A 1-year follow-up study on leakage of four root canal sealers at different thicknesses

Stereomicroscopic evaluation of sealing ability of four different root canal sealers: an in-vitro study

AIM

To compare and evaluate the sealing ability of four different commercially available sealers to provide seal against the dye penetration test using a stereomicroscope-an in-vitro study.

MATERIAL/METHOD

80 extracted single rooted mandibular premolar with single canal were used in this study. The samples were divided in 4 groups (20 in each) based on sealer. Group I (Diaproseal), Group II (apexit Plus), Group III (MTA Fillapex) and Group IV (Bio-C). The samples were analyzed using a stereomicroscope and data analysis was done with one-way Anova And post hoc Tukey's test.

RESULT

The mean dye penetration score was 1.2400 ± 0.778 mm for Group I. 2.6000 ± 0.897 mm for Group II, 4.2000 ± 0.923 mm for Group III and 4.225 ± 2.055 mm for Group IV. One-way Anova analysis shows that intergroup comparison was statistically significant between the four groups. The post hoc Tukey's test reveals that the difference was statistically non-significant between group III and group IV.

CONCLUSION

It was concluded that between the four groups the Group I (Diaproseal) showed the least dye penetration followed by Group II (Apexit Pus), Group III (MTA Fillapex) and then Group IV (Bio-C), where there was no significant difference between the Group III (MTA Fillapex) and Group IV (Bio-C).

Comparison of the penetration depth of five root canal sealers: A confocal laser scanning microscopic study

Background:

Sealer penetration into dentinal tubules eliminates the pathways for bacterial leakage and entombs intratubular bacteria.

Aim:

The aim of this study was to evaluate and compare the depth of radicular dentinal tubule penetration of five root canal sealers using confocal laser scanning microscopy.

Methods:

Fifty freshly extracted single-rooted maxillary anterior teeth were used. After decoronation at the cementoenamel junction, they were prepared to ProTaper size F3. After irrigation with 5 mL smear clear, 5 mL 5% sodium hypochlorite and 5 mL distilled water alternatively, the samples were randomly divided into five groups (n = 10) and obturated by lateral compaction technique using the test sealers labeled by fluorescent rhodamine B dye (Mayor Diagnostics, Mumbai, India). Zinc oxide eugenol (ZOE) (Prime Dental Products), EndoREZ (Ultradent), Sealapex (SybronEndo), AH Plus (Dentsply Maillefer), and MTA-Fillapex (Angelus) formed the test groups. Teeth were then positioned in blocks of orthodontic resin. Three horizontal sections of 1-mm representing coronal middle and apical thirds were made and examined with Zeiss (laser scanning microscope [LSM] 780) confocal LSM. Images were analyzed using ZEN 2.1 software.

Statistical Analysis:

Data were recorded and subjected to statistical analysis using one-way ANOVA test.

Results:

Maximum penetration depth was demonstrated by AH Plus in the coronal and apical thirds, MTA-Fillapex in the middle thirds, while minimum penetration depth was seen in ZOE in the coronal and middle thirds and Sealapex in the apical thirds. None of the root canal sealers were able to penetrate the complete depth of radicular dentinal tubules.

Conclusion:

While AH Plus and MTA-Fillapex showed the highest penetration into radicular dentinal tubules, ZOE and Sealapex demonstrated the least penetration.

Sealing ability of three different materials to repair furcation perforations using computerized fluid filtration method

Background. The present study aimed to evaluate the sealing ability of three different calcium silicate-based materials in furcation perforations.

Methods. Seventy-six human mandibular molar teeth were selected. Perforations were created in the center of the pulp chamber floor. The experimental teeth were randomly divided into three groups (n=22). Perforations were repaired with MTA Angelus, Endocem MTA, or EndoSequence BioCeramic Root Repair Material Fast Set Putty (BC-RRM Putty). Microleakage of the different repair materials to be tested was measured by computerized fluid filtration method at 24- and 72-hour intervals.

Results. For each time interval, no statistically significant difference was observed between the groups. For Endocem MTA and BC-RRM Putty groups, the difference between the leakage values measured at both periods was not statistically significant (P > 0.05). However, there was a significant difference for the MTA Angelus group (P < 0.05).

Conclusion. All the calcium silicate-based materials used in the present study showed similar performance in repairing furcation perforations at 24- and 72-hour intervals.

Ultrasonic vibration and thermo-hydrodynamic technique for filling root canals: Technical overview and a case series

AIM

To present a novel root canal filling technique: Ultrasonic Vibration & Thermo-Hydrodynamic Obturation (VibraTHO), and its rationale with a series of cases.

SUMMARY

The VibraTHO technique was used to fill the root canals of three clinically challenging cases: A C-shaped mandibular molar with complex anatomy, a C-shaped mandibular molar with an infected root canal system and a periapical lesion that required retreatment, and apically bifurcating mesiobuccal canals with a common orifice in a maxillary second molar. The cases were followed up for 15, 7 and 37 months, respectively. After follow-up, normal periapical status was observed without any noticeable radiographic change in the root canal fillings in each case. Periapical radiographs revealed complete healing of the periapical area in cases with pre-operative periapical lesions.

Comparison of apical sealing ability of bioceramic sealer and epoxy resin-based sealer using the fluid filtration technique and scanning electron microscopy

Background/purpose

A perfect sealing of root canal system is essential for preventing ingress of bacteria from the oral environment. The purpose of this study was to evaluate the apical sealing ability of bioceramic (EndoSequence BC Sealer®) and epoxy resin-based (AH Plus®) sealers at 24 h, 7 days and 4 weeks.

Materials and methods

Forty two extracted human upper anterior teeth were sectioned to leave the root 15-mm long, then all the roots were instrumented using a set of ProTaper® rotary instruments. Four roots were selected randomly as controls, and the remaining 38 roots were randomly divided into 2 groups of 19 roots each: group 1: EndoSequence BC Sealer® and gutta-percha, and group 2: AH Plus® and gutta-percha using a multiple wave condensation technique. The apical sealing ability of the filled root canal was measured using the fluid filtration method with 200 mmHg (26.67 KPa) above atmospheric pressure at 24 h, 7 days and 4 weeks. Scanning electron microscopy (SEM) was used to assess the adaptation and penetration of the sealers. The apical microleakage between 2 groups was compared using Student's t-test. P < 0.05 was considered statistically significant.

Results

EndoSequence BC Sealer® had significantly better sealing ability than AH Plus® at all test periods (P < 0.001). SEM showed EndoSequence BC Sealer® had better penetration into dentinal tubules.

Conclusion

Bioceramic sealer could promote proper sealing of root canals obturated with multiple wave condensation.

In-vitro bioactivity evaluation and physical properties of an epoxy-based dental sealer reinforced with synthesized fluorine-substituted hydroxyapatite, hydroxyapatite and bioactive glass nanofillers

The purpose of this study was to evaluate the physical properties and bioactivity potential of epoxy-based dental sealers modified with synthesized bioactive glass (BAG), hydroxyapatite (HA) and fluorine substituted hydroxyapatite (FHA) nanoparticles.

The synthesized powders were incorporated at 10% and 20% into the epoxy-based dental sealer. The setting time, flow and solubility and microhardness of the modified and unmodified samples were examined. The bioactivity was evaluated using FESEM-EDX and elemental mapping, ATR-FTIR and XRD.

The flow value of all of the experimental groups except the FHA modified samples, was greater than 20 mm. Concerning solubility, no specimens exhibited more than 1% weight loss. The solubility value of the FHA groups was statistically significant lower than other groups (p ≤ 0.001). The mean hardness values of all of the modified samples were significantly higher than the unmodified group (p ≤ 0.001).

Regarding bioactivity, in vitro study revealed that after 3 days immersion in SBF a compact and continuous calcium phosphate layer formed on the surface of epoxy sealers containing BAG and HA nanoparticles.

Based on these results, the addition of BAG and HA nanoparticles did not adversely alter the physical properties of epoxy sealers. Additionally, they improved the in vitro bioactivity of the epoxy sealer.

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Since root canal sealers are in direct contact with the periapical tissue, ideally, they should be composed of a bioactive material.

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It is important that the added bioactive fillers don't adversely affect the physical properties of the material.

Novel endodontic sealer with dual strategies of dimethylaminohexadecyl methacrylate and nanoparticles of silver to inhibit root canal biofilms

OBJECTIVE

Endodontic treatment failures and recontamination remain a major challenge. The objectives of this study were to: (1) develop a new root canal sealer with potent and long-lasting antibiofilm effects using dimethylaminohexadecyl methacrylate (DMAHDM) and nanoparticles of silver (NAg); (2) determine the effects of incorporating DMAHDM and NAg each alone versus in combination on biofilm-inhibition efficacy; and (3) determine the effects on sealer paste flow, film thickness and sealing ability, compared to a commercial control sealer.

METHODS

Dual-cure endodontic sealers were formulated using DMAHDM mass fractions of 0%, 2.5% and 5%, and NAg mass fractions of 0.05%, 0.1% and 0.15%. The sealing ability of the sealers was measured using linear dye penetration method. Colony-forming units (CFU), live/dead assay, and polysaccharide production of biofilms grown on sealers were determined.

RESULTS

The sealer with 5% DMAHDM and 0.15% NAg yielded a flow of (22.18 ± 0.58) which was within the range of ISO recommendations and not statistically different from AH Plus control (23.3 ± 0.84) (p > 0.05). Incorporating DMAHDM and NAg did not negatively affect the film thickness and sealing properties (p > 0.05). The sealer with 5% DMAHDM and 0.15% NAg greatly reduced polysaccharide production by the biofilms, and decreased the biofilm CFU by nearly 6 orders of magnitude, compared to AH Plus and experimental controls (p < 0.05).

SIGNIFICANCE

A therapeutic root canal sealer was developed using 5% DMAHDM with biofilm-inhibition through contact-mediated mechanisms, plus 0.15% of NAg to release silver ions into the complex and difficult-to-reach root canal environment. The novel root canal sealer exerted potent antibiofilm effects and reduced biofilm CFU by 6 orders of magnitude without compromising sealer flow, film thickness and sealing ability. This method provided a promising approach to inhibit endodontic biofilms and prevent recurrent endodontic infections.

Effect of titanium tetrafluoride addition on the physicochemical and antibacterial properties of Biodentine as intraorfice barrier

OBJECTIVE

To evaluate the influence of titanium tetrafluoride (TiF₄) incorporation on the physicochemical and antibacterial properties of Biodentine (BD; Septodont, Saint Maur des Faussés, France) as an intraorfice barrier material.

METHODS

Three different proportions of TiF₄ powder were used with BD; 1wt%, 2wt%, and 3wt%; respectively. BD without TiF₄ addition was used as the control group. The setting time (ST) was determined using Gillmore needle apparatus. Diametral tensile strength (DTS) and fracture resistance were measured in a universal testing machine. Solubility was assessed using mass variation after 7days water storage. The hardness test was conducted using Vickers microhardness tester. The antibacterial activity was assessed using direct contact test against Enterococcus faecalis. Radiopacity was assessed and expressed in thickness of aluminum. Surface topography and elemental composition of modified BD were also assessed. The pH of soaking water was measured up to 168h. Data of tested properties were analyzed using one-way analysis of variance, the paired t-test, two-way repeated measures analysis of variance, and Tukey post hoc tests (P<0.05).

RESULTS

BD-incorporating 2wt% TiF₄ revealed the highest surface microhardness, DTS, and fracture resistance compared with the unmodified group (P<0.001). Higher concentrations of TiF₄ (3wt%) compromised the solubility and prolonged the ST of BD (P<0.05). Bacterial growth of BD-incorporating TiF₄ was significantly reduced when compared with the control group (P<0.05). The tested materials induced alkalization of the soaking water that decreased with time.

SIGNIFICANCE

Biodentine-incorporating TiF₄ (1wt% and 2wt%) is a promising intraorfice barrier material with enhanced physicochemical and antibacterial properties.

Chemical-physical Properties and Apatite-forming Ability of Mineral Trioxide Aggregate Flow

INTRODUCTION

This study aimed to analyze the chemical-physical properties, including pH, volumetric change, radiopacity, and apatite-forming ability in simulated body fluid, of a new tricalcium silicate material (MTA Flow; Ultradent Products Inc, South Jordan, UT).

METHODS

MTA Flow was tested in comparison with MTA Angelus (Angelus, Londrina, PR, Brazil). The pH of soaking water was tested up to 168 hours in deionized water. In the solubility test, the root-end fillings of 20 acrylic teeth were scanned twice by micro-computed tomographic imaging before and after immersion in ultrapure water for 168 hours. In addition, using an aluminum step wedge, the radiopacity of each material was evaluated as recommended by international standards. The mean gray values of the test materials were measured using ImageJ software (National Institutes of Health, Bethesda, MD). The morphologic and chemical analyses of the material surface were performed using scanning electron microscopic energy-dispersive X-ray spectroscopic analysis after 28 days in Hank's balanced salt solution (HBSS). The data were analyzed using 2-way analysis of variance with the Student-Newman-Keuls test (P < .05).

RESULTS

MTA Flow showed similar alkalizing activity to that of MTA Angelus. In the solubility test, both materials presented lower values without statistical differences. Both materials showed a marked alkalinizing activity within 3 hours, which continued for 168 hours. MTA Angelus showed statistically higher radiopacity values (P < .05). All materials showed the ability to nucleate calcium phosphate on their surface after 28 days in HBSS.

CONCLUSIONS

MTA Flow showed remarkable alkalinizing capability, low solubility, good radiopacity, and the ability to form calcium phosphate deposits after being soaked in simulated body fluid, showing values similar to those of MTA Angelus.

Expansion of Gutta-percha in contact with various concentrations of zinc oxide-eugenol sealer: A three-dimensional volumetric study using spiral computed tomography

Aim:

The purpose of this study was to evaluate the three-dimensional expansion of Gutta-percha (GP), at various powder/liquid ratios, of a zinc oxide-eugenol (ZOE)-based sealer using spiral computed tomography (SCT).

Materials and Methods:

Thirty-five freshly extracted human mandibular premolars were selected for this study. Cleaning and shaping were performed in all the teeth initially with hand K-files up to #25 and finally with RaCe rotary instruments (25/06). Teeth were randomly divided into five groups of 7 teeth each. Specimens were scanned using SCT. They were then viewed both cross-sectionally and longitudinally, with a constant thickness of 1 mm/slice. The volume of root canal in each tooth was estimated. Obturation was performed by GP points (25/04) and ZOE-based root canal sealer in all groups with different powder-liquid ratio. Groups 1, 2, 3, and 4, had powder/liquid ratio of 1:1, 1:2, 1:3, and 1:4, respectively, while in the control group, no sealer was used. The obturation was performed by sealer coated single cone GP. A second SCT scan was performed to determine the volume of GP and sealer in all four groups 1 day after obturation. The third and fourth SCT scans were taken 7 and 30 days after obturation, respectively. The mean volume of GP per group was calculated. Data were statistically analyzed using one-way ANOVA. Inter-group comparisons were done using Scheffe post hoc multiple comparisons test.

Results:

All groups with sealer showed expansion of GP at both 7^th day and 30^th day, which was statistically significant from the GP volume at 1^st day. Groups 2 and 3 with powder/liquid ratio of 1:2 and 1:3 gave the highest mean volume values during 30 days period and showed significant expansion in comparison with Groups 1 and 4 with powder/liquid ratio of 1:1 and 1:4, respectively.

Conclusion:

Increasing the ratio of eugenol in sealer resulted in the volumetric expansion of GP. However, further studies should be performed to confirm the expansion of GP, leading to the achievement of fluid impervious seal.

Comparison of the Apical Sealing Ability of Calcium Silicate-Based Sealer and Resin-Based Sealer Using the Fluid-Filtration Technique

OBJECTIVE

The aim was to evaluate the apical sealing ability of tricalcium silicate-based (MTA Fillapex®) and resin-based (AH Plus®) sealers at 24 h, 7 days and 4 weeks.

MATERIALS AND METHODS

Thirty-four extracted human upper anterior teeth were used. All the teeth were sectioned to leave the root 15 mm long, and then all the roots were instrumented using a set of ProTaper® rotary instruments. Four roots were selected randomly as controls, and the remaining 30 were randomly divided into 2 groups of 15 each: MTA Fillapex and gutta-percha (group 1) and AH Plus and gutta-percha (group 2) using a warm vertical compaction technique. The apical sealing ability of the filled root canal was measured using the fluid-filtration method with 200 mm Hg (26.67 KPa) above atmospheric pressure at 24 h, 7 days and 4 weeks. The apical microleakage of the 2 groups was compared using Student's t test. p < 0.05 was considered statistically significant.

RESULTS

The mean apical microleakage in group 1 at 24 h, 7 days and 4 weeks was 1.01 ± 0.24, 0.43 ± 0.07 and 0.24 ± 0.08 nl/s. The corresponding values in group 2 were 1.15 ± 0.40, 0.32 ± 0.09, and 0.38 ± 0.10 nl/s. MTA Fillapex had significantly more leakage than AH Plus at 7 days, but at 4 weeks, MTA Fillapex showed a significantly better sealing ability than AH Plus (p < 0.05).

CONCLUSIONS

In this study, the tricalcium silicate-based sealer promoted proper sealing when used for filling the root canals.

Filling Effectiveness and Dentinal Penetration of Endodontic Sealers: A Stereo and Confocal Laser Scanning Microscopy Study

Abstract: The aim of this study was to evaluate the filling effectiveness and dentinal penetration of the sealers AH Plus, Pulp Canal Sealer EWT, Sealapex and MTA Fillapex applied according to the vertical condensation technique using thermoplastic gutta-percha. Forty single-rooted teeth were selected. After chemical-mechanical preparation and root-canal filling, sections of the root (2, 4 and 6 mm from the apex) were obtained and analyzed by stereo microscopy and confocal laser scanning microscopy. Data were tabulated and statistically analyzed. With regard to the assessment of void spaces in the filling material at 2 mm from the apex, the sealers showed similar results, but at 4 and 6 mm from the apex, MTA Fillapex had inferior performance compared to AH Plus (at 4 mm), Pulp Canal Sealer EWT (at 4 and 6 mm) and Sealapex (at 6 mm) (p<0.05). With regard to the penetration into dentinal tubules at 2 mm from the apex, the sealers also showed similar results, but at 4 and 6 mm Pulp Canal Sealer EWT had an inferior performance compared to MTA Fillapex and AH Plus, respectively (p<0.05). All four sealers were found to be similar regarding adaptation of the filling material to the root canal walls, except the MTA Fillapex, which showed failures at 4 and 6 mm from the root apex. With regard to the ability to penetrate into the dentinal tubules, the sealers were found to be equivalent, except for the Pulp Canal Sealer EWT as it had poorer results at 4 and 6 mm compared to MTA Fillapex and AH Plus, respectively.

Sealing Efficacy of Single-cone Obturation Technique with MTA and CEM Cement: An in Vitro Bacterial Leakage Study

Background and aims. Various materials and methods have been introduced for obturating cleaned and shaped root canal systems. This in vitro study aimed to evaluate the sealing ability of single-cone obturation technique with mineral trioxide aggregate and calcium-enriched mixture based on bacterial leakage approach.

Materials and methods. Sixty-four single-canal teeth were prepared and randomly divided into 5 groups, consisting of three experimental groups (n = 16) and two control groups (n = 8).In group 1, root canal obturation was performed using gutta-percha with 0.02 taper and AH26 sealer by lateral compaction technique. In groups 2 and 3, single Protaper gutta-percha cone was used for obturation with MTA and CEM cement, respectively. A bacterial leakage apparatus was utilized for leakage assessment for 60 days. Leakage comparison between the experimental groups was performed by one-way ANOVA using SPSS 16 statistical software.

Results. The mean bacterial leakage intervals in groups 1, 2 and 3 were 33.68 ± 9.39, 40.68 ± 11.03 and 39.56 ± 9.03 days, respectively. One-way ANOVA indicated no significant differences in bacterial leakage between the three experimen-tal groups (P = 0.109).

Conclusion. Single-cone obturation with well-fitted gutta-percha and MTA and CEM cement is an appropriate alternative for traditional lateral compaction technique.

The effect of different sealer placement techniques on sealing Ability: An in vitro study

Aim:

The aim of this in vitro study was to evaluate the sealing ability of an endodontic sealer following different techniques of its placement.

Materials and Methods:

A total of 119 permanent human anterior teeth were prepared by using manual Protaper^® and randomly divided into three equal groups of 33 teeth each. The teeth were obturated with the cold lateral condensation technique and AH26 sealer which was placed by using the following: G1: rotary lentulo spiral; G2: manual lentulo spiral; and G3: master gutta-percha coating. The remaining 20 teeth served as positive and negative controls. The samples were immersed in the methylene blue solution for 3 days and longitudinally sectioned for dye penetration assessment and analyzed using a stereomicroscope.

Results:

There was no statistically significant difference (P = 0.305) among the three groups. However, the rotary lentulo spiral technique and the master gutta-percha coating technique showed the highest (4.5 mm) and the lowest (3.8 mm) microleakage values, respectively.

Conclusion:

Different techniques of sealer placement used in this study provided a comparable seal. However, the master gutta-percha coating technique might be preferable because of its ease of use.

Expansion of gutta-percha in contact with various concentrations of zinc oxide-eugenol sealer: a three-dimensional volumetric study

INTRODUCTION

Successful endodontic treatment depends on achievement of a fluid-tight seal that is not possible solely with gutta-percha and requires the use of a root canal sealer. Eugenol, which is a principal component in zinc oxide-eugenol (ZOE) based sealers, is reported to produce a volumetric expansion of gutta-percha. The aim of this study was to evaluate the three-dimensional expansion of gutta-percha at various powder/liquid ratios of ZOE-based sealer by using spiral computed tomography (SCT).

METHODS

Fifty freshly extracted premolars with single canal were decoronated and instrumented by using RaCe rotary instruments (35/06). The teeth were divided into 5 groups of 10 each, and volume of the canal was measured by using SCT. The teeth were then obturated with gutta-percha cones (35/04) in groups ZE 1:1 to ZE 1:4 with Pulp Canal Sealer EWT (ZOE-based) with powder/liquid ratio of 1:1, 1:2, 1:3, and 1:4, respectively, and gutta-percha alone in control group (no sealer group). The filled volume in each canal was measured by using SCT 1 day, 7 days, and 1 month after obturation, and percentages of obturated volume and of volume changes in groups over time were calculated. The data were statistically analyzed by using one-way analysis of variance and post hoc multiple comparison tests.

RESULTS

The groups ZE 1:2 and ZE 1:3 gave the highest mean volume values during a 1-month period and were significantly different in comparison with groups ZE 1:1 and ZE 1:4 (P < .05).

CONCLUSIONS

Increasing the ratio of eugenol in sealer resulted in volumetric increase of gutta-percha. However, further studies should be performed to confirm the expansion and sealing ability of gutta-percha of the size corresponding to the prepared canal, leading to the achievement of fluid impervious seal.

Properties and applications of calcium hydroxide in endodontics and dental traumatology

Calcium hydroxide has been included within several materials and antimicrobial formulations that are used in a number of treatment modalities in endodontics. These include, inter-appointment intracanal medicaments, pulp-capping agents and root canal sealers. Calcium hydroxide formulations are also used during treatment of root perforations, root fractures and root resorption and have a role in dental traumatology, for example, following tooth avulsion and luxation injuries. The purpose of this paper is to review the properties and clinical applications of calcium hydroxide in endodontics and dental traumatology including its antibacterial activity, antifungal activity, effect on bacterial biofilms, the synergism between calcium hydroxide and other agents, its effects on the properties of dentine, the diffusion of hydroxyl ions through dentine and its toxicity. Pure calcium hydroxide paste has a high pH (approximately 12.5-12.8) and is classified chemically as a strong base. Its main actions are achieved through the ionic dissociation of Ca(2+) and OH(-) ions and their effect on vital tissues, the induction of hard-tissue deposition and the antibacterial properties. The lethal effects of calcium hydroxide on bacterial cells are probably due to protein denaturation and damage to DNA and cytoplasmic membranes. It has a wide range of antimicrobial activity against common endodontic pathogens but is less effective against Enterococcus faecalis and Candida albicans. Calcium hydroxide is also an effective anti-endotoxin agent. However, its effect on microbial biofilms is controversial.

Fluid-transport evaluation of lateral condensation, ProTaper gutta-percha and warm vertical condensation obturation techniques

The purpose of this study was to compare the microleakage of four obturation techniques (lateral condensation, lateral condensation of ProTaper Gutta-percha, single ProTaper Gutta-percha and warm vertical condensation) over a 3-month period. A fluid-transport model was used to measure microleakage. Sixty human-extracted teeth, divided into four groups, were prepared with ProTaper rotary instruments before the root canals were filled by one of the four examined techniques. All groups were obturated using Sultan as a root canal sealer. Microleakage was measured 7 days, 1 month and 3 months after the procedures. There were no statistically significant differences between the four groups at any of examination points (P > 0.05). The leakage was increased in all obturation techniques over the 3-month period.

Analysis of sealing ability of root canal sealers using scanning electronic microscopy technique

Introduction. An ideal endodontic sealer should adhere firmly both to dentin and to gutta-percha. Objective. The aim of this study was to evaluate the adhesion of the root canal filling to dentin and gutta-percha using scanning electronic microscopy (SEM). Methods. The sealing ability of endodontic sealers to dentinal walls of the root canal was assessed in recently extracted human single canal premolars. Twenty teeth were prepared using the crown-down technique and irrigated with 3% NaOCl. A total of 20 samples were divided into two groups. The root canals were obturated using Ketac-Endo Aplicap and GutaFlow. The sealing ability and adhesion properties at the sealer-dentin interface were studied using SEM and the results were rated from 1 to 3; extremely good adhesion (rated 1), good adhesion (rated 2) and a relatively good adhesion (rated 3). Results. The results showed extremely good adhesion on Ketac-Endo and GuttaFlow dentin interface. GuttaFlow has strong adhesion (rated 1) to gutta-percha in comparison with Ketac-Endo to gutta-percha interface (rated 2). Conclusion. New GuttaFlow filling material has a strong sealing ability and excellent adhesion to dentinal walls and gutta-percha cones. Ketac-Endo showed excellent bond to dentin with a slightly weaker adhesion capacity to the gutta-percha cones in comparison to GuttaFlow.

Evaluation of the effect of four self-etching adhesives on dentin permeability

OBJECTIVE

The aim of this study was to evaluate the effect of two two-step and two single-step self-etching adhesives on dentin permeability using a computerized fluid filtration (CFF) test method.

METHODOLOGY

Forty recently extracted sound human molar teeth were sectioned at the mid level of the crown to obtain dentin discs of 1 +/- 0.2 mm. A total of 40 discs were obtained and randomly divided into four groups (n = 10). The permeability of the discs was measured using the CFF test method before and after application of the following self-etching adhesives: Hybrid Bond, G-Bond, AdheSE, and Protect Bond. Fluid movement measurements were made at 2-min intervals for 8 min, and a mean of the values obtained was calculated for each specimen.

RESULTS

The in vitro fluid conductance of dentin discs treated with Hybrid Bond and AdheSE were lower than the dentin discs treated with G-Bond and Protect Bond (p < 0.05).

CONCLUSION

1-Treating dentin discs with self-etching adhesives caused significant reduction of dentin permeability. 2-All self-etching adhesives allowed diffusion of distilled water. However, AdheSE and Hybrid Bond showed the lowest permeability.

Comparison of apical and coronal sealing in canals having tapered cones prepared with a rotary NiTi system and stainless steel instruments

The purpose of this study was to compare the sealing ability of different tapered gutta percha cones that were used with lateral compaction and single cones in canals prepared with various root canal instruments. One hundred extracted maxillary incisor roots were used. In group 1, 30 roots were prepared with stainless steel instruments (SS) and then filled by the lateral compaction technique using .02 tapered master cones. In group 2, 30 roots were prepared with ProFile nickel titanium instruments (NiTi) and filled in the same way as group 1. In group 3, 30 roots were filled by the single cone technique using 0.06 tapered gutta-percha cones. The remaining 10 teeth were taken as two control groups. Apical and coronal leakage was evaluated using the fluid filtration model. Considering the effects of the instrumentation, no statistically significant differences were found between the groups prepared with SS and NiTi (P > 0.05). When the effects of obturation technique were taken into consideration, the ProFile instruments and lateral compaction resulted in significantly less coronal leakage than the SS instruments and lateral compaction (P < 0.05). There were no significant differences in apical leakage among any of the groups (P > 0.05).

Leakage of 4 resin-based root-canal sealers used with a single-cone technique

OBJECTIVE

The aim of this study was to measure leakage of 4 resin-based sealers.

STUDY DESIGN

Four groups of premolars (n = 60) were prepared using GT Rotary files and the crown-down technique and filled by the single-cone technique with AH26, AHPlus, EndoREZ, and an experimental MBP as sealer. Leakage was measured using the fluid filtration method after 15, 30, and 60 days and determined as microL/min(-1) x 10 psi.

RESULTS

Statistical analysis by ANOVA and Tukey HSD test indicated that root fillings with AH Plus and the MBP showed lower leakage values after 15 days (P < .05). At 30 days, AH26 presented higher leakage values when compared to other sealers (P < .05). At 60 days, MBP and AH Plus presented the lower leakage values, differing significantly from EndoREZ (P < .05).

CONCLUSION

It was observed that AH Plus and the experimental MBP showed lower leakage after 60 days than AH 26 and EndoREZ.

Apical sealing ability of Resilon/Epiphany versus gutta-percha/AH Plus: immediate and 16-months leakage

AIM

To compare the long-term apical sealing ability of gutta-percha/AH Plus and Resilon/Epiphany.

METHODOLOGY

The root canals of 90 single-rooted human mandibular premolars with single narrow root canals were prepared with ProFile 0.4 taper instruments to apical size 40. After each instrument, the canals were irrigated with 1% sodium hypochlorite. Subsequently, the teeth were randomly divided into four groups containing 20 teeth each. Additionally, 10 prepared premolars served as positive and 10 counterparts with intact crowns as negative controls. The root canals were filled with gutta-percha/AH Plus or Resilon/Epiphany using lateral or vertical compaction. Specimens were allowed to set for 7 days at 37 degrees C and 100% humidity. Subsequently, the root fillings were removed down to the apical 4 mm. Fluid movement was then assessed using a fluid transportation model and re-evaluated after 16 months of water storage. Leakage within and between groups was compared using nonparametric tests.

RESULTS

Negative controls revealed no fluid movement and positive controls displayed gross fluid movement at both times of observation. At the immediate measurement, there were no significant differences between the experimental groups (Kruskal-Wallis, P > 0.05). Gutta-percha/AH Plus fillings retained their seal after 16-months storage (Wilcoxon, P > 0.05), whilst the Resilon/Epiphany groups lost their sealing capacity (Wilcoxon, P < 0.001). In these groups, 29 of the 40 specimens exhibited gross leakage similar to positive controls.

CONCLUSION

Initially, Resilon/Epiphany root fillings prevented fluid movement to the same degree as gutta-percha/AH Plus counterparts, but showed more fluid movement when tested at 16 months.

An In Vitro Evaluation of the Apical Sealing Ability of a New Resin-Based Root Canal Obturation System

The purpose of this study was to assess the apical sealing ability of the new resin-based Epiphany-Resilon root canal filling system, and to compare this with the sealing abilities of different pairings of AH plus, gutta-percha, Epiphany, and Resilon. Seventy extracted human single-rooted teeth were used. All teeth were instrumented using a set of ProTaper rotary instruments. The canal spaces were filled with different combinations of core and sealer using lateral condensation, as follows: group 1, AH Plus + gutta-percha; group 2, AH Plus + Resilon; group 3, Epiphany + Resilon; group 4, Epiphany + gutta-percha. Apical leakage quantity was measured with the computerized fluid filtration meter. Statistical analysis indicated that Epiphany gutta-percha combination had the least amount of microleakage than all the other groups; AH Plus gutta-percha combination proved to have second least amount of microleakage among the groups. AH Plus-Resilon combination demonstrated the greatest amount of microleakage. There were a significant difference between Epiphany gutta-percha and AH Plus-Resilon combinations (p < 0.05). It was found that there were no significant differences between Epiphany-Resilon combination and all the other groups (p > 0.05).

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.

Microleakage along Glassix glass fibre posts cemented with three different materials assessed using a fluid transport system

AIM

To evaluate the microleakage along Glassix fibre posts cemented with three different materials.

METHODOLOGY

The root canals of maxillary central incisor teeth were filled and restored with Glassix posts (Harald Nordin sa, Chailly/Montreux, Switzerland) cemented with either a zinc-phosphate Harvard cement (Richter & Hoffmann, Harvard Dental GmbH, Berlin, Germany), Fuji PLUS cement (GC Corporation, Tokyo, Japan) or Variolink II cement (Vivadent, Schaan, Lichtenstein) in three groups of 15 canals each. Twenty unrestored canals served as a control group, 10 filled with gutta-percha and sealer (negative control group), the remaining 10 with gutta-percha only (positive control group). Coronal microleakage was evaluated using a fluid transport system. The movement of an air bubble in a capillary glass tube connected to the apex of the experimental root section was measured over 5-min periods. Measurements were performed four times for each specimen and the mean values recorded. ANOVA and Duncan's test were performed.

RESULTS

The positive control group had the highest values of microleakage. Amongst experimental groups, the highest values of microleakage occurred in the group with the posts cemented with Harvard cement, followed by Fuji PLUS and Variolink II cements. Groups with Fuji PLUS, Variolink II and the negative control group had significantly (P < 0.00001) less microleakage compared with the Harvard cement group and the positive control group.

CONCLUSION

Canals with Glassix posts cemented with Variolink II and Fuji PLUS cement had the least leakage when assessed using a fluid transport system.

The influence of root canal shape on the sealing ability of two root canal sealers

AIM

To evaluate the influence of root canal form on the sealing ability of two root canal sealers.

METHODOLOGY

Twenty radiographically confirmed straight and 20 curved root canals were prepared with a stepback hand filing technique. Root canal aberrations created during preparation were determined by the use of double exposure radiographic technique. The prepared canals were filled with lateral condensation of gutta-percha and one or other of two root canal sealers (Pulp Canal Sealer and Sealapex). Leakage along the apical 10 mm of roots was measured with a fluid transport model at 1, 3, 6, 9 and 12-month intervals.

RESULTS

There were no statistically significant differences between straight and curved root canals (P > 0.05) for prevalence of root canal transportation. The prevalence of apical transportation was 80% in the straight and 85% in the curved root canals. A complete seal was more frequently observed in straight canals compared with curved canals. Utilizing the pi* index, analysis showed the filling with Sealapex allowed more leakage than Pulp Canal Sealer at 1 year.

CONCLUSION

Under the conditions of the study, root canal form influenced short-term sealing ability. In the long-term the seal was affected by the sealer rather than root canal form.

The Quantitative Evaluation of Apical Sealing of Four Endodontic Sealers

The aim of this in vitro study was to evaluate the apical seal obtained with four root canal sealers: Rocanal 2, Sealapex, AH Plus, and RC Sealer. Forty root canals were prepared using the step-back technique. The specimens were divided into four groups of 10 samples and obturated by laterally condensed gutta-percha with one of the tested sealers. The computerized fluid filtration method was used for evaluation of apical sealing properties. The quantitative apical leakage of each specimen was measured after 7, 14, and 21 days. Statistical analysis indicated that the apical leakage of all sealers used in this study decreased gradually from 7 days to 21 days (p < 0.05). Sealapex showed better apical sealing than the other sealers at 7, 14, and 21 days (p < 0.05). RC Sealer, AH Plus, and Rocanal 2 showed similar apical leakage values at every period (p > 0.05).

Sealing properties of different resin-based root canal sealers

In this study, a comparison of the sealing properties of three different resin-based sealers, AH26, Diaket, and EndoREZ with those of the root canal sealer zinc oxide-eugenol-based U/P Root Canal Sealer was performed. Eighty extracted single-rooted human mandibular first premolar teeth were used. The coronal part of each tooth was removed at the apical 17-mm of roots. The root canals were prepared to a size 7 with ProFile 0.06 taper Series 29 rotary instruments in a crown-down manner before lateral condensation of gutta-percha with the tested sealers (n = 20). A fluid filtration method was used for quantitative evaluation of apical leakage. Statistical analysis revealed that there were no significant differences between the resin-based sealers groups (AH26, Diaket, and EndoREZ) (p > 0.05). U/P Root Canal Sealer, zinc oxide-eugenol-based sealer, leaked significantly more than other tested groups (p < 0.05). Under the limitations of this study, resin-based root canal sealers were found more effective in sealing root canals than the zinc oxide-eugenol-based sealer.

Presence of pores and vacuoles in set endodontic sealers

AIM

To assess qualitatively the presence of pores and vacuoles in the structure of various endodontic sealers when set.

METHODOLOGY

Eight specimens were prepared in keeping with Instituto Argentino de Racionalización de Materiales (IRAM) and ISO regulations for each of the 10 sealers assessed. Four specimens per sealer were examined to identify the presence of structural defects, termed pores, on the external surface. The remaining four specimens were used to examine the presence of defects on the surface exposed by cross-sectional fracture; these were termed vacuoles. The largest and smallest diameters of the pores and vacuoles were measured by scanning electron microscope on both surfaces. The structural defects were classified according to their frequency as abundant, frequent, scarce or exceptional.

RESULTS

Pores and vacuoles were consistently found in every specimen of each sealer. However, their frequency and dimensions were greater in zinc-eugenol-based sealers than in epoxy-resins and glass-ionomer sealers; they increased if the sealer contained calcium hydroxide. The diameter of the pores ranged from 5 to 320 microm and the diameter of the vacuoles ranged from 80 to 500 microm. The diameter of the vacuoles always exceeded that of the pores.

CONCLUSIONS

Pores and vacuoles were a consistent finding in set sealers. Their frequency and size depended on the density of the sealer and increased when the sealers contained calcium hydroxide.