A comparative evaluation of gutta-percha filled areas in curved root canals obturated with different techniques

The aim of this study was to compare different obturation techniques in severely curved canals in terms of the percentage of gutta-percha filled area and voids. The obturation times and the incidence of extrusion of filling material were also compared. Curved root canals (curvature, 25–35°) of 48 extracted human teeth were enlarged with Mtwo rotary NiTi instruments and obturated as follows: Group A: 0.04/35 matched-single-cone; Group B: cold lateral compaction with 0.04/35 gutta-percha master cone; Group C: warm vertical compaction; Group D: lateral compaction with standardized gutta-percha master cone. In all groups AHPlus was used as sealer. The teeth were sectioned horizontally at 2, 3, 4, 6 and 8 mm from the apex. The total area of each canal segment was measured and the areas of gutta-percha, sealer and voids were converted to percentages of the total area. Data were subjected to the Kruskal–Wallis and post hoc Dunn test. Obturation times were compared using ANOVA and post hoc Student–Newman–Keuls test. The matched-single-cone obturation (group A) was significantly the fastest method while warm vertical compaction (group C) required significantly more time than all other techniques (p < 0.05). No significant differences were obtained between the groups in terms of percentage of voids at any level (p > 0.05). At all levels, groups B, C, and D produced significantly higher gutta-percha filled areas (p < 0.05) and lower sealer-filled areas (p < 0.05) than group A. No significant differences were found between groups B, C, and D (p > 0.05) regarding gutta-percha and sealer-filled areas. Within the limitations of the in vitro study, it can be concluded that lateral compaction of greater taper gutta-percha cones is a fast and efficient method for obturation of curved canals.     

Sealing ability of three materials in the orifice of root canal systems obturated with gutta-percha

There were 130 single roots randomly assigned to one of 12 experimental or two control groups. Forty specimens each were sealed with 1, 2, 3, or 4 mm of Cavit, ProRoot MTA, or Tetric. After creation of a uniform orifice diameter, the smear layer was removed and the canal systems obturated using warm lateral compaction of gutta-percha (GP). GP was removed to the experimental depth, experimental materials placed in the orifice, and roots submerged in India ink in a vacuum flask. Specimens were demineralized and leakage measured using a 10x stereomicroscope and graded for depth of leakage by one calibrated, blinded rater. There was no significant interaction (p > 0.05) between test materials and orifice depths, nor main effect of orifice depth (p > 0.05). However, there was a statistically significant main effect of test materials with Tetric demonstrating a significantly better seal than Pro Root or Cavit (p < 0.0001) irrespective of orifice depth.     

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目的比较氯仿和丁克除(Desocclusol)对根管充填后再通的能力。方法2007年7月至12月,在吉林大学口腔医学院牙体牙髓科选取60颗离体牙随机分成手动组和超声组。手动组分为A组(H型锉和氯仿去除根管内容物)和B组(H型锉和丁克除去除根管内容物);超声组分为C组(超声K型锉和氯仿去除根管内容物)和D组(超声K型锉和丁克除去除根管内容物)。A、B、C、D每组各15颗牙,比较各组根管再通的操作时间、液体用量和根管内残留物情况。结果各组均能使根管再通,氯仿去除根管内容物操作时间快于丁克除,用量多于后者且差异均有统计学意义(P(0.05);氯仿和丁克除去除牙胶尖的能力相似,手动组和超声组去除牙胶尖的能力也相似,超声组去除根管充填物的彻底程度比手动组强。结论丁克除可以取代氯仿作为牙胶尖的辅助溶剂,辅以超声器械有更好的应用效果。     

An In-vitro evaluation of the influence of canal curvature on the sealing ability of Thermafil

The sealing ability of lateral condensation and Thermafil were compared in root canals with curvatures either greater or less than 25 degrees. Forty-eight canals in roots of extracted human mandibular molar teeth were divided into four groups of 12. The root canals in two groups had curvatures of less than 25° and the remaining two groups had canals with curvatures greater than 25°. Four canals acted as positive and negative controls. All canals were enlarged to accept a size 30 file to the working length and flared using the step-back technique. Roth's sealer was used in all canals. Lateral condensation and Thermafil obturators thermoplasticized in an open flame were used to obturate two groups each of canals, one group with curvatures greater than 25° and the other less than 25°. After immersion in India ink, the teeth were rendered transparent and the linear penetration of dye measured. It was found that Thermafil sealed significantly better than lateral condensation in canals with curvatures greater than 25° (P < 0.05). However, there were no significant differences between the techniques in the groups with canal curvature less than 25°. There was no significant difference in the performance of each of the techniques when analysed with respect to canal curvature.     

Three-step versus single-step use of system B: evaluation of gutta-percha root canal fillings and their adaptation to the canal walls

This study aimed to evaluate the quality of gutta-percha (GP) root canal fillings and their adaptation to the root canal walls, when the System B was used in three steps and a single step to fill three different split-tooth models. Each model was filled 10 times in two different ways. Group A: the System B plugger was used to fill the apical 3 mm of the canal in three steps, and then the Obtura II was used to backfill the rest of the canal. Group B: the System B plugger was inserted just once to a distance 3 mm short of the working length and then backfilled as in Group A. Replication of artificial depressions, presence of voids within the GP mass, and presence of spaces between the GP mass and the root canal walls were evaluated and scored. The individual scores of each parameter evaluated were compared between the two groups and statistically analyzed by use of the Mann-Whitney U test. Group A showed statistically significant (p < 0.05) better scores than Group B concerning the replication of artificial depressions and spaces between the GP mass and the canal walls. It was concluded that better adaptation of the GP mass to the canal walls in the apical third was obtained when the System B plugger was used in three steps.     

The effect of formalin storage on the apical microleakage of obturated canals

Infection control guidelines recommend disinfection of extracted teeth in 10% formalin for 2 weeks before use. Although extracted teeth are routinely used for in vitro endodontic research, the potential influence of formalin has not been evaluated. The purpose of this study was to investigate the effect of formalin storage on the apical seal integrity of obturated canals. There were 100 single-rooted human teeth decoronated, accessed, and randomly divided into four groups. Group 1 was composed of specimens that were instrumented and obturated after extraction without storage in formalin. Groups 2, 3, and 4 were stored in formalin for 2, 4, and 8 weeks, respectively, before treatment. Canals were instrumented to a master apical file size #7 ProFile .04 Taper Series 29 and obturated with Obtura II thermoplasticized gutta-percha and Roth 801 sealer. The teeth were immersed in India ink, cleared, and the greatest extent of linear dye leakage was measured. Microleakage testing displayed significantly less microleakage after 2 and 4 weeks of formalin storage. Leakage measurements after 4 weeks of storage were 62.3% lower than nonfixed specimens. The 8-week storage group demonstrated lower dye penetration compared with the nonfixed group; however, the difference was not statistically significant. Within the scope of this study, storage of extracted teeth in formalin for 2 and 4 weeks resulted in a significant decrease in apical microleakage compared with nonfixed specimens.     

The effect of MTAD on the coronal leakage of obturated root canals

The purpose of this study was to evaluate the effect of smear-layer removal using MTAD on coronal leakage of obturated root canals using a dye-leakage test. Fifty, extracted, single-rooted, human teeth were cleaned and shaped and divided into 5 equal groups of 10 each. The smear layer in groups 1 to 3 was left intact. The smear layer in groups 4 and 5 was removed using 17% EDTA or MTAD, respectively. After obturation of root canals, the access opening to each canal was filled with India ink for 48 h. The depth of coronal-dye penetration was measured using the Sigmascan software. ANOVA showed statistically significant differences among the groups (p < 0.05). Samples treated with MTAD yielded significantly less leakage than samples treated with sodium hypochlorite. The amount of dye penetration was not statistically different between teeth treated with MTAD or EDTA (p = 0.062).     

In vitro evaluation of the obturation ability, adaptation and compaction of gutta-percha in the root canal system employing different filling techniques

The aim of this study was to evaluate the in vitro obturation quality of four filling methods: active lateral condensation, a modification of Tagger's hybrid technique, ENAC ultrasound technique and the Microseal technique. The study was performed on one hundred and sixteen single-rooted human teeth, divided into four groups of twenty nine teeth, embedded in resin, longitudinally sectioned and placed together on a wooden device with screws. After instrumentation, a cavity was made with a bur in the cervical, medium and apical thirds of the root canal in order to simulate lateral canals. The teeth were filled with the different techniques. Obturation quality was evaluated employing photographs and radiographs. The statistical analysis using the Chi square (chi2) test revealed that the Microseal technique reached the best results followed by the modified Tagger's hybrid technique, the ENAC ultrasound technique and the active lateral condensation technique.     

Evaluation of apical leakage of root canals obturated with Nd: YAG laser-softened gutta-percha,System-B,and lateral condensation techniques

In endodontics, a laser can be used as a heat source and gutta-percha can be softened by a laser and used in the root canals. The System-B endodontic heat source unit was designed for the obturation of the root canal system with a single continuous wave of thermoplasticized gutta-percha. The aim of this study was to compare the apical leakage of lateral condensation; Nd: YAG laser-softened gutta-percha and System-B techniques. Fifty-five extracted, single root human maxillary anterior and premolar teeth were used in this study. After working length determination, the "step-back technique" was used to prepare the root canals. The teeth were randomly divided into three experimental groups of 15 each and two control groups of 5 specimens each. The first group was obturated by lateral condensation, the second group by gutta-percha softened with an Nd: YAG laser, and the third group was obturated using the System-B technique. Apical leakage of the roots was evaluated by dye penetration using a stereomicroscope after sectioning the roots. The results of the first and third groups were similar, and the results of the second group showed differences when compared with the other groups. However, variance analysis revealed there was no statistically significant difference among the results.     

"In vitro" evaluation of the apical sealing of root canals obturated with different techniques

The purpose of this study was to compare the apical sealing of root canals obturated with different techniques. One hundred-six human mandibular incisors were submitted to instrumentation by means of the step-back technique. After instrumentation, one hundred teeth received an impermeable coating on the external surfaces of the crown and root (except for the area nearby the apical foramen). Afterwards, they were divided in five groups containing twenty elements each, according to the obturation technique employed: 1. lateral condensation with Kerr file; 2. continuous wave of condensation technique with System B; 3. thermoplasticized injectable gutta-percha technique with the Ultrafil system; 4. mechanically thermoplasticized gutta-percha with the JS Quick-Fill system and 5. thermoplasticized gutta-percha associated to a master cone with the Microseal system. The six remaining teeth were employed as negative and positive controls. After obturation, the access cavities were sealed and the teeth were immersed in aqueous 2% methylene blue dye for 72 hours at 37oC. After that, the teeth were longitudinally sectioned and the apical microleakage was evaluated in a stereomicroscope. The Microseal system presented the best apical sealing ability, followed by System B, JS Quick-Fill, Ultrafil and the lateral condensation technique. The statistical analysis of the results demonstrated that: 1. the Microseal system presented an apical sealing similar to System B and better than the other groups; 2. System B presented better apical sealing than the lateral condensation technique, being similar to the other groups; and 3. the lateral condensation, Ultrafil and JS Quick-Fill groups demonstrated similar sealing ability.     

热牙胶连续波技术充填前磨牙的效果评价

目的比较热牙胶连续波技术与冷牙胶侧方加压技术充填前磨牙的临床效果。方法选取急慢性牙髓炎及根尖周炎的前磨牙120颗,随机分为2组,每组60颗患牙,热牙胶组采用SuperEndoα2/β(BL)热牙胶根管充填系统行热牙胶连续波充填,冷侧压组行冷牙胶侧方加压充填。评价根充恰填率、侧副根管充填情况及术后疼痛发生情况。结果热牙胶组恰填率为93.3%(56/60),冷侧压组恰填率为80.0%(48/60),热牙胶组恰填率高于冷侧压组,差异具有统计学意义(χ2=4.615,P=0.032)。热牙胶组侧副根管的充填率13.3%(8/60),冷侧压组1.7%(1/60),热牙胶组高于冷侧压组,差异具有统计学意义(χ2=5.886,P=0.015)。术后1周复诊,热牙胶组与冷侧压组疼痛率分别为23.3%(14/60)、20.0%(12/60),差异无统计学意义(P0.05)。结论热牙胶连续波技术充填前磨牙根管效果优于冷牙胶侧方加压充填术。     

Quality of obturation achieved by an endodontic core-carrier system with crosslinked gutta-percha carrier in single-rooted canals

Objectives

The present study examined the quality of obturation in root canals obturated by GuttaCore, a gutta-percha-based core-carrier system with a cross-linked thermoset gutta-percha carrier, by comparing the incidence of gaps and voids identified from similar canals obturated by cold lateral compaction or warm vertical compaction.

Methods

Thirty single-rooted premolars with oval-shaped canals were shaped and cleaned, and obturated with one of the three obturation techniques (N = 10): GuttaCore, warm vertical compaction or cold lateral compaction. Filled canals were scanned with micro-computed tomography (micro-CT); reconstructed images were analysed for the volumetric percentage of gaps and voids at three canal levels (0–4 mm, 4–8 mm and 8–12 mm from working length). The roots were subsequently sectioned at the 4-mm, 8-mm and 12-mm levels for analyses of the percentage of interfacial gaps, and area percentage of interfacial and intracanal voids, using scanning electron microscopy (SEM) to examine negative replicas of root sections. Data were analysed with parametric or non-parametric statistical methods at α = 0.05.

Results

Both micro-CT and SEM data indicated that canals obturated with GuttaCore core-carriers had the lowest incidence of interfacial gaps and voids, although the results were not significantly different from canals obturated by warm vertical compaction. Both the GuttaCore and the warm vertical compaction groups, in turn, had significantly lower incidences of gaps and voids than the cold lateral compaction group.

Conclusions

Because of the similarity in obturation quality between GuttaCore and warm vertical compaction, practitioners may find the GuttaCore core-carrier technique a valuable alternative for obturation of oval-shaped canals.

Clinical Significance

The quality of obturation achieved by GuttaCore in single-rooted canals is not significantly different from that achieved by warm vertical compaction.     

13例下颌前磨牙C形根管的锥束CT分析

目的：采用锥束CT（CBCT）分析下颌前磨牙C形根管形态。方法：选取13例22个下颌前磨牙C形根管患者的CBCT数据,使用NNT软件分析下颌前磨牙C形根管的形态、根面沟、根管分叉和双侧根管对称性。结果：下颌第一前磨牙根管C1型为23.8%、C2型61.9%、C3型14.3%,下颌第二前磨牙1例C3型。61.9%的下颌第一前磨牙C形根管在根中1/3分叉,下颌第二前磨牙在根冠1/3处根管分叉。下颌第一前磨牙C形根管对称率为61.5%,下颌第二前磨牙无对称性发生。结论：下颌前磨牙C形根管解剖结构复杂,CBCT可准确研究根管系统。     

BeeFill-TM-2in1热牙胶根充系统封闭能力的评价

目的评价BeeFill-TM-2in1热牙胶根充系统的根管封闭性能。方法选取50颗单根管离体前磨牙,沿釉牙骨质界截冠,用镍钛器械采用冠向下法进行预备,预备至统一标准。按随机数字表法分为2组:A组采用BeeFill-TM-2in1热牙胶根充系统进行充填;B组采用冷牙胶侧方加压充填技术进行充填。用亚甲基蓝染色,颊舌向纵切后,在根管显微镜下放大20倍后测量染料渗透长度。结果 A组根充后染料渗透长度平均为(0.78±0.13)mm,B组根充后染料渗透长度平均为(1.96±0.46)mm,两组差异有统计学意义(P<0.05)。结论 BeeFill-TM-2in1热牙胶根充系统对根管的封闭能力优于冷侧压法,适宜临床推广。     

The influence of root canal sealer on extended intracanal survival of Enterococcus faecalis with and without gelatinase production ability in obturated root canals

Enterococcus faecalis can survive for extended periods in obturated root canals. In this study, the hypotheses tested were that long-term survival of E. faecalis is dependent on (1) the type of endodontic sealer and (2) the capacity for microbial gelatinase activity, a potential "virulence" trait identified previously in clinical isolates. Root canals of extracted human canines (n=95) were inoculated with either E. faecalis OG1RF or its gelatinase-negative mutant E. faecalis TX5128. After 48 hours of incubation at 37 degrees C, canals were obturated with gutta-percha and either the epoxy-resin-based AH-Plus (Dentsply, De Trey, Konstanz, Germany), the silicone-based RoekoSeal (Coltène/Whaledent, Langenau, Germany), or zinc oxide eugenol-based Roth's sealer (Root Canal Cement Type 801; Roth International Ltd, Chicago, IL). Access cavities were sealed. After 8 months of incubation at 37 degrees C, viable E. faecalis was recovered from more teeth sealed with RoekoSeal (95%) compared with AH-Plus (40%) (p=0.0004, Fisher's exact test) and Roth's sealer (45%) (p=0.0012, Fisher's exact test). In the RoekoSeal groups, viable counts of E. faecalis OG1RF were higher than E. faecalis TX5128 (p=0.03, Mann-Whitney U test) suggesting that gelatinase activity plays a role in long-term survival of E. faecalis in obturated root canals.