• Restorative Dentistry and Endodontics
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• v.29 no.5
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• pp.439-445
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• 2004

The purpose of this study was to evaluate the influence of plugger penetration depth on the apical extrusion of root canal sealer during root canal obturation with Continuous Wave of Condensation Technique. Root canals of forty extracted human teeth were divided into four groups and were prepared up to size 40 of 0.06 taper with ProFile. After drying. canals of three groups were filled with Continuous Wave of Condensation Technique with System $B^{TM}$ and different plugger penetration depths of 3. 5, and 7 mm from the apex. Canals of one group were filled with cold lateral compaction technique as a control. Canals were filled with non-standardized master gutta-percha cones and 0.02 mL of Sealapex. Apical extruded sealer was collected in a container and weighed. Data was analyzed with one-way ANOVA and Duncan's Multiple Range Test. 3 and 5 mm penetration depth groups in Continuous Wave of Condensation Technique showed significantly more extrusion of root canal sealer than 7 mm penetration depth group (p < 0.05). However, there was no significant difference between 7 mm depth group in Continuous Wave of Condensation Technique and cold lateral compaction group (p < 0.05). The result of this study demonstrates that deeper plugger penetration depth causes more extrusion of root canal sealer in root canal obturation by Continuous Wave of Condensation Technique. Therefore, special caution is needed when plugger penetration is deeper in the canal in Continuous Wave of Condensation Technique to minimize the amount of sealer extrusion beyond apex.

• Restorative Dentistry and Endodontics
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• v.16 no.2
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• pp.143-154
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• 1991

The purpose of this study was to evaluate the sealing ability of five obturation methods in conjunction with sealer. Fifty extracted upper and lower anterior teeth were selected and the access cavities were prepared lingually with a round bur. The working length was determined with a #15K file, and the root canals were instrumented with a #40K file 1mm short of the apical foramen. The apical third of root canal was flared by step-back technique and the coronal two thirds of root canal using #2 - 3 Gates Glidden drills. And then, the teeth were randomly assigned to five groups of 10 teeth each. A thin coat of Tubliseal was placed into the canal into the canal using the # 35 reamer and the canals were filled by lateral condensation, vertical condensation, ultrasonic activated lateral condensation, ULTRAFIL injecting, and McSpadden compaction methods. All teeth were stored in 100 % relative humidity at 31c for 48 hours. The roots were suspended in 2 % methylene blue solution for 48 hours, left to dry for 24 hours and then, half side of root was removed longitudinally using the fissure bur. A Boley gauge wes used to measure the distance, to the nearest 0.1mm, from the apical foramen to the most coronal level of dye penetration. The measurement of dye penetration was statistically compared by Duncan's multiple range test The results were as follows 1. Ultrasonic group showed the best sealing ability among the all experimental groups, but there were statistically no significant difference in the sealing ability between ultrasonic group and vertical condensation group. 2. There were no statistically significant difference in the sealing ability among the lateral, vertical, and ultrasonic groups. 3. McSpadden group showed the worst sealing ability among the all exprimental groups.

• Restorative Dentistry and Endodontics
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• v.27 no.5
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• pp.521-529
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• 2002

The purpose of this study was to compare the shaping time of two shaping methods and the leakage of three different obturation techniques. Ninty three canaled human molar teeth were used, which were randomly divided into two groups of forty teeth each and ten control teeth. After working length determination, the one group was prepared crown-down technique using rotary root canal instruments of GT rotary files .12/20, .10/20, .08/20 and .06/20 taper(Maillefer Instrument SA. Switzerland). The other group was instrumented with Gates Glidden burs(#1, #2, and #3) to coronal preparation and GT rotary files .08/20 and .06/30 taper to apical preparation. Shaping time was measured. After root canals were instrumented, they were divided to three subgroups and obturated as follows : Subgroup 1, obturated with single cone method Subgroup 2, obturated with lateral condensation : Subgroup 3, obturated with continuous wave technique. Three subgroups were obturated using non-standardized gutta-percha cone(Diadent, Korea, .06 or .08 taper) and AH-26(Dentsply DeTrey, Germany) as a root canal cement. Ten unobturated teeth served as positive and negative controls. After immersion in 2% methylene blue solution for 1 month, the teeth were washed during 24h. The teeth were demineralized in 10% nitric acid and dehydrated by immersion in 80, 90 and 100% ethyl alcohol. The teeth were finally cleared and stored in 100% methylsalicylate, and apical dye penetration was evaluated under stereomicroscope(Leica M420, LC, U.S.A)at $\times$8.75 magnification. Liner measurement of dye penetration was assessed with the use of digitalized image analysing system (analySIS, GmbH, Germany) The data were analysed statistically using independent T-test and Two-way ANOVA and Tukey test. The result were as follows 1. In canal prepared with GT$^{TM}$ rotary file, shaphing time taked more than the group of using Gates Glidden drill to coronal preparation without statistical significance (p>0.05) 2. The group of single cone obturation using canal preparation of GT$^{TM}$ rotary files showed significantly more apical leakage than those of lateral condensation and continuous wave technique regardless of shaping method (p<0.05). 3 The group of single cone obturation using canal preparation of GT$^{TM}$ rotary files and Gates Glidden drill showed significantly more apical leakage than those of continuous wave technique regardless of shaping method (p<0.05). 4. Regardless of shaping method, The group of continuous wave obturation showed less apical leakage than those of lateral condensation without statistical significance (p>0.05). 5. The group of single cone obturation using canal preparation of GT$^{TM}$ rotary files and Gates Glidden drill showed more apical leakage than the group of lateral condensation using same shaping method with-out statistical significance (p＞0.05).

• Restorative Dentistry and Endodontics
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• v.15 no.1
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• pp.81-87
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• 1990

The purpose of this study was to evaluate the apical seal produced by low temperature($70^{\circ}C$) injection gutta percha technique(ULTRAFIL) with & without sealer, warm latero-vertical cindensation technique (ENDOTEC) with & without sealer, and the lateral condensation technique with sealer. 100 extracted, single rooted human teeth were divided into 5 groups and root canals were enlarged & obturated according to the purpose of this study. Obturated teeth were immersed in 2.5% methylene blue for 48hrs. at $37^{\circ}C$ incubator and split. The apical sealing ability was evaluated by measuring the degree of dye penetration into the canal. The results were as follows: 1. All group showed varying depth of dye penetration. 2. There were no significant difference among Group I (lateral condensation), Group II (ULTRAFIL with sealer) & Group IV (ENDOTEC with sealer) (P>0.05). 3. There were less dye penetration when used in conjunction with sealer (P<0.001).

• Restorative Dentistry and Endodontics
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• v.9 no.1
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• pp.59-68
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• 1983

The purpose of this study was to examine the influence of canal irrigants and the method of canal filling on the quality of canal obturation. Sixty extracted human teeth with single root were selected and divided into three different groups; In group I (control); 5 cc normal saline irrigated after each instrumentation In group II; 2.5 cc-3% NaOCl in combination with 2.5 cc-3% $H_2O_2$ In group III; RC-Prep in combination with 5 cc-3% NaOCl All specimens were cleaned, shaped(#50 file size), irrigated and obturated by lateral condensation and automated thermatic condensation filling method of gutta-percha and AH-26. After all the specimens were immersed in 2% methylene blue dye solution in $37^{\circ}C$ for 7 days and the degree of dye penetration into the canals observed by magnifying glass(${\times}$20) and reflected light microscope The results were as follows: 1. All the the teeth showed some degree of the dye penetration. 2. There were no significant difference among three groups in the degree of the dye penetration in each canal filling method. 3. There were no significant difference of the dye penetration between each canal filling method in group I. 4. There were no statistically significant difference of the dye penetration between each canal filling method in group II and group III, but lateral condensation group was showed slightly more than automated thermatic condensation group.

• Restorative Dentistry and Endodontics
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• v.31 no.1
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• pp.66-71
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• 2006

To evaluate the ratio of gutta-percha area in the canal after canal obturation with Continuous Wave of Condensation Technique (CWCT) with varying depths of plugger penetration, forty root canals of extracted human teeth were prepared up to size 40 of 0.06 taper with $ProFile^{(R)}$. Canals of three groups were filled with CWCT with System $B^{TM}$ (Analytic Tech. , USA) and different plugger penetration depths of 3, 5, or 7 mm from the apex. Canals of one group were filled with lateral condensation technique as a control The felled teeth were cross-sectioned at 1, 2 and 3 mm levels from the apical foramen. The ratio of gutta-percha area in the canal was analyzed using $Auto^{(R)}$ Cad 2000. Data were analyzed with one-way ANOVA and Duncan's multiple range test. At all levels, higher gutta-percha area ratio was found with deeper plugger penetration depth in CWCT, and cold lateral condensation group showed higher ratio than group of plugger penetration to apical 7 mm in CWCT. At apical 1 mm and 2 mm levels, group of plugger penetration to apical 3 mm showed significantly high or gutta-percha area ratio than those of apical 7 mm and lateral condensation (p<0.05). It is concluded therefore that, under the conditions of the present study, deeper plugger penetration depth results in more favorable and efficient obturation in CWCT.

• Advances in aircraft and spacecraft science
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• v.3 no.1
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• pp.45-59
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• 2016

In this paper, the condensation method which is based on the Rayleigh-Ritz method, is described for the free vibration analysis of axially loaded slightly curved beams subject to partial axial restraints. If the longitudinal inertia is neglected, some of the Rayleigh-Ritz minimization equations are independent of the frequency. These equations can be used to formulate a relationship between the weighting coefficients associated with the lateral and longitudinal displacements, which leads to "connection coefficient matrix". Once this matrix is formed, it is then substituted into the remaining Rayleigh-Ritz equations to obtain an eigenvalue equation with a reduced matrix size. This method has been applied to simply supported and partially clamped beams with three different shapes of imperfection. The results indicate that for small imperfections resembling the fundamental vibration mode, the sum of the square of the fundamental natural and a non-dimensional axial load ratio normalized with respect to the fundamental critical load is approximately proportional to the square of the central displacement.

• Restorative Dentistry and Endodontics
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• v.10 no.1
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• pp.127-134
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• 1984

This study was conducted to evaluate the sealing ability of McSpadden technique compared with lateral condensation and Engine reamer technique, and according to the degree of canal enlargement and the use and nonuse of sealer. Seventy single-rooted teeth were divided into 14 groups and each tooth was enlarged and obturated according to the purpose of this study. Obturated teeth were infiltrated by Indian ink and decalcified and cleared. The apical sealing ability was evaluated by measuring the degree of ink penetration into the canal. The results were as follows: 1. All the teeth filled by lateral condensation using gutta-percha cone and sealer proved better in canal sealing ability than McSpadden technique and Engine reamer technique, showing less ink penetration. 2. In the McSpadden technique, there was less ink penetration detected in using the sealer than not. 3. In all of the experimental methods, the difference of the degree of ink penetration according the degree of canal enlargement could not be accepted. 4. There was no significant difference in ink penetration degree between Engine reamer technique using sealer and McSpadden technique without sealer.

• Restorative Dentistry and Endodontics
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• v.23 no.1
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• pp.346-356
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• 1998

The purpose of this study was to evaluate the sealing ability of various canal filling methods. Palatal roots of ninety extracted human maxillary molar teeth were resected at cementoenamel junction. Eighty of them were randomly assigned to four experimental groups, ten were served as positive and negative controls. All canals were prepared to # 40 using Profile. Experimental groups were obturated by lateral condensation technique, Thermafil technique, Continuous Wave of Condensation Technique, and down-pack & back-fill technique of Obtura-II, each with root canal sealer. Control groups were not obturated. Teeth were immersed in resorcinol-formaldehyde resin for 5 days at $4^{\circ}C$, and the resin was allowed to polymerize completely for 4 days at room temperature. Teeth were then ground horizontally at 1.5mm(level 1), 2.5mm(level 2), 3.5 mm(level 3) from the anatomical apex and examined with a stereomicroscope at ${\times}40$ magnification. The gap between the canal wall and the filling material, which was filled with the resin, was measured at each of the three levels. Each ratio of leakage was obtained by calculating the ratio of the area of the resin to the total area of the canal and was analyzed statistically (Rank-sum test). The results were as follows : 1. At the level 1, there was the greatest leakage in the Thermafil group and Obtura-II group, and the difference between the Obtura-II group and Continuous Wave of Condensation Technique group was statistically significant(p<0.05). 2. At the level 2, there was the least leakage in the Continuous Wave of Condensation Technique group, but there was no statistically significant difference between each group (p>0.05). 3. At the level 3, there was no statistically significant difference between each group(p>0.05).

• Restorative Dentistry and Endodontics
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• v.23 no.1
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• pp.366-378
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• 1998

Thermocondensation root canal filling technique have been used to fill accessary canals or to obtain homogeneous root caral fillings. But these thermocondensation technique inevitably produce heat in the canal which can be transmitted through the dentin and cementum and consequently damage periodontal ligamental cells and osteoblasts. In this study, System $B^{TM}$(Analytic technology, WA.D.S.A.) was used to evaluate the reaction of periodontal ligament tissue to "Continous Wave condensation technique" introduced by Buchanan, and the transmitted root surface temperature was measured according to measured root thicknesses. 12 Mandibular incisors of two adult dogs were used for the experiment. 6 controls were filled by lateral condensation technique with sealer.3 specimens were apically filled by Continuous Wave technique at $200^{\circ}C$ for 5 seconds and remaining 3 specimens were additionally backfilled using System $B^{TM}$(Analytic technology, WA.D.S.A.) was used to evaluate the reaction of periodontal ligament tissue to "Continous Wave condensation technique" introduced by Buchanan, and the transmitted root surface temperature was measured according to measured root thicknesses. 12 Mandibular incisors of two adult dogs were used for the experiment. 6 controls were filled by lateral condensation technique with sealer.3 specimens were apically filled by Continuous Wave technique at $200^{\circ}C$ for 5 seconds and remaining 3 specimens were additionally backfilled using System $B^{TM}$ at $100^{\circ}C$ for 20 seconds. Six weeks later, the dogs were sacrificed and the teeth stained with Hematoxylin and Eosin for histologic examination. 6 extracted human teeth were used to measure the transmitted temperature. After cutting off the crown, the canals were prepared and divided into 3 groups with root thickness of 1.5mm, 1.0mm, 0.5mm, 2 teeth in each group. Inside each root canal, System $B^{TM}$ was heated as with the temperature for the apically condensed and the back filled group, and the transmitted heat was measured on the external surface of the root. The temperature of System $B^{TM}$ heat spreader at $200^{\circ}C$ and $100^{\circ}C$ was also measured at root temperature. It can be concluded as follows: 1. In the thin area (200-$250{\mu}m$) of the root, root resorption could be seen even with heating at $200^{\circ}C$ for 5 seconds. 2. When the spreader was heated at $200^{\circ}C$ for 5 seconds and additionally at $100^{\circ}C$ for 20 seconds for backfill, all teeth showed root resorption regardless of their root thickness. 3. The transmitted external root surface temperature was higher as the root thickness decreased and as the heating time increased. In the thermocompaction technique using System $B^{TM}$, the spreader should be heated for the minimal time and used only in the apical area. The heated spreader shouldn't inserted to the binding point of the canal and backfilling should be done with other means of minimally heated gutta percha technique.