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The purpose of this study was to investigate the curriculum of geriatric dentistry for undergraduates in Korean dental schools.For development purposes, it was necessary to compare geriatric dentistry education programmes in South Korea to programmes in the United States and Europe.The most recent curriculum and related information on geriatric dentistry at the undergraduate level in all 11 dental schools in South Korea were collected by both official letter and e-mail. A symposium for gathering expert opinions to improve geriatric dentistry education in South Korea was also held. The collected data were analysed, and the expert opinions at the symposium were summarised.Six of 11 schools had a didactic course as compulsory and three schools as elective. The course was usually conducted as a form of integrated lectures, and the level of standardisation of lecture content was very low. There were no topics for older people who cannot access dental clinics due to functional frailty or disability. No dental school-affiliated hospitals had an independent department for geriatric dentistry. No schools provided clinical teaching for geriatric dentistry. There were no outreach programmes for geriatric dentistry.The educational curriculum for geriatric dentistry in South Korea was insufficient to cope with social and demographic changes. Curriculum content should include clinical practice education and needs to be focused on frail and dependent older adult patients. An essential educational curriculum and core competency for geriatric dentistry should be prepared.

Aquagenic urticaria is a rare form of physical urticaria in which a 1-2 mm wheal is produced by contact with water. Treatment options include antihistamines, ultraviolet monotherapy, topical barrier creams, and acetylcholine antagonists. Despite these pharmacologic measures, the symptoms are frequently refractory to therapy. Aquagenic urticaria lowers the patient’s quality of life and causes daily discomfort. Recently, a patient with aquagenic urticaria treated with omalizumab was reported. Here, we describe a 22-year-old man with a 3-year history of aquagenic urticaria confirmed by a water immersion test. Because he showed no improvement with antihistamines, the patient began omalizumab treatment and demonstrated an excellent response. This case provides new information for clinicians.

The early detection and treatment of sepsis and septic shock patients in emergency departments are critical. Ischemia modified albumin (IMA) is a biomarker produced by ischemia and oxygen free radicals which are related to the pathogenesis of sepsis-induced organ dysfunction. This study aimed to investigate whether IMA was associated with short-term mortality in quick sequential organ failure assessment (qSOFA)-positive sepsis or septic shock patients screened by the sepsis management program.From September 2019 to April 2020, patients who arrived at the emergency departments with qSOFA-positive sepsis or septic shock were included in this retrospective observational study.Among 124 patients analyzed, IMA was higher in the non-surviving group than in the surviving group (92.6 ± 8.1 vs. 86.8 ± 6.2 U/mL, p 0.001). The area under the receiver operating characteristics curve was 0.703 (95% CI: 0.572-0.833, p 0.001). The optimal IMA cutoff was 90.45 (sensitivity 60.9%, specificity 79.2%). IMA values were independently associated with 28-day mortality in the multivariate Cox proportional hazard model (adjusted hazard ratio (aHR) = 1.16, 95% CI: 1.06-1.27, p 0.01).In this study, we showed that IMA in the emergency departments was associated with 28-day mortality in qSOFA-positive sepsis and septic shock patients. Further studies are needed to evaluate the clinical value of IMA as a useful biomarker in large populations and multicenter institutions.

Globally, renewable energies are indispensable resources on account of RE100 and the Paris Agreement. The most developed renewable energies are photovoltaics (PV) and wind energy, and they are continuously expanding. This study aims to optimize and analyze the nuclear power plant (NPP) load-following operation in various PV conditions in a metropolitan region. With theoretically estimated power demand and PV power, a mixed-integer problem (MIP) with ramping cycle constraint (RCC) was constructed for a safe load-following operation and simulated through duck curves under various NPP load-following regions (the extreme, normal, and safe regions). The simulation showed two major results for NPP load-following. Technically, RCC successfully controlled the NPP ramp cycle and was assured to be an optimization tool for NPP operation. Numerically, NPP load-following alleviated PV intermittency to almost 50%, 30%, and 15% depending on the load-following region. However, these effects were restricted when the PV capacity rate was high, especially when it exceeded 60%. Thus, PV system capacity is recommended to be 63% of the maximum power demand in the metropolitan region with NPP load-following, and larger PV systems need more flexibility.

The acceleration of super-heavy ions (SHIs) from plasmas driven by ultrashort (tens of femtoseconds) laser pulses is a challenging topic waiting for breakthrough. The detecting and controlling of the ionization process, and the adoption of the optimal acceleration scheme are crucial for the generation of highly energetic SHIs. Here, we report the experimental results on the generation of deeply ionized super-heavy ions (Au) with unprecedented energy of 1.2 GeV utilizing ultrashort laser pulses (22 fs) at the intensity of 10^22 W/cm2. A novel self-calibrated diagnostic method was developed to acquire the absolute energy spectra and charge state distributions of Au ions abundant at the charge state of 51+ and reaching up to 61+. The measured charge state distributions supported by 2D particle-in-cell simulations serves as an additional tool to inspect the ionization dynamics associated with SHI acceleration, revealing that the laser intensity is the crucial parameter for the acceleration of Au ions over the pulse duration. The use of double-layer targets results in a prolongation of the acceleration time without sacrificing the strength of acceleration field, which is highly favorable for the generation of high-energy super heavy ions.

Vasoactive and inotropic medications are essential for sepsis management, however, the association between the maximum Vasoactive-Inotropic score (VISmax) and clinical outcomes is unknown in adult patients with sepsis. We investigated the VISmax as a predictor for mortality among such patients in the emergency department (ED) and compared its prognostic value with that of the sequential organ failure assessment (SOFA) score. This single-center retrospective study included 910 patients diagnosed with sepsis between January 2016 and March 2020. We calculated the VISmax using the highest doses of vasopressors and inotropes administered during the first 6 h on ED admission and categorized it as 0–5, 6–15, 16–30, 31–45, and &gt, 45 points. The primary outcome was 30-day mortality. VISmax for 30-day mortality was significantly higher in non-survivors than in survivors. The mortality rates in the five VISmax groups were 17.2%, 20.8%, 33.3%, 54.6%, and 70.0%, respectively. The optimal cut-off value of VISmax to predict 30-day mortality was 31. VISmax had better prognostic value than the cardiovascular component of the SOFA score and initial lactate levels. VISmax was comparable to the APACHE II score in predicting 30-day mortality. Multivariable analysis showed that VISmax 16–30, 31–45, and &gt, 45 were independent risk factors for 30-day mortality. VISmax in ED could help clinicians to identify sepsis patients with poor prognosis.

Objective Accurate interpretation of computed tomography (CT) scans is critical for patient care in the emergency department. We aimed to identify factors associated with an incorrect interpretation of abdominal CT by novice emergency residents and to analyze the characteristics of incorrectly interpreted scans.Methods This retrospective analysis of a prospective observational cohort was conducted at three urban emergency departments. Discrepancies between the interpretations by postgraduate year-1 (PGY-1) emergency residents and the final radiologists’ reports were assessed by independent adjudicators. Potential factors associated with incorrect interpretation included patient age, sex, time of interpretation, and organ category. Adjusted odds ratios (aORs) for incorrect interpretation were calculated using multivariable logistic regression analysis.Results Among 1,628 eligible cases, 270 (16.6%) were incorrect. The urinary system was the most correctly interpreted organ system (95.8%, 365/381), while the biliary tract was the most incorrectly interpreted (28.4%, 48/169). Normal CT images showed high false-positive rates of incorrect interpretation (28.2%, 96/340). Organ category was found to be a major determinant of incorrect interpretation. Using the urinary system as a reference, the aOR for incorrect interpretation of biliary tract disease was 9.20 (95% confidence interval, 5.0–16.90) and the aOR for incorrectly interpreting normal CT images was 8.47 (95% confidence interval, 4.85–14.78).Conclusion Biliary tract disease is a major factor associated with incorrect preliminary interpretations of abdominal CT scans by PGY-1 emergency residents. PGY-1 residents also showed high false-positive interpretation rates for normal CT images. Emergency residents’ training should focus on these two areas to improve abdominal CT interpretation accuracy.

Objective This study aimed to describe the timely strategies used to prevent the spread of the emerging coronavirus disease 2019 (COVID-19) and present the activities performed in a regional base hospital in South Korea, from the identification of the index patient until the pandemic declaration. Methods This is a descriptive study detailing the step-by-step guidelines implemented to manage COVID-19 in a regional tertiary base hospital from January to March 2020. We described our three-phase response to the COVID-19 outbreak as per the national and global quarantine procedures applied during each critical event and highlighted the activities implemented from the perspective of public health crisis preparedness involving emerging infectious diseases. Results During the COVID-19 outbreak in Korea, we improved and implemented a rapid and flexible screening system for visiting patients using patient history and radiological testing and created a separate isolation zone for patients under investigation. This active identification-isolation strategy has been effectively applied in the COVID-19 outbreak. Conclusions The step-by-step enforced strategies to prevent the spread of COVID-19, though not perfect, adequately reduced the risk of transmission of the highly contagious infectious disease in the hospital while maintaining the emergency medical system.

Background: This study evaluated the prognostic value of lactate levels and lactate clearance for the prediction of mortality in sepsis and septic shock patients.Methods: We performed a retrospective cohort study of sepsis and septic shock patients with initial lactate levels of ≥2 mmol/L. All patients met the Sepsis-3 definitions. The prognostic value of 6-hour lactate levels, lactate clearance, 6-hour lactate metrics (≥2 mmol/L), and lactate clearance metrics (Results: Of the 363 sepsis and septic shock patients, 148 died (30-day mortality: 40.8%). Nonsurvivors had significantly higher 6-hour lactate levels and lower lactate clearance than those of survivors. Six-hour lactate levels and lactate clearance were associated with 30-day mortality after adjusting for potential confounders (odds ratio, 1.191 [95% confidence interval (CI), 1.097–1.294] and 0.989 [0.983–0.995], respectively). Six-hour lactate levels had better prognostic value than lactate clearance (area under the curve, 0.720 [95% CI, 0.670–0.765] vs. 0.656 [0.605–0.705]; p = 0.018). A 6-hour lactate level of ≥3.5 mmol/L and a lactate clearance of Conclusions: Six-hour lactate levels proved to be more accurate in predicting 30-day mortality than lactate clearance.

With the recent advances in ultrahigh intensity lasers, exotic astrophysical phenomena can be investigated in laboratory environments. Collisionless shock in a plasma, prevalent in astrophysical events, is produced when a strong electric or electromagnetic force induces a shock structure in a time scale shorter than the collision time of charged particles. A near-critical-density (NCD) plasma, generated with an intense femtosecond laser, can be utilized to excite a collisionless shock due to its efficient and rapid energy absorption. We present electrostatic shock acceleration (ESA) in experiments performed with a high-density helium gas jet, containing a small fraction of hydrogen, irradiated with a 30 fs, petawatt laser. The onset of ESA exhibited a strong dependence on plasma density, consistent with the result of particle-in-cell simulations on relativistic plasma dynamics. The mass-dependent ESA in the NCD plasma, confirmed by the preferential reflection of only protons with two times the shock velocity, opens a new possibility of selective acceleration of ions by electrostatic shock.

Aim We designed this study to evaluate the prevalence of comorbidities, their monitoring states and association with treatment medication in Korean rheumatoid arthritis (RA) patients compared with patients from other countries. Methods We analyzed 1050 RA patients from 11 Korean centers and compared them with 3520 patients from 16 other countries using an international, cross-sectional study evaluating comorbidities of RA (COMORA) database. Results Annual evaluations of cardiovascular (CV) risk were less frequently performed in Korea (P = 0.0011). The prevalence of CV-associated morbidity was similar between Korean and international RA patients, although the proportions of current smokers, patients with a family history of CV disease, patients with hyperlipidemia, and patients with Framingham score > 20% were significantly lower in Korea (P < 0.0001 for all), and the antiplatelet agents were more optimally used in Korea (P = 0.0004). Prostate cancer screening was less frequently performed compared to other countries (P < 0.0001). Less than 10% of Korean RA patients were given influenza and pneumococcal vaccinations according to current recommendations. Conclusions There are differences in the prevalence of comorbidities and monitoring states of the risk factors between patients in Korea and in other countries. The prevalence of CV morbidity was similar between the two groups although the prevalence of CV risk factors was significantly low in Korea, suggesting that rheumatologists in Korea need to pay more attention to yearly CV risk monitoring, in addition to the screening of malignancy and vaccination of RA patients against infectious diseases.

The 2016 Surviving Sepsis Campaign guidelines suggest guiding resuscitation to normalize lactate levels in patients with sepsis-associated hyperlactatemia as a marker of tissue hypoperfusion. This study evaluated the prognostic value of lactate levels and lactate clearance for 30-day mortality in patients with sepsis and septic shock diagnosed in the emergency department.We performed a retrospective cohort study of sepsis patients with initial lactate levels of ≥2 mmol/L. All patients met the Sepsis-3 definitions. The prognostic value of 6-hour lactate levels, 6-hour lactate clearance, 6-hour lactate metrics (≥2 mmol/L), and lactate clearance metrics (

We present a proof of principle for onsite calibration of a radiochromic film (EBT3) using CR-39 as an absolute proton-counting detector and laser-accelerated protons as a calibration source. A special detector assembly composed of aluminum range filters, an EBT3 film, and a CR-39 detector is used to expose the EBT3 film with protons in an energy range of 3.65 MeV-5.85 MeV. In our design, the proton beam is divided into small beamlets and their projection images are taken on the EBT3 film and the CR-39 detector by maintaining a certain distance between the two detectors. Owing to the geometrical factor of the configuration and scattering inside the EBT3, the areal number density of protons was kept below the saturation level of the CR-39 detector. We also present a method to relate the number of protons detected on the CR-39 in a narrow energy range to protons with a broad energy spectrum that contribute to the dose deposited in the EBT3 film. The energy spectrum of protons emitted along the target normal direction is simultaneously measured using another CR-39 detector installed in a Thomson parabola spectrometer. The calibration curves for the EBT3 film were obtained in the optical density range of 0.01-0.25 for low dose values of 0.1 Gy-3.0 Gy. Our results are in good agreement with the calibrations of the EBT3 film that are traditionally carried out using conventional accelerators. The method presented here can be further extended for onsite calibration of radiochromic films of other types and for a higher range of dose values.

We present a highly efficient double plasma mirror (DPM) that provides ultrahigh-contrast multi-petawatt (PW) laser pulses with a temporal contrast ratio reaching 1 0 17 up to 160 ps and 1 0 12 up to 2 ps before the main pulse. The high reflectivity of 70%, along with the high-contrast enhancement factor of 700,000, was achieved from the DPM installed after the final stage of a 4 PW Ti:sapphire laser. The 4 PW laser was equipped with cross-polarized wave generation and optical parametric chirped-pulse amplification stages for initial high-contrast operation. The DPM operation was undertaken with conditions that did not modify the spatiotemporal profiles of incident multi-PW laser pulses. This highly efficient DPM with the high-contrast enhancement promises the utilization of multiple PMs as a practical rear end for upcoming tens of petawatt lasers to achieve ultrahigh temporal contrast.

A 20 fs, 4 PW Ti:sapphire laser with a repetition rate of 0.1 Hz was developed and its performance has been tested in laser-driven charged particle acceleration.

The experimental results that demonstrate the changes in the characteristics of laser-driven proton beams are presented along with numerical simulations, as the relativistic laser profile changes from Gaussian to Laguerre-Gaussian.

Bilateral sagittal split ramus osteotomy is considered a standard technique in mandibular orthognathic surgeries to reduce unexpected bilateral stress in the temporomandibular joints. Unilateral sagittal split ramus osteotomy (USSO) was recently introduced to correct facial asymmetry caused by asymmetric mandibular prognathism and has shown favorable outcomes. If unilateral surgery could guarantee long-term postoperative stability as well as favorable results, operation time and the incidence of postoperative complications could be reduced compared to those in bilateral surgery. This report highlights three consecutive cases with long-term follow-up in which USSO was used to correct asymmetric mandibular prognathism. Long-term postoperative changes in the condylar contour and ramus and condylar head length were analyzed using routine radiography and computed tomography. In addition, prior USSO studies were reviewed to outline clear criteria for applying this technique. In conclusion, patients showing functional-type asymmetry with predicted unilateral mandibular movement of less than 7 mm can be considered suitable candidates for USSO-based correction of asymmetric mandibular prognathism with or without maxillary arch surgeries.

To compare the prognostic abilities of lactic acidosis and hyperlactatemia and determine the influence of metabolic acidosis when attempting to predict the outcome of septic patients using serum lactate levels.126 patients with severe sepsis or septic shock were prospectively included in this study at an emergency department. Haemodynamic variables, simplified acute physiology score (SAPS) II, arterial blood gas studies and serum lactate levels were obtained at the time of presentation (0 h) and 4 h after presentation. The probability of mortality was calculated using SAPS II scores and compared with actual inhospital mortality at different serum lactate levels and arterial pH. Survival curves for lactic acidosis and severe hyperlactatemia were analysed using the Kaplan-Meier method.The calculated probability of mortality decreased from 35.7% (95% CI 30.2 to 41.2) at presentation to 29.3% (95% CI 24.2 to 34.4) at 4 h post-presentation. 27.0% of patients (34) died in hospital. Arterial pH and SAPS II scores were independent factors for predicting mortality of septic patients, at 0 h and 4 h. Serum lactate levels were closely related to severity of illness and metabolic acidosis in septic patients. Patients with lactic acidosis had significantly higher inhospital mortality than patients with normal pH and normal lactate levels by Kaplan-Meier survival analysis as determined based on measurements made at 0 h and 4 h (p0.001, p0.001 by the log-rank test, respectively). No significant difference in survival was found between patients with hyperlactatemia and those with normal pH and serum lactate levels.Lactic acidosis not hyperlactatemia was found to predict inhospital mortality more exactly in severe sepsis and septic shock patients. The acid-base state should be considered when attempting to predict the outcome of septic patients using serum lactate levels.

In this paper, we present modeling and simulation of microlens formation by means of a deep X-ray lithography followed by a thermal treatment of a PMMA (Polymethylmethacrylate) sheet. According to this modeling, X-ray irradiation causes the decrease of molecular weight of PMMA, which in turn decreases the glass transition temperature and consequently causes a net volume increase during the thermal cycle resulting in a swollen microlens. In this modeling, the free volume theory including the relaxation process during the cooling process was considered. The simulation results indicate that the modeling in this study is able to predict the fabricated microlens shapes and the variation pattern of the maximum heights of microlens which depends on the conditions of the thermal treatment. The prediction model could be applied to optimization of microlens fabrication process and to designing a micro mold insert for micromolding processes.

Background: Diagostic imaging can help in the management of toxicologic emergencies. The authors report on a patient who presented to the emergency department with coma and suppressed respirations after ingestion of an unknown substance. Methods: Ingestion of chloroform with radiopaque material in the bowel on abdominal radiograph was documented. The patient was treated with haemoperfusion, activated charcoal, and laxatives to decrease the toxicities. Results: Hepatotoxicity occurred on post-ingestion day 3 and elevation of liver enzymes reached peak levels on post-ingestion day 5. The patient received N-acetylsystein and supportive care during hospitalisation. The patient improved from hepatic dysfunction and was discharged without complication on post-ingestion day 11. Conclusion: Radiographic studies in toxicology may confirm a diagnosis and assist in therapeutic intervention.

Fieldbus provides a real-time data communication among field devices in the process control and manufacturing automation systems. In this paper, discrete-event simulation model of the 1993 draft of IEC/ISA fieldbus, which is proposed as an international standard of fieldbus network, is developed. The logical behavior of a simplified model of the data link layer protocol of IEC/ISA fieldbus is described by a Petri net model. Using the simulation model, this paper evaluates the network-induced delay in the data link layer of the IEC/ISA fieldbus. In addition, an integrated discrete-event/continuous-time simulation model of fieldbus and distributed control systems is developed. The integrated simulation model is used to investigate the real-time data communication capability of IEC/ISA fieldbus and the effect of network-induced delay on the performance of control system.

This paper presents a retrospective review and analysis of 20 bimaxillary protrusion patients who visited the authors' hospital between 1986 and 1998 following surgical correction. The lateral cephalometric radiographs of each patient were taken preoperatively (T0), within 1 week after surgery (T1), and at least 1 postoperative year later (T2). Hard and soft tissue analysis was performed on each cephalometric radiograph. The matched pair t test was employed for T0-T1, T1-T2, and T0-T2 periods. The sample consisted of 20 Korean adult patients with bimaxillary protrusion (18 women and 2 men), aged 21 to 33 years. The first premolars were removed in 18 of the 20 cases. The Wunderer method was selected in 18 of the 20 maxillary cases, and the anterior subapical osteotomy was selected in all mandibular cases. Augmentation genioplasty was combined in 3 cases, and reduction glossoplasty was combined in 2 cases. Orthodontic treatment was accompanied in 8 cases. The statistical analysis of all the variables revealed that, except for overbites, there were significant differences between T1-T2 and between T0-T2 periods (P.01). This suggests that most of the bimaxillary patients want instant esthetic facial results and that their soft tissue profiles were improved significantly. However, the postoperative course should be cautiously observed.

Castleman’s disease is a rare atypical lymphoproliferative disorder. Although HHV-8 has been reported to be a cause of Castleman’s disease, the etiology and pathogenesis of the disease remains mostly unknown. We experienced a 51year-old female patient who was concurrently diagnosed with Castleman’s disease and systemic lupus erythematosus. Castleman’s disease has been rarely reported in patients with systemic lupus erythematosus. Thus, we report the case and briefly discuss relevant articles.

Soon Myung Jung 1 , Jin Taek Yoo 1 , Young Hwan Kim 1 , Yu Na Seo 2 , Na Young Lee 3 , Seong Geun Lee 4 , Seong Hu Park, Young Eun Park, Seung Hoon Baek, Geun Tae Kim, Sung-Il Kim, Joung Wook Lee Departments of Internal Medicine, Radiology and Pediatrics, Busan St. Mary’s Medical Center, Department of Internal Medicine, Pusan National University School of Medicine, Kosin University College of Medicine, Busan, Korea

Background: Brachial ankle pulse wave velocity (BaPWV) and cardio ankle vascular index (CAVI), as indicators of arterial stiffness, are increased in type 2 diabetes. Albuminuria, as a cardiovascular risk factor in type 2 diabetes, can cause endothelial dysfunction and atherosclerosis, and these can increase arterial stiffness. So we investigated the hypothesis that increased albuminuria reflects increased BaPWV and CAVI in type 2 diabetes. Methods: We retrospectively analyzed 106 patients (58 men and 48 women) with type 2 diabetes from March 2005 to September 2006. Urine albumin creatinine ratio (ACR) to evaluate urinary albumin excretion, BaPWV and CAVI were measured in all patients. Results: All patients were divided 3 groups, normal group (ACR 300 mg/g Cr., n = 33). BaPWV and CAVI in microalbuminuria group and proteinuria group are faster than normal group. In bivariate correlation analysis, BaPWV was not associated with ACR, but CA VI was positively correlated to ACR (r = 0.285, P = 0.003). BaPWV was positively correlated to age, diabetes duration, body mass index, systolic blood pressure, diastolic pressure, pulse pressure and negatively correlated to glomerular filtration rate (GFR). CAVI was positively correlated to age, diabetes duration and negatively correlated to GFR. In multiple linear stepwise regression analysis, BaPWV was not associated with ACR, but ACR was independent predictor for CAVI (P = 0.002). Conclusion: In type 2 diabetes, albuminuria was independent predictor for indicators of arterial stiffness

Systemic lupus erythematosus(SLE) is autoimmune disease in which involves systemic organs. Hematological manifestations are common in patients with SLE but aplastic anemia is very rare and, although various immunosuppressants have been tried, there is no established treatment in aplastic anemia associated with SLE. Furthermore, disease course and prognosis may be different from other aplastic anemia. A 42-year-old woman presented with fever, chilling, myalgia, general weakness, pancytopenia. Her bone marrow aspirate and biopsy revealed almost acellular bone marrow with rare foci of hematopoietic elements and she was diagnosed with SLE simultaneously. High-dose methyprednisolone, prednisolone and cyclophosphamide therapies had been unsuccessful in controlling pancytopenia. Cyclosproine was started and the aplastic anemia was responded. Now she was free of transfusion with more than 10 g/dL of hemoglobin.

Purpose: If damage to the neurovascular bundle of the mandibular canal during dental implant surgery of the mandible is to be prevented, accurate measurement of the distance between the alveolar crest and the mandibular canal, as seen on panoramic radiographs, is important. The purpose of this study was to compare the accuracy of panoramic radiography using a lead ruler with that of computed tomography for the measurement of the distance between the alveolar crest and superior border of the mandibular canal and to evaluate the usefulness of panoramic radiography using a lead ruler. Materials and Methods: For control study, panoramic radiography of the dry mandible was undertaken using a lead ruler, and computed tomography was added. The distances between the alveolar crest and the superior border of the mandibular canal and between the alveolar crest and the lowest border of the body of the mandible were measured at the level of the 2nd premolar to the 3rd molar. These measurements were compared with actual measurements of the dry mandible in the same areas. The cases of 87 patients[49 men, 38 women; age range, 20-84 (mean, 42) years] who had undergone panoramic radiography using a lead ruler were reviewed. They were catergorized according to sex, the presence of teeth, and whether under or over 50 years of age. All measurements were compared and analyzed using the Student t-test. Results: Measured values obtained from a panoramic radiograph using a lead ruler(magnification:100.32%5.92) and from a computed tomograph(magnification:100.22%5.55) deviated less from actual measurements on the dry mandible (p 0.05). The distance from the 2nd premolar to the 3rd molar was greater in male adults (19.62 mm 3.95) than in female (17.54 mm 4.04) (p 0.05), except the 3rd molar. In addition, the distance was greater in dentulous patients(18.81 mm 3.33) than in edentulous (16.23 mm 1.75)(p 0.05), except the 3rd molar. There was, howerer, no significant difference between patients under and over 50 years of age (p 0.05), except 2nd pre molar and 1st molar in the female. Conclusion: Panoramic radiography using a lead ruler is a simple and accurate modality for the presurgical planning of dental implant surgery. It is suggested that the successful long-term rate of dental implantation may be higher in dentulous male than in edentulous female molars.