Homogeneity and adaptation of a new gutta-percha paste to root canal walls

A new flowable root canal filling material (GuttaFlow) was tested. Under simulated clinical conditions, the middle and coronal thirds of 90 human teeth with 169 root canals were shaped with 6% taper rotary HERO instruments and the apical third with rotary LightSpeed instruments. The root canals were divided into three similar groups and were filled with GuttaFlow (GF), conventional cold laterally condensed gutta-percha (LC), and warm vertically condensed gutta-percha (VC). Roots were sectioned at five levels, digitally photographed and traced. The percentage of voids area showed a statistically significant difference between GF and both LC and VC [GF 1.9% (95% CI = 1.4-2.4), LC 4.4% (95% CI = 2.2-6.6), VC 6.8% (95% CI = 5.4-8.1)]. The frequency of voids was significantly different between all groups [GF 37% (95% CI = 34%-40), LC 10% (95% CI = 8-12), VC 22% (95% CI = 19-24)]. In most sections, GuttaFlow completely filled the prepared root canal, but small voids were frequently present within the core of the filling material.     

三种根管充填技术根管系统充盈致密度的实验观察

目的 比较3种根管充填技术对根管系统充盈的致密度,以期为临床提供参考.方法 将57颗去除牙冠、预备好的上、下颌前磨牙按随机数字表法分为3组,每组19颗牙,其中单根管牙10颗,双根管牙9颗.分别采用常温流动牙胶技术又称GuttaFlow技术(GF组)、冷侧压技术(LC组)、热垂直加压技术(VC组)充填根管.使用Leica SP 600切片机自冠方向根尖每间隔1 mm垂直于牙长轴制备牙根横断面切片,每个切片可有冠方和根方两个截面作为研究的观测面,GF组的切片截面数为363个,LC组为361个,VC组为355个.用ZOOM-630连续变倍立体显微镜放大45倍观测切片截面上根充物中的空隙.结果 ①空隙发生率:VC组为21.4%(76/355),显著低于GF组(47.7%,173/363)和LC组(52.6%,190/361),P＜0.0167;GF组与LC组相比差异无统计学意义(P＞0.0167);②空隙面积百分比:3组有空隙切片截面的空隙面积百分比的中位数GF组为2.67,LC组为1.55,VC组为1.01,经非参数检验GF组显著高于VC组、LC组(P=0.000,P=0.008),而VC组与LC组的差异无统计学意义(P=0.076);③根管峡部的充盈完好率:VC组充盈完好率为86%(85/99),显著高于GF组(55%,43/78)和LC组(58%,49/84),P＜0.0167;GF组和LC组相比差异无统计学意义(P＞0.0167).结论 VC组根管系统充盈的致密度最高,优于LC组与GF组.     

Comparison of the area of resin-based sealer and voids in roots obturated with Resilon and gutta-percha

The aim of this study was to compare the cross-sectional area of sealer plus voids of Epiphany sealer surrounding root fillings completed with Resilon cones and laterally compacted gutta-percha. The root canals of extracted human mandibular premolars were prepared to a final size of 40 (0.06 taper). The teeth were then randomly assigned into 2 groups (n = 12/group) for the filling procedures in conjunction with Epiphany sealer: group 1, Resilon cones, and group 2, gutta-percha. Horizontal sections were obtained every 1 mm up to 5 mm from the apical foramen. The sections were digitally photographed under magnification, and the cross-sectional area of the root canal and the area occupied by the sealer and voids were calculated, after which statistical comparisons were made. No differences were found between the sealer plus void or void area of Resilon or gutta-percha groups at any level of sectioning (P > .05). Comparisons within each obturation group showed that there was no significant difference between any level of sectioning with regard to the ratio of sealer plus void area or void area to that of the root canal (P > .05). Within the experimental conditions of the present study, both obturating techniques with the Epiphany sealer exhibited similar amounts of sealer and void area, regardless of the apical level of sectioning compared.     

Comparison of cold lateral compaction and continuous wave of obturation techniques following manual or rotary instrumentation

AIM: To compare different combinations of root canal preparation and obturation technique. METHODOLOGY: A total of 48 freshly extracted human maxillary central incisors were divided into two identical groups on the basis of root canal length and apical diameter. The root canals were prepared by manual crown-down pressureless technique or with a rotary system (ProFile; Dentsply Maillefer, Ballaigues, Switzerland) in a crown-down technique. The coronal diameter and apical size of the root canals were standardized in both preparation techniques. Each main group was then divided into two subgroups and obturated with either cold lateral compaction or continuous wave of obturation with System B (EIE-Analytic Technology, Orange, CA, USA). The distribution of filling material in each canal was assessed by stereomicroscopic examination of eight cross-sections on each tooth. Areas of sealer, gutta-percha and voids were measured on the digital images of a total of 384 samples. Manipulation time and apical extrusion for each group was also determined. Data were statistically analysed using Kruskal-Wallis, anova (Bonferroni/Dunn) or Student's t-test. RESULTS: The percentage of sealer, gutta-percha and voids area between the obturation techniques was not significantly different (P > 0.05). Continuous wave groups had significantly more apical extrusion of sealer (P < 0.05), while none of the obturation techniques had gutta-percha extrusion. Rotary instrumentation was significantly faster than the manual technique (P < 0.05); continuous wave obturation was significantly faster than lateral compaction (P < 0.05). Total manipulation time in the rotary/continuous wave group was significantly shorter than the other groups (P < 0.0001). CONCLUSION: The distribution of filling materials was similar in all combinations of instrumentation and obturation techniques. The continuous wave technique was faster than lateral compaction and it extruded more sealer.     

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.     

Assessment of different gutta-percha brands during the filling of simulated lateral canals

AIM: To compare the ability of five different commercially available gutta-percha points to fill simulated lateral canals when subjected to warm vertical compaction. METHODOLOGY: Fifty clear plastic teeth with a lateral canal in each third of the root were used. All teeth were filled using warm vertical compaction. Backfilling was completed with a sealer and the same gutta-percha point used during the apical condensation. After this, they were horizontally sectioned using a diamond disc adapted to a low-speed saw. The resulting sections were embedded in epoxy resin. The extent of gutta-percha and sealer filling were measured in each lateral canal using an IMAGE-PRO 4.0 software system. The voids in each canal were measured using the same system. Data were ranked and analysed using the Kruskal-Wallis statistical test. RESULTS: The mean percentage of the three lateral canals filled with gutta-percha and sealer were respectively: Konne (68.23% and 24.50%), Analytic (67.90% and 25.28%), Obtura (63.80% and 29.60%), Tanari (49.42% and 45.86%) and Dentsply (44.60% and 47.05%). There was significantly (P < 0.05) more gutta-percha in the lateral canal filled with Analytic, Obtura and Konne points than with Tanari and Dentsply points. CONCLUSIONS: The brand of gutta-percha cone had an influence on the length of filling within lateral canals. This may be a reflection of the chemical formulation of the gutta-percha points.     

In vivo performance of the new non-instrumentation technology (NIT) for root canal obturation

AIM: The aim of this in vivo study was to compare the radiographic quality of root fillings performed by the NIT-obturation method versus conventional mechanical obturation. METHODOLOGY: Sixty-six patients needing root canal treatment participated in this study. The treatments were performed by three private practitioners. The root canals were instrumented with K-Flexofiles to a master apical file between sizes 25 and 60, followed by step-back flaring up to size 70. Copious irrigation was used throughout the instrumentation procedure with NaOCl (3%). The teeth were obturated either by lateral condensation, the McSpadden technique (control) or by the new non-instrumentation technology (NIT) with and without using gutta-percha points. In the NIT method, a low pressure was created within the tooth, and AH 26 sealer was sucked into the root canal system. Radiographs of the root-filled teeth were analysed and the length of the root filling, the presence of voids and the area of any other fillings determined. RESULTS: The root canal fillings of the control group (0.1 +/- 0.1 mm) and those of the NIT/gutta-percha group (0.3 +/- 0.1 mm) were both overextended when taking the apical constriction as a reference point. Root canal fillings of the NIT/gutta-percha group were statistically (P < 0.05) significantly longer than those of the NIT without gutta-percha group. The latter showed slightly underextended root canal fillings (-0.14 +/- 0.1 mm). CONCLUSIONS: The present investigation demonstrated the performance of the NIT-obturation method in vivo. Root canals filled by the reduced-pressure-method using sealer combined with gutta-percha cones exhibited equivalent radiographic quality compared to conventionally filled canals.     

Comparison of the obturation of lateral canals by six techniques.

The following obturation techniques were compared on their ability to obturate lateral canals in vitro, lateral condensation (LC), continuous wave of condensation (CW), warm vertical condensation (WV), carrier-based thermoplasticized gutta-percha (CB), warm lateral condensation (WL), and vertically condensed high-temperature gutta-percha (HT). A root canal system with lateral canals in the coronal, middle, and apical thirds was prepared in resin blocks. Each block was obturated using each technique (n = 30, 15 each, with and without sealer). The length of gutta-percha and sealer in each of the lateral canals was measured with a measuring microscope and statistically compared. All techniques obturated all three levels of lateral canals with sealer. WV, CB, and CW were able to fill the lateral canals with gutta-percha significantly better when root canal sealer was used. WV, CB, CW, and HT filled the coronal and middle lateral canals significantly better with gutta-percha than LC or WL condensation. CB and CW filled the apical lateral canal significantly better with gutta-percha than HT, WV, WL, or LC.     

The quality of root fillings remaining in mandibular incisors after root-end cavity preparation

AIM: The aim of this study was to determine the quality of root fillings remaining in mandibular incisors after root-end resection and root-end cavity preparation. METHODOLOGY: Roots of 40 mandibular incisors,12 mm in length, were divided into two groups and instrumented using a balanced force technique and obturated by vertically compacted warm gutta-percha. In one group sealer was used when back-filling the root canal with the Obtura System. The other group was also back-filled with the Obtura System but without sealer. The apical 4 mm of each root filling was removed by root-end resection and root-end cavity preparation. Fluid transport along the 7 mm of remaining root filling was measured. After the leakage test, horizontal sections were cut at a level 3 mm from the apical end of the remaining root filling. The cross sectional area of the canal and gutta-percha was measured using an image analysis program. The quality of the remaining root fillings was also evaluated by calculating the percentage of gutta-percha filled canal area. RESULTS: In total, 27 (67%) out of the 40 roots demonstrated leakage. No significant difference was found between the two groups (P = 0.265). In the cross-sections the bucco-lingual canal diameter was up to 2.6 mm long (mean 1.6 mm). The average percentage of gutta-percha filled canal area was 85.6%. Warm gutta-percha could not obturate areas where debris remained after instrumentation. CONCLUSIONS: The quality of the root fillings in mandibular incisors was poor, probably because the unprepared recesses of oval canals were not clean.     

Root canal obturation by ultrasonic condensation of gutta-percha. Part II: an in vitro investigation of the quality of obturation

AIM: To compare the quality of root canal obturation using ultrasonic or cold condensation of gutta-percha and to determine the effect of power setting and activation time on the quality of obturation using the former technique. METHODOLOGY: An extracted human maxillary canine was used in an in vitro split tooth model to allow repeated obturation of the same root canal system using an ultrasonic device to thermocompact gutta-percha without sealer. After each obturation, the root filling was removed from the tooth to allow evaluation of its quality and for the tooth to be re-obturated. The influence of combinations (n = 10 per combination) of power setting (1, 3, 5) and activation times (4, 10, 15 s) was tested on the quality of root filling, assessed by measuring the voids within the body of the root filling as well as at the surface. Image analysis was used to quantify the voids within the body of the root filling. Cold lateral condensation of gutta-percha served as a control. RESULTS: Both surface and cross-sectional analyses revealed that different power setting and activation time combinations produced significantly fewer voids than cold lateral condensation (P < 0.05) at the apical, mid-root and coronal levels. CONCLUSIONS: Taking surface and cross-sectional analysis together only power setting 5 and activation times of 10 and 15 s consistently produced ultrasonically thermocompacted root canal fillings with fewer voids than cold lateral condensation without sealer.     

Evaluation of Root Canal Obturation: A Three-dimensional In Vitro Study

The aim of the study was to measure percentage of volume of voids and gaps in root canals obturated with different obturation materials by using micro–computed tomography (micro-CT). Forty-eight single-rooted teeth were collected and decoronated, and root canals were prepared by using rotary files. The roots were randomly allocated into 4 groups, and each group was obturated by using cold lateral compaction with a different material (gutta-percha and TubliSeal sealer, EndoRez points and EndoRez sealer, RealSeal points and RealSeal sealer, and a gutta-percha point and GuttaFlow sealer). Roots were scanned with micro-CT, and volume measurements for voids and gaps in the obturated roots were carried out by using specialized CT software. Percentage of gaps and voids was calculated. Statistical analysis showed that gutta-percha exhibited an overall significantly lower percentage (1.02%) of voids and gaps. The present study showed that none of the root canal filled teeth were gap-free. Roots filled with gutta-percha showed less voids and gaps than roots filled with the remaining filling materials.     

Comparison of MicroSeal and System B/Obtura II obturation techniques

AIM: To compare the proportion of gutta-percha, sealer and voids following the filling of simulated root canals in plastic blocks using two warm gutta-percha techniques. METHODOLOGY: Ten simulated root canals in plastic blocks were prepared using System GT Rotary Files and a.02 taper size 40 Quantec rotary nickel-titanium instrument and then filled with MicroSeal and Kerr EWT sealer. A further 10 simulated canals were prepared solely with System GT Rotary Files and obturated with System B/Obtura II and Kerr EWT sealer. All blocks were sectioned at 1 mm intervals. The sectioned root fillings were photographed through a stereomicroscope and the resultant slides scanned. The images were analysed using adobe photoshop 6.0 to give the proportions of gutta-percha, sealer or void at each level. The data were analysed using unpaired Student's t-test and Mann-Whitney U-test. RESULTS: The MicroSeal technique produced a dense homogeneous gutta-percha fill at the apical 1 and 2 mm levels similar to the System B/Obtura II technique, but further coronally the sealer became mixed into the MicroFlow gutta-percha producing a heterogeneous mass with significantly less (P < 0.05) solid gutta-percha in the root filling compared to System B/Obtura II. The MicroSeal technique generally had more pooling of cement than the System B technique, however, this was only significantly different (P < 0.05) at the 4 mm level. The System B/Obtura II obturation gave an average of 99.27% +/- 1.09 gutta-percha fill at all levels. CONCLUSIONS: The MicroSeal technique produced a heterogeneous fill consisting of the MicroFlow Master Cone and gutta-percha from the MicroFlow Cartridge mixed with sealer. The System B/Obtura II technique produced a homogeneous fill at all levels.     

Ex vivo study of the efficacy of H-files and rotary Ni-Ti instruments to remove gutta-percha and four types of sealer

AIM: To compare the efficacy of ProFile rotary Nickel-Titanium (Ni-Ti) instruments and Hedstroem-files (H-files) combined with Gates-Glidden (GG) drills during removal of gutta-percha root fillings used in combination with one of the four representative sealers. METHODOLOGY: Forty-eight single-rooted human teeth, with fully formed apices and straight root canals were used. The root canals were accessed and instrumented using a stepback technique with H-files. They were randomly assigned to four groups and subsequently filled with a combination of lateral and vertical condensation of gutta-percha and one of the following sealers: Roth 811, AH26, Endion and Roekoseal. The root fillings were removed 1 year later, using either H-files in combination with GG drills or the ProFile Ni-Ti system. Teeth were then grooved longitudinally and split. The amount of gutta-percha and sealer remaining on the root canal walls was traced and scored visually with the aid of a stereomicroscope. The scores were analysed and statistically compared with the Kruskal-Wallis test between the ProFile and H-file groups, as well as among the four sealer subgroups. Two samples from each group were studied under the scanning electron microscope to enhance inspection of canal walls and remaining material. RESULTS: Sealer remnants were observed with both techniques mainly in the middle and apical third of the root canal. The ProFile system and the H-files were associated with similar amounts of remaining filling material (P > 0.05). In the cervical third of the root canal all sealer remnants were removed with both techniques. In the middle and apical third AH26 was associated with a statistically significant greater quantity of remnants on the root canal walls with both removal techniques (P < 0.05). Endion, Roth 811 and Roekoseal were associated with approximately the same amount of filling material in the middle third of the root canal (P > 0.05), whereas in the apical third Endion was associated with significantly more remnants of filling material than the other two sealers with either ProFile or H-files (P < 0.05). CONCLUSIONS: None of the methods used for the removal of root fillings was totally effective, especially in the apical third of the root canal.     

In vitro analysis of thermocompaction time and gutta-percha type on quality of main canal and lateral canals filling

The aim of this study was to evaluate the quality of filling in main and lateral root canals performed with the McSpadden technique, regarding the time spent on the procedure and the type of gutta-percha employed. Fifty simulated root canals, made with six lateral canals placed two apiece in the cervical, middle and apical thirds of the root, were divided into 5 groups. Group A: McSpadden technique with conventional gutta-percha, performed with sufficient time for canal filling; Group B: McSpadden technique with conventional gutta-percha, performed in twice the mean time used in Group A; Group C: McSpadden technique with TP gutta-percha, performed with sufficient time for canal filling; Group D: McSpadden technique with TP gutta-percha, performed in twice the mean time used in Group C; Group E: lateral condensation technique. Images of the filled root canals were taken using a stereomicroscope and analyzed using the Leica QWIN Pro software for filling material flow, gutta-percha filling extension and sealer flow. Data were analyzed by analysis of variance (ANOVA) and Tukey test (p < 0.05). The best values of penetration in lateral canals in the middle third occurred in the groups where TP gutta-percha was used. However, in the apical third, group B showed the best values. Although a longer time of compactor use allows greater penetration of the filling material into the lateral canals, the presence of voids resulted in bad quality radiographic images, suggesting porosity. The best quality of filling material was observed in Group A (McSpadden technique with conventional Gutta-Percha, performed with sufficient time for root canal filling).     

Ex-vivo area-metric analysis of root canal obturation using gutta-percha cones of different taper

Aim  To evaluate the percentage of gutta-percha and sealer-filled canal area when four different types of master gutta-percha cones were used.
Methodology  Sixty mandibular premolars with straight canals were instrumented using System ProTaper rotary instruments with a crown-down technique and assigned to four groups. Canals were obturated with AH-26 sealer either using lateral condensation and 0.02 taper gutta-percha cones (group A), 0.04 taper gutta-percha cones (group B), nonstandardized F- medium (group C) master gutta-percha cones, or a single System ProTaper gutta-percha cone (group D). The percentage of gutta-percha and sealer-filled area was calculated in horizontal sections of the apical portion of each canal, using image analysis software. The data was statistically analysed using Kruskal–Wallis test.
Results  The distribution of filling materials amongst groups was not significantly different at each level of sectioning ( P  > 0.05).
Conclusion  The percentage of gutta-percha and sealer-filled canal area was similar when canals were filled with different master cones using lateral condensation or single cone techniques.     

Qualitative evaluation of two endodontic obturation techniques: tapered single-cone method versus warm vertical condensation and injection system: an in vitro study

Forty two single-rooted teeth, prepared with the Mtwo system, were divided into three groups based on the filling method: control, "Single-cone" (n = 20) (Mtwo gutta-percha single-cone tapered according to the diameter, length and conicity of the preparation) and "Combined system" (n = 20) (BeeFill 2in1). The parameters studied were apical leakage, gutta-percha adjustment, number of voids, presence/absence of sealer, root canal morphology, residual fragments, and filling of lateral/accessory canals. A dye penetration test was carried out (methylene blue). The teeth were embedded in resin, cut transversally and observed. The data were analyzed with non-parametric Mann-Whitney and Spearman tests. Comparative tests between the two groups showed that the "Combined system" was superior in terms of apical leakage (P < 0.01), gutta-percha adjustment (P < 0.05) and filling of lateral/accessory canals (P < 0.05). There were statistically significant correlations between master cone adjustment and root canal morphology (P < 0.01) in the "Single-cone" group. In the "Combined system" group, a relation was observed between the voids and root canal morphology (P < 0.05) and between voids and residual fragments (P < 0.05). The quality of obturation with warm gutta-percha was better than that of the tapered single-cone technique. Root canal morphology influences gutta-percha adjustment. Residual fragments on the root canal reduce sealing ability.     

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 new adhesive root canal filling materials measured by new dye penetration method

The sealing ability of new adhesive root canal filling materials was evaluated using a new dye penetration method. Twenty-eight single-rooted mandibular premolars were randomly divided into four groups of seven teeth each and filled by lateral condensation using one of these combinations: Resilon point with Epiphany sealer (RE); gutta-percha point with Sealapex sealer (GS); gutta-percha point with dentin activator and Superbond sealer (GDS); or gutta-percha point with Accel primer, dentin activator, and Superbond sealer (GADS). Amount of 0.06% methylene blue dye solution (MB) that leaked from the coronal portion to the apical area was measured with a spectrophotometer at one, four, eight, 15, and 30 days in an accumulative manner. The total amount of leaked MB on day 30 was significantly higher for GDS than the other combinations (p < 0.05).     

5种根管充填糊剂的根管封闭能力的比较

目的：比较5种根管充填糊剂的根管封闭能力。方法：选择75个直根管的恒牙,经开髓拔髓,Mtwo镍钛根管器械预备后反复冲洗后随机分为5组,分别采用实验组1：氧化锌丁香油糊剂,实验组2：Endomethasone根管充填糊剂,实验组3：Cortisomol根管充填糊剂,实验组4：Vitapex糊剂,实验组5：AH-plus糊剂,加牙胶尖严密充填。将所有离体牙置于37℃,100%湿度的恒温箱3d后选用透明牙染色法测量微渗漏深度。结果：实验组1：（2.35±0.768）mm,实验组2：（1.78±0.548）mm,实验组3：（1.54±0.322）mm,实验组4：（3.22±0.452）mm,实验组5：（0.98±0.536）mm。各组微渗漏深度值差异有显著性（P〈0.05）。其中实验组4的微渗漏值显著高于其他各组（P〈0.05）,实验组5的微渗漏值显著低于其他各组（P〈0.05）,实验组2的微渗漏值稍高于实验组3,结果无显著差异。结论：在Mtwo镍钛器械预备下,AH-Plus糊剂充填根管可有效的减少根管微渗漏的发生,但长远疗效有待进一步的观察。