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Oculofaciocardiodental (OFCD) syndrome is a rare genetic disease, first reported by Hayward in 1980. This syndrome presents with various ocular, facial, cardiac, and dental symptoms, including congenital cataract, dysmorphic facial features, congenital heart disease, and enlarged roots, respectively. The most important criteria for the diagnosis of OFCD syndrome are dental abnormalities, especially extreme elongation of canine roots. Here, we report detailed analysis of the dentofacial region, as well as ocular, facial, cardiac, and dental findings in a female with OFCD syndrome. To the best of our knowledge, the patient in this case is the first such patient reported in South Korea.

목적: 본 연구는 천연성분 Ectoin의 피부 보습, 모공, 피부색, pH 등에 미치는 전반적인 효과를 규명하고자 하였다. 방법: Ectoin 분말 추출 시료는 클렌징폼, 토너, 크림, 로션으로 제조하여 실험군과 대조군에게 매일 아침, 저녁으로 2회씩 4주간 안면에 사용하 도록 하였다. 수집된 자료는 통계 프로그램 SPSS 24.0o fr Windows를 이용하여 분석하였다. 결과: 유분의 경우, 대조군은 T존과 U 존 모두에서 유분 증가가 나타난 반면, 실험군은 T존에서는 유분이 감소하였고, U존에서는 유분이 증가하였다. 수분의 경우, 대조 군과 실험군 모두 수분이 증가했지만, 모든 항목에서 대조군보다 실험군의 수분 함유량 증가가 크게 나타났으며, 실험군은 턱을 제 외한 모든 항목에서 수분이 유의하게 증가하였다. Transepidermal water loss (TEWL)의 경우, 대조군은 턱을 제외한 모든 항목에 서 TEWL이 증가했고, 실험군은 모든 항목에서 TEWL의 감소를 나타냈다. 모공의 경우, 대조군에서는 모공의 증가와 감소가 교차 하는 경향을 나타냈지만, 실험군에서는 모든 항목에서 모공의 감소를 나타냈다. pH는 사전, 사후 모두 평균 4.5-6.5에 해당하는 피 부의 정상 pH 범주를 보였으며, 유의한 변화는 나타나지 않았다. 피부색의 경우, 대조군의 멜라닌은 증가와 감소가 교차하는 반면, 실험군의 멜라닌은 좌우 모두에서 유의한 감소를 나타냈고, 홍반은 대조군과 실험군 모두 감소를 나타냈으나, 실험군의 홍반이 대 조군에 비해 크게 감소하였다. 결론: 본 실험결과를 통해 천연성분인 Ectoin이 함유된 크림이 피부 보습 및 수분에 미치는 긍정적인 영향을 객관화, 수치화하였고, 이를 통해 화장품에 들어가는 천연 보습 원료로서의 가능성을 확인하였다

DNA-mediated self-assembly of colloidal particles is one of the most promising approaches for constructing colloidal superstructures. For nanophotonic materials and devices, DNA-functionalized colloids with diameters of around 100 nm are essential building blocks. Here, we demonstrate a strategy for synthesizing DNA-functionalized polymer nanoparticles (DNA-polyNPs) in the size range of 55–150 nm using block copolymer micelles as a template. Diblock copolymers of polystyrene-b-poly(ethylene oxide) with an azide end group (PS-b-PEO-N3) are first formed into spherical micelles. Then, the micelle cores are swollen with the styrene monomer and polymerized, thus producing PS NPs with PEO brushes and azide functional end groups. DNA strands are conjugated onto the ends of the PEO brushes through a strain-promoted alkyne–azide cycloaddition reaction, resulting in a DNA density of more than one DNA strand per 12.6 nm2 for 70 nm particles. The DNA-polyNPs with complementary sequences enable the formation of CsCl-t...

Purpose This study was conducted to evaluate the accuracy of linear measurements of 3-dimensional (3D) images generated by cone-beam computed tomography (CBCT) and facial scanning systems, and to assess the effect of scanning parameters, such as CBCT exposure settings, on image quality. Materials and Methods CBCT and facial scanning images of an anthropomorphic phantom showing 13 soft-tissue anatomical landmarks were used in the study. The distances between the anatomical landmarks on the phantom were measured to obtain a reference for evaluating the accuracy of the 3D facial soft-tissue images. The distances between the 3D image landmarks were measured using a 3D distance measurement tool. The effect of scanning parameters on CBCT image quality was evaluated by visually comparing images acquired under different exposure conditions, but at a constant threshold. Results Comparison of the repeated direct phantom and image-based measurements revealed good reproducibility. There were no significant differences between the direct phantom and image-based measurements of the CBCT surface volume-rendered images. Five of the 15 measurements of the 3D facial scans were found to be significantly different from their corresponding direct phantom measurements (P

Osseointegrated implants are now commonplace in contemporary dentistry. However, a number of complications can occur around dental implants, including peri-implantitis, maxillary sinusitis, osteomyelitis, and neoplasms. There have been several reports of a malignant neoplasm occurring adjacent to a dental implant. In this report, we describe 2 such cases. One case was that of a 75-year-old man with no previous history of malignant disease who developed a solitary plasmacytoma around a dental implant in the left posterior mandible, and the other was that of a 43-year-old man who was diagnosed with squamous cell carcinoma adjacent to a dental implant in the right posterior mandible. Our experiences with these 2 cases suggest the possibility of a relationship between implant treatment and an inflammatory cofactor that might increase the risk of development of a malignant neoplasm.

Selective hydrodechlorination (HDC) of trichloromethane (TCM, CHCl 3 ) to dichloromethane (DCM, CH 2 Cl 2 ) was studied on the mesoporous bimetallic Pt-Pd/KIT-6 to verify the roles of the active bimetals to catalytic activity and product distribution. The optimal bimetal ratio of 2 wt%Pt-0.05 wt%Pd on the highly ordered mesoporous KIT-6 calcined at 400 °C showed a maximum TCM conversion with DCM yield, and the optimal calcination temperature of Pt-Pd/KIT-6 was mainly responsible for the formation of homogeneously and closely distributed smaller Pt-Pd nanoparticles with higher oxidation states of Pt crystallites supported by XPS and EXAFS analysis. Based on the proposed kinetic models on the optimal Pt-Pd/KIT-6, the competitive reaction mechanisms of the formations of CH 4 and monochloromethane (MCM, CH 3 Cl) from DCM intermediate can well explain the product distributions. Using the seven different kinetic models, the best model on the basis of the Akaike’s Information Criteria showed the activation energies of the HDC of TCM to be in the range of 18–60 kJ/mol. The kinetic model also revealed the inverse relationship between the conversion of TCM and selectivity to DCM. Either an increase of space velocity or decrease of H 2 /TCM ratio increased the DCM yield, while there existed the optimal operating conditions. The DCM productivity of 1.5 mol-DCM/(g cat ·h) was achievable at the highest space velocity and lowest H 2 /TCM ratio under a specific reaction condition of 190 °C and 0.1 MPa.

BackgroundPredicting how long a patient with far advanced cancer has to live is a significant part of hospice and palliative care. Various prognostic models have been developed, but have not been fully compared in South Korea.ObjectivesWe aimed to compare the accuracy of the Prognosis in Palliative Care Study (PiPS), Palliative Prognostic Index (PPI), Palliative Prognostic Score (PaP) and Objective Prognostic Score (OPS) for patients with far advanced cancer in a palliative care unit in South Korea.MethodsThis prospective study included patients with far advanced cancer who were admitted to a single palliative care unit at the National University Hospital. Variables for calculating the prognostic models were recorded by a palliative care physician. The survival rate was estimated using the Kaplan-Meier method. The sensitivity, specificity, positive predictive value and negative predictive value of each model were calculated.ResultsA total of 160 patients participated. There was a significant difference in survival rates across all groups, each categorised through the five prognostic models. The overall accuracy (OA) of the prognostic models ranged between 54.5% and 77.6%. The OA of clinicians’ predictions of survival ranged between 61.9% and 81.3%.ConclusionThe PiPS, PPI, PaP and OPS were successfully validated in a palliative care unit of South Korea. There was no difference in accuracy between the prognostic models, and OA tended to be lower than in previous studies.

Highly ordered mesoporous Fe2O3–ZrO2 mixed bimetal oxides (FeZr) without any additional chemical promoters were first applied to produce the value-added hydrocarbons by CO hydrogenation through Fischer–Tropsch synthesis (FTS) reaction of syngas. To enhance a catalytic activity and structural stability, an irreducible ZrO2 as a structural promoter was incorporated in the ordered mesoporous Fe2O3 structures with a different Zr/Fe molar ratio from 0 to 1 prepared by using a hard template of KIT-6. When an optimal amount of zirconia (Zr/Fe molar ratio = 0.25) was incorporated in the ordered mesoporous Fe2O3 frameworks, the catalytic activity was significantly improved and almost 10 times higher than the mesoporous monometallic Fe2O3. The highly ordered mesoporous structures were stably preserved even under reductive FTS reaction conditions. The ordered mesoporous FeZr catalysts showed a higher C5+ selectivity even at a higher CO conversion above 80%. This improved catalytic activity and stability on the optim...

Colloids with patches, which refer physically or chemically distinct domains at their surface, have broaden the range of complex superstructures that can be achieved by self-assembly. Similarly, patches are recently introduced on micelles which are called “soft patchy micelles”. Due to soft interaction potential between patches on micelles, it holds great potential to form unique soft superstructures at nanoscale. In this review, we first describe a recent development in the synthesis of soft patchy micelles. Diblock amphiphilic copolymers are encapsulated into uniform emulsion which are then aggregated and reformed into patchy micelles with surfactants at interface. Alternatively, triblock amphiphilic copolymers are assembled into uniform spherical patchy micelles via stepwise micellization process. For cylindrical or platelet micelles, block copolymers with crystallizable core-forming blocks are introduced for monodisperse cylindrical or platelet patchy micelles by sequential growth of core blocks. Finally, we discuss how those soft patchy micelles are assembled into two or three-dimensional superstructures by hydrophobic-hydrophobic interaction, electrostatic attraction or coordination between patches, showing potentials of micellar structure as a soft designer micelles.

PurposeTo evaluate knowledge of secondhand smoke (SHS) risks, sources of information, and associated factors and behaviors among hospital staff.MethodsWe conducted a cross-sectional survey using a 40-item self-administered questionnaire among 328 employees at a university hospital. The questions on representative diseases related to SHS were used to measure the degree of knowledge of SHS. Multiple regression analysis was used to determine the correlation between SHS knowledge scores and variables.ResultsFemales had better SHS knowledge scores than males, regardless of smoking status (pConclusionSHS knowledge is high among females, when hospital staff are educated about SHS risks, and when they have experienced any SHS exposure-related symptoms or felt uncomfortable when exposed to SHS. SHS risk education is an effective tool to increase SHS knowledge in hospital staff.

Background: The waitlist period for kidney transplantation (KT) has been increasing due to intractable shortage of brain-dead donors in Korea. To solve this organ shortage issue, KT cases with expanded criteria brain-dead donor (ECD) organs have been increasing. This study intended to analyze the willingness of waitlist patients to undergo KT with ECD in a single institution in or der to use as the basic data for selecting and managing patients waiting for deceased donor KT (DDKT). Methods: We carried out a survey with 1,069 patients who were enrolled at the waitlist for DDKT from 2015 to 2019 at a single in stitution. They were asked whether they were willing to undergo KT with ECD of type 1 and 2. The answers were analyzed through descriptive statistics. ECD type 1: age over 60 years, but serum creatinine is normal (

All‑trans retinoic acid (ATRA) can protect fibroblasts against ultraviolet (UV)‑induced oxidative damage, however, its underlying molecular mechanism is still unclear. The present study aimed to investigate the role of 3‑hydroxy‑3‑methylglutaryl reductase degradation (Hrd1) in the protective effect of ATRA on human skin fibroblasts exposed to UV. The expression of Hrd1 in human or mice skin was assessed by immunohistochemistry (IHC) staining and western blot analysis. Hrd1 siRNA (si‑Hrd1) and Hrd1 recombinant adenoviruses (Ad‑Hrd1) were used to downregulate and upregulate Hrd1 expression in fibroblasts, respectively. The interaction between Hrd1 and NF‑E2‑related factor 2 (Nrf2) was assessed by co‑immunoprecipitation (co‑IP) and immunofluorescence analysis. The results revealed that Hrd1 expression was increased but Nrf2 expression was decreased in UV‑exposed human skin fibroblasts. In addition, ATRA could reverse the increase of Hrd1 expression induced by UV radiation in vivo and in vitro. ATRA or knockdown of Hrd1 could increase Nrf2 expression in fibroblasts exposed to UV radiation, and Hrd1 could directly interact with Nrf2 in skin fibroblasts. Notably, overexpression of Hrd1 abolished the protective effect of ATRA on the UV‑induced decrease of Nrf2 expression, the production of reactive oxygen species (ROS) and the decrease of cell viability. In conclusion, the present data demonstrated that ATRA protected skin fibroblasts against UV‑induced oxidative damage through inhibition of E3 ligase Hrd1.

Purpose: This study was performed to evaluate the feasibility of visualizing soft tissue lesions and vascular structures using contrast-enhanced cone-beam computed tomography (CE-CBCT) after the intravenous administration of a contrast medium in an animal model. Materials and Methods: CBCT was performed on six rabbits after a contrast medium was administered using an injection dose of 2 mL/kg body weight and an injection rate of 1 mL/s via the ear vein or femoral vein under general anesthesia. Artificial soft tissue lesions were created through the transplantation of autologous fatty tissue into the salivary gland. Volume rendering reconstruction, maximum intensity projection, and multiplanar reconstruction images were reconstructed and evaluated in order to visualize soft tissue contrast and vascular structures. Results: The contrast enhancement of soft tissue was possible using all contrast medium injection parameters. An adequate contrast medium injection parameter for facilitating effective CE-CBCT was a 5-mL injection before exposure combined with a continuous 5-mL injection during scanning. Artificial soft tissue lesions were successfully created in the animals. The CE-CBCT images demonstrated adequate opacification of the soft tissues and vascular structures. Conclusion: Despite limited soft tissue resolution, the opacification of vascular structures was observed and artificial soft tissue lesions were visualized with sufficient contrast to the surrounding structures. The vascular structures and soft tissue lesions appeared well delineated in the CE-CBCT images, which was probably due to the superior spatial resolution of CE-CBCT compared to other techniques, such as multislice computed tomography. (Imaging

Ultrasound (US)-guided salivary gland irrigation is a popular conservative treatment method that improves the success rate and reduces complications of the sialo-irrigation procedure. US is routinely used for evaluation of various salivary gland diseases because of its easy accessibility and absence of ionizing radiation. US also allows dynamic studies with real-time imaging during diagnostic or surgical procedures. However, conventional US images have limitations in salivary duct visualization. Although US images acquired with saline irrigation have improved visualization because of ductal system dilation by the pulling effect, the resultant image quality remains insufficient for diagnosis. Therefore, contrast agents are required during US-guided sialo-irrigation procedures to produce diagnostic image quality. Air bubbles in saline solution have high echogenicity and enhance image quality by acting as a US contrast agent. The aim of this study was to assess the clinical significance of US-guided sialo-irrigation with a saline-air contrast medium, to estimate its diagnostic and treatment efficacy, and to examine the procedure in two patients. In the study, two patients underwent US-guided salivary gland irrigation with air-bubble mixed saline solution. During the procedure, we were able to visualize the salivary gland duct and subsequently irrigate and clean the inside of the duct. As a result, the patients' symptoms were relieved and saline solution mixed with air bubbles was confirmed to be an effective contrast agent.

Purpose This study was performed to investigate the influence of object shape and distance from the center of the image on the volumetric accuracy of cone-beam computed tomography (CBCT) scans, according to different parameters of tube voltage and current. Materials and methods Four geometric objects (cylinder, cube, pyramid, and hexagon) with predefined dimensions were fabricated. The objects consisted of Teflon-perfluoroalkoxy embedded in a hydrocolloid matrix (Dupli-Coe-Loid TM; GC America Inc., Alsip, IL, USA), encased in an acrylic resin cylinder assembly. An Alphard Vega Dental CT system (Asahi Roentgen Ind. Co., Ltd, Kyoto, Japan) was used to acquire CBCT images. OnDemand 3D (CyberMed Inc., Seoul, Korea) software was used for object segmentation and image analysis. The accuracy was expressed by the volume error (VE). The VE was calculated under 3 different exposure settings. The measured volumes of the objects were compared to the true volumes for statistical analysis. Results The mean VE ranged from -4.47% to 2.35%. There was no significant relationship between an object's shape and the VE. A significant correlation was found between the distance of the object to the center of the image and the VE. Tube voltage affected the volume measurements and the VE, but tube current did not. Conclusion The evaluated CBCT device provided satisfactory volume measurements. To assess volume measurements, it might be sufficient to use serial scans with a high resolution, but a low dose. This information may provide useful guidance for assessing volume measurements.

// Guideock Kwon 1, * , Md Jamal Uddin 1, * , Gayoung Lee 1 , Songling Jiang 1 , Ahreum Cho 1 , Jung Hwa Lee 1 , Sae Rom Lee 2 , Yun Soo Bae 2 , Sung Hwan Moon 3 , Soo Jin Lee 3 , Dae Ryong Cha 4 and Hunjoo Ha 1 1 Graduate School of Pharmaceutical Sciences, College of Pharmacy, Ewha Womans University, Seoul, Korea 2 Department of Life Science, Ewha Womans University, Seoul, Korea 3 Aptabio Therapeutics Inc, Yongin-si, Korea 4 Department of Internal Medicine, Division of Nephrology, Korea University, Seoul, Korea * These authors contributed equally to this work Correspondence to: Hunjoo Ha, email: hha@ewha.ac.kr Keywords: APX-115, diabetic kidney disease, mitochondria and peroxisome, oxidative stress, pan-Nox inhibitor Received: March 24, 2017 Accepted: June 05, 2017 Published: June 16, 2017 ABSTRACT NADPH oxidase (Nox)-derived reactive oxygen species (ROS) are increasingly recognized as a key factor in inflammation and extracellular matrix accumulation in diabetic kidney disease. APX-115 (3-phenyl-1-(pyridin-2-yl)-4-propyl-1-5-hydroxypyrazol HCl) is a novel orally active pan-Nox inhibitor. The objective of this study was to compare the protective effect of APX-115 with a renin-angiotensin system inhibitor (losartan), the standard treatment against kidney injury in diabetic patients, on streptozotocin (STZ)-induced diabetic kidney injury. Diabetes was induced by intraperitoneal injection of STZ at 50 mg/kg/day for 5 days in C57BL/6J mice. APX-115 (60 mg/kg/day) or losartan (1.5 mg/kg/day) was administered orally to diabetic mice for 12 weeks. APX-115 effectively prevented kidney injury such as albuminuria, glomerular hypertrophy, tubular injury, podocyte injury, fibrosis, and inflammation as well as oxidative stress in diabetic mice, similar to losartan. In addition, both APX-115 and losartan treatment effectively inhibited mitochondrial and peroxisomal dysfunction associated with lipid accumulation. Our data suggest that APX-115, a pan-Nox inhibitor, may become a novel therapeutic agent against diabetic kidney disease by maintaining peroxisomal and mitochondrial fitness.

Recent studies have suggested that renal Nox is important in the progression of diabetic nephropathy. Therefore, we investigated the effect of a novel pan-NOX-inhibitor, APX-115, on diabetic nephropathy in type 2 diabetic mice. Eight- week-old db/m and db/db mice were treated with APX-115 for 12 weeks. APX-115 was administered by oral gavage at a dose of 60 mg/kg per day. To compare the effects of APX-115 with a dual Nox1/Nox4 inhibitor, db/db mice were treated with GKT137831 according to the same protocol. APX-115 significantly improved insulin resistance in diabetic mice, similar to GKT137831. Oxidative stress as measured by plasma 8-isoprostane level was decreased in the APX-115 group compared with diabetic controls. All lipid profiles, both in plasma and tissues improved with Nox inhibition. APX-115 treatment decreased Nox1, Nox2, and Nox4 protein expression in the kidney. APX-115 decreased urinary albumin excretion and preserved creatinine level. In diabetic kidneys, APX-115 significantly improved mesangial expansion, but GKT137831 did not. In addition, F4/80 infiltration in the adipose tissue and kidney decreased with APX-115 treatment. We also found that TGF-β stimulated ROS generation in primary mouse mesangial cells (pMMCs) from wild-type, Nox1 KO, and Duox1 KO mice, but did not induce Nox activity in pMMCs from Nox2 knockout (KO), Nox4 KO, or Duox2 KO mice. These results indicate that activating Nox2, Nox4, or Duox2 in pMMCs is essential for TGF-β-mediated ROS generation. Our findings suggest that APX-115 may be as effective or may provide better protection than the dual Nox1/Nox4 inhibitor, and pan-Nox inhibition with APX-115 might be a promising therapy for diabetic nephropathy.

This study was conducted to compare the preference and satisfaction for Korean traditional foods (Jeonju Bibimbap, Daetongbap, Jeonbokjuk, Jorangiddockguk, Hobakbumbuk, Darkgalbee, Eonyang Bulgogi, Moyackgwa, Insam Jeonggwa, Maejackgwa) in foreigners and Koreans. In this study, 27 foreign and 31 Korean university students were surveyed. Statistical analysis and Mann-Whitney U test were performed using the SPSS statistical package (17.0). The major findings were as follows: 1) Foreigners had higher experience of eating Darkgalbee (84.6%), Jeonju Bibimbap (80.8%), Daetongbap (53.8%), and Jeonbokjuk (53.8%) among Korean traditional foods, whereas their eating experience of Insam Jeonggwa (3.8%), Maejackgwa (11.5%), Moyackgwa (15.4%) and Jorangiddockguk (23.1%) was lower. 2) Foreigners and Koreans both liked sweet taste, but disliked sour taste, bitter taste, garlic flavor, sesame flavor, and soy sauce flavor among the sensory characteristics of Korean traditional foods. 3) Foreigners scored their overall satisfaction of Korean traditional foods in the order of Jeonju Bibimbap (), Eonyang Bulgogi (), Daetongbap (), Darkgalbee (), and Jeonbokjuk (), whereas Koreans rated higher scores for Eonyang Bulgogi (), Darkgalbee (), Jeonju Bibimbap (), Jeonbokjuk (), and Moyackgwa ().

In this paper, we propose a new multi-input multi-output (MIMO) channel modeling method for mobile-to-mobile (M2M) communications based on IEEE 802.16n. To reflect the mobilities at the transmitter and the receiver, we propose a new channel model by invoking the geometrical two-ring scattering model and modifying the conventional IEEE 802.16m fixed-to-mobile (F2M) channel model considering M2M communication environments. Through computer simulations, we analyze the statistical properties of proposed channel model in terms of the time correlation and the spatial correlation. Finally, the performance of the system using the proposed M2M channel model is compared with that using the conventional 802.16m F2M channel model by link level simulations.

In this paper, we propose a new channel selection method for IEEE 802.11 based wireless local area network (WLAN) using the 2.4GHz band. The proposed algorithm searches the nearby access points (APs) through channel scanning. The scanned APs are classified into shared APs using the target channel and interference APs using the channels adjacent to the target channel. The proposed method evaluates the achievable rate by separately considering the losses by shared APs and interference APs, and selects the channel with the maximum achievable rate. The performance of the proposed algorithm is compared to those of existing channel selection techniques through field tests in practical WLAN environments.

The purpose of the study was to determine fat contents and fatty acid compositions of the lipids in sweetfish cultured in Korea and lipid oxidation during storage at refrigeration temperature (2 o C). Whole or minced sweetfish were vacuum-packaged or treated with ascorbic acid. Changes in thiobarbituric acid (TBA) values, peroxide values (PV) and free fatty acid (FFA) in the fish were determined. Sweetfish contained 72.5% moisture, 5.3% lipid and 1.1% ash. Palmitic acid was the highest (27.4% (w/w) of the total fatty acids) among the saturated fatty acids. Total monounsaturated fatty acids (MUFA) were 33.9% and oleic acid (21.0%) was the highest, followed by palmitoleic acid (7.8%). Total PUFA were 28.2%. Predominant PUFA were linoleic acid (8.1%), EPA (5.7%) and DHA (12.1%). TBA values and PV of the whole sweetfish treated with ascorbic acid and vacuum- packaged were not different from the control. TBA values of the minced sweetfish treated with ascorbic acid were significantly lower than the other groups (p

Purpose: This study was performed to investigate the incidence and configuration of the bifid mandibular canal in a Korean population by using cone-beam computed tomography (CBCT) imaging. Materials and Methods: CBCT images of 1933 patients (884 male and 1049 female) were evaluated using PSR9000N and Alphard-Vega 3030 Dental CT units (Asahi Roentgen Ind. Co., Ltd, Kyoto, Japan). Image analysis was performed by using OnDemand3D software (CyberMed Inc., Seoul, Korea). The bifid mandibular canal was identified and classified into four types, namely, the forward canal, buccolingual canal, dental canal, and retromolar canal. Statistical analysis was performed by using the chi-squared test and one-way analysis of variance (ANOVA). Results: Bifid mandibular canals were observed in 198 (10.2%) of 1933 patients. The most frequently observed type of bifid mandibular canal was the retromolar canal (n=104, rate: 52.5%) without any significant difference among the incidence of each age and gender. The mean diameter of the accessory canal was 1.27 mm (range: 0.27-3.29 mm) without any significant difference among the mean diameter of each type of the bifid mandibular canal. The mean length of the bifid mandibular canals was 14.97 mm (range: 2.17-38.8 mm) with only a significant difference between the dental canal and the other types. Conclusion: The bifid mandibular canal is not uncommon in Koreans and has a prevalence of 10.2% as indicated in the present study. It is suggested that a CBCT examination be recommended for detecting a bifid canal. (Imaging Sci Dent 2014; 44 : 53-60)