• Restorative Dentistry and Endodontics
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• v.19 no.1
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• pp.73-84
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• 1994

Using a model system that can compare the before and after of canal preparation in the same tooth, we measured the area of the cross section, and canal wall thickness of the distal portion of the mesial root of the mandibular molar, and compared the amount of reduction in the canal using hand flared preparation the Gates-Glidden drill flared preparation according to the changes in the MAF. The results were as follows. 1. After canal preparation, the canal wall thickness had no significant difference between the hand flared preparation and Gates-Glidden drill flared preparation. 2. The canal wall thickness, after canal preparation, there was no significant difference between the sizes of the MAF. 3. The area variation range of each cross section of root had no significant difference between MAF size and methods of canal preparation. 4. After canal preparation, the frequency of the canal wall thickness under 0.5mm showed 3.5mm below the furcation to be the most frequent with statistical significance(p<0.05). 2mm below the furcation and 5mm below the furcation followed but there was no statistical significance. 5. The danger zone of the mesial root of the mandibular molar seems to be around 3.5mm.

• Restorative Dentistry and Endodontics
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• v.14 no.2
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• pp.103-110
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• 1989

The purpose of this study was to evaluate the cleansing effect of Glyoxide on the dentinal walls of the root canal. Fourty teeth were divided into four groups and the canals in each group were individually enlarged with K-file by step-back technic and irrigated with one of four irrigants. The four used irrigants were Glyoxide (Marion lab. U.S.A.) in combination with 3.5% sodium hypochlorite, 3.5% sodium hypochlorite, 3.5% sodium hypochlorite in combination with 3% hydrogen peroxide and normal saline solution. All the irrigants were used in conjunction with instrumentation as they would be during clinical conditions. After final irrigation, the canals were dried with paper points and the teeth were split longitudinally. The cleaness of canal walls according to the size and the level of canals were evaluated under steroscope by t analysed statistically The results were as follows. 1. The use of 3.5% sodium hyphochlorite in combination with 3.0% hydrogen peroxide revealed the most clean canal surface regardless of the size of canal at apical third of root canal (p < 0.05). 2. Glyoxide in combination with 3.5% sodium hyphchlorite showed no significant difference in cleaning effect of canal surface compared with 3.5% sodium hypochlorite and normal saline solution at the apical third of narrow canal. 3. Glyoxide in combination with 3.5% sodium hypochlorite revealed no significant difference in debridement of canal walls compared with 3.5% sodium hypochlorite in combination with 3% hydrogen peroxide and saline solution at the middle third of narrow and large canals.

• Restorative Dentistry and Endodontics
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• v.8 no.1
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• pp.147-153
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• 1982

The purpose of this study is to observe the effect of cleansing action of irrigation solutions which are 3% hydrogen peroxide, 5% sodium hypochlorite and 15% EDTA solution on the root canal wall. After the root canal wall is enlarged with K-file in distilled water, the canal wall which is irrigated with each irrigant for 2 minutes, is compared with the. control group without using any irrigants. Each sample is dehydrated, and coated with 200-250${\AA}$ of gold, and observations are made with the use of scanning electron microscope. The results are as follows: 1. The canal walls irrigated with 3% hydrogen peroxide, 5% sodium hypochlorite and 15% EDTA solution are cleaner than the walls without using irrigants. 2. There are no significant difference of cleansing effect among 3% hydrogen peroxide, 5% sodium hypochlorite and 15% EDTA. 3. After using 3% hydrogen peroxide and 5% sodium hypochlorite solution, large debris are removed on root canal walls, but micro debris remain on the canal walls. 4. The root canal walls irrigated with 15% EDTA solution are decalcifed slightly and show clean surfaces.

• Restorative Dentistry and Endodontics
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• v.28 no.3
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• pp.232-240
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• 2003

This study is to investigate the canal system in the mesiobuccal root of the maxillary first molar. 61 maxillary first molars were randomly selected. Serial transverse sections were made perpendicular to the long axis of the mesiobuccal root. Each section was placed in 3% sodium hypochlorite for 24 hours and rinsed in water and dried. The resected surface was stained with 2% methylene blue dye and examined with stereomicroscope. 1 Canal configuration analysis showed that 36.1% of the specimen classified as type I, 16.4% as type II , 37.7% as type III and 9.8% as type IV. 2. Type II canal was merged in one canal within 1 to 4mm of the apex. 40% of type II canal converged at 2mm of the apex. 3. Type IV canal was divided into two canal within 2 to 4mm of the apex. 66.6% of type IV canal branched off at 2mm of the apex. 4. None of the sections had more than two main root canal. 5. 48.4% of the sections in 3mm with two canals contained an isthmusand more than 70% with two canals has isthmus at 4 to 5mm sections. 63.9% of the mesiobuccal root of maxillary first molar had two canaland 76.5% of sections with two canals in 5 MM had an isthmus. Because of this complexity the clinician should always search for extra canal carefullyand root canal system, including an isthmus, should be cleaned and shaped completelyand obturated three dimensionally for successful endodontic treatment.

• Restorative Dentistry and Endodontics
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• v.10 no.1
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• pp.55-62
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• 1984

This experimental study was made to evaluate the efficacy of root canal preparation of engine reamer versus hand reamer. Eighty extracted human teeth were prepared with the following treatments and devided into 4 groups; Group 1: Canal preparation with hand reamer, and irrigation with normal saline solution. Group 2: Canal preparation with engine reamer, and irrigation with normal saline solution. Group 3: Canal preparation with hand reamer, and irrigation with 3% hydrogen peroxide and 3.5% sodium hypochlorite solution. Group 4: Canal preparation with engine reamer, and irrigation with 3% hydrogen peroxide and irrigation with 3% hydrogen peroxide and 3.5% sodium hypochlorite solution. After decalcification, 5p. sections at levels 1-, 3-, and 5-mm from the apex were evaluated microscopically. The results were as follows; The effectiveness of hand reamer and engine reamer were equal in preparing the root canal at all levels from the apex, and were equal in normal saline solution groups, and 3% $H_2O_2$ and 3.5% NaOCl solution groups. Both in hand reaming groups and in engine reaming groups, some canal walls had still untouched portion, and canal irregularities and debris were still remained.

• Restorative Dentistry and Endodontics
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• v.25 no.1
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• pp.116-122
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• 2000

On the instrumented root canal wall, amorphous, irregular smear layer can be observed with Scanning Electron Microscope(SEM). The purpose of this study was to evaluate the effect of the presence or absence of smear layer on the adhesion of Staphylococcus aureus to the dentin of the root canal. Human incisors, extracted within 7 days, with no caries, no fracture, no calcification of canal, were selected. After cutting crown portion at cemento-enamel junction, root canal preparation was done by modified crown-down technique using Profile and Gates - Glidden Drill. During canal preparation, 10ml physiologic saline solution(group1&3) or 10ml 3.5% NaOCl(group2&4) was used as irrigation solution. And 10ml physiologic saline solution(group1&3) or 10ml 0.5M EDTA(group2&4) was applicated for final flush. After vertical sectioning and ethylene oxide gas sterilization, samples(group1&2) were immersed into BHIYHM broth inoculated with Staphylococcus aureus (ATCC 31153) and incubated for 3hrs at $37^{\circ}C$. All samples were prepared for and observed with SEM(JEOL JSM840S). The data were analyzed by Mann-Whitney rank sum test. The conclusions are as follows ; 1. Smear layer covers entire root canal surface after root canal preparation. 2. Smear layer has been removed away and the entrances of dentinal tubules have opened widely, when applying 0.5M EDTA and 3.5% NaOCl. 3. A significantly higher number of bacteria were adhered to the root canal dentin without smear layer(p<0.0001). 4. Smear layer produced during root canal preparation impedes bacterial adhesion and colonization to dentin matrix, therefore inhibits canal reinfection.

• Journal of Oral Medicine and Pain
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• v.6 no.1
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• pp.15-18
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• 1981

The author had selected the roots and root-canal as measurable parts and sought the area ratio by measuring the respective areas of the root. Further, heplotted out a root caual index and studied the correlation with age. The teeth used as reserch material were permanent maxillary central incisors of Korean female. Some 296 teeth of known age were selected on condition that there is no caries or filling material and that they were not malformed in showing normal signs in roentgenograms. The $3" {\times} 4"$ printing paper so as to measure easily. On the ocassion of measureing the area of measured parts with a planimeter (Koizumi, type kp-27, Japan), the cervical lines were joined up into a straight line on a photograph (Figure 1) Root canal index = Area of the root / Area of the root canal The results of the root canal index in Korean female age groups were as follows : 1. The root canal index of maxilary central incisor in women was 4.74 im 20 years of age, 5.44 in 30, 5.90 in 40, 6.32 in 50, 6.63 in 60 in the order. 2. Root canal index and age were in positive correlation ; there was a tendency that the root canal index increase as age advances. 3. The regression equation was as follows : Y = 5.36x + 7.71 (r = 0.54, n= 296 ) (Y = estimated age, x = root canal index)

• Restorative Dentistry and Endodontics
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• v.12 no.2
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• pp.11-15
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• 1987

Thirty maxillary second premolars were fixed, decalcified, washed and embedded in celloidin to observe the root canal size and morphology at apical 5mm area. The results were as follows: 1. Single canaled teeth and two canaled teeth were approximately equal numbered. 2. Single canaled teeth have round canal but two canaled teeth have long, slender buccal canal and ovoid lingual canal. 3. The canal size of single canaled teeth was $380{\pm}30{\mu}m,\;340{\pm}22{\mu}m$, but that of buccal canal of two canaled teeth was $360{\pm}32{\mu}m,\;240{\pm}28{\mu}m$, lingual canal was $330{\pm}28{\mu}m,\;280{\pm}20{\mu}m$.

• Restorative Dentistry and Endodontics
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• v.15 no.2
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• pp.115-121
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• 1990

Forty extracted human mandibular second molars with C-shaped canal were chosen to study the anatomy of the root canal. The experimental teeth were injected with china ink, decalcified and cleared with Winter green oil, in vitro, to study the number of root, root canal, canal per root, frequency and location of lateral canal and transverse anastomosis. 1. All teedth had one root. 2. Mesial roots with two canals were 25%, and mesial roots with one canal were 75%. All distal roots had one canal. 3. In the roots with two canals, the common apical foramen appeared in 20% and the separte apical foramen appeared in 80%. 4. The frequence of lateral canal was 33.3% and the most frequent region was middle 1/3. 5. All teeth had the transverse anastomosis in all region of the roots.

• Journal of The Korean Society of Agricultural Engineers
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• v.50 no.5
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• pp.3-15
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• 2008

This study aims to simulate the 3 dimensional (3D) model of Keum-man connection canal using geographic information system (GIS) as well as considering design in viewpoint of engineering. The canal connects from Keumkang to Mangyungkang in order to supply fresh water into Saemankeum lake. This study used 3 dimensional spatial planning model (3DSPLAM) process to generate the 3D model, which has not only several planning layers in actual process, but also their corresponding layers in modeling process to simulate 3D space of rural villages. The discharge of the canal is $20m^3/s$ on slope of 1/28,400 in the canal length of 14.2km, which consists of pipe line and open channel. This study surveyed the route of the canal and its surrounding environment for facilities to make images in the 3D graphic model. Besides, the present study developed data set in GIS for geogrphical surface modeling as well as parameters in hydraulic analysis for water surface profile on the canal using HEC-RAS model. From the data set constructed, this study performed analysis of water surface profile with HEC-RAS, generation of digital elevation model (DEM) and 3D objects, design of the canal section and route on DEM in AutoCAD, and 3D canal model and its surrounding 3D space in 3DMAX with virtual reality. The study result showed that the process making 3D canal model tried in this study is very useful to generate computer graphic model with the designed canal on the surface of DEM. The generated 3D canal can be used to assist decision support for the canal policy.