Comparison of different techniques for obturating experimental internal resorptive cavities

Forty extracted maxillary central incisors were instrumented at the working length to a #50 file. The roots were sectioned transversely with a diamond disk at 7 mm from the anatomical apex. At the opening of the root canal of each section, hemicircular cavities were drilled with a specially designed bur. The corresponding root sections were cemented with glue, thus obtaining root canals with similar cavities that simulated internal resorptions. Teeth were embedded in plaster casts to facilitate their handling. The specimens were randomly separated into four groups of 10. The following obturation techniques were evaluated: lateral compaction (group A), hybrid technique (group B), Obtura II (group C), and Thermafil (group D). AH26 was used as the sealer. After obturation, the plaster was removed and the teeth were radiographed in buccolingual and mesiodistal directions to evaluate the quality of the obturation at the IRC. The incisors were then cut with a scalpel at the same level as the previous section, to examine, under a stereomicroscope, the type of material that filled the IRC. Obtura II gave the best results and in most of the specimens obturated with this technique, the IRC were filled mainly with gutta-percha. Statistical analysis of the data indicated that the differences between group C and the other groups were significant (P < 0.05).     

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.     

Stress distributions in internal resorption cavities restored with different materials at different root levels: A finite element analysis study

The aim of this study was to evaluate the stresses within simulated roots with internal resorption cavities at the apical, middle and coronal root levels, after obturation with gutta‐percha and/or MTA utilising finite element analysis (FEA). Mandibular premolar teeth with internal resorption cavities at different root levels were modelled. Models were restored with gutta‐percha and/or MTA. An oblique force of 300 N was applied and stress evaluations were carried out. In the MTA‐filled resorption models, the stresses were distributed more homogeneously than the gutta‐percha filled models, and the stress concentrations were lower in the remaining dentinal tissues. If the whole root is considered, the fully gutta‐percha‐filled models generated the highest stress values. Differences between the fully MTA‐filled models and hybrid techniques were present only in the apical resorption models. Both the MTA and combination of MTA and gutta‐percha can be suggested for use in clinical practice, in cases of internal root resorption cavity obturation.     

Evaluation of the anti‐resorptive ability of an experimental acetazolamide paste for the treatment of late replanted teeth: a study in rats

Abstract – When late replantation is performed, the root surface and root canal should be treated. Notwithstanding failures still occur, because of the high rates of root resorption, evidencing the need to search for substances that may inhibit root resorption. The acetazolamide is a known anti‐resorptive agent, and its use as root canal dressing may increase the success rates in the treatment of root resorption. Therefore, this study evaluated the effect of an acetazolamide paste used as root canal dressing in late replanted teeth. The study was conducted on 24 maxillary right incisors of rats, which were avulsed and divided in two groups. In group I, the teeth were kept dry for 30 min, had their root surfaces rubbed with a blade, and were treated with 2% sodium fluoride at pH 5.5 for 20 min; the root canals were instrumented and filled with acetazolamide paste; and then the teeth were replanted. In group II, the treatment was similar to group I, except for the root canal dressing, with utilization of calcium hydroxide in group II. At 15 and 60 days after replantation, the animals were killed and the specimens were processed in a histotechnical laboratory for microscopic and morphometric analysis. The results demonstrated the ability of both intracanal substances to limit root resorption, yet they were unable to completely inhibit the root resorption. Replacement resorption lacunae were present in greater proportion in group II, at 60 days. It was concluded that the acetazolamide paste was effective to limit the root resorption, being more effective in limiting the replacement resorption compared with calcium hydroxide.     

Quality of different gutta‐percha techniques when filling experimental internal resorptive cavities: A micro‐computed tomography study

The purpose of this ex vivo study was to determine the quality of root fillings in experimental internal resorptive cavities filled using cold lateral condensation (CLC), vertical condensation and Thermafil techniques. Forty‐five extracted maxillary canine teeth were selected. After root canal instrumentation, the roots were sectioned horizontally and experimental internal resorption cavities were prepared. The root sections were re‐approximated with a luting agent and randomly assigned to three groups (n = 15) to be filled using CLC, vertical condensation and Thermafil, respectively. Assessment of obturation quality in the internal resorptive cavity was performed using a desktop X‐ray micro focus computed tomography scanner, and the percentage of gutta‐percha (GP), sealer and voiding was calculated for each specimen. Data were statistically analysed using non‐parametric tests, with P < 0.05 denoting a statistically significant difference. Vertical condensation filled 96.25 ± 8.31% of the total artificial cavity, and was superior to CLC (63.20 ± 16.87%) and Thermafil (59.26 ± 18.47%). The mean percentage of voids was 3.75 ± 8.31% in the vertical condensation group, 37.09 ± 17.13% in the CLC group and 41.06 ± 18.60% in the Thermafil group. We conclude that obturation of experimental resorption cavities is significantly better when using vertical condensation than when using other GP‐based techniques.     

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.     

Effectiveness of different obturation techniques in the filling of simulated lateral canals

The purpose of this in vitro study was to evaluate the ability of lateral compaction of gutta-percha and of five thermoplasticized gutta-percha filling techniques to obturate simulated lateral canals. Sixty extracted single-rooted human teeth were instrumented at the working length to a #35 file before creating three simulated lateral canals on the mesial and distal surfaces of the root, one in each third, using a #15 engine reamer. After enlarging root canals to a #45 file, the teeth were randomly divided into six equal groups of 10 and obturated according to the following techniques: lateral compaction of gutta-percha (group A), hybrid technique (group B), Ultrafil (group C), Obtura II (group D), System B + Obtura II (group E), and Thermafil (group F). AH26 was used as the sealer. A greater number of simulated lateral canals were obturated when Ultrafil, Thermafil, and System B + Obtura II were used, in comparison with canals obturated with the hybrid technique, Obtura II, or lateral compaction of gutta-percha. This difference was statistically significant (p < 0.05). No statistically significant differences were found between results obtained in the obturation of simulated lateral canals in the different thirds of the root (p > 0.05).     

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.     

Effectiveness of hand and rotary instrumentation for removing a new synthetic polymer-based root canal obturation material (Epiphany) during retreatment

Aim To evaluate the effectiveness of hand and rotary instrumentation for removal of vertically compacted Epiphany and gutta‐percha during retreatment. Methodology Sixty extracted single‐rooted maxillary central incisors were enlarged to size 40 using FlexMaster instruments. The teeth were randomly divided into four groups of 15 specimens each. The canals of two groups were obturated using vertically compacted Epiphany. The others were filled with vertically compacted gutta‐percha and AH Plus sealer. One Epiphany group and one gutta‐percha group was reinstrumented with Gates Glidden burs and Hedström files. In the other two groups, obturation material was removed using Gates Glidden burs and RaCe rotary instruments. After clearing the roots, the area of remaining obturation material on the root canal wall was measured using a computer image analysis program. Statistical analysis was performed using Repeated Measures Analysis of Variance and anova . Results Retreatment of specimens obturated with gutta‐percha showed significantly more remaining obturation material than specimens filled with Epiphany (P < 0.05). No difference was found between the removal with Hedström files and with RaCe instruments (P > 0.05). Regarding the mean time of retreatment and time required for reaching the working length, Hedström files were significantly faster than RaCe instruments (P < 0.05). The times did not depend on the kind of obturation material (P > 0.05). Conclusions Vertically compacted Epiphany in combination with Epiphany Root Canal Sealant was removed more effectively than gutta‐percha and AH Plus sealer. Hedström files were more rapid than RaCe rotary instruments.     

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

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.     

Clinical and radiographic evaluation of root-canal obturation with obtura II

This study evaluated clinical and radiographic healing of 236 root-canal treatments in 131 cases obturated with the Obtura II system. One operator performed all canal preparation and obturation with sealer. A standardized apical-coronal preparation technique instrumented all canals. Clinical symptoms, periodontal condition, and radiographic findings were evaluated at 3, 6, and 12 months. Radiographs taken immediately postobturation were compared to recall radiographs. The level of the final root filling was classified as short (more than 2 mm short of the apex), flush (within 2 mm), or over (beyond) in 12.7%, 81.4%, and 5.9% of cases, respectively. More than 96% of cases were treated successfully by the Obtura II system. Where roots were filled flush, over, or short, lesions healed in 97%, 93%, and 93% of cases, respectively, with no significant differences (p < 0.05). Root filling excess had no impact on the healing process.     

Obtura Ⅱ热塑牙胶改良充填法的实验研究

目的探讨将常温流动牙胶充填术融入高温注射式热牙胶充填技术的可行性。方法 70颗单根管离体牙根管预备后随机分组,分别采用ObturaⅡ充填(A组)、Touch-heat+ObturaⅡ充填(B组)、GuttaFlow+ObturaⅡ充填(C组)、冷牙胶侧压充填(D组)、不做充填(E组),根充完成后修整所用充填根管内牙胶长度为10 mm,建立葡萄糖微渗漏模型,通过对葡萄糖定量分析检测根管充填后根尖部微渗漏,观察比较根尖封闭效果。结果各组葡萄糖微渗漏随观察时间延长持续增加,3组实验组微渗漏差异无统计学意义(P>0.05)。结论 GuttaFlow+ObturaⅡ充填法封闭效果可靠且操作易行,有一定的可行性。     

三种根管充填方法对下颌第一前磨牙根尖区侧枝根管充填效果的实验研究

目的:比较ObturaⅡ&SystemB与Thermafil对下颌第一前磨牙侧枝根管的充填效果。方法:通过光透射选出在根尖区具有侧枝根管的离体下颌第一前磨牙60个,运用TF锉进行根管预备后随机分为3组,分别在手术显微镜下采用ObturaⅡ&SystemB、Thermafil及冷牙胶侧方加压进行根管充填,在距根尖孔2 mm侧枝根管处作横断面切片,电子显微镜下观察并记录侧枝根管内的牙胶、糊剂及空隙占根管横断面的比例,分析不同充填方式对根尖区侧枝根管的充填效果。结果:两种热牙胶充填组在距根尖2 mm处侧枝根管的充填效果均明显优于冷侧压充填组(P<0.05);ObturaⅡ&SystemB充填组稍优于Thermafil充填组,但无统计学差异(P>0.05)。结论:采用ObturaⅡ&SystemB充填技术可有效封闭下颌第一前磨牙根尖区侧枝根管。     

Comparison of volumetric analysis of lateral compaction & three different vertically compacted thermoplasticized obturation techniques using spiral CT – An in vitro study

The objective of endodontic obturation is to provide a complete seal along the length of root canal system. This study was conducted to compare volumetrically, the laterally compressed gutta percha with three different vertically compacted thermoplasticized obturating systems using spiral CT, an in vitro study. Materials and methods included preparation of access cavities in 20 single rooted mandibular first premolars, followed by cleaning and shaping. Obturation was done with different thermoplasticized obturation systems: Group A – cold lateral; Group B – Calamus dual; Group C – E & Q Plus; Group D – Obtura II. Volume analysis was done using spiral computed tomography (CT). The percentage difference was calculated & statistically analyzed using one-way ANOVA and multiple comparisons between groups using Tukey's HSD test. The results of study has shown the statistical significance between all the groups with the p-value <0.0001. Multiple comparisons between different groups show statistical significance in all groups except Group C and Group D. With this significance in results, it can be concluded that Calamus dual showed the highest volume of obturation, followed by Obtura II and E & Q Plus. The least volume of obturation was observed in cold lateral condensation technique.     

Evaluation of dowel space preparation on the apical seal using an image processing system

The effect of post preparation on the apical seal of endodontically treated specimens was studied. The canals prepared in bovine bone were instrumented and obturated using five obturation techniques: the silver point technique, the lateral condensation of gutta-percha technique, the warm vertical condensation of gutta-percha technique, the Hygenic Ultrafil injection system and the Obtura technique. In addition to these five control groups, the five experimental groups were also subjected to post preparation. In the latter group, the gutta-percha was removed with an engine-driven root canal reamer 48 hours after obturation. Both the control and experimental groups were suspended in a 0.5 per cent crystal violet solution for 48 hours. After dye penetration, the specimens were immersed in liquid nitrogen and then split longitudinally. Linear measurements of the resultant apical dye leakage were determined by image processing. For each obturation technique, all specimens in both the control and experimental groups were recorded if they showed leakage. Using Fisher's exact probability test, it was shown that there was no significant difference between the obturation techniques used.     

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.     

Effectiveness of gutta-percha and Resilon in filling lateral root canals using the Obtura II system

The aim of this study was to evaluate the effectiveness of gutta-percha and Resilon in filling lateral root canals by using the Obtura II system. Root canals of artificial teeth were prepared using a standard protocol, and lateral canals were made in three thirds of the root canal. The root canals were filled with either Obtura gutta-percha (OB), Endo-points flow gutta-percha (ED), or Resilon (RE) by using the Obtura II system. The fillings were evaluated using digitized radiographs and analyzed by using Image Tool software. Outlines of the total areas of the lateral canals and the filled areas were used to determine the percentage of filling in each lateral canal. Data were analyzed with the Kruskal-Wallis and Dunn tests at a 5% significance level. RE and ED showed better results than OB did in the three thirds of the root canals. When the root canal thirds were compared, OB and RE were more effective in the cervical third than in the apical third (p < 0.05). In conclusion, Resilon and EndoFlow gutta-percha were effective in filling lateral canals by using the Obtura II system.     

Effectiveness of different gutta-percha techniques when filling experimental internal resorptive cavities

Aim To determine the quality of root fillings in teeth with artificial internal resorptive cavities filled with Thermafil, JS Quick‐Fill, Soft Core, System B and Microseal, and by cold lateral compaction (LC) technique. Methodology Sixty maxillary incisor teeth were selected. After access cavity preparation and root canal instrumentation, the roots were sectioned horizontally and artificial internal resorption cavities were prepared on the canal walls. The tooth sections were cemented together and the root canals were filled using one of six different techniques: Thermafil, JS Quick‐Fill, Soft Core, System B and Microseal, and by LC. The roots were then divided at the level of the previous section and each root surface was photographed. Image analysis program was used to calculate the percentage of sealer, gutta‐percha and void in the internal resorptive cavities. All measurements were analysed statistically using One‐way anova and Newman–Keuls tests. Results The Microseal technique filled 99% of the artificial resorptive area followed by LC (92%), SystemB (89%), Quick‐Fill (88%), Thermafil (74%) and Soft‐Core (73%). Warm gutta‐percha compaction techniques filled the resorption areas with more gutta‐percha than sealer (Microseal 68%, System B 62%) compared to the other techniques (LC 48%, Quick Fill 41%, Soft Core 34%, Thermafil 35%). In addition, core techniques left a considerable volume of voids in the resorptive areas (Quick‐Fill 12%, Thermafil 26%, Soft Core 27%). Conclusions Warm gutta techniques filled artificial resorption cavities significantly better than the other gutta‐percha techniques.     

四种根管充填法对根管密合度的实验研究

目的：使用新型根管糊剂，比较四种充填方法对根管密合度的影响，从而指导临床根管充填法的选择。方法：在离体前牙上行根管预备及根管充填，而后用印度墨水染色法在显微镜下比较充填效果。结果：显微镜下观察糊剂加牙胶的侧方加压充填法组和单纯使用糊剂的机用螺旋充填法组有较好的封闭性能。结论：本实验为新型糊剂的合理应用提供了可靠的参考依据。     

Evaluation of intracanal sealer distribution with 5 different obturation techniques.

OBJECTIVE: The aim of this study was to determine the distribution patterns of sealer relative to the gutta-percha and the canal wall following the use of different obturation techniques: vertical condensation, Obtura II, System B, SimpliFill, and Thermafil Plus; lateral condensation was used as a comparison. METHODS AND MATERIALS: One hundred five extracted single-rooted teeth were divided into 5 groups of 20 according to obturation technique, with 5 in the lateral condensation group. Instrumentation technique and sealer selection were based on the manufacturer's recommendations. Following obturation, teeth were stored for 4 months at 37 degrees C in 100% humidity. Roots were split longitudinally and halves were examined under a stereomicroscope (x 10) to determine the amount of sealer coverage between the gutta-percha and canal wall. Coverage was categorized as slight (0 to 1/3), low partial (1/3 to 2/3), high partial (2/3 to 9/10), and complete (9/10 to 10/10). RESULTS: Different techniques showed different patterns, but no obturation technique had sealer forming a continuous layer between the gutta-percha and canal wall. The vertical condensation group generally had low partial coverage. Obtura II was the only group to have slight coverage, which occurred in the coronal half. Coronal and apical halves in both the System B and Thermafil Plus groups had the most samples with high partial coverage. SimpliFill had the most samples with complete coverage in both the coronal and the apical portions. All lateral condensation samples showed low partial coverage. CONCLUSION: Sealer distribution patterns were incomplete and inconsistent, regardless of the obturation technique. No technique had sealer forming a continuous layer between the gutta-percha and canal wall.