Retreatability of a bioceramic root canal sealing material

An international survey on the use of calcium silicate-based sealers in non-surgical endodontic treatment

OBJECTIVES

To gain insight on the current clinical usage of bioceramic root canal sealers (BRCS) by general dental practitioners (GDPs) and endodontic practitioners (EPs) and to determine if BRCS clinical application is in accordance with the best available evidence.

MATERIAL AND METHODS

An online questionnaire of 18 questions addressing BRCS was proposed to 2335 dentists via a web-based educational forum. Participants were asked about socio-demographic data, clinical practice with BRCS, and their motivation for using BRCS. Statistical analysis (chi-squared test or Fisher's exact test) was applied, as appropriate, to assess the association between the variable categories (p value < 0.05).

RESULTS

The response rate was 28.91%. Among respondents, 94.8% knew BRCS (EPs more than GDPs, p < 0.05) and 51.70% were using BRCS. The primary reason for using BRCS was their belief of its improved properties (87.7%). Among BRCS users, single-cone technique (SCT) was the most employed obturation method (63.3%) which was more applied by GDPs (p < 0.05); EPs utilized more of the thermoplasticized obturation techniques (p < 0.05). A proportion of 38.4% of BRCS users indicated the usage of SCT with BRCS regardless of the root canal anatomy (GDPs more than EPs p < 0.05) and 55.6% considered that BRCS may influence their ability to re-establish apical patency during retreatment (GDPs more than EPs p < 0.05).

CONCLUSIONS

This study highlights wide variation in the clinical use of BRCS which is not in accordance with the current literature.

CLINICAL RELEVANCE

This inconsistency among EPs and GDPs on BRCS clinical application requires further clarifications to better standardize their use and improve their future evaluation.

A micro-computed tomographic study of remaining filling materials of two bioceramic sealers and epoxy resin sealer after retreatment

Objective

This study evaluated the presence of residual root canal filling material after retreatment using micro-computed tomography (micro-CT).

Materials and Methods

Extracted human teeth (single- and double-rooted, n = 21/each; C-shaped, n = 15) were prepared with ProFile and randomly assigned to three subgroups for obturation with gutta-percha and three different sealers (EndoSeal MTA, EndoSequence BC sealer, and AH Plus). After 10 days, the filling material was removed and the root canals were instrumented one size up from the previous master apical file size. The teeth were scanned using micro-CT before and after retreatment. The percentage of remaining filling material after retreatment was calculated at the coronal, middle, and apical thirds. Data were analyzed using the Kruskal-Wallis test and Mann-Whitney U test with Bonferroni post hoc correction.

Results

The tested sealers showed no significant differences in the percentage of remaining filling material in single- and double-rooted teeth, although EndoSeal MTA showed the highest value in C-shaped roots (p < 0.05). The percentage of remaining filling material of AH Plus and EndoSeal MTA was significantly higher in C-shaped roots than in single- or double-roots (p < 0.05), while that of BC sealer was similar across all root types. EndoSeal MTA showed the highest values at the apical thirds of single- and double-roots (p < 0.05); otherwise, no significant differences were observed among the coronal, middle, and apical thirds.

Conclusions

Within the limitations of this study, a large amount of EndoSeal MTA remained after retreatment, especially in C-shaped root canals.

Retreatability of root canals filled with Gutta percha and a novel bioceramic sealer: A scanning electron microscopy study

Aim:

This study aimed to evaluate the residual filling material and the reestablishment of working length (WL) and apical patency after retreatment of BioRoot™ RCS, versus TotalFill^® BC Sealer, and AH26, used in a single cone obturation technique.

Materials and Methods:

Sixty single-rooted permanent canines were instrumented up to size 40/.04 (Sendoline, Täby, Sweden). The samples were filled with GP/AH26 (Group 1), GP/TotalFill BC Sealer (Group 2), and GP/BioRoot RCS (Group 3). Eight teeth were used in the positive and negative control groups. Canals were retreated using the Protaper Universal retreatment files (Dentsply Maillefer, Ballaigues, Switzerland) and further instrumented up to size 50/.04 (Sendoline, Täby, Sweden). The ability to reestablish WL and apical patency was recorded. Furthermore, the samples were observed under a scanning electron microscope, in order to evaluate the residual filling material. Data were analyzed statistically with the Fisher's exact and the Kruskal–Wallis tests (P < 0.05).

Results:

There was no statistically significant difference in the WL and patency recovery among the groups. Neither the intragroup comparison among canal thirds nor the intergroup comparison in each canal third or in total canal area revealed any significant differences in the percentage of the remaining filling material after retreatment.

Conclusion:

Residual material debris was observed in all samples regardless of the sealer used. All the sealers were removed to a similar extent. The WL and patency were reestablished sufficiently in all groups.

Evaluation of apoptosis/necrosis and cytokine release provoked by three root canal sealers in human polymorphonuclears and monocytes

AIM

To evaluate the in vitro cytotoxicity and cytokine release of three fresh root canal sealers and to determine the type of cell death they induce.

METHODOLOGY

The sealers tested were Sealer 26 (S26), AH Plus (AHP), and Endosequence BC Sealer (END). Fresh sealers were cultivated in contact with monocytes and polymorphonuclears (PMNs) obtained from the peripheral blood of humans. Cell viability, apoptosis and necrosis were analysed at 4 h (PMNs) or 24 h (monocytes) using Annexin-V and propidium iodide in a cytometer. The supernatants were used to quantify Interleukin (IL)-4, IL-6, IL-10, IL-12 and tumour necrosis factor-α (TNF-α) in monocytes and IL-8 in PMNs by ELISA. One-way ANOVA and the Tukey post-test were used to compare data for cytotoxicity, and the multiple T-test was used to determine the differences between sealers in the release of cytokines that were statistically significant.

RESULTS

After 4 h of treatment, S26 was associated with greater cell viability than the other sealers (P < 0.05) in the PMN culture and had similar values of necrosis as END (P > 0.05). After 24 h of treatment, AHP and END had greater monocyte cell viability than S26 (P < 0.05), which had more necrosis (P < 0.05). END had the lowest levels of IL-12 compared to the other sealers (P < 0.05) and higher levels of IL-6 compared to S26 (P < 0.05). The tested sealers did not differ in the release of IL-8, IL-10, TNF-α and IL-4 (P > 0.05).

CONCLUSIONS

The effect of toxic agents released varied depending on the cell type studied. The composition of the sealers appeared to alter the form of self-regulation in the production of these cytokines by cells.

The Effect of BC Sealer, AH-Plus and Dorifill on Push-out Bond Strength of Fiber Post

Introduction:

Dentinal canal walls are in direct contact with endodontic sealers prior to post space preparation and luting cements after post space preparation. This direct contact may affect the bond strength of intraradicular posts to root dentin. This study aimed to assess the effect of three different sealers on the bond strength of fiber posts to root dentin.

Methods and Materials:

The canals of 56 extracted single-rooted human premolars after selection and decoronation were prepared. For obturation of the canals, specimens were randomly divided into four groups (n=14) according to the type of sealer used in conjunction with gutta-percha: group 1 (control) without any sealer; group 2 with AH-Plus sealer (resin based); group 3 with Dorifill sealer (ZOE-based); and group 4 with BC Sealer (calcium silicate-based). Nine mm-deep post space was prepared in the canal of each specimen. Intraradicular fiber posts were cemented using dual-cure resin cement (Panavia F2.0). Sections of 1 mm thickness were made at the coronal, middle and apical thirds of the post space of each specimen. The push-out bond strength of post to root dentin was measured in a universal testing machine. The data were analyzed using one-way ANOVA and post-hoc Tukey’s test.

Results:

The mean push-out bond strength in the coronal third was significantly lower in Dorifill group compared to AH-Plus (P=0.004). This value was significantly lower in BC Sealer group than AH-Plus (P=0.000) and control group (P=0.03). In middle and apical thirds, the mean push-out bond strength was not significantly different among the four groups (P=0.407, P=0.065, respectively). The mean push-out bond strength was significantly lower in apical than coronal third in AH-Plus group (P=0.001).

Conclusion:

Application of BC Sealer and Dorifill decreased the mean push-out bond strength of intracanal post to root dentin in the coronal third in comparison to AH-Plus.

Mineral trioxide aggregate and other bioactive endodontic cements: an updated overview - part II: other clinical applications and complications

Mineral trioxide aggregate (MTA) is a dental material used extensively for vital pulp therapies (VPT), protecting scaffolds during regenerative endodontic procedures, apical barriers in teeth with necrotic pulps and open apices, perforation repairs as well as root canal filling and root-end filling during surgical endodontics. A number of bioactive endodontic cements (BECs) have recently been introduced to the market. Most of these materials have calcium and silicate in their compositions; however, bioactivity is a common property of these cements. These materials include the following: BioAggregate, Biodentine, BioRoot RCS, calcium-enriched mixture cement, Endo-CPM, Endocem, EndoSequence, EndoBinder, EndoSeal MTA, iRoot, MicroMega MTA, MTA Bio, MTA Fillapex, MTA Plus, Neo MTA Plus, Ortho MTA, Quick-Set, Retro MTA, Tech Biosealer, and TheraCal LC. It has been claimed that these materials have properties similar to those of MTA but without the drawbacks. In Part I of this review, the available information on the chemical composition of the materials listed above was reviewed and their applications for VPT was discussed. In this article, the clinical applications of MTA and other BECs will be reviewed for apexification, regenerative endodontics, perforation repair, root canal filling, root-end filling, restorative procedures, periodontal defects and treatment of vertical and horizontal root fractures. In addition, the literature regarding the possible drawbacks of these materials following their clinical applications is reviewed. These drawbacks include their discolouration potential, systemic effects and retreatability following use as a root filling material. Based on selected keywords, all publications were searched regarding the use of MTA as well as BECs for the relevant clinical applications. Numerous publications were found regarding the use of BECs for various endodontic applications. The majority of these investigations compared BECs with MTA. Despite promising results for some materials, the number of publications using BECs for various clinical applications was limited. Furthermore, most studies had several methodological shortcomings and low levels of evidence.

Physicochemical Properties and Volumetric Change of Silicone/Bioactive Glass and Calcium Silicate-based Endodontic Sealers

INTRODUCTION

This study evaluated setting time (ST), radiopacity, pH, flow, solubility, and volumetric change (VC) of a silicone, gutta-percha, and bioactive glass-based sealer, GuttaFlow Bioseal (GFB), and a calcium silicate-based sealer, TotalFill BC Sealer (TFBC), in comparison with AH Plus.

METHODS

ST and flow were evaluated in accordance with the ISO 6876 Standard. pH was evaluated after different time intervals (1, 3, 7, 14, 21, and 28 days). Radiopacity was evaluated by radiographic analysis in millimeters of aluminum. Solubility was evaluated by means of mass loss (%) after 7 and 30 days of immersion in distilled water. VC was evaluated by micro-computed tomography, by using cavities 3 mm deep and 1 mm in diameter in acrylic resin, filled with the materials. The materials were evaluated after setting and after 7 and 30 days of immersion in distilled water. The data were submitted to analysis of variance and Tukey statistical tests (P < .05).

RESULTS

TFBC demonstrated the highest pH and solubility. GFB had the shortest ST, and lowest radiopacity and flow values. VC was similar for the sealers in both time intervals.

CONCLUSIONS

TFBC presented the highest pH and solubility, but showed similar VC to GFB and AH Plus. GFB showed proper physicochemical properties. Micro-computed tomography complements the physicochemical analysis of endodontic sealers.

Influence of root canal obturation using gutta-percha with three different sealers on root reinforcement of endodontically treated teeth. An in vitro comparative study of mandibular incisors

Aim

The purpose of this in vitro study was to evaluate the vertical force required to fracture mandibular incisor teeth, obturated using gutta-percha with three different sealers.

Materials and Methods

Seventy-five extracted mandibular incisors with intact and fully formed apices, exhibiting single root and canal were acquired. The teeth were decoronated obtaining a root segments of 15 mm and were divided into five groups (n = 15). Group 1: left uninstrumented and unfilled (negative control). For groups 2-5, samples were instrumented using Protaper NEXT (X1 and X2). Group 2: left unobturated (positive control). Groups 3-5 were obturated using lateral compaction by gutta-percha and three sealers (AH Plus^®, Apexit^®, and EndoSequence^® BioCeramic™). All the samples were prepared for fracture testing and vertical load was applied till fracture. Statistical analysis was performed using ANOVA and Tukey's post hoc test, for the data recorded of the force required in Newton (N).

Results

The load required to fracture exhibited a significant difference. The intergroup analysis revealed, samples obturated using bioceramic sealer exhibited higher fracture resistance (P < 0.01).

Conclusion

The use of gutta-percha and a root canal sealer reinforces the root dentin, leading to increased fracture resistance against vertical forces. Bioceramic sealer group in them exhibited better results.

Retreatability of two endodontic sealers, EndoSequence BC Sealer and AH Plus: a micro-computed tomographic comparison

OBJECTIVES

Recently, bioceramic sealers like EndoSequence BC Sealer (BC Sealer) have been introduced and are being used in endodontic practice. However, this sealer has limited research related to its retreatability. Hence, the aim of this study was to evaluate the retreatability of two sealers, BC Sealer as compared with AH Plus using micro-computed tomographic (micro-CT) analysis.

MATERIALS AND METHODS

Fifty-six extracted human maxillary incisors were instrumented and randomly divided into 4 groups of 14 teeth: 1A, gutta-percha, AH Plus retreated with chloroform; 1B, gutta-percha, AH Plus retreated without chloroform; 2A, gutta-percha, EndoSequence BC Sealer retreated with chloroform; 2B, gutta-percha, EndoSequence BC Sealer retreated without chloroform. Micro-CT scans were taken before and after obturation and retreatment and analyzed for the volume of residual material. The specimens were longitudinally sectioned and digitized images were taken with the dental operating microscope. Data was analyzed using an ANOVA and a post-hoc Tukey test. Fisher exact tests were performed to analyze the ability to regain patency.

RESULTS

There was significantly less residual root canal filling material in the AH Plus groups retreated with chloroform as compared to the others. The BC Sealer samples retreated with chloroform had better results than those retreated without chloroform. Furthermore, patency could be re-established in only 14% of teeth in the BC Sealer without chloroform group.

CONCLUSION

The results of this study demonstrate that the BC Sealer group had significantly more residual filling material than the AH Plus group regardless of whether or not both sealers were retreated with chloroform.

Bioceramic-Based Root Canal Sealers: A Review

Bioceramic-based root canal sealers are considered to be an advantageous technology in endodontics. The aim of this review was to consider laboratory experiments and clinical studies of these sealers. An extensive search of the endodontic literature was made to identify publications related to bioceramic-based root canal sealers. The outcome of laboratory and clinical studies on the biological and physical properties of bioceramic-based sealers along with comparative studies with other sealers was assessed. Several studies were evaluated covering different properties of bioceramic-based sealers including physical properties, biocompatibility, sealing ability, adhesion, solubility, and antibacterial efficacy. Bioceramic-based sealers were found to be biocompatible and comparable to other commercial sealers. The clinical outcomes associated with the use of bioceramic-based root canal sealers are not established in the literature.

Evaluation of root canal sealer filling quality using a single-cone technique in oval shaped canals: An In vitro Micro-CT study

The aim of this study was to evaluate and compare the presence of voids in oval root canals filled with different root canal sealers (EndoSequence BC Sealer, Smartpaste bio, ActiV GP) and to compare those with root canals filled with AH Plus sealer using micro-CT. In total, 40 freshly extracted human single-root maxillary premolars were used. Specimens instrumented with the EndoSequence NiTi rotary instrument were assigned randomly into four groups. In each group, root canals were filled with single-cone gutta-percha and one of the tested sealers. Each specimen was then scanned using micro-CT at a voxel resolution of 13.47 μm. Proportions of sections with voids in cross-sectional images and void volumes for each sealer were calculated in the apical, middle, and coronal thirds. Differences according to root canal sealers were evaluated statistically using the Kruskal-Wallis test and the Mann-Whitney U-test at a significance level of 5%. The analysis showed a decrease in void formation in the apical third, with a significant difference between the apical and coronal thirds among bioceramic sealers, ActiV GP, and AH Plus (p < 0.05) but no significant difference between the apical and middle thirds or between the middle and coronal thirds was found for the sealers tested (p > 0.05). All root canal sealers tested resulted in voids. The bioceramic sealers (EndoSequence BC Sealer, Smartpaste bio) produced similar voids which had the fewest in the apical third of root canals among the sealers tested which can be related due to root canal anatomy variations.

Re-establishing apical patency after obturation with Gutta-percha and two novel calcium silicate-based sealers

Objective:

Aim of the present study was to evaluate the retreatability and reestablishment of apical patency of two calcium silicate-based sealers, TotalFill BC Sealer (BCS) and mineral trioxide aggregate Fillapex (MTA F), versus AH Plus, when used in combination with Gutta-percha (GP).

Materials and Methods:

The canals of 54 single-rooted anterior teeth were instrumented and filled with GP/AH Plus (Group A), GP/MTA F (Group B), or GP/BCS (Group C) using continuous wave obturation technique. The groups were subdivided into subgroups with the master-GP cone placed to the working length (WL) or intentionally 2 mm short. The retreatment procedures were performed using ultrasonics, chloroform, rotary, and hand files. The ability to establish the patency and reach WL was determined as well as the time taken to reach WL was calculated in minutes. Furthermore, the samples were observed under a dental, optical microscope, after vertically splitting them.

Results:

The WL and patency were reestablished in 100% of specimens in all groups. The Mann–Whitney U-test indicated that there was a significant difference in the amount of time required to reach WL between the groups (P < 0.05) with group GP/BCS short of the WL showing the most amount of time to be retreated.

Conclusion:

The novel calcium silicate-based sealers are negotiable under simple root canal anatomy. However, the conventional retreatment techniques are not able to fully remove them.

Combined Antibacterial Effect of Sodium Hypochlorite and Root Canal Sealers against Enterococcus faecalis Biofilms in Dentin Canals

INTRODUCTION

The present study aimed to evaluate the antibacterial effect of the combined use of sodium hypochlorite (NaOCl) and root canal sealers on Enterococcus faecalis biofilms using a dentin infection model.

METHODS

Cells of E. faecalis were introduced into the dentinal tubules by centrifugation and incubated in brain-heart infusion for 3 weeks. The biofilms in dentin were first subjected to 5% NaOCl or sterile water for 10 minutes followed by an equal thickness of AH Plus (Dentsply International Inc, York, PA), Endosequence BC Sealer (Brasseler USA, Savannah, GA), or MTA Fillapex (Angelus Indústria de Produtos Odontológicos S/A, Londrina, Brazil) placed on the root canal wall of the dentin specimens for 7, 30, and 60 days. Gutta-percha and water were used in a similar manner as controls. The proportions of dead and live bacteria inside the dentinal tubules were assessed by confocal laser scanning microscopy and viability staining.

RESULTS

The combined use of NaOCl and sealers (30 and 60 days) killed significantly more bacteria than NaOCl or sealers alone (P < .05). NaOCl + MTA Fillapex was the most effective antibacterial combination by killing 83% bacteria in dentin tubules in 60 days. Thirty and 60 days of exposure to the sealers resulted in significantly more dead bacteria in dentin biofilms than 7-day exposures (P < .05).

CONCLUSIONS

The placement of root canal sealer after NaOCl treatment enhanced antibacterial effects against E. faecalis in the dentinal tubules. Little additional effect was obtained after 30 days of exposure to sealers.

Sealing ability of three hydrophilic single-cone obturation systems: An in vitro glucose leakage study

Aim:

The aim of this study is to compare the corono-apical sealing ability of three single-cone obturation systems using a glucose leakage model.

Materials and Methods:

A total of 90 freshly extracted human maxillary single-rooted teeth was selected, and their crowns were cut. The root canal of each sample was instrumented using a rotary crown down technique and then divided into four experimental (n = 20 each) and two control groups (n = 5 each). Samples in the experimental groups were filled as follows: Group 1, cold lateral condensation using gutta-percha/AH Plus; group 2, single-cone C-points/smart-paste bio-sealer; group 3, single-cone bio-ceramic (BC) impregnated gutta-percha/endo-sequence BC sealer; group 4, single-cone Resilon/RealSeal SE after 7 days, the sealing ability of root canal fillings was tested at different time intervals using glucose leakage model. Glucose leakage values were measured using a spectrophotometer and statistically analyzed.

Results:

The four experimental groups presented significantly different glucose leakage values at all test periods (P < 0.05). At the end of the observation period, the cumulative glucose leakage values of groups 2 and 3 were significantly lower than those of groups 1 and 4 (P < 0.05).

Conclusion:

C-points/smart-paste Bio and BC impregnated gutta-percha/endo-sequence BC sealer combinations provided the superior sealing ability over the lateral condensation technique.

Stress distribution of oval and circular fiber posts in amandibular premolar: a three-dimensional finite element analysis

PURPOSE

The aim of the present study was to evaluate the effects of posts with different morphologies on stress distribution in an endodontically treated mandibular premolar by using finite element models (FEMs).

MATERIALS AND METHODS

A mandibular premolar was modeled using the ANSYS software program. Two models were created to represent circular and oval fiber posts in this tooth model. An oblique force of 300 N was applied at an angle of 45° to the occlusal plane and oriented toward the buccal side. von Mises stress was measured in three regions each for oval and circular fiber posts.

RESULTS

FEM analysis showed that the von Mises stress of the circular fiber post (426.81 MPa) was greater than that of the oval fiber post (346.34 MPa). The maximum distribution of von Mises stress was in the luting agent in both groups. Additionally, von Mises stresses accumulated in the coronal third of root dentin, close to the post space in both groups.

CONCLUSION

Oval fiber posts are preferable to circular fiber posts in oval-shaped canals given the stress distribution at the post-dentin interface.

In vitro fracture resistance of roots obturated with epoxy resin-based, mineral trioxide aggregate-based, and bioceramic root canal sealers

INTRODUCTION

The aim of this study was to evaluate the fracture resistance of teeth filled with 3 different endodontic sealers.

METHODS

Seventy-five single-rooted extracted mandibular premolars were decoronated to a length of 13 mm. The teeth were randomly divided into 5 groups (n = 15 for each group). In group 1, the teeth were left unprepared and unfilled (negative control), and in group 2, the teeth were left unobturated (positive control). The rest of the roots were prepared by using the ProTaper System up to a master apical file size of F3: group 3, bioceramic sealer (Endosequence BC sealer) + gutta-percha; group 4, mineral trioxide aggregate-based sealer (Tech Biosealer Endo) + gutta-percha; and group 5, epoxy resin-based sealer (AH Plus Jet) + gutta-percha. All root specimens were stored for 2 weeks at 100% humidity to allow the complete setting of the sealers. Each specimen was then subjected to fracture testing by using a universal testing machine at a crosshead speed of 1.0 mm/min(-1) until the root fractured. The force required to fracture each specimen was recorded, and the data were analyzed statistically.

RESULTS

The fracture values of groups 3 and 5 were significantly higher than those of group 4 (P < .05). There was no significant difference between groups 3 and 5 (P > .05).

CONCLUSIONS

In contrast to Tech Biosealer Endo, Endosequence BC and AH Plus Jet sealer increased the force to fracture in root-filled single-rooted premolar teeth.

Infrared thermographic comparison of temperature increases on the root surface during dowel space preparations using circular versus oval fiber dowel systems

PURPOSE

The purpose was to evaluate temperature increases during dowel space preparations with oval and circular fiber dowel systems.

MATERIALS AND METHODS

This study included 42 single-rooted human mandibular premolars. Roots were scanned with cone-beam computerized tomography (CBCT) to determine the ovoid root canal morphology. Root canals were treated with Ni-Ti rotary instruments and obturated. A second CBCT was taken to determine the thinnest dentin thickness of each root. Roots were randomly divided into two groups (n = 21) according to the fiber dowel system used: group 1, circular fiber dowel system (D.T. Light-Post); group 2, oval fiber dowel system (Ellipson Post). Dowel spaces were prepared using a circular fiber dowel drill and a diamond-coated ultrasonic tip with an oval section under water cooling until 9 mm dowel spaces were obtained. Temperature changes were recorded from the thinnest root surfaces using a FLIR E60 thermal imaging camera.

RESULTS

Temperature increases were significantly greater with the circular fiber dowel system than with the oval fiber dowel system (p < 0.05).

CONCLUSIONS

Although both dowel systems generated high temperature increases on root surfaces, the relatively lower temperature increase associated with the use of oval fiber dowels in ovoid canals makes it preferable to the use of circular fiber dowels.