Effect of three different sealers on the sealing ability of both thermafil obturators and cold laterally compacted Gutta-Percha

Thermal, chemical and physical analysis of VDW.1Seal, Fill Root ST, and ADseal root canal sealers

This study aimed to evaluate the thermal, chemical, and physical properties of VDW.1Seal, Fill Root ST, and ADseal sealers. Thermal properties were analyzed using Thermogravimetric analysis (TGA) and Differential thermal analysis (DTA). Attenuated total reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR) analysis was performed as a complementary test to confirm TGA/DTA analysis. The chemical composition of the set sealer material was identified using an X-ray powder diffraction (XRD) system. Other physical properties of each sealer were investigated; ten specimens were used to measure the solubility (at 24 h and 28 days), and another ten specimens were used to assess pH changes and calcium ion release (after 7 and 14 days). Film thickness was done according to ISO 6876 specs. The data were analyzed using the two-way ANOVA test. Results showed that for all sealers, TGA analysis revealed a direct relationship between sealer mass loss and temperature rise. In addition, the decomposition of the tested sealers started at 145 °C, 135 °C and 91 °C for VDW.1Seal, ADseal sealer, and Fill Root ST, respectively. XRD analysis revealed a higher degree of crystallinity for VDW.1Seal and ADseal. ADseal showed the least solubility; VDW.1Seal exhibited the highest alkalinity, calcium ion release, and the lowest film thickness.

A Review of the research methods and progress of biocompatibility evaluation of root canal sealers

The function of root canal sealer was to achieve an appropriate three-dimensional filling effect by filling the root canal and some irregular lumen, thereby inhibiting the residual bacteria. There were many types of sealers, but research to find the most suitable ones was still ongoing. In recent years, researchers had continuously improved the performance of sealers by developing new sealers or adding active ingredients to the sealers. However, most sealers exhibit varying degrees of cytotoxicity and tissue responses, which affect clinical therapy efficacy. This review describes different technical approaches, and recent research progress in the biocompatibility evaluation of root canal sealers and provides brief insights into this field by summarising the performance studies of different root canal sealers.

Biological Evaluation of the Effect of Root Canal Sealers Using a Rat Model

Gutta-percha points and root canal sealers have been used for decades in endodontics for root canal obturation. With techniques such as single cone methods, the amount of sealer is larger, making their properties more critical. However, relatively few reports have comprehensively evaluated their biological effects. To this end, we evaluated three types of sealers, zinc oxide-fatty acid-, bio-glass- and methacrylate resin-containing sealers were considered. Their biological effects were evaluated using a rat subcutaneous implantation model. Each sealer was loaded inside a Teflon tube and implanted subcutaneously in the backs of rats. Inflammatory cells were observed around all samples 7 days after implantation and reduced after 28 days. Our results revealed that all samples were in contact with the subcutaneous tissue surrounding the sealer. Additionally, Ca and P accumulation was observed in only the bio-glass-containing sealer. Furthermore, each of the three sealers exhibited unique immune and inflammatory modulatory effects. In particular, bio-glass and methacrylate resin sealers were found to induce variable gene expression in adjacent subcutaneous tissues related to angiogenesis, wound healing, muscle tissue, and surrounding subcutaneous tissue. These results may help to understand the biological impacts of root canal sealers on surrounding biological tissues, guiding future research and comparisons with new generations of materials.

Coronal and apical leakage among five endodontic sealers

PURPOSE

The aim of this study was to use dye penetration to measure apical and coronal leakage simultaneously in single-canal teeth that had been treated endodontically using a single-cone obturation technique.

METHODS

One hundred single-canal, extracted human teeth were cleaned and shaped with ProTaper NEXT rotary files to size-X5 (50/.06), then randomly assigned to five sealer groups for single-cone gutta-percha obturation. The teeth were soaked in 0.6% rhodamine B at 37°C for seven days, then the roots were ground mesiodistally and the maximum apical and coronal dye penetration was measured. Differences in leakage among the sealer groups were examined using the Kruskal-Wallis test. Pairwise comparisons were made using the Mann-Whitney test with Bonferroni correction.

RESULTS

The mean values (mm) of dye penetration for AH Plus, Pulp Canal Sealer, NeoSEALER Flo, EndoSequence BC, and Super-Bond RC Sealer were 0.200, 0.300, 0.675, 0.850, and 0.900 apically, whereas 1.675, 2.075, 4.800, 6.500, and 4.125 coronally. Pairwise comparisons showed significant apical differences between AH Plus/Super-Bond RC Sealer (P = 0.047) and significant coronal differences between AH Plus/NeoSEALER Flo (P = 0.001), AH Plus/EndoSequence BC (P < 0.01), AH Plus/Super-Bond RC Sealer (P < 0.01), Pulp Canal Sealer/NeoSEALER Flo (P = 0.010), Pulp Canal Sealer/EndoSequence BC (P < 0.01), and Pulp Canal Sealer/Super-Bond RC Sealer (P < 0.01).

CONCLUSION

Coronal leakage was worse than apical leakage for all sealers. AH Plus exhibited the least leakage apically and coronally; Super-Bond RC Sealer showed the most leakage apically, and EndoSequence BC showed the most leakage coronally.

Complete Obturation-Cold Lateral Condensation vs. Thermoplastic Techniques: A Systematic Review of Micro-CT Studies

To prevent re-infection and provide a hermetic seal of the root canal system, an endodontist must aim to produce a void-free obturation. This review aimed to compare the completeness of root canal obturation between the two most prevalent methods-cold lateral condensation and warm gutta-percha techniques-using micro-CT (PROSPERO reg no. 249815).

MATERIALS AND METHODS

A search of Scopus, Embase, PubMed (Medline via PubMed), and Web of Science databases was done without any time restriction according to the PRISMA protocol. Articles that compared both techniques and were published in English were included. Data was extracted and the risk of bias was assessed using an adapted tool based on previous studies.

RESULTS

A total of 141 studies were identified by the search. Following the screening and selection of articles, 9 studies were included for review. Data was extracted manually and tabulated. Most studies had a moderate risk of bias. None determined operator skill in both methods before comparison. The data extracted from the included studies suggests that both techniques produce voids in the obturation. The thermoplasticized gutta-percha techniques may result in fewer voids compared to cold lateral condensation.

CONCLUSION

Considering the limitations of the included studies, it was concluded that neither technique could completely obturate the root canal. Thermoplasticized gutta-percha techniques showed better outcomes despite a possible learning bias in favor of cold lateral condensation. Establishing operator skills before comparison may help reduce this bias.

Cytotoxic effects of four different root canal sealers on human osteoblasts

The aim of this study was to evaluate the effect of an epoxy resin-based (AH-Plus), a zinc oxide eugenol containing (Pulp-Canal-Sealer) and two calcium silicate containing (MTA-Fillapex and BioRoot-RCS) sealers on primary human osteoblasts (hOB) in freshly mixed and set state. All sealers were mixed strictly according to the manufacturers´ instructions and identically samples were produced. In a pretest cytotoxic sealer concentrations were determined. Thus, for the main cell culture study, dilutions of sealer extract 1:1, 1:2, and 1:10 were used. To simulate a clinical scenario, extracts from freshly mixed sealer were added to the cells on day one. Extracts form set sealers were used for subsequent culturing for 24h, 7d, 14d, and 21d. Cell viability was analyzed by living-cell-count, MTT-assay, and living/dead-staining, cytotoxicity by LDH-assay, and changes by Richardson-staining. All data were statistically evaluated by one way ANOVA and a posthoc analysis with Bonferroni-Holm testing (p<0.05). AH-Plus was cytotoxic in a freshly mixed state, but not when the sealer was set. MTA-Fillapex and Pulp-Canal-Sealer were cytotoxic in a fresh as well as in a set state. BioRoot-RCS showed the lowest toxicity in both states; where as a regeneration of the cells could be observed over time (p<0.05). Contact of freshly mixed AH-Plus to osteoblasts should be avoided. Pulp Canal Sealer and MTA-Fillapex showed no biocompatibility in contact with osteoblasts at all. BioRoot-RCS had a positive influence on the cell metabolism (bioactivity) and is biocompatible.

Importance and methodologies of endodontic microleakage studies: A systematic review

INTRODUCTION

It is very important to obtain a tight seal in obturated root canal, making it necessary to conduct clinical or laboratory studies on the sealability of endodontic materials. Different methodologies have been historically used to assess microleakage of different endodontic materials. The aim of the present study was to comprehensively review different material testing methods used in microleakage studies, their interpretation and importance in endodontic literature.

MATERIAL AND METHODS

A systematic search was conducted in Medline, Cochrane, and Web of Science databases. In addition, the reference lists of review articles on the topic were searched. No language restriction was applied. Two independent reviewers screened the article.

RESULTS

Microleakage is considered the single most important risk factor responsible for apical periodontitis. Dye penetration, dye diffusion, bacterial and endototoxin infiltration, fluid filtration, glucose, caffeine and protein infiltration, radioisotope penetration, animal studies, and electrochemical or 3D evaluation are different methodologies used to assess dental leakage. 91 out of 177 articles in the primary search were included in the study. These methods are very divergent in their viewpoints; that is why their results cannot be easily compared. It is necessary to standardize microleakage detection methods in order to more correctly evaluate the phenomena that are found between the root canal wall and the root canal filling materials.

CONCLUSIONS

All the methods are useful if studies are performed strictly with large sample sizes and proper control groups and if the technique can be standardized. Furthermore, more evaluations of the reliability of the methods are strongly recommended. Key words:Dental leakage, review, root canal, material testing methods, data interpretation.

Sealing efficacy of system B versus Thermafil and Guttacore obturation techniques evidenced by scintigraphic analysis

BACKGROUND

This study compared root canal sealing ability, filled by Continuous Wave compaction and two carrier-based obturation systems, using the nuclear medicine approach.

MATERIAL AND METHODS

Fifty-five single-rooted extracted teeth were selected. The crowns were sectioned and each tooth was instrumented using rotary Protaper® Universal system. The roots were divided into 3 experimental groups and two control groups. Forty-five root canals were filled, using Continuous Wave, GuttaCore or Thermafil system and TopSeal sealer. Ten teeth were used as control. On the 7th days the apices were submersed in a solution of sodium pertechnetate 99mTc for 3 hours and the radioactivity was counted.

RESULTS

Although apical leakage in the Continuous Wave group was lower compared with GuttaCore and Thermafil groups, there was no statistical difference (p>0.05).

CONCLUSIONS

System B, GuttaCore and Thermafil techniques showed a similar sealing effect. Key words:Continuous wave compaction, Gutta percha core-carrier, leakage, nuclear medicine.

Microleakage of Single-Cone Gutta-Percha Obturation Technique in Combination with Different Types of Sealers

Introduction:

Various materials and methods have been recommended for successful root canal obturation. The aim of this experimental in vitro study was to compare the sealing ability of three root canal sealers AH-26, glass ionomer cement (GIC) and zinc oxide eugenol (ZOE) in single gutta-percha obturating system.

Methods and Materials:

Seventy extracted single-rooted human teeth were decoronated. The teeth were randomly divided into 3 experimental groups (n=20) and 2 positive and negative control groups. After root canal preparation, canals were obturated with single-cone method using either AH-26, GIC and ZOE. The leakage was evaluated using the dye penetration method. The samples were sectioned to evaluate the linear leakage using a stereomicroscope. The data were analyzed using the One-way ANOVA test.

Results:

All the specimens in the positive control group showed evidence of leakage. In the experimental groups, the lowest leakage scores were observed in the AH-26 group (P<0.05). However, there were no statistically significant differences between GIC and ZOE samples (P=0.676).

Conclusion:

AH-26 showed a superior seal and less microleakage compared to the two other materials in single gutta-percha obturating system.

Sealing ability of a novel hydrophilic vs. conventional hydrophobic obturation systems: A bacterial leakage study

Aim:

Comparative assessment of apical sealing ability of a novel Smart-Seal System, Resilon, and conventional Gutta-Percha system using a bacterial leakage model.

Materials and Methods:

Seventy freshly extracted human single rooted teeth with fully formed apices were randomly divided into three groups (20 each) and two control groups (5 positive and 5 negative). Teeth were de-coronated, and roots were standardized to a working length of 16 mm. Root canal preparation was done with rotary pro-taper file system in all groups. Group A was obturated using Smart-Seal system (Hydrophilic), Group B using Resilon/Epiphany system (Hydrophilic), and Group C using Gutta-Percha (GP)/AH plus system (Hydrophobic) in a single cone technique. Using Enterococcus faecalis, a split chamber bacterial leakage model was developed to evaluate the sealing ability of three obturation systems. Samples will be monitored every 24 hours for 60 days.

Results:

All three groups have shown leakage. Novel Smart-Seal System and Resilon have shown similar results and relatively lesser samples leaked in comparison to GP obturations at the end of the observation period. There was no significant difference amongst Resilon and Smart-Seal System (P > 0.05) but there was a significant difference amongst them when compared to GP obturations (P < 0.05).

Conclusion:

Hydrophilic obturations of the root canal shows a better resistance to bacterial leakage as compared to hydrophobic obturations.

Comparative analysis of three different filling techniques and the effects of experimental internal resorptive cavities on apical microleakage

Objectives:

The aim of this study was to evaluate the sealing abilities of three different gutta-percha techniques in experimentally defective roots (EDR) and non-defective roots (NR).

Materials and Methods:

Sixty canine teeth were divided into six groups of ten; Group 1, NR + cold lateral condensation (CLC); Group 2, EDR + LC; Group 3, NR + BeeFill; Group 4, EDR + BeeFill; Group 5, NR + Thermafil; and Group 6, EDR + Thermafil. Apical leakage was measured using a computerized fluid filtration meter with a laser system.

Results:

Statistical analysis revealed that the CLC demonstrated more microleakage in the EDR than in the NR (P < 0.01). Thermafil demonstrated more microleakage in the NR than in the EDR (P < 0.01). No statistically significant differences were found between the BeeFill groups (P > 0.05).

Conclusions:

The results of this study indicate that internal resorptive cavities can affect the apical sealing properties of different root canal filling techniques, with Thermafil ensuring the lowest apical microleakage.

A Comparative in Vitro Study of Apical Microleakage with Five Obturation Techniques: Lateral Condensation, Soft-Core®, Obtura II®, Guttaflow® and Resilon®

AIM

A comparison was made between the root canal lateral condensation technique and other condensation techniques in which physical (temperature: Soft-Core®, Obtura II®) or chemical changes (condensation: Guttaflow®, Resilon®) may affect the dimensional stability of obturation and thus favor apical microleakage.

MATERIALS AND METHODS

A total of 212 single-root teeth removed for orthodontic or periodontal reasons were randomized to 5 groups of 40 teeth each. Six samples were used as positive controls, and another 6 as negative controls. The teeth were worked with the Hero 642 system, and each group was obturated using a different technique: lateral condensation, Obtura II®, Soft-Core®, Guttaflow® or Resilon®. The samples were immersed in black ink, and after 72 hours the teeth were transparentized using the technique described by Robertson. Filtration of the ink was measured under the stereoscopic microscope. Analysis of variance and post-hoc testing were used for the statistical analysis.

RESULTS

The Soft-Core® obturated group showed significantly greater microleakage than the other groups, with no differences among the rest of the groups.

CONCLUSIONS

Under the conditions of this study, the teeth obturated with the Soft-Core® technique showed greater apical microleakage than the other systems.

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.

Carrier-based root canal filling materials: a literature review

A review of the literature on the use of carrier based obturation materials focusing on Thermafil and Resilon based obturator (RealSeal 1) are presented in this article. The review addressed the history, apical leakage, coronal leakage, biocompatibility, sealing ability and clinical success of Thermafil and RealSeal 1. Based on the studies gathered, this review concluded that both treatment techniques (Thermafil and RealSeal 1) did not provide excellent apical sealing ability. More research should be done to try to overcome their main drawback, its sealing ability.

An in vitro comparative study of the adaptation and sealing ability of two carrier-based root canal obturators

The study was done to assess the sealing ability and adaptation of RealSeal 1, and to compare it with Thermafil. 65 single-rooted extracted teeth were selected and root canal treatment was performed. Root canals were obturated with RealSeal 1 or Thermafil. A double chamber bacterial leakage model using E. faecalis was developed to assess the sealing ability. Samples were monitored daily for 60 days. After the bacterial leakage test, samples were embedded in resin and sectioned horizontally at 2 and 4 mm from the apical foramen. Specimens were examined under scanning electron microscope and digitally photographed. AutoCAD software was used to measure the gap between the canal surface and obturation material. Results were statistically analyzed using nonparametric Kaplan-Meier survival analysis for the bacterial leakage and t-test to compare the means of gap in RealSeal 1 and Thermafil at 2 and 4 mm. There was no significant difference between the RealSeal 1 and Thermafil with respect to leakage over time. At 2 mm and 4 mm, RealSeal 1 had significantly more gaps than Thermafil. From the observations it can be concluded that RealSeal 1 and Thermafil have comparable performance in terms of adaptation and sealing ability.

Effect of bleaching agents on sealing properties of different intraorifice barriers and root filling materials

Objective: To evaluate the effect of intracoronal bleaching agents on the sealing properties of different intraorifice barriers and root filling materials. Study Design: The root canals of extracted human premolars (n=180) were prepared by using System GT rotary files and filled with either gutta-percha+AH Plus or Resilon+Epiphany sealer. In both groups, the coronal 3mm of root filling was removed and replaced with one of the following materials applied as intraorifice barriers (n=30/group): 1. ProProot-MTA; 2. Conventional Glass ionomer cement; and 3. Hybrid resin composite. In each subgroup, intracoronal bleaching was performed using either sodium perborate with distilled water or 35% hydrogen peroxide gel for 3 weeks. The leakage of specimens was measured using fluid-filtration and dye penetration tests. The data were analyzed statistically with One-way ANOVA, Repeated Measures t-test and Independent Samples t-test (p=0.05). Results: The fluid conductance values of the test groups were not influenced by the type of the bleaching agent, the intraorifice barrier, or the root filling material (all p>0.05). However, the extent of dye leakage was significantly affected by the type of intraorifice barrier material (p<0.05), which showed the following statistical ranking: glass ionomer cement > resin composite > ProRoot-MTA (p<0.05). Conclusions: The effect of 35% hydrogen peroxide gel or sodium perborate/distilled water on the sealing properties of tested intraorifice barriers and root filling materials varied conforming leakage assessment. These properties were not affected by using fluid filtration test, while the glass ionomer barrier showed the greatest amount of dye leakage in both gutta-percha and Resilon root-filled teeth.

Key words:Tooth Bleaching, root canal filling materials, glass ionomer cement, mineral trioxide aggregate, micro leakage

Fracture resistance of roots filled with three different obturation techniques

Objectives: The aim of this study was to compare in vitro root fracture resistance following root canal filling with AH 26 using lateral condensation, BeeFill, and Thermafil techniques. Study Design: Eighty extracted human mandibular premolars with similar dimensions were selected. In order to standardize the roots, measurements were taken in two separate regions of the teeth—at the cemento-enamel junction and 8 mm apically from the junction—buccolingual as well as mesiodistal for every tooth. Teeth were then randomly divided into five groups (n=16). With the exception of the non-prepared group (Group 1), instrumentation was done in all groups. In group 2, instrumentation but no filling was performed; in group 3, the obturation was done with AH 26 + gutta-percha; in group 4, with AH 26 + BeeFill and in group 5, AH 26 + a Thermafil obturator was used. All the roots were mounted vertically in copper rings and filled with acrylic resin, exposing 8 mm of the coronal part. A universal testing machine was used for the strength test. Results: The results were analyzed using the one-way ANOVA test. The significance between the groups was tested with Temhane’s T2 test. The results indicate that instrumentation of root canals had a significant effect on fracture resistance (p<0.05). In addition, there were no differences between the root canal obturation techniques; furthermore, these techniques did not create a statistically important resistance to vertical fracture (p>0.05). Conclusions: The results suggest that instrumentation of root canals significantly weakens the tooth structure to fracture and the root canal obturation techniques that are used are not able to form reinforcement.

Key words:AH 26, obturation technique, vertical fracture.

Comparative evaluation of the apical sealing ability and adaptation to dentine of three resin-based sealers: An in vitro study

OBJECTIVE

To evaluate the apical sealing ability and adaptation of three resin-based sealers to the dentine.

MATERIALS AND METHODS

A total of 66 recently extracted human maxillary anterior teeth were subjected for the study. The teeth were prepared and obturated with gutta-percha by a lateral condensation using AH Plus, Endorez and Epiphany sealers. Fifteen teeth from each group were used for the apical leakage test and the remaining five teeth from each group were used for examination under the scanning electron microscope. Data were analyzed using one-way ANOVA and the Student Newman-Keuls test.

RESULTS

Epiphany sealer showed better sealing ability and adaptation to dentine.

CONCLUSION

The Epiphany sealer has a better apical sealing ability and adaptation to dentine than the AH Plus and Endorez sealers.

Definition and endodontic treatment of dilacerated canals: a survey of Diplomates of the American Board of Endodontics

AIM

To gather data from Diplomates of the American Board of Endodontics regarding treatment of dilacerated canals.

MATERIALS AND METHODS

A questionnaire addressing definition, endodontic treatment procedures and prognosis was constructed and distributed via e-mail to 708 Diplomates of the American Board of Endodontics. Data from 150 respondents, a 21% response rate, were collected by using a Web-based interface. For statistical analysis, Chi-square tests were used.

RESULTS

More than 25% of respondents believed that a dilacerated root should have a curvature > 40°. One-visit treatment is the best therapeutic approach and transportation is the most likely complication in preparation of these canals. A crown-down technique, watch-winding motion and a master apical file # 25 are the best choices for preparation of these canals. Any warm obturation technique is preferred over lateral compaction by most respondents.

CONCLUSION

A crown-down technique for root canal preparation and a thermoplastic obturation technique are recommended for canals whose curvature is more than 40°. The prognosis of the treatment of these canals is judged not lower than normal canals.

CLINICAL SIGNIFICANCE

Crown-down technique and thermoplastic obturation are recommended for dilacerated canals.

Sealing ability of Hybrid Root SEAL (MetaSEAL) in conjunction with different obturation techniques

OBJECTIVE

The objective of this study was to evaluate the apical sealing ability of Hybrid Root SEAL (MetaSEAL) in conjunction with different obturation techniques.

METHODOLOGY

Sixty-eight extracted human mandibular straight single-rooted teeth with mature apices were prepared using a step-back technique and divided into 4 experimental groups (n = 15). An additional 8 teeth were prepared for controls (3 for positive, 3 for negative control, and 2 more for calculating 100% leakage). The experimental groups were obturated with Hybrid Root SEAL (MetaSEAL) using cold lateral condensation, vertical condensation, Thermafil, and Ultrafil techniques. Fluid movement along the filled canals was measured using a fluid filtration method. Measurements were made at 2-minute intervals for 8 minutes. The data were calculated as microL/min and statistically analyzed using 1-way ANOVA and Duncan Test.

RESULTS

Cold lateral and vertical condensation had significantly less fluid movement than the Thermafil and Ultrafil groups. Thermafil group had the highest fluid movement values when compared with the other groups (P < .01).

CONCLUSION

Hybrid Root SEAL (MetaSEAL) had less fluid movement with cold lateral and vertical condensation techniques when compared with Thermafil and Ultrafil techniques.

Sealing efficiency of BeeFill 2in1 and System B/Obtura II versus single-cone and cold lateral compaction techniques

OBJECTIVE

The objective of this study was to investigate the sealing properties of 2 warm vertical compaction techniques (BeeFill 2in1, System B/Obtura II) in comparison with single-cone and cold laterally compacted gutta-percha.

STUDY DESIGN

The root canals of single-rooted human teeth were prepared by using Mtwo rotary files and divided into 4 groups (n = 10/group) with respect to the filling technique tested: Group 1, cold laterally compacted gutta-percha + AH-26; Group 2, single-cone tapered Mtwo gutta-percha + AH-26; Group 3, System B/ObturaII + AH-26; Group 4, BeeFill 2in1 + 2seal. The leakage of specimens was measured using a fluid-filtration method after 1 and 2 weeks. The data were analyzed statistically with 2-way repeated measures ANOVA (P = .05).

RESULTS

After 1 week, the System B/Obtura II group showed the greatest amount of leakage(P < .05) compared with the other test groups that had similar levels of fluid conductance(P < .05). By the end of the second week, the BeeFill group yielded the greatest amount of leakage (P < .05). Compared with their 1-week values, the fluid conductance of all test groups decreased significantly (P < .05).

CONCLUSION

The apical sealing efficiency of System B/Obtura II and BeeFill were inferior to the other obturation techniques after 2-week fluid conductance testing in vitro.

Comparative in vivo analysis of the sealing ability of three endodontic sealers in dog teeth after post-space preparation

This study compared the sealing ability of RoekoSeal, AH Plus and EndoRez in dog premolars after post-space preparation and exposure to the oral environment. Seventy-four root canals were cleaned, shaped and filled with gutta-percha and one of the sealers. Post spaces were prepared with about 4-mm root canal filling remaining in the apex. Teeth were sealed for 24 h for sealer setting. Teeth were exposed to the oral environment for 45 days. The dogs were killed and root canals were soaked in India ink and sealed for 96 h. The teeth were cleared, and leakage was measured under stereoscopy. The Kruskal-Wallis test was used for analysis. A significant difference was found between EndoRez and RoekoSeal groups (P < 0.05). EndoRez had lower leakage values than RoekoSeal after 45-day exposure to the oral environment. No statistic difference was found in the comparison of AH Plus with the other sealers under study.

Filling of artificial lateral canals and microleakage and flow of five endodontic sealers

AIM

To evaluate the flow characteristics of AH Plus, Epiphany Root Canal Sealant, Endométhasone, Pulp Canal Sealer (EWT) and Sealapex and their ability to fill artificial lateral canals and prevent microleakage.

METHODOLOGY

Flow of the sealers was analysed using the American Dental Association (ADA) 57 and the International Standards Organization (ISO) 6,876 specifications. Two lateral canals were produced in the middle and apical third of 64 roots using 0.1 mm cylindrical drills. Lateral condensation of gutta-percha or Resilon and one or other of the sealers were used to fill the root canals. Buccal-lingual digital radiographs were exposed. After the sealer had set, the roots were immersed in Indian ink and cleared in methyl salicylate. The extent of filling and dye penetration were measured on the buccal and lingual root surfaces under 30 x magnification with a stereoscope.

RESULTS

AH Plus, Epiphany and Pulp Canal Sealer (EWT) complied with ADA 57 and ISO 6,876 specifications. Sealapex complied with the ADA 57 specification but not with ISO 6,876. Endométhasone did not comply with either specification. Filling of lateral canals was similar for the five sealers tested. Dye leakage demonstrated that AH Plus, Epiphany and Sealapex permitted less leakage than Pulp Canal Sealer (EWT) (P < 0.05).

CONCLUSIONS

All the sealers flowed into the 0.1 mm artificial lateral canals. AH Plus, Epiphany and Sealapex allowed less linear leakage than Pulp Canal Sealer (EWT). The flow of Endométhasone did not comply with either ADA 57 or ISO 6,876 specifications and Sealapex did not comply with ISO 6,876.

The sealing ability of GuttaFlow in oval-shaped canals: an ex vivo study using a polymicrobial leakage model

AIM

To compare systematically the sealing ability provided by four endodontic cements: AH Plus, Pulp Canal Sealer EWT, RoekoSeal and GuttaFlow.

METHODOLOGY

A sample of 100 human mandibular incisors with oval-shaped canals was selected from an initial sampling of two hundred teeth. The root canals in 80 teeth were prepared and filled by the same operator using the cold lateral compaction technique with one of the following four cements (n = 20): G1: AH Plus; G2: Pulp Canal Sealer EWT; G3: RoekoSeal and G4: GuttaFlow. Ten teeth with intact crowns served as negative controls and 10 teeth that were not root filled served as positive controls. All teeth were mounted in a two chamber apparatus and then exposed to human saliva. The number of days over a 9-weeks-period was recorded for the appearance of turbidity in the BHI broth. A Log-rank test was used to analyse the leakage data.

RESULTS

Overall, 30% of the samples of the AH Plus group (G1) and 35% of the Pulp Canal Sealer EWT group (G2) were fully contaminated after 9 weeks, whereas 15% of RoekoSeal (G3) and GuttaFlow (G4) groups were fully contaminated. There was a significant difference between (G1/G2) and (G3/G4) (P < 0.05). There was no significant difference between G1 and G2 or between G3 and G4 (P > 0.05).

CONCLUSION

The silicone-based sealers revealed the best results throughout the experimental period. Leakage patterns of AH plus and Pulp Canal Sealer were statistically similar.

The influence of smear layer in lateral channels filling

This in vitro study evaluated the ability of a warm gutta-percha obturation system Thermafil to fill lateral channels in presence/absence of smear layer. Forty single-rooted extracted human teeth were randomly divided into two groups for which different irrigation regimens were used: group A, 5 ml of 5% NaOCl + 2.5 ml of 3.6% H(2)O(2); group B, 5 ml of 5% NaOCl 5% + 2.5 ml of 17% ethylenediamine tetraacetic acid. A conventional crown-down preparation technique was employed. Obturation was performed using epoxy resin-based cement (AH Plus) and a warm gutta-percha plastic carrier system (Thermafil). Specimens were cleared in methyl salicylate and analyzed under a stereomicroscope to evaluate the number, length, and diameter of lateral channels. Lateral channels were identified in both groups at medium and apical thirds. Additional samples were prepared for scanning electron microscopy inspection to confirm the presence of smear layer in group A, and the absence of smear layer in group B. All lateral channels resulted filled in both groups. No statistically significant differences regarding number, length, and diameter were observed between the two groups. Smear layer did not prevent the sealing of lateral channels.

Sealer area associated with cold lateral condensation of gutta-percha and warm coated carrier filling systems in canals prepared with various rotary NiTi systems

AIM

To compare the area of sealer surrounding root fillings completed by two coated carrier systems (Thermafil Obturator and System GT Obturator) and the cold lateral compaction technique, following root canal preparation with two different NiTi rotary systems (Profile ISO and System GT).

METHODOLOGY

Sixty extracted human mandibular premolars were instrumented with ProFile ISO 0.06 taper and System GT instruments (n = 30 each). The teeth were divided into four subgroups (n = 15) for filling as following: group 1: ProFile + Thermafil Obturator, group 2: ProFile + Cold Lateral Compaction, group 3: System GT + GT Obturator, and group 4: System GT + Cold Lateral Compaction. In all groups the canals were prepared to a final size of 40, 0.06 taper in accordance with the manufacturer's instructions and Topseal was used as a sealer. Horizontal sections were obtained every 1 mm up to 12 mm from the apical foramen. Sections were digitally photographed under a stereomicroscope and the images were transferred to an IBM-compatible PC for image analysis. The cross-sectional area of the root canal and the area filled by sealer were calculated for each section and compared statistically both at all levels and by grouping the data as apical, middle and coronal segments; using the Kruskal-Wallis test with Bonferroni correction and chi-square tests (P = 0.05).

RESULTS

In the apical third (1-4 mm), the GT Obturator (group 3) had significantly less area of sealer (P < 0.05), while the difference between groups 1 and 2 was not significant (P > 0.05). For the middle and coronal thirds, both coated-carrier systems had significantly less area of sealer compared with their laterally compacted counterparts (P < 0.05).

CONCLUSIONS

With the combined use of ProFile + Thermafil Obturator and System GT + GT Obturator, significantly less area of sealer occurred than that achieved with both NiTi preparation systems followed by cold lateral compaction.

Methodologies for assessment of apical and coronal leakage of endodontic filling materials: a critical review

Apical leakage continues to be a topic of great interest, because in spite of the advances in Endodontics, clinical failures still occur. Most failures are probably attributed to the proliferation of bacteria that remain viable after chemical-mechanical preparation and cause periapical tissue irritation. Coronal leakage has aroused researchers' interest over the last few years, since canals may be re-contaminated after loss of coronal sealing or fracture of the remaining tooth. In this review, the various methodologies used for assessing root canal sealing capacity are critically analyzed, as they are not standardized, which makes it difficult to compare the results obtained when different methodologies are used, even though the same substrate is being assessed.

Polymicrobial Leakage of Four Root Canal Sealers at Two Different Thicknesses

The present study investigated the sealing ability of four root canal sealers at two different thicknesses. There were 82 maxillary incisors roots prepared with Gates Glidden drills up to size 6 and divided into four groups: Pulp Canal Sealer, EndoREZ, Sealapex, and AH Plus. Each group was divided in two subgroups and gutta-percha cylinders 1.5 or 1 mm wide were used, respectively. The roots were mounted in a bacterial leakage model and the system was checked daily during the following 12 wk. Data were analyzed by Log-Rank test and Student t-test. In the thin layer samples, the sealers demonstrated similar results while, in the thick layer samples, AH Plus revealed the best performance. Generally, greater sealer thickness influenced negatively the sealing ability of the root canal filling, except in AH Plus samples.

Completeness of Root Canal Obturations: Epiphany Techniques versus Gutta-Percha Techniques

This project was designed to determine how a new resin based obturation material compared with traditional gutta-percha techniques in its ability to fill the prepared root canal space. Eighty single-rooted palatal and distal roots of extracted human first molars were used. The root canals were instrumented with hand and rotary files and divided into four groups. Gutta-percha and the new resin based material was used with lateral condensation or continuous wave obturation. The roots were sectioned at 1, 3, and 5 mm from the apex and examined under magnification. Using a computer program, the surface areas of voids were calculated and compared. The gutta-percha, lateral condensation method was the only group that demonstrated significantly more voids. There were no statistically significant differences among any of the other three groups.

Coronal Leakage of Sealer-Only Backfill: An In Vitro Evaluation

We tested the hypothesis that AH Plus and Roeko Seal Automix (RSA) sealers alone are no less effective in preventing coronal microleakage than gutta-percha compacted with sealer. Freshly prepared sheep incisor root canals were obturated with warm gutta-percha alone, AHPlus or RSA alone, or warm gutta-percha with AH Plus or RSA (n = 20 each group). Coronal leakage was assessed under vacuum conditions with Indian ink and tooth clearing. Sealer-only backfills with AH Plus and RSA yielded significantly more dye-free canals than backfills of gutta-percha alone or with sealer (p < 0.001). Warm gutta-percha with or without sealer kept no more canals sealer free than the positive control. Mean dye penetration was 0.92% of canal length for AH Plus and RSA backfills, 27.42% for gutta-percha only backfills, 26.47% for gutta-percha with RSA and 13.92% for gutta-percha with AH Plus. Sealer only backfills allowed significantly less leakage than those including warm gutta-percha (p < 0.001). Sealer-only backfills may be a viable alternative to traditional gutta-percha and sealer compaction methods.

Evaluation of apical sealing ability and adaptation to dentine of two resin-based sealers

The purpose of this study was to evaluate the apical sealing ability and adaptation to dentine of two resin-based root canal sealers. The root canals of 55 human maxillary anterior teeth were prepared using a step-back technique and the smear layer removed with 17% ethylenediaminetetraacetic acid. The teeth were divided into two groups of 25 teeth and the remaining five teeth served as control. Then the teeth were prepared and obturated with gutta-percha by a lateral condensation and either AH plus and EndoRez used as a sealer. Twenty teeth from each group were used for the apical leakage test and the remaining five teeth from each group were used for examination under the scanning electron microscope (SEM). For apical leakage test, teeth were covered with nail varnish and sticky wax to within 1 mm of the apical foramen and placed in 2% methylene blue for 7 days. After this period, the teeth were sectioned longitudinally and apical leakage measurements made. The mean value of dye penetration for AH plus was 2.87 +/- 0.43 mm, while that of EndoRez was 4.54 +/- 0.36 mm. The difference between mean of dye penetration was statistically significant (P < 0.01). The SEM examination showed both sealers had better adaptation and penetration in coronal and middle thirds than apical third of root canal. In apical third, AH plus was adapted better adpated to dentine than EndoRez. In conclusion, AH plus sealer has better apical sealing ability and adaptation to dentine than EndoRez sealer.