• Restorative Dentistry and Endodontics
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• v.21 no.1
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• pp.339-352
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• 1996

Many dentists have been taken an interest in restoration of severly damaged teeth after endodontic treatment and it is a true that there are lots of studies about it. In these days, although we have used Para-Post, pins, threaded steel post, cast gold post and core, and so on, as a method of restoration frequently, it has been in controversy with the effects of them on the teeth and surrounding periodontal tissue. In this study, we assume that the crown of the upper 1st premolar was severly damaged, and after the root canal therapy, two most common types of restoration were carried out ; 1) coronal-radicular amalgam restoration, 2) after setting up the Para-Post, restore with amalgam core and gold crown. After restoration, in order to present the concentration of stress at internal portion of the tooth and the surrounding periodontal tissue, we doveloped a 2-dimensional finite element model of labiopalatal section, then loaded forces from 2 long perpendicular to the lingual incline of buccal ridge an the middle point, parallel to the long direction axis of tooth at the fossa-were applied. The analyzed results were as follows : 1. Stress of the normal first premolar was concentrated on the most weakest anatomical structure, that is, cervical area, and no stress on the bifurcated area of the canal. 2. Crown restoration after root canal therapy causes large stress concentration on the bifurcated area of the canal. This stress concentration has larger value in case of lateral movement of mandible, and there are decrease in the stress concentration compared with natural tooth. 3. Coronal-radicular amalgam restoration method transports more stress to the tooth structure than restoration using Para-Post. 4. There are more stress concentration around Para-Post in the case of lateral movement, and we have more favo rable result when restored with Para-Post. 5. Generally, stress in the lateral movement is larger than stress in the perpendicular load.

• Restorative Dentistry and Endodontics
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• v.19 no.2
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• pp.549-567
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• 1994

Restoration of severly damaged teeth after endodontic treatment had been an interest to many dentists, and it is a fact that there have been lots of studies about it. In these days, although we have used Para-Post, pins, threaded steel post, cast gold post and core, and so on, as a method of restoration frequently, it has been in controversy with the influence of them on the teeth and surrounding periodontal tissue. In this study, we assume that the crown of the upper incisor have severly damaged, so, after the root canal therapy, 4 types of restoration had been carried out; 1) coronal-radicular amalgam restoration, 2) after setting up the Para-Post, restore with composite resin core only, 3) after setting up the Para-Post; restore with amalgam core, then cover with the PPM crown 4) after setting up the Para-Post, restore with composite core, then cover with the PPM crown. After restoration, in order to observe the concentration of stress at internal portion of the teeth and the sourrounding periodontal tissue, developing a 2-dimensional finite element model of labiopalatal section, then loading forces from 3 direction - direction of 45 degrees from lingual side near the incisal edge, horizontal direction from labial height of contour, vertical direction at the incisal edge-were applied. The analyzed results were as follows: 1. Stress of the normal central incisor was concentrated on the dentin aroundpulp chamber, labiocervical portion of a tooth and root apex, but with the alveolar bone, in the case of load from the direction of 45 degrees from lingual side near the incisal edge showed remarkable concentration of stress: 2. Coronal-radicular amalgam technique -showed less concentration of stress on the root and surrounding periodontal tissue than the restoration with the Para-Post. 3. The von Mises equivalent stress on the Para-Post showed maximum value at root-core junction rather than both ends and model with PPM restoration with amalgam core showed the least concentration of stress. Only the force from horizontal direction showed large shear stress on internal portion of the root, root apex and alveolar bone. 4. PPM crown with composite core rarely showed the concentration of stress on root and periodontal tissue. 5. As for alveolar bone, remarkable shear stress was concentrated on labial and palatal side by horizontal load.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.3
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• pp.280-293
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• 2004

Statement of problem. Glass fiber post is one of recent developments to accommodate esthetic restoration for endodontically treated teeth. This has many advantages over conventional post system in physical properties, esthetic factor, risk of root and restoration fracture, adhesion to core, radiopacity, removal and retrievabilty, biocompatibility and chemical stability. Purpose. This in vitro study was to evaluate the most suitable type of resin core for the glass fiber post through surveying the fracture modes and the maximum load that fractures the tooth. Material and methods. 50 sound maxillary premolars restored with glass fiber posts($ParaPost^{(R)}$ Fiber White) and different types of resin cores(ParaCore, $Z100^{TM}$, $Rebilda^{(R)}$ and $Admira^{(R)}$) were prepared and loaded to faiure in a universal test machine. The maximum fracture load and fracture mode were investigated in the specimens that were restored with resin and those of metal cast and core. With the data, Wilcoxon rank sum test was used to validate the significance between the test groups, and Tukey' s studentized range test was used to check if there is any significant statistical difference between each test group. Every analysis was approved with 95% reliance. Results. On measuring the maximum fracture load of teeth specimens, there was a significant difference between the maximum fracture loads of the tooth specimens. ParaCore showed the highest mean maximum fracture load followed by $Z100^{TM}$. And, the distribution of fracture mode of tooth specimens showed generally Type D, the three parted fracture of the core around the post was mostly seen(62.5%), and specifically, ParaCore showed 90% and $Z100^{TM}$ showed 100% Type D fracture. Conclusion. Referring to the values of maximum fracture load and mean compressive fracture load, ParaCore and $Z100^{TM}$ had high values and are recommended as tooth colored resin core material for glass fiber post. CLINICAL IMPLICATIONS. This study was carried out intending to be of aid in selecting the appropriate resin core for the glass fiber post. The dual cure type composite resin ParaCore and light cure type composite resin $Z100^{TM}$ have good properties and are recommended as tooth colored resin core material for glass fiber post.

• Restorative Dentistry and Endodontics
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• v.35 no.4
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• pp.257-266
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• 2010

The purpose of this study was to determine the effect of post types and sizes on fracture resistance in immature tooth model with various restorative techniques. Bovine incisors were sectioned 8 mm above and 12 mm below the cementoenamel junction to simulate immature tooth model. To compare various post-and-core restorations, canals were restored with gutta-percha and resin core, or reinforced dentin wall with dual-cured resin composite, followed by placement of D.T. LIGHT-POST, ParaPost XT, and various sizes of EverStick Post individually. All of specimens were stored in the distilled water for 72 hours and underwent 6,000 thermal cycles. After simulation of periodontal ligament structure with polyether impression material, compressive load was applied at 45 degrees to the long axis of the specimen until fracture was occurred. Experimental groups reinforced with post and composite resin were shown significantly higher fracture strength than gutta-percha group without post placement (p < 0.05). Most specimens fractured limited to cervical third of roots. Post types did not influence on fracture resistance and fracture level significantly when cement space was filled with dual-cured resin composite. In addition, no statistically significant differences were seen between customized and standardized glass fiber posts, which cement spaces were filled with resin cement or composite resin individually. Therefore, root reinforcement procedures as above in immature teeth improved fracture resistance regardless of post types and sizes.

• Journal of Gastric Cancer
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• v.17 no.1
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• pp.93-97
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• 2017

An 84-year-old man was diagnosed with two synchronous adenocarcinomas, a Borrmann type IV advanced gastric adenocarcinoma in his antrum and a well-differentiated Borrmann type I carcinoma on the anterior wall of the higher body of his stomach. Pre-operatively, computed tomography of the abdomen revealed the presence of advanced gastric cancer with peri-gastric and para-aortic lymph node (LN) metastasis. He planned for palliative total gastrectomy owing to the risk of obstruction by the antral lesion. We performed a frozen biopsy of a para-aortic LN during surgery and found that the origin of the para-aortic LN metastasis was from undiagnosed prostate cancer. Thus, we performed radical total gastrectomy and D2 LN dissection. Post-operatively, his total prostate-specific antigen levels were high (227 ng/mL) and he was discharged 8 days after surgery without any complications.

• Restorative Dentistry and Endodontics
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• v.21 no.1
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• pp.70-86
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• 1996

The purpose of this study was to analyze the stress distribution in mandibular second premolars restored with different post and core techniques. Sixteen two-dimensional finite element model of mandibular second premolars restored with post and core and complete crown were developed according to the diameter, length, and material of post and core. Vertical force, 10N in magnitude, was applied first to the central fossa and then $45^{\circ}$ oblique force of same magnitude was applied to the buccal contact surface of buccal cusp. The obtained results were as follows : 1. Stress distribution within the dentin 1) Regardless of the material of the post and core and the diameter and length of the post, the pattern of stress distribution within the dentin was similar. 2) Maximum dentinal stress was observed on the lingual root surface of alveolar crest level with oblique loading and on lingual side of root dentin at the crown margin on vertical loading. 3) Cast post and cores produced the lowest dentinal stress concentrations and the highest stress concentration was observed in composite resin post and cores. 2. Stress distribution within the post and core 1) Within the amalgam and composite resin post and core, the patterns and maximum values of stress were similar. Maximum stress located at the central fossa of core portion on vertical loading and at the lingual junction of post and core with oblique loading. 2) Among the all post and cores, the cast post and core registered the highest stress concentration and maximum stress value within the post. Maximum stress located at the post apex on vertical loading and at lingual half of the post surface with oblique loading. 3) In case of Para-post and amalgam core, maximum stress located at the central fossa of core portion and lingual tip of the post head on vertical loading. With oblique loading, maximum stress located at the lingual half of the post surface.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.6
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• pp.582-587
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• 2009

A 59-year-old woman who was diagnosed with malignant pheochromocytoma underwent $^{18}F$-fluorodeoxyglucose positron emission tomography/computed tomography ($^{18}F$-FDG PET/CT). She had undergone left adrenalectomy for pheochromocytoma 4 years previously. Recent multiple metastatic pulmonary nodules were noted on the chest X-ray. After treatment with $^{131}I$-metaiodobenzylguanidine ($^{131}I$-MIBG) with 7.4 GBq, post-therapy $^{131}I$-MIBG scintigraphy depicted multiple distant metastases including lung, liver, abdominal para-aortic and mesenteric lymph nodes. $^{18}F$-FDG PET/CT also depicted multiple metastases in lung, liver, and abdominal para-aortic lymph nodes, but some lesions were not shown. In this case, $^{131}I$-MIBG scintigraphy found additional lesions in metastatic malignant pheochromocytoma.

• Korea Journal of Hospital Management
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• v.10 no.3
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• pp.1-24
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• 2005

This study purports to investigate the determinants of individual personnel rating of the employees at a university hospital in Seoul, Korea. The sample used in this study consisted of 63 nurses, 41 para-medical staff (Clinical Pathologist, and Radiologist), and 67 administrative staff. Independent variables of the study included the achievement level of the selection test (English, major subject, and interview), post-entrance development factors (education and training, career development, supervisory support, co-worker support, and organizational support), and demographic characteristics. Data for the achievement level of the entrance exam and years for the first promotion were collected from the administrative records of the study hospital, while data for the post-entrance development factors were collected from the survey with self-administered questionnaires using 5-point Likert Scale during June 10-25, 2003. Collected data were analyzed using hierarchical multiple regression. The results of the study showed that achievement level of the interview and English exam at the selection test, education and training, organizational support, and supervisory support while working at the hospital, and length of duration (below 8 years) and educational background (4-year college graduates) among demographic variables had significant positive effects on the personnel rating. The results of the study imply that hospital administrators should make an effort to improve the validity of the selection test, and to motivate the employees to receive more education and training.

• The Korean Journal of Pesticide Science
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• v.3 no.3
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• pp.11-19
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• 1999

A some of synthesized 2-(4-(6-chloro-2-benzoxazolyloxy)phenoxy)-N-phenyl propionamide derivativesa substrates were found to selectivity significantly with both rice plant (Oryza sativa L.) and barnyard grass (Echinochloa crus-galli) for those her- bicidal activities with post emergence in up land. The selectivity of substrates against rice plant better than that of Fenoxaprop-ethyl. The structure activity relationship (SAR) n the selectivity of N-phenyl substituents were analyzed by the Free-Wilson and Hansch method. The SAR approach against barnyard grass is shown that the optimal ($({\pi})_{opt.}=1.60$) hydrophobicity and electron donating effects ($0<{\sigma}$ & 0$(ES)_{opt.}=0.87$) so that the herbicidal activity against rice plant can be decreased. The significance of these results on the selectivity between barnyard grass and rice plant is discussed. And it is assumed that the 2-ethoxy-3-methoxy-4-dimethylamino group substituent ($pI_{50}$=6.60, 1g/ha) is selected as the most highest herbicidal activity against barngard grass in green house.

• The Korean Journal of Pesticide Science
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• v.4 no.2
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• pp.32-36
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• 2000

A series of synthesized N-(2-fluoro-4-chloro-5-alkyloxyphenyl)-3,4-dimethyl-2-arylthio-5-oxo-2,5-dihydropyrrole derivatives as substrates were found to selectivity significantly with both rice plant (Oryza sativa L.) and weeds, barnyard grass (Echinochloa crus-galli) and bulrush (Scriptus juncoides) for those herbicidal activities at a rate of 0.1 kg/ha with post emergence under submerged conditions. The structure activity relationships (SARs) on herbicidal activity of $SR_{2}$=2-arylthio substituents on the pyrrole ring were analysized. From the results, the relative contribute orders of the $SR_{2}$ with phenyl group on the activity are meta > para > ortho-substituents. Among these compounds, the $R_{1}=propargyl$ (IA) subsrituents, $1{\sim}12$ showed higher activity than the $R_{1}$=2-chloro-2-propenyl (IB) substituents, $13{\sim}16$. The $SR_{2}$ groups of IA substituents shown that the optimal steric constant, $(Es)_{opt.}=3.25$ and m-phenylthio substituents were found to be -contribute the activity against barnyard grass. But the herbicidal activity of IB substituents against bulrush would depend upon the molar refractivity, $M_{R}$ constant of $SR_{2}$ group.