Leakage along warm gutta-percha fillings in the apical canals of curved roots

Abstract – The aim of this study was to investigate the leakage along the apical portion of warm gutta‐percha obturated curved canals. Human mandibular premolars with single, curved (21°–40°) canals were prepared using the Lightspeed technique. Two groups of prepared canals, matched according to curvature and prevalence of apical transportation, were obturated by two techniques. Coronal gutta‐percha was removed immediately after root obturation was completed to simulate the procedure for post space preparation. Leakage along the apical 3 mm of root filling was measured with a fluid transport device. Vertical condensation of warm gutta‐percha and Pulp Canal Sealer provided less leakage than Thermafil plastic obturators and AH26 sealer (P=0.002).     

不同锥度牙胶尖热垂直加压法根管充填的临床疗效分析

目的研究采用不同锥度牙胶尖热垂直加压法行根管充填的临床X线片评价及术后1年的临床疗效。方法选择上颌前牙单、直根管患牙40颗为研究对象,采用Hero 642机用镍钛锉预备至0.06锥度30号锉,随机分为2组,每组20颗患牙。分别使用0.02锥度和0.06锥度牙胶尖采用热垂直加压法充填根管。对术后即刻X线片进行2组患牙根管充填质量、侧支根管充填及超填情况的比较;并比较2组患牙术后1年的临床疗效。结果0.02锥度组与0.06锥度组根管充填质量、侧支根管充填及超填情况没有明显差异。术后1年复查,0.02锥度组与0.06锥度组的治疗成功率一致,但0.06锥度组病变愈合趋势快于0.02锥度组。结论对于镍钛旋转器械预备的较大锥度单、直根管,采用热牙胶垂直加压法行根管充填,使用与根管预备锥度相一致的大锥度牙胶尖能够提高根管治疗的临床疗效。     

不同根管充填技术对椭圆形根管充填效果的比较

目的:通过比较3种不同方法充填椭圆形根管后的牙胶充填面积百分数来评价各种充填法的效果。方法:选取人离体单根管前磨牙30个,手用ProTaper预备后随机分为3组,分别用冷牙胶侧方加压法、热塑牙胶注射加压法(ObturaⅢ)和连续波充填法(System B+ObturaⅢ)进行充填,然后分别在距根尖2、5、8 mm处横断,各个横断面在手术显微镜下拍照,再用图像分析软件记录横断面的根管面积和牙胶充填面积,从而计算出牙胶充填面积百分数。结果:在2 mm处,3种充填法的牙胶充填面积百分数无显著性差异(P>0.05);在5 mm处,ObturaⅢ组和SystemB+ObturaⅢ组无显著性差异(P>0.05),但都显著大于冷牙胶侧压组(P<0.05),8 mm与5 mm处结果相同。结论:在5,8 mm水平,ObturaⅢ和SystemB+ObturaⅢ充填法的效果好于冷牙胶侧压法,而在2 mm水平,3种充填法的的效果无明显差别。     

Clinical experience of root canal filling by ultrasonic condensation of gutta-percha

Abstract— Ninety human teeth with a total of 181 prepared root canals were filled with the use of ultrasonically energized spreaders as an aid for lateral condensation of gutta-percha cones. The results were evaluated on the basis of clinical and radiographic criteria. Adequate fillings were found in 93% of the canals and the overall success rate was 93%. All of the recalled patients were clinically comfortable.     

Quality of cold and warm gutta-percha fillings in oval canals in mandibular premolars

AIM: The aim of this study was to determine the quality of cold and warm gutta-percha fillings in oval canals. METHODOLOGY: Two groups of mandibular premolars with oval canals were selected after bucco-lingual and mesio-distal radiographs indicated an internal long: short diameter of > or =1.6 at a level 5 mm from the apex. After instrumentation they were obturated, respectively, by cold lateral compaction of gutta-percha cones (cold GP) and vertical compaction of warm gutta-percha (warm GP). Leakage along apical root fillings was measured using a fluid transport model. After the leakage test, horizontal sections were cut 2 and 4 mm from the apex. The area of the canal and gutta-percha in cross-sections was measured using an image analysis program. The quality of root fillings was evaluated by calculating the percentage of gutta-percha-filled canal area (PGP). RESULTS: No significant difference in leakage was found between the two groups (P = 0.570). The warm GP group produced significantly higher PGPs than the cold GP group 4 mm from the apex only (P = 0.522 at 2 mm: P = 0.000 at 4 mm). CONCLUSIONS: The percentage of gutta-percha-filled canal area using warm GP was greater than that of the cold GP in oval canals.     

An in vitro comparison of thermoplasticised gutta-percha obturation techniques with cold lateral condensation

Abstract— This study compared the apical sealing ability, obturation time and extrusion of gutta-percha and sealer when root canals were ohturated using either cold lateral condensation or one of the three methods using thermoplasticised gutta-percha (Alpha Seal, Thermafil or JS Quick Fill) in vitro . One hundred and thirty-one root canals from 78 extracted human teeth were used; 116 canals were divided into five groups so that they were balanced with respect to prepared canal anatomy, and the remaining 15 canals were used as positive and negative controls. The canals in the first four groups were prepared with hand files using the step-down technique to a standard apical size and flare. The last group was prepared using engine-driven rotary nickel-titanium files (McSpad-den) to a similar apical size and Hare. One of the four obturating techniques was used to fill the canals in each of the first four groups. The fifth group was obturated using the Alpha Seal technique. The roots were immersed in india ink, demineralised and rendered transparent to assess the extent of maximum linear dye penetration. The Alpha Seal groups had the highest number of specimens without any leakage. There was a significant difference in the proportions of specimens that did not leak when the Alpha Seal ( P <0.01) and cold lateral condensation groups ( P <0.05) were compared with JS Quick Fill. Cold lateral condensation had a higher proportion of specimens with leakage in canals with curvature greater than 20' than in canals with curvatures less than 20 ( P <0.05). The curvature of canals had no effect on the sealing ability of the other techniques. The method of canal preparation had no effect on the sealing ability of Alpha Seal. Alpha Seal, Thermafil andJS Quick Fill were significantly quicker to perform than cold lateral condensation.     

Apical placement of needle tip with an injection-thermoplasticized gutta-percha technique for root canal obturation

Abstract It is recommended that when injection-thermoplasticized gutta-percha is used as the obturation technique, the root canal space should be prepared in such a way that the 23-gauge injection needle tip can be placed at a distance 3 to 5 mm short of the working length. In this study the apical seal and extent of gutta-percha were evaluated when the 23-gauge tip was placed at a distance 4 mm, 6 mm, and 8 mm short of the working length. Ninty-nine human single-rooted mandibular incisors and premolars divided into 3 equal groups were used. Their crowns were separated at the cementoenamel junction and their roots were stored in sodium hypochlorite for 1 week. The roots were then instrumented from size 20 at the working length to size 70:4 mm short of the working length in group A, 6 mm in group B, and 8 mm in group C. Following instrumentation, 3 randomly selected roots of each group were used as control. The remaining 30 roots of each group were covered with aluminium foil and embedded in acrylic blocks. The root canals were then dried, coated with sealer (Roth 811) and obturated by injection of thermoplasticized gutta-percha using the single-phase technique. Vertical condensation followed. The roots were immersed in dye for 3 days and then demineralized, dehydrated and cleared in xylene. Measurements of linear dye penetration for the apical seal and for underextension were done by 2 independent examiners under a stereomicroscope. The results of this study showed no statistically significant difference in leakage between the groups. However, statistically significant differences were found in linear underextension between groups A and C as well as between groups B and C, while no significant difference was found between groups A and B.     

Periodontal tissue reactions following root canal obturation with an injection-thermoplasticized gutta-percha technique

Abstract The thermoplasticized gutta-percha obturation technique is a relatively recent development in endodontics. In this study we evaluated the possible effects of heat transmitted to the periodontal tissues when the Obtura root canal filling device was used in dog teeth. Two 8-month-old beagle dogs were used; 56 root canals of 36 teeth (maxillary incisors and first, second and third premolars of both jaws) were divided into two groups. In Group A 26 root canals were obturated with the lateral condensation technique, while in Group B 30 root canals were obturated using the Obtura device, without sealer. Observation periods were 1, 3, 7, 28 and 56 days. After routine laboratory procedures, hematoxylin-eosin stained sections were examined under a light microscope. In this experimental model the thermoplasticized gutta-percha obturation technique caused a periapical inflammatory reaction at all observation periods. Inflammatory reaction and destruction of collagen fibers were localized in the area around the apical delta, while the alveolar founding bone, the roots of the teeth and the periodontal ligament at the side of the root surfaces remained normal.     

Sealing ability of thermoplasticized gutta-percha in root canal obturation using a sectional vs. a single-phase technique

Abstract Properly prepared straight root canals of freshly extracted maxillary canines and central incisors were used to evaluate the sealing ability of the sectional thermoplasticized gutta-percha obturation technique, with or without sealer and the single-phase thermoplasticized gutta-percha filling technique. The teeth were divided into 3 groups (A, B, C) of 20 teeth and were obturated using the 3 thermoplasticized gutta-percha techniques. Group A: single phase with sealer; group B: sectional technique without sealer; and group C: sectional technique with sealer. The obturated teeth were immersed in India ink for 3 days followed by clearing procedures. The teeth were then examined under a stereo microscope and the linear leakage was recorded. Statistical unpaired Student's t-tests showed significantly less dye penetration in teeth obturated using the sectional technique with sealer (group C) than in teeth obturated with the single-phase technique with sealer (group A) or the sectional technique without sealer (group B).     

Comparison of lateral condensation and thermomechanically compacted warm alpha-phase gutta-percha with a single cone for obturating curved root canals

OBJECTIVE: To evaluate and compare the sealability and radiographic quality of root fillings in extracted teeth by using lateral condensation of gutta-percha or alpha-phase gutta-percha in conjunction with a single gutta-percha cone. STUDY DESIGN: A total of 108 single-rooted teeth were divided into 2 groups of 54 teeth based on canal shape. Canals were prepared to a minimum 0.055 taper and enlarged to a size 35 at the working distance. Irrigation was done with 17% EDTA and 2.5% sodium hypochlorite (NaOCl) to remove smear layer. One group was obturated by using cold lateral condensation of gutta-percha; the other group was obturated with thermomechanically compacted alpha-phase gutta-percha and a single cone of gutta-percha. Apical extrusion of sealer or gutta-percha was recorded. Sealability of each technique was assessed by dye penetration. The radiographic quality of obturation was also determined. RESULTS: Root canals filled with alpha-phase gutta-percha and a single cone had significantly more extrusion of sealer than canals filled by lateral condensation. Lateral condensation achieved significantly better scores for radiographic quality. There was no significant difference between the 2 filling techniques in terms of apical or coronal leakage. CONCLUSIONS: Thermomechanically condensed alpha-phase gutta-percha used in conjunction with a single gutta-percha cone had poorer radiographic quality than laterally condensed gutta-percha.     

热牙胶根管充填技术研究进展

热牙胶根管充填技术是目前研究较多、运用较广的根管充填技术，其种类大致包括：热牙胶加压、机械热压、超声震动热压、热塑牙胶注射、固核载体插入等充填技术。本文对这些技术的原理、改良和优缺点作一综述，为临床选用提供参考。     

热牙胶连续波充填技术的临床应用

目的：总结热牙胶连续波充填技术的充填质量及临床效果。方法：成人牙髓病及根尖周病30例,常规根管预备,使用热牙胶充填根管,并在治疗后3-6个月进行回访,观察临床疗效。结果：30例中,根充恰填率90％,根管充填后未发生疼痛。x线片显示根充严密合适,咬合关系良好,根尖瘘道2～3周愈合。术后3个月和6个月复查,x线片显示根尖周透射区缩小,骨质密度增加。结论：热牙胶连续波充填技术安全、可靠,操作简便,近期观察临床效果好。     

An in vitro study of the quality of root fillings in teeth obturated by lateral condensation of gutta-percha or Thermafil obturators

The aim of this in vitro study was to assess the quality of root canal obturation and degree of linear apical dye penetration in teeth root filled with either laterally condensed gutta-percha or Thermafil obturators, A total of 150 teeth with single roots were included in the study. All canals were prepared using a standard step-back technique with anticurvature filing. Radiographs taken of the teeth to show the maximum degree of canal curvature were then exposed and the angle, radius and position of curvature determined. This information about the canals, together with their working length and diameter at end-point, was used to divide the teeth into two experimental and two control groups. A total of eight teeth were excluded because of technical difficulties, 65 were filled with Thermafil obturators, 63 were filled with laterally condensed gutta-percha whilst 14 teeth remained unfilled and acted as controls. Following obturation, the teeth were radiographed in two planes and the technical quality of fill assessed on a four-point scale. All access cavities were then sealed and the teeth immersed in dye for 48 h before being split longitudinally. Linear dye penetration via the apical foramen was then assessed. Canal obturation with Thermafil obturators (0.7 min) was significantly quicker (P > 0.001) than lateral condensation (6.4 min). Apical extrusion of sealer and gutta-percha occurred significantly more often with Thermafil obturators but there was little difference in the technical quality of the fillings and no significant difference in dye penetration. Under the conditions of this study, Thermafil obturators proved a satisfactory alternative to lateral condensation of gutta-percha.     

Effect of irrigation solutions on the filling of lateral root canals

Abstract An in vitro study involving 66 single–rooted human teeth was performed. The teeth were divided into 3 groups: control group, root canals instrumented and irrigated with distilled water; experimental group A, root canals instrumented and irrigated with 15% EDTA; and experimental group B, root canals instrumented and irrigated with 5% sodium hypochlorite. All canals were filled with laterally condensed gutta-percha and Diaket® A. Radiographs were taken mesiodistally and buccolingually and the number of lateral canals filled in the various teeth was counted. The group treated with 15% EDTA showed a significantly larger number of filled lateral canals than the groups irrigated with distilled water or sodium hypochlorite.     

A comparative study of lateral condensation,heat-softened gutta-percha,and a modified master cone heat-softened backfilling technique

AIM: The aim of the study was to compare the quality of root fillings completed by lateral condensation (L), Thermafil (TF), and a new technique using Thermafil for backfilling (BF), with special emphasis on control of overfilling. METHODOLOGY: Sixty curved canals in plastic blocks were prepared with the ProFile system to size 40/04 taper in the apical half and to 06 taper in the coronal half. The canals were divided into three groups of 20. Apical patency was verified with a size 15 K-file. The canals were then filled using three different techniques: LC (20 canals), TF (20 canals), and BF, where a size 40 master point with sealer was seated prior to the introduction of a size 30 Thermafil point (20 canals). The same resin-based sealer was used on each occasion. The root fillings were assessed using stereo-microscopy for material extrusion, digital radiography for occurrence of voids, and microscopy of sections for voids and thickness of sealer layer. RESULTS: Extrusion of both gutta-percha and sealer occurred in all 20 canals filled with the TF technique, but only three and five cases of sealer extrusion were detected with LC and BF techniques, respectively. No voids were detected in the TF group, whereas small voids were present in most fillings in the LC and BF groups. The average total length of the voids was less than 1 mm per canal. The thickness of the sealer layer in the middle and apical parts was greater in the LC and BF groups than in the TF group. CONCLUSIONS: LC and BF techniques resulted in fewer overfills than TF. Voids were absent in TF fillings, whilst small voids were found in the LC and BF groups.     

An evaluation of .06 tapered gutta-percha cones for filling of .06 taper prepared curved root canals

AIM: To compare the area occupied by gutta-percha, sealer, or void in standardized .06 tapered prepared simulated curved canals and in mesio-buccal canals of extracted maxillary first molars filled with a single .06 gutta-percha point and sealer or lateral condensation of multiple .02 gutta-percha points and sealer. METHODOLOGY: Simulated canals in resin blocks with either a 30 degrees curve and radius of 10.5 mm (n = 20) or a 58 degrees curve and 4.7 mm radius (n = 20) and curved mesio-buccal canals of extracted maxillary first molars (n = 20) were prepared using .06 ProFiles in a variable tip crown-down sequence to an apical size 35 at 0.5 mm from the canal terminus or apical foramen. Ten 30 degrees and 58 degrees curved resin canals and 10 canals in the extracted teeth group were obturated with .02 taper gutta-percha cones and AH 26 sealer using lateral condensation. The time required to obturate was recorded. The remaining canals were obturated with a single .06 taper gutta-percha cone and AH 26 sealer. Excess gutta-percha was removed from the specimens using heat and the warm mass vertically condensed. Horizontal sections were cut at 0.5, 1.5, 2.5, 4.5, 7.5 and 11.5 mm from the canal terminus or apical foramen. Colour photographs were taken using an Olympus 35 mm camera attached to a stereomicroscope set at x40 magnification, and then digitized using a flatbed scanner. The cross-sectional area of the canal contents was analysed using Adobe PhotoShop. The percentage of gutta-percha, sealer or voids to the total root canal area were derived and data analysed using unpaired Student's t-test and the Mann-Whitney U-test. RESULTS: In the 30 degrees curved canals the levels had between 94 and 100% of the area filled with gutta-percha with no significant difference (P > 0.05) between the lateral condensation and single cone techniques. In the 58 degrees curved canals the levels had 92-99% of the area filled with gutta-percha, with the single cone technique having significantly (P < 0.05) more gutta-percha fill at the 2.5 mm level only. In the mesio-buccal canals of the teeth the levels had between 72 and 96% of the area filled with gutta-percha with no significant difference (P > 0.05) between the lateral condensation and single cone technique. The time for obturation was significantly (P < 0.05) greater for lateral condensation compared with the single cone technique in all groups. CONCLUSIONS: The .06 taper single cone technique was comparable with lateral condensation in the amount of gutta-percha occupying a prepared .06 tapered canal. The .06 single cone technique was faster than lateral condensation.     

不同锥度牙胶尖冷侧压充填根尖封闭性能的比较研究

目的：对比研究0.02锥度和0.06锥度牙胶尖冷侧压充填后根尖封闭效果.方法：收集离体单根管前牙53颗,经根管清理、机用ProTaper预备成型后随机分为2个实验组和1个阳性对照组,实验组每组26个样本,对照组1个样本.实验组分别用0.02锥度牙胶尖和0.06锥度牙胶尖作主尖冷侧方加压进行充填,阳性对照组不进行充填.用透明标本法配合染料渗透技术测量根尖染料的线性渗透长度,评价各组标本的根尖封闭效果.结果：阳性对照组标本染料全部进入根管.0.02锥度组染料渗透长度（0.761 ±0.457） mm,0.06锥度组（0.906±0.490） mm,差异无统计学意义（P＞0.05）.结论：机用ProTaper预备根管后,冷牙胶侧方加压充填时0.06锥度牙胶尖和0.02锥度牙胶尖的根尖封闭效果差异无统计学意义.     

In vitro evaluation of apical leakage of root canal fillings after in situ obturation with thermoplasticized and laterally condensed gutta-percha

The purpose of this investigation was to compare In vitro the sealing ability of root canal treatments performed In situ with injected thermoplasticized gutta- percha compared with the lateral condensation technique. Thirty single-rooted teeth with straight canals, due for extraction For orthodontic or periodontal reasons were prepared using a step-back technique. Teeth were then divided randomly into groups A and B and obturated, respectively, with the sectional injection thermoplasticized gutta-percha and the lateral condensation techniques. Teeth were extracted after 15 days, immersed in India ink for 3 days and the leakage was determined using area-metric analysis. The roots were ground transversally and the root portion was incrementaly removed with successive steps of 250 μm each, up to the coronal level of the dye penetration. Every section was photographed with a stereoscopic microscope under the same magnification (×20); 310 photographs were taken. Measurements of the area covered by ink as well as the whole cross-sectional area of the canal were made from each photograph with the aid of a digitizing computer. The measurements were subjected to non-parametric statistical analysis. No significant difference was found (P>0.05). The technique of lateral condensation proved to be better in the first five sections (1.2 mm from the foramen) while thermoplasticized gutta-percha technique was superior in the rest of the root canal.     

Comparative study of retreatment of Thermafil and lateral condensation endodontic fillings

The aim of the present study was to evaluate the possibility of retreating teeth obturated with: (i) Thermafil with plastic carrier, (ii) Thermafil with metallic carrier and (iii) laterally condensed gutta-percha. The following aspects were analysed: removal of obturation, time required for removal, remaining filling material and apical extrusion during reinstrumentation. Thirty human teeth with a single canal were instrumented up to a size 45 K-type file, divided into three groups of 10 teeth each and obturated with Thermafil with plastic carrier (group 1), Thermafil with metallic carrier (group 2), and laterally condensed gutta-percha (group 3) with AH26 as the sealer. Reinstrumentation was performed manually after 30 days storage using Hedstroem files and xylene as a solvent. The average time needed to remove the obturation was 12 min 1 s for group 1, 14 min 36 s for group 2 and 11 min 26 s for group 3. Although no statistically significant differences were observed between groups 1 and 2, and 1 and 3 ( P > 0.05), the differences between groups 2 and 3 were significant ( P < 0.05). The amount of remaining filling material was significantly higher in group 2 when compared with groups 1 and 2 ( P < 0.01). Although the lowest incidence of apical extrusion during reinstrumentation was found in group 3, the differences among groups were not statistically significant.