• Restorative Dentistry and Endodontics
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• v.34 no.6
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• pp.467-476
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• 2009

The aim of this study was to measure the dentinal tubular fluid flow (DFF) during and after amalgam and composite restorations. A newly designed fluid flow measurement instrument was made. A third molar cut at 3 mm apical from the CEJ was connected to the flow measuring device under a hydrostatic pressure of 15 $cmH_2O$. Class I cavity was prepared and restored with either amalgam (Copalite varnish and Bestaloy) or composite (Z-250 with ScotchBond MultiPurpose: MP, Single Bond 2: SB, Clearfil SE Bond: CE and Easy Bond: EB as bonding systems). The DFF was measured from the intact tooth state through restoration procedures to 30 minutes after restoration, and re-measured at 3 and 7days after restoration. Inward fluid flow (IF) during cavity preparation was followed by outward flow (OF) after preparation, In amalgam restoration, the OF changed to IF during amalgam filling and slight OF followed after finishing. In composite restoration, application CE and EB showed a continuous OF and air-dry increased rapidly the OF until light-curing, whereas in MP and SB, rinse and dry caused IF and OF, respectively. Application of hydrophobic bonding resin in MP and CE caused a decrease in flow rate or even slight IF. Light-curing of adhesive and composite showed an abrupt IF. There was no statistically significant difference in the reduction of DFF among the materials at 30 min. 3 and 7 days after restoration (p > 0.05).

• Journal of Pharmaceutical Investigation
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• v.34 no.2
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• pp.139-145
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• 2004

The purpose of the present study was to evaluate the bioequivalence of two risperidone tablets, Risperdal (Janssen Korea Co., Ltd.) and Rispen (Myung In Pharm. Co., Ltd), according to the guidelines of Korea Food and Drug Administration (KFDA). The risperidone release from the two risperidone formulations in vitro was tested using KP VIII Apparatus II method with various of dissolution media (pH 1.2, 4.0, 6.8 buffer solution and water). Twenty four healthy male subjects, $23.33\;{\pm}2.10$ years in age and $69.24{\pm}8.05\;kg$ kg in body weight, were divided into two groups and a randomized $2\;{\times}\;2$ cross over study was employed. After one tablet containing 2 mg as risperidone was orally administered, blood was taken at predetermined time intervals and the concentrations of risperidone in serum were determined using HPLC method with UV detector. The dissolution profiles of two formulations were similar at all dissolution media. Besides, the pharmacokinetic parameters such as $AUC_t$,$C_{max},\;and\;T_{max}$ were calculated and ANOVA test was utilized for the analysis of the parameters using logarithmically transformed $AUC_t$,$C_{max}$ and untransformed $T_{max}$. The results showed that the differences between two formulations based on the Risperdal were 0.20, -1.29 and -11-09% for $AUC_t$,$C_{max},\;and\;T_{max}$, respectively There were no sequence effects two formulations in parameters. The 90% confidence intervals using logarithmically transformed data were within the acceptance range of log(0.8) to log(1.25) (e.g.,$log(0.90){\sim}log(1.30)$ and $log(0.84){\sim}log(1.09)$ for$AUC_t$ and $C_{max}$, respectively). Thus, the criteria of the KFDA guideline for the bioequivalence were satisfied, indicating Rispen tablet and Risperdal tablet were bioequivalent.

• Korean Journal of Clinical Laboratory Science
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• v.50 no.4
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• pp.470-476
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• 2018

Facial motor evoked potential (FMEP) by multi-pulse transcranial electrical stimulation (mpTES) can complement free-running electromyography (EMG) and direct facial nerve stimulation to predict the functional integrity of the facial nerve during cerebello-pontine angle (CPA) tumor surgery. The purpose of this paper is to examine the standardized test methods and the usefulness of FMEP as a predictor of facial nerve function and to minimize the incidence of facial paralysis as an aftereffect of surgery. TES was delivered through electrode Mz (cathode) - M3/M4 (anode), and extracranially direct distal facial muscle excitation was excluded by the absence of single pulse response (SPR) and by longer onset latency (more than 10 ms). FMEP from the orbicularis oris (o.oris) and the mentalis muscle simultaneously can improve the accuracy and success rate compared with FMEP from the o.oris alone. Using the methods described, we can effectively predict facial nerve outcomes immediately after surgery with a reduction of more than 50% of FMEP amplitude as a warning criterion. In conclusion, along with free-running EMG and direct facial nerve stimulation, FMEP is a useful method to reduce the incidence of facial paralysis as a sequela during CPA tumor surgery.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.1
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• pp.116-123
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• 2019

Thermal batteries are also called molten-salt batteries as the electrolyte is mainly composed of molten salt. The molten-salt electrolyte is a solid that does not conduct electricity at room temperature, but when it is melted by a pyrotechnic heat source, it becomes an excellent ionic conductor. Thermal batteries are a kind of pyrotechnic battery because they operate only when the solid electrolyte is melted by the heat energy provided by pyrotechnic materials. Pyrotechnic components used in a thermal battery include heat sources, fuse strips, and an igniter. The reliability of these pyrotechnic components critically affects the reliability and performance of the battery that must supply electricity stably to guided munitions even under extreme environmental conditions. Different igniter types offer different advantages: notch-type igniters offer improved ignition probability, whereas film-type igniters offer improved safety. The addition of metal oxides to the heat paper could improve the burn rate, and the ignition reliability could be greatly improved by using it with a flame igniter at the same time. Using a two-step reduction process, high-purity Fe particles in coral form can be safely obtained.

• The korean journal of orthodontics
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• v.52 no.1
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• pp.3-19
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• 2022

Objective: The purpose of this study was to investigate the accuracy of one-step automated orthodontic diagnosis of skeletodental discrepancies using a convolutional neural network (CNN) and lateral cephalogram images with different qualities from nationwide multi-hospitals. Methods: Among 2,174 lateral cephalograms, 1,993 cephalograms from two hospitals were used for training and internal test sets and 181 cephalograms from eight other hospitals were used for an external test set. They were divided into three classification groups according to anteroposterior skeletal discrepancies (Class I, II, and III), vertical skeletal discrepancies (normodivergent, hypodivergent, and hyperdivergent patterns), and vertical dental discrepancies (normal overbite, deep bite, and open bite) as a gold standard. Pre-trained DenseNet-169 was used as a CNN classifier model. Diagnostic performance was evaluated by receiver operating characteristic (ROC) analysis, t-stochastic neighbor embedding (t-SNE), and gradient-weighted class activation mapping (Grad-CAM). Results: In the ROC analysis, the mean area under the curve and the mean accuracy of all classifications were high with both internal and external test sets (all, > 0.89 and > 0.80). In the t-SNE analysis, our model succeeded in creating good separation between three classification groups. Grad-CAM figures showed differences in the location and size of the focus areas between three classification groups in each diagnosis. Conclusions: Since the accuracy of our model was validated with both internal and external test sets, it shows the possible usefulness of a one-step automated orthodontic diagnosis tool using a CNN model. However, it still needs technical improvement in terms of classifying vertical dental discrepancies.

• The korean journal of orthodontics
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• v.52 no.4
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• pp.287-297
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• 2022

Objective: To investigate the pattern of accuracy change in artificial intelligence-assisted landmark identification (LI) using a convolutional neural network (CNN) algorithm in serial lateral cephalograms (Lat-cephs) of Class III (C-III) patients who underwent two-jaw orthognathic surgery. Methods: A total of 3,188 Lat-cephs of C-III patients were allocated into the training and validation sets (3,004 Lat-cephs of 751 patients) and test set (184 Lat-cephs of 46 patients; subdivided into the genioplasty and non-genioplasty groups, n = 23 per group) for LI. Each C-III patient in the test set had four Lat-cephs: initial (T0), pre-surgery (T1, presence of orthodontic brackets [OBs]), post-surgery (T2, presence of OBs and surgical plates and screws [S-PS]), and debonding (T3, presence of S-PS and fixed retainers [FR]). After mean errors of 20 landmarks between human gold standard and the CNN model were calculated, statistical analysis was performed. Results: The total mean error was 1.17 mm without significant difference among the four time-points (T0, 1.20 mm; T1, 1.14 mm; T2, 1.18 mm; T3, 1.15 mm). In comparison of two time-points ([T0, T1] vs. [T2, T3]), ANS, A point, and B point showed an increase in error (p < 0.01, 0.05, 0.01, respectively), while Mx6D and Md6D showeda decrease in error (all p < 0.01). No difference in errors existed at B point, Pogonion, Menton, Md1C, and Md1R between the genioplasty and non-genioplasty groups. Conclusions: The CNN model can be used for LI in serial Lat-cephs despite the presence of OB, S-PS, FR, genioplasty, and bone remodeling.

• The korean journal of orthodontics
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• v.54 no.1
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• pp.48-58
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• 2024

Objective: To quantify the effects of midline-related landmark identification on midline deviation measurements in posteroanterior (PA) cephalograms using a cascaded convolutional neural network (CNN). Methods: A total of 2,903 PA cephalogram images obtained from 9 university hospitals were divided into training, internal validation, and test sets (n = 2,150, 376, and 377). As the gold standard, 2 orthodontic professors marked the bilateral landmarks, including the frontozygomatic suture point and latero-orbitale (LO), and the midline landmarks, including the crista galli, anterior nasal spine (ANS), upper dental midpoint (UDM), lower dental midpoint (LDM), and menton (Me). For the test, Examiner-1 and Examiner-2 (3-year and 1-year orthodontic residents) and the Cascaded-CNN models marked the landmarks. After point-to-point errors of landmark identification, the successful detection rate (SDR) and distance and direction of the midline landmark deviation from the midsagittal line (ANS-mid, UDM-mid, LDM-mid, and Me-mid) were measured, and statistical analysis was performed. Results: The cascaded-CNN algorithm showed a clinically acceptable level of point-to-point error (1.26 mm vs. 1.57 mm in Examiner-1 and 1.75 mm in Examiner-2). The average SDR within the 2 mm range was 83.2%, with high accuracy at the LO (right, 96.9%; left, 97.1%), and UDM (96.9%). The absolute measurement errors were less than 1 mm for ANS-mid, UDM-mid, and LDM-mid compared with the gold standard. Conclusions: The cascaded-CNN model may be considered an effective tool for the auto-identification of midline landmarks and quantification of midline deviation in PA cephalograms of adult patients, regardless of variations in the image acquisition method.

• Journal of agricultural medicine and community health
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• v.27 no.2
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• pp.55-66
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• 2002

This study aims to clarify the socio-economic factors which have an effectiveness on the social support in rural areas and analyze how it relates to the Individual Health promotion behavior. It is advised to improve social support in the community. The target population was all residents with no chronic and no serious disease who live in five villages of Chuncheon in Kangwon province during July of 2002. This study was done by the interview survey using questionnaire which was composed with questions about Medical Outcomes Study-Social Support Survey(MOS-SSS) and the health promotion behavior. MOS-SSS was translated to Korean and modified to be suitable for the study. The functional and social support variables were also added. The health promotion behavior was formed through the questions about whether or not stop smoking, stop drinking, the excise, the health examinations, attending health education, and hormone replacement therapies. The results are as follows; 1) the case of low-educated, divorce or separation to death, or the subject of social assistance, the social support was low. 2) the case of high social class, the social support was high. 3) there were no significant findings in the health status. 4) according to the analysis of correlation of health promotion behavior, the group with the most social support showed a high percentage of getting health examinations, attending health education, Hormone replacement therapies. However, the adjusted rate of smoking and drinking of trying to stop smoking and stop drinking resulted in low figures. The well-structured social support which the community can provide should be firstly given a priority for the group with low-income, low-educated, divorce or separation to death, and social assistance who are provided poor social support. Moreover, the social support service should be actively reflected to the health promotion program in the community.

• Restorative Dentistry and Endodontics
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• v.29 no.2
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• pp.170-176
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• 2004

Objectives : In the unique metal iris method. the developing interfacial gap at the cavity floor resulting from the cavity wall property during polymerizing composite resin might affect the nominal shear bond strength values. The aim of this study is to evaluate that the iris method reduces the cohesive failure in the substrates and the cavity wall property effects on the shear bond strength tests using iris method. Materials and Methods : The occlusal dentin of 64 extracted human molars were randomly divided into 4 groups to simulate two different levels of cavity wall property (metal and dentin iris) and two different materials ($ONE-STEP^{\circledR}$ and $ALL-BOND^{\circledR}$ 2) for each wall property. After positioning the iris on the dentin surface. composite resin was packed and light-cured. After 24 hours the shear bond strength was measured at a crosshead speed of 0.5 mm/min. Fracture analysis was performed using a microscope and SEM. The data was analyzed statistically by a two-way ANOV A and t-test. Results : The shear bond strength with metal iris was significant higher than those with dentin iris (p＝0.034). Using $ONE-STEP^{\circledR}$, the shear bond strength with metal iris was significant higher than those with dentin iris (p＝0.005), but not in $ALL-BOND^{\circledR}$ 2 (p＝0.774). The incidence of cohesive failure was very lower than other shear bond strength tests that did not use iris method. Conclusions：The iris method may significantly reduce the cohesive failures in the substrates. According to the bonding agent systems. the shear bond strength was affected by the cavity wall property.

• Restorative Dentistry and Endodontics
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• v.29 no.2
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• pp.177-184
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• 2004

Objectives : This study investigated the hypothesis that increasing light-curing time would leave the oxygen-inhibited layer (OIL) of the adhesive thinner, and in turn, result in lower shear bond strength (SBS) than those obtained by the routine curing procedures. Methods：120 human extracted posterior teeth were randomly divided into three groups for bonding with three adhesives：All Bond 2/sup (R)/, One Step/sup (R)/, and Adper Prompt/sup (R)/. They were subsequently divided into four subgourps with different light-curing time (10, 20, 30 and 60s). The assigned adhesives were applied on superficial occlusal dentin according to the manufacturer's instructions and cured with one of the four curing times. Composite resin cylinder, 2.35㎜ in diameter, were built on the cured adhesive and light-cured for 40s. SBS were measured after 24h from the bonding using a universal testing machine (crosshead speed 1.0 ㎜/min). The relative thickness of the OIL and the degree of conversion (DC) were determined from the adhesive on a slide glass using FT-NIR in an absorbance mode. Data were analysed with One-way ANOVA and Duncan's multiple test (p〈0.05), Results：With increasing cure time, although there were no significant difference in th SBS of One-step and Adper Prompt (p〉0.05), those of All Bond 2 decreased significantly (p〈0.05). The relative thicknesses of the OIL on each adhesive were not affected by the cure time (p〉0.05). Although the DC of All-Bond 2 were statistically not different with increasing cure time (p〉0.05), those of One-Step and Adper Prompt showed an increasing trends with increasing cure time (p〈0.05). Conclusions：Increasing light-curing time did not affect on the relative thickness of the OIL of the adhesives, and in turn, on the SBS to dentin.