• Restorative Dentistry and Endodontics
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• v.44 no.3
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• pp.29.1-29.7
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• 2019

Endodontic microsurgery is defined as the treatment performed on the root apices of an infected tooth, which was unresolved with conventional root canal therapy. Recently, the advanced technology in 3-dimensional model reconstruction based on computed tomography such as cone beam computed tomography has opened a new avenue in application of personalized, accurate diagnosis and has been increasingly used in the field of dentistry. Nevertheless, direct intra-oral localization of root apex based on the 3-dimensional information is extremely difficult and significant amount of bone removal is inevitable when freehand surgical procedure was employed. Moreover, gingival flap and alveolar bone fenestration are usually required, which leads to prolonged time of surgery, thereby increasing the chance of trauma as well as the risk of infection. The purpose of this case report is to present endodontic microsurgery using the guide template that can accurately target the position of apex for the treatment of an anterior tooth with calcified canal which was untreatable with conventional root canal therapy and unable to track the position of the apex due to the absence of fistula.

• Restorative Dentistry and Endodontics
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• v.42 no.3
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• pp.200-205
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• 2017

Objectives: The aim of this in vivo study was to assess the accuracy of 2 third-generation electronic apex locators (EALs), Propex II (Dentsply Maillefer) and Root ZX II (J. Morita), and radiographic technique for locating the major foramen (MF). Materials and Methods: Thirty-two premolars with single canals that required extraction were included. Following anesthesia, access, and initial canal preparation with size 10 and 15 K-flex files and SX and S1 rotary ProTaper files, the canals were irrigated with 2.5% sodium hypochlorite. The length of the root canal was verified 3 times for each tooth using the 2 apex locators and once using the radiographic technique. Teeth were extracted and the actual WL was determined using size 15 K-files under a ${\times}25$ magnification. The Biostat 4.0 program (AnalystSoft Inc.) was used for comparing the direct measurements with those obtained using radiographic technique and the apex locators. Pearson's correlation analysis and analysis of variance (ANOVA) were used for statistical analyses. Results: The measurements obtained using the visual method exhibited the strongest correlation with Root ZX II (r = 0.94), followed by Propex II (r = 0.90) and Ingle's technique (r = 0.81; p < 0.001). Descriptive statistics using ANOVA (Tukey's post hoc test) revealed significant differences between the radiographic measurements and both EALs measurements (p < 0.05). Conclusions: Both EALs presented similar accuracy that was higher than that of the radiographic measurements obtained with Ingle's technique. Our results suggest that the use of these EALs for MF location is more accurate than the use of radiographic measurements.

• Clinics in Shoulder and Elbow
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• v.24 no.4
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• pp.253-260
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• 2021

Background: To suggest a reasonable isometric point based on the anatomical consistency of interosseous membrane (IOM) attachment in association with topographic characteristics of the interosseous crests, the footprints of the central band (CB) of the IOM on the radial and ulnar interosseous crests (RIC and UIC) were measured. Methods: We measured the distance from the CB footprints from each apex of both interosseous crests in 14 cadavers and the angles between the forearm axis of rotation (AOR) and the distal slopes of the RIC and UIC in 33 volunteers. Results: The CB footprints lay on the downslope of both interosseous crests with its upper margin on average 3-mm proximal from the RIC's apex consistently in the radial length, showing normality (p>0.05), and on average 16-mm distal from the UIC's apex on the ulna without satisfying normality (p<0.05). The average angle between the UIC's distal slope and the AOR was 1.3°, and the RIC's distal slope to the AOR was 14.0°, satisfying the normality tests (p>0.05), and there was no side-to-side difference in both forearms (p<0.05). Conclusions: The CB attached to the downslope just distal to the RIC's apex constrains the radius to the UIC that coincides with the AOR of the forearm circumduction, maintaining itself both isometrically and isotonically.

• Restorative Dentistry and Endodontics
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• v.14 no.1
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• pp.71-84
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• 1989

The purpose of this study was to evaluate the effect of tricalcium phosphate and Vitapex on the dogs' periapical tissues. Twenty mandibular premolars from 5 healthy dogs were used for this study. After the animals were anesthetized intramuscularly, pulp chambers were open and pulp tissue was extirpated with a barbed broach and H-file. Then the working length of the root canal was measured with H-file and pulp tissue was completely removed. Before the actual canal filling, the root canals of twenty teeth have been experimentally infected with opening the pulp chamber for 5 weeks. Periapical radiographs of the experimental teeth were taken to monitor the periapical pathological condition. Each root apex of 20 premolars was perforated with engine reamer and the root canals were enlarged with No. 30-60 H-files. They were divided into treated as follows. Control group: The root canal was filled with gutta-percha. Experimental group 1: The canal was dried with sterile paper points and mixture of tricalcium phosphate and physiological saline was overfilled beyond the root apex with a lentulo spiral. Then the root canal was filled gutta-percha and lateral condensation and the pulp chamber was filled with Caviton. Experimental group 2: The root canals were overfilled with Vitapex and were treated in the same manner as those in experimental group 1 At 1,2,3, and 8 weeks after experiment, the periapical tissues including the alveolar bone were fixed with 10% formalin solution for I week and decalcified with Plank-Rycho solution for 5 weeks. The specimens were embedded in paraffin and serial sections were cut into a thickness of 6 ${\mu}m$ at the plane of the root apex. Hematoxyline-eosin and Masson's trichrome stain were made for the histo-pathological examinations. The results were as follows: 1. Ingrowth of collagen fiber was observed from 1 week in control group and experimental groups. 2. The rate of bone formation of experimental group 1 was accelerated more than that of experimental group 2. 3. Resorption of cementum was seen in control group, but apposition of cementum was seen in experimental groups.

• Restorative Dentistry and Endodontics
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• v.21 no.1
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• pp.187-201
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• 1996

The purpose of this study was to evaluate the sealing ability of a calcium hydroxide plug treated with a bonding agent. Ninety extracted human anterior teeth and premolars with single canal were used in this study. Crowns were removed. the canal's were instrumented. and the roots were randomly divided into three groups of 30 each. In control group. a single apical seat was prepared with #60 K file 1mm short of the apex and the root canal was obturated with Gutta-percha and Sealapex by the lateral condensation method. In experimental group 1 and group 2. to prepare an apical isthmus of 1mm in length. the first apical seat was prepared with a #45 K file 1mm short of the anatomical apex and with a #60 K file 2mm short for the second apical seat. Dry calcium hydroxide powders were packed in the apical isthmus with a hand plugger and #60 K file and then. the root canal was obturated with Gutta-percha and Seal apex by the lateral condensation method. In experimental group 2. following an application of the bonding agent to the plug. the root canal was obturated in the same way. The teeth of each group were immersed in a 2% methylene blue dye solution. for 1, 2, and 4 weeks. The distance from the tip of the cone to the deepest penetration was measured using the Tool maker's microscope. The results were as follows : 1. The teeth having the calcium hydroxide plug treated with the dentin bonding agent (experimental group 2) showed the lowest leakage with 1.4705mm and the control group without apical plug(no apical isthmus) showed the highest leakage with 3.1735mm. 2. The control group without apical plug showed higher leakage than experimental group 1 having the calcium hydroxide plug treated without the dentin bonding agent(p>0.05). 3. The control group without apical plug and experimental group 1, having the calcium hydroxide plug treated without the dentin bonding agent. showed higher leakage than experimental group 2. having the calcium hydroxide plug treated with the dentin bonding agent(p<0.001). 4. The immersion time had no significant effect on the degree of leakage. In conclusion, the results showed that the calcium hydroxide plug treated with the dentin bonding agent could decrease the microleakage from the root apex effectively.

• The Journal of Korean Academy of Prosthodontics
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• v.31 no.4
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• pp.580-610
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• 1993

The purpose of this study was to analyse the deflection and stress distribution at the supporting bone and it's superstructure by the alteration of angulation between implant and it's implant abutment. For this study, the free-end saddle case of mandibular first and second molar missing would be planned to restore with fixed prosthesis. So the mandibular second premolar was prepared for abutment, and the cylinder type osseointegrated implant was placed at the site of mandibular second molar for abutment. The finite element stress analysis was applied for this study. 13 two-dimensional FEM models were created, a standard model at $0^{\circ}$ and 12 models created by changing the angulation between implant and implant abutment as increasing the angulation mesially and distally with $5^{\circ}$ unittill $30^{\circ}$. The preprocessing decording, solving and postprocessing procedures were done by using FEM analysis software PATRAN and SUN-SPARC2GX. The deflections and von Mises stresses were calculated under concentrated load (load 1) and distributed load(load 2) at the reference points. The results were as follows : 1. Observing at standard model, the amount of total deflection at the distobuccal cusp-tip of pontic under concentrated load was largest of all, and that at the apex of implant was least of all, and the amount of total deflection at the buccal cusp-tip of second premolar under distributed load was largest of all, and that at the apex of implant was least of all. 2. Increasing the angulation mesially or distally, the amounts of total deflection were increased or decreased according to the reference points. But the order according to the amount of total deflection was not changed except apex of second premolar and central fossa of implant abutment under concentrated load during distal inclination. 3. Observing at standard model, the von Mises stress at the distal joint of pontic under concentrated load was largest of all, and that at the apex of implant was least of all. The von Mises stress at the distal margin of second premolar under distributed load was largest of all, and that at the apex of Implant was least of ail. 4. Increasing the angulation of implant mesially, the von Mises stresses at the mesial crest of implant were increased under concentrated load and distributed load, but those were increased remarkably under distributed load and so that at $30^{\circ}$ mesial inclination was largest of all. 5. Increasing the angulation of implant distally, the von Mises stresses at the distal crest of implant were increased remarkably under concentrated load and distributed load, and so those at $30^{\circ}$ distal inclination were largest of all.

• Journal of Korean Neurosurgical Society
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• v.45 no.4
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• pp.224-230
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• 2009

Objective : We aimed to analyze clinical and radiological outcomes retrospectively in patients with basilar apex aneurysms treated by coiling or clipping. Methods : Outcomes of basilar bifurcation aneurysms were assessed retrospectively in 77 consecutive patients (61 women, 16 men), ranging in age from 25 to 79 years (mean, 53.7 years) from 1999 to 2007. Results : Forty-nine patients out of 77 patients (63.6%) presented with subarachnoid hemorrhages of the 49 patients treated with coiling, 27 (55.1 %) showed complete occlusion of the aneurysm sac. Of these, 13 patients (26.5%) developed coil compaction on angiographic or MRI follow-up, with recoiling required in 9 patients (18.4%). Procedural complications of coiling were acute infarction in nine patients and the bleeding of the aneurysms in six patients. The remaining 28 patients underwent microsurgery : twenty-six of these (92.9%) with microsurgery followed up with conventional angiography. Complete occlusion of the aneurysm sac was achieved in 19 patients (73.1%). Operation-related complications of microsurgery were thalamoperforating artery injuries in three patients, retraction venous injury in two, postoperative epidural hemorrhage (EDH) in one, and transient partial or complete occulomotor palsy in 14 patients. Glasgow Outcome Scores (GOS) were 4 or 5 in 21 of 28 (75%) patients treated with microsurgery at discharge, and at 6 month follow-up, 20 of 28 (70.9%) maintained the same GOS. In comparison, GOS of four or 5 was observed in 36 of 49 (73.5%) patients treated with coiling at discharge and at 6 month follow-up, 33 of 49 patients (67.3%) maintained the GOS from discharge. Conclusion : Basilar top aneurysms were still challenging lesions based on our series. Endovascular or microsurgery endowed with its inborn risks and procedural complications for the treatment of basilar apex aneurysms individually. Microsurgery provided better outcome in some specific basilar apex aneurysms. For reaching the most favorable outcome, endovascular modality as well as microsurgery was inevitably considered for each specific basilar apex aneurysm.

• Journal of The Korean Society of Agricultural Engineers
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• v.63 no.6
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• pp.1-16
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• 2021

Global warming due to climate change is expected to significantly affect the hydrological cycle of agriculture. Therefore, in order to predict the magnitude of climate impact on agricultural water resources in the future, it is necessary to estimate the water demand for irrigation as the climate change. This study aimed at evaluating the future changes in water demand for irrigation under two Shared Socioeconomic Pathways (SSPs) (SSP2-4.5 and SSP5-8.5) scenarios for paddy rice in Gimje, South Korea. The APEX-Paddy model developed for the simulation of paddy environment was used. The model was calibrated and validated using the H₂O flux observation data by the eddy covariance system installed at the field. Sixteen General Circulation Models (GCMs) collected from the Climate Model Intercomparison Project phase 6 (CMIP6) and downscaled using Simple Quantile Mapping (SQM) were used. The future climate data obtained were subjected to APEX-Paddy model simulation to evaluate the future water demand for irrigation at the paddy field. Changes in water demand for irrigation were evaluated for Near-future-NF (2011-2040), Mid-future-MF (2041-2070), and Far-future-FF (2071-2100) by comparing with historical data (1981-2010). The result revealed that, water demand for irrigation would increase by 2.3%, 4.8%, and 7.5% for NF, MF and FF respectively under SSP2-4.5 as compared to the historical demand. Under SSP5-8.5, the water demand for irrigation will worsen by 1.6%, 5.7%, 9.7%, for NF, MF and FF respectively. The increasing water demand for irrigating paddy field into the future is due to increasing evapotranspiration resulting from rising daily mean temperatures and solar radiation under the changing climate.

• Restorative Dentistry and Endodontics
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• v.38 no.1
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• pp.26-30
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• 2013

Objectives: The aim of this study was to investigate the relationship between the apical foramen morphology and the length of merged canal at the apex in type II root canal system. Materials and Methods: This study included intact extracted maxillary and mandibular human premolars (n = 20) with fully formed roots without any visible signs of external resorption. The root segments were obtained by removing the crown 1 mm beneath the cementum-enamel junction (CEJ) using a rotary diamond disk. The distance between the file tip and merged point of joining two canals was defined as Lj. The roots were carefully sectioned at 1 mm from the apex by a slow-speed water-cooled diamond saw. All cross sections were examined under the microscope at ${\times}50$ magnification and photographed to estimate the shape of the apical foramen. The longest and the shortest diameter of apical foramen was measured using ImageJ program (1.44p, National Institutes of Health). Correlation coefficient was calculated to identify the link between Lj and the apical foramen shape by Pearson's correlation. Results: The average value of Lj was 3.74 mm. The average of proportion (P), estimated by dividing the longest diameter into the shortest diameter of the apical foramen, was 3.64. This study showed a significant negative correlation between P and Lj (p < 0.05). Conclusions: As Lj gets longer, the apical foramen becomes more ovally shaped. Likewise, as it gets shorter, the apical foramen becomes more flat shaped.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.3
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• pp.311-317
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• 2021

Growth differences in Caulerpa okamurae thallus parts and the effects of apex removal on growth were examined. Erect fronds, stolons, and erect fronds with stolons (erect+stolon) were grown for 14 days, whereas erect fronds without and with apex removal (-A and +A fronds, respectively), were grown for 25 days. The relative growth rates (RGR) of C. okamurae thallus parts ranged from 1.91% to 4.93% day^-1 with maximal and minimal RGR for the stolon and erect+stolon treatments, respectively. Over the 25 days in culture, the -A fronds showed a higher RGR (2.48% day^-1) than the +A fronds (1.96% day^-1). More new erect fronds and stolons were produced by -A fronds than those by +A fronds. In addition, basal cutting of erect C. okamurae fronds resulted in a greater plant length increase than that obtained from top cutting. These findings indicate that vegetative growth is common in C. okamurae, which has excellent wound healing ability, and cutting damage to erect fronds may stimulate enhanced vegetative growth. Thus, we suggest that stolons and erect fronds of C. okamurae could be used as seeding materials for large scale cultivation. Furthermore, this edible species could be a potential seaweed resource for rapid skin regeneration cosmetics.