarks based on convolutional neural network.

INTRODUCTION: Cephalometry plays an important role in the diagnosis and treatment of orthodontics and orthognathic surgery. This study intends to develop an automatic landmark location system to make cephalometry more convenient. METHODS: In this study, 512 lateral cephalograms were collected, and 37 landmarks were included. The coordinates of all landmarks in the 512 films were obtained to establish a labeled dataset: 312 were used as a training set, 100 as a validation set, and 100 as a testing set. An automatic landmark location system based on the convolutional neural network was developed. This system consisted of a global detection module and a locally modified module. The lateral cephalogram was first fed into the global module to obtain an initial estimate of the landmark's position, which was then adjusted with the locally modified module to improve accuracy. Mean radial error (MRE) and success detection rate (SDR) within the range of 1-4 mm were used to evaluate the method. RESULTS: The MRE of our validation set was 1.127 ± 1.028 mm, and SDR of 1.0, 1.5, 2.0, 2.5, 3.0, and 4.0 mm were respectively 45.95%, 89.19%, 97.30%, 97.30%, and 97.30%. The MRE of our testing set was 1.038 ± 0.893 mm, and SDR of 1.0, 1.5, 2.0, 2.5, 3.0, and 4.0 mm were respectively 54.05%, 91.89%, 97.30%, 100%, 100%, and 100%. CONCLUSIONS: In this study, we proposed a new automatic landmark location system on the basis of the convolutional neural network. The system could detect 37 landmarks with high accuracy. All landmarks are commonly used in clinical practice and could meet the requirements of different cephalometric analysis methods.

Augmented Reality Technology Could Be an Alternative Method to Treat Craniomaxillofacial Foreign Bodies: A Comparative Study Between Augmented Reality Technology and Navigation Technology.

PURPOSE: Removal of foreign bodies in the craniomaxillofacial region can be challenging. The purpose of the present study was to explore the feasibility of using augmented reality (AR) technology to remove craniomaxillofacial foreign bodies. PATIENTS AND METHODS: A prospective study of patients with granular metal foreign bodies retained in the craniomaxillofacial region from March 2017 to March 2019 was performed. AR technology and navigation technology were both used to localize the foreign bodies. The face was divided into upper and lower parts by the ala-tragus line. In groups A and B, navigation technology was used to locate the foreign bodies in the upper face and lower face, respectively. Similarly, AR technology was used in the upper face and lower face in groups C and D, respectively. The primary predictor variable was the technology type. The primary outcome variables were the positioning deviation and the time required for surface positioning. The paired t test and independent samples t test were used for statistical analysis. RESULTS: Five patients with 24 craniomaxillofacial foreign bodies were included in the present study. The positioning deviation with navigation technology (1.42 ± 0.49 mm) did not differ from that with AR technology (1.52 ± 0.58 mm; P = .116). The positioning deviation of groups A, B, C, and D was 1.01 ± 0.37, 1.73 ± 0.29, 1.02 ± 0.44, and 1.89 ± 0.36 mm, respectively. The differences for groups A and B were statistically significant (P < .01), as were the differences for groups C and D (P < .01). The time required to position the 2 technologies was significantly different (10.04 ± 2.88 seconds for navigation technology and 3.46 ± 0.83 seconds for AR technology; P < .01). CONCLUSIONS: AR technology positioning was similar to that of navigation technology; however, it does not require an invasive registration device and provides real-time dynamic image guidance. AR technology could be an alternative method for treating foreign bodies in the craniomaxillofacial region.