Automatic 3D Registration of Dental CBCT and Face Scan Data using 2D Projection images

This paper presents a fully automatic registration method of dental cone-beam computed tomography (CBCT) and face scan data. It can be used for a digital platform of 3D jaw-teeth-face models in a variety of applications, including 3D digital treatment planning and orthognathic surgery. Difficulties in accurately merging facial scans and CBCT images are due to the different image acquisition methods and limited area of correspondence between the two facial surfaces. In addition, it is difficult to use machine learning techniques because they use face-related 3D medical data with radiation exposure, which are difficult to obtain for training. The proposed method addresses these problems by reusing an existing machine-learning-based 2D landmark detection algorithm in an open-source library and developing a novel mathematical algorithm that identifies paired 3D landmarks from knowledge of the corresponding 2D landmarks. A main contribution of this study is that the proposed method does not require annotated training data of facial landmarks because it uses a pre-trained facial landmark detection algorithm that is known to be robust and generalized to various 2D face image models. Note that this reduces a 3D landmark detection problem to a 2D problem of identifying the corresponding landmarks on two 2D projection images generated from two different projection angles. Here, the 3D landmarks for registration were selected from the sub-surfaces with the least geometric change under the CBCT and face scan environments. For the final fine-tuning of the registration, the Iterative Closest Point method was applied, which utilizes geometrical information around the 3D landmarks. The experimental results show that the proposed method achieved an averaged surface distance error of 0.74 mm for three pairs of CBCT and face scan datasets.Comment: 8 pages, 6 figures, 2 table

ECG measurement on a chair without conductive contact

For the purpose of long-term, everyday electrocardiogram (ECG) monitoring, we present a convenient method of ECG measurement without direct conductive contact with the skin while subjects sat on a chair wearing normal clothes. Measurements were made using electrodes attached to the back of a chair, high-input-impedance amplifiers mounted on the electrodes, and a large ground-plane placed on the chair seat. ECGs were obtained by the presented method for several types of clothing and compared to ECGs obtained from conventional measurement using Ag-AgCl electrodes. Motion artifacts caused by usual desk works were investigated. This study shows the feasibility of the method for long-term, convenient, everyday use

Age-Related Incidence of Cervical Spondylosis in Residents of Jeju Island

Study DesignCervical spine radiograms of 460 Jeju islanders.PurposeTo investigate the age-matched incidences and severity of the cervical disc degeneration and associated pathologic findings.Overview of LiteratureSeveral related studies on the incidences of disc and Luschka's and facet joint degeneration have provided some basic data for clinicians.MethodsCervical radiographs of 460 (220 males and 240 females) patients in their fourth to ninth decade were analyzed. Ninety patients in their third decade were excluded because of absence of spondylotic findings.ResultsOverall incidence of cervical spondylosis was 47.8% (220 of 460 patients). The percentile incidences of spondylosis in the fourth, fifth, sixth, seventh, eighth and ninth decade was 13.2% (10 of 76 patients), 34.6% (37 of 107 patients), 58.9% (66 of 112 patients), 58.8% (50 of 85 patients), 70.3% (45 of 64 patients) and 75.0% (12 of 16 patients), respectively. The percentile incidences of one, two, three, four and five level spondylosis among 220 spondylosis patients was 45.5% (n=100), 34.1% (n=75), 15.0% (n=33), 4.5% (n=10), and 0.9% (n=2). Severity of disc degeneration ranged from ± to ++++, and was ± in 6.0% (24 segments), + in 49.6% (198 segments), ++ in 35.3% (141 segments), +++ in 9.0% (36 segments) and ++++ in 0.25% (one segment). Spurs and anterior ligament ossicle formed at the spondylotic segments, mostly at C4~6. The rate of posterior corporal spurs formation was very low. Olisthesis and ossification of the posterior longitudinal ligament were rarely combined with spondylosis. Cervical lordotic curve decreased gradually according to the progress of severity of spondylosis.ConclusionsThe incidence of cervical spondylosis and number of spondylotic segments increase, and degeneration gradually becomes more severe with age

Chemical composition and anti-inflammatory effects of essential oil from Hallabong flower

A number of essential oils derived from plants are claimed to have several medicinal functions, including anti-cancer and anti-inflammation effects. However, the chemical composition and biological activities of flower-derived components have not been sufficiently characterized. Therefore, we investigated the composition of essential oils from Hallabong flower [(Citrus unshiu Marcov × Citrus sinensis Osbeck) × Citrus reticulata Blanco] and their anti-inflammatory effects. Hydro-dist illed essential oils (HEOs) were analyzed using gas chromatography–mass spectrometry (GC–MS). In total, 21 components were identified, representing more than 98 % of the oils, with sabinene (34.75 %), linalool (14.77 %), β-ocimene (11.07 %), 4-terpineol (9.63 %), L-limonene (5.88 %), and γ-terpinene (4.67 %) as the main components. In the present study, we also investigated the anti-inflammatory effects of HEOs on lipopolysaccharide (LPS)-stimulated RAW 26 4.7 macrophage cells. HEOs were found to inhibit nitric oxide (NO) and prostaglandin E2 (PGE2) production and to suppress the LPS- induced expression of cyclooxygenase-2 (COX-2) protein. In addition, HEOs downregulated the production of the inflammatory cytokines, tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1 β(IC50 values are 0.05 %, 0.02 %, and 0.01 %, respectively). On the basis of these results, we suggest that HEOs can be consid ered potential anti-inflammatory candidates for therapeutic use in humans

Enhanced Solubility of the Support in an FDM-Based 3D Printed Structure Using Hydrogen Peroxide under Ultrasonication

Fused deposition modeling (FDM), one of the archetypal 3D printing processes, typically requires support structures matched to printed model parts that principally have undercut or overhung features. Thus, the support removal is an essential postprocessing step after the FDM process. Here, we present an efficient and rapid method to remove the support part of an FDM-manufactured product using the phenomenon of oxidative degradation of hydrogen peroxide. This mechanism was significantly effective on polyvinyl alcohol (PVA), which has been widely used as a support material in the FDM process. Compared to water, hydrogen peroxide provided a two times faster dissolution rate of the PVA material. This could be increased another two times by applying ultrasonication to the solvent. In addition to the rapidness, we confirmed that amount of the support residues removed was enhanced, which was essentially caused by the surface roughness of the FDM-fabricated part. Furthermore, we demonstrated that there was no deterioration with respect to the mechanical properties or shape geometries of the obtained 3D printed parts. Taken together, these results are expected to help enhance the productivity of FDM by reducing the postprocessing time and to allow the removal of complicated and fine support structures, thereby improving the design capability of the FDM technique

Spontaneous aortic rupture in a patient with neurofibromatosis type 1

Neurofibromatosis type I (NF-1) is a rare autosomal dominant genetic disorder occurring in 1 in 3,000 individuals. Vasculopathy is a rarely reported finding in patients with NF-1. Here, we report a case of recurrent aortic pseudoaneurysm after endovascular aneurysm repair in a 49-year-old male patient with NF-1. On the sixth postoperative day following a successful open surgical repair of an aortic pseudoaneurysm, he developed hemoperitoneum due to a delayed rupture of the mesenteric artery branch. This was treated with endovascular coil embolization. We report the clinical features and histologic findings of this rare vascular disorder with a review of the relevant literature