Article in PDF
How to Cite
Citation Manager
Readers' Comments (0)
Audio Visual Article Statistics
Link
to PUBMED
Print this Article
Send to a Friend
Advertisers
Access Statistics Resources
Authors are the souls of any journal, and deserve much respect. To publish a journal manuscripts are needed from authors. Authors have a great responsibility for producing facts of their work in terms of number and results truthfully and an individual honesty is expected from authors in this regards. Both ways its true "No authors-No manuscripts-No journals" and "No journals–No manuscripts–No authors". Reviewing a manuscript is also a very responsible and important task of any peer-reviewed journal and to be taken seriously. It needs knowledge on the subject, sincerity, honesty and determination. Although the process of reviewing a manuscript is a time consuming task butit is expected to give one's best remarks within the time frame of the journal.
Salient features of the JCDR: It is a biomedical, multidisciplinary (including all medical and dental specialities), e-journal, with wide scope and extensive author support. At the same time, a free text of manuscript is available in HTML and PDF format. There is fast growing authorship and readership with JCDR as this can be judged by the number of articles published in it i e; in Feb 2007 of its first issue, it contained 5 articles only, and now in its recent volume published in April 2011, it contained 67 manuscripts. This e-journal is fulfilling the commitments and objectives sincerely, (as stated by Editor-in-chief in his preface to first edition) i e; to encourage physicians through the internet, especially from the developing countries who witness a spectrum of disease and acquire a wealth of knowledge to publish their experiences to benefit the medical community in patients care. I also feel that many of us have work of substance, newer ideas, adequate clinical materials but poor in medical writing and hesitation to submit the work and need help. JCDR provides authors help in this regards.
Timely publication of journal: Publication of manuscripts and bringing out the issue in time is one of the positive aspects of JCDR and is possible with strong support team in terms of peer reviewers, proof reading, language check, computer operators, etc. This is one of the great reasons for authors to submit their work with JCDR. Another best part of JCDR is "Online first Publications" facilities available for the authors. This facility not only provides the prompt publications of the manuscripts but at the same time also early availability of the manuscripts for the readers.
Indexation and online availability: Indexation transforms the journal in some sense from its local ownership to the worldwide professional community and to the public.JCDR is indexed with Embase & EMbiology, Google Scholar, Index Copernicus, Chemical Abstracts Service, Journal seek Database, Indian Science Abstracts, to name few of them. Manuscriptspublished in JCDR are available on major search engines ie; google, yahoo, msn.
In the era of fast growing newer technologies, and in computer and internet friendly environment the manuscripts preparation, submission, review, revision, etc and all can be done and checked with a click from all corer of the world, at any time. Of course there is always a scope for improvement in every field and none is perfect. To progress, one needs to identify the areas of one's weakness and to strengthen them.
It is well said that "happy beginning is half done" and it fits perfectly with JCDR. It has grown considerably and I feel it has already grown up from its infancy to adolescence, achieving the status of standard online e-journal form Indian continent since its inception in Feb 2007. This had been made possible due to the efforts and the hard work put in it. The way the JCDR is improving with every new volume, with good quality original manuscripts, makes it a quality journal for readers. I must thank and congratulate Dr Hemant Jain, Editor-in-Chief JCDR and his team for their sincere efforts, dedication, and determination for making JCDR a fast growing journal.
Every one of us: authors, reviewers, editors, and publisher are responsible for enhancing the stature of the journal. I wish for a great success for JCDR."
Thanking you
With sincere regards
Dr. Rajendra Kumar Ghritlaharey, M.S., M. Ch., FAIS
Associate Professor,
Department of Paediatric Surgery, Gandhi Medical College & Associated
Kamla Nehru & Hamidia Hospitals Bhopal, Madhya Pradesh 462 001 (India)
E-mail: drrajendrak1@rediffmail.com
On May 11,2011
Dr. Shankar P.R.
"On looking back through my Gmail archives after being requested by the journal to write a short editorial about my experiences of publishing with the Journal of Clinical and Diagnostic Research (JCDR), I came across an e-mail from Dr. Hemant Jain, Editor, in March 2007, which introduced the new electronic journal. The main features of the journal which were outlined in the e-mail were extensive author support, cash rewards, the peer review process, and other salient features of the journal.
Over a span of over four years, we (I and my colleagues) have published around 25 articles in the journal. In this editorial, I plan to briefly discuss my experiences of publishing with JCDR and the strengths of the journal and to finally address the areas for improvement.
My experiences of publishing with JCDR: Overall, my experiences of publishing withJCDR have been positive. The best point about the journal is that it responds to queries from the author. This may seem to be simple and not too much to ask for, but unfortunately, many journals in the subcontinent and from many developing countries do not respond or they respond with a long delay to the queries from the authors 1. The reasons could be many, including lack of optimal secretarial and other support. Another problem with many journals is the slowness of the review process. Editorial processing and peer review can take anywhere between a year to two years with some journals. Also, some journals do not keep the contributors informed about the progress of the review process. Due to the long review process, the articles can lose their relevance and topicality. A major benefit with JCDR is the timeliness and promptness of its response. In Dr Jain's e-mail which was sent to me in 2007, before the introduction of the Pre-publishing system, he had stated that he had received my submission and that he would get back to me within seven days and he did!
Most of the manuscripts are published within 3 to 4 months of their submission if they are found to be suitable after the review process. JCDR is published bimonthly and the accepted articles were usually published in the next issue. Recently, due to the increased volume of the submissions, the review process has become slower and it ?? Section can take from 4 to 6 months for the articles to be reviewed. The journal has an extensive author support system and it has recently introduced a paid expedited review process. The journal also mentions the average time for processing the manuscript under different submission systems - regular submission and expedited review.
Strengths of the journal: The journal has an online first facility in which the accepted manuscripts may be published on the website before being included in a regular issue of the journal. This cuts down the time between their acceptance and the publication. The journal is indexed in many databases, though not in PubMed. The editorial board should now take steps to index the journal in PubMed. The journal has a system of notifying readers through e-mail when a new issue is released. Also, the articles are available in both the HTML and the PDF formats. I especially like the new and colorful page format of the journal. Also, the access statistics of the articles are available. The prepublication and the manuscript tracking system are also helpful for the authors.
Areas for improvement: In certain cases, I felt that the peer review process of the manuscripts was not up to international standards and that it should be strengthened. Also, the number of manuscripts in an issue is high and it may be difficult for readers to go through all of them. The journal can consider tightening of the peer review process and increasing the quality standards for the acceptance of the manuscripts. I faced occasional problems with the online manuscript submission (Pre-publishing) system, which have to be addressed.
Overall, the publishing process with JCDR has been smooth, quick and relatively hassle free and I can recommend other authors to consider the journal as an outlet for their work."
Dr. P. Ravi Shankar
KIST Medical College, P.O. Box 14142, Kathmandu, Nepal.
E-mail: ravi.dr.shankar@gmail.com
On April 2011 Anuradha
Dear team JCDR, I would like to thank you for the very professional and polite service provided by everyone at JCDR. While i have been in the field of writing and editing for sometime, this has been my first attempt in publishing a scientific paper.Thank you for hand-holding me through the process.
Dr. Anuradha
E-mail: anuradha2nittur@gmail.com
On Jan 2020
Reviews
Full Version
Retrievability of Bioceramic Sealers Assessed using Micro-computed Tomography and Scanning Electron Microscopy: A Literature Review
Correspondence Address :
Dr. Faisal Alnassar,
Department of Restorative and Prosthetic Dental Sciences, College of Dentistry, Majmaah University, Al-Majmaah, 11952, Saudi Arabia.
E-mail: f.alnassar@mu.edu.sa
Endodontic retreatment is a procedure to remove root canal filling material from the tooth, followed by cleaning, shaping, and obturation of the canals. Treatment outcomes may be influenced by incomplete removal of filling materials. The present literature review aimed to identify the techniques and materials used to remove Bioceramic Sealers (BCS) from the root canal system using Micro-Computed Tomography (Micro-CT) and Scanning Electron Microscopy (SEM). A search of the PubMed, Web of Science, Scopus, Science Direct, and Google Scholar databases using applicable keywords such as “BCS” and “calcium silicate-based sealer” and “retreatment” and “retreatability” and “micro-CT” and “SEM” identified studies on techniques and materials used to remove BCSs from the root canal system, as assessed by micro-CT and SEM. A total of 46 studies were included in the review. Of these, 32 studies used Nickel-titanium (NiTi) rotary instruments, 11 used reciprocating systems, and three compared continuous nickel-titanium rotary and reciprocating systems with rotary systems and reciprocation in removing filling materials. Apical patency and Working Length (WL) could be achieved in a canal obturated with gutta-percha and a BCS. The review revealed that removing filling materials using various instrumentation protocols can be successful but incomplete. Both rotary and reciprocating systems can efficiently remove root-filling material. Using supplemental techniques can improve the cleanliness of the root canal during retreatment. Solvents require less time to reach the WL and achieve patency; however, they leave a larger amount of residual root canal-filling material than non solvents. Additionally, the formation of dentinal microcracks remains controversial during the non surgical retreatment of canals filled using BCSs.
Gutta-percha, Retreatment, Root canal, Root canal filling materials, Treatment outcome
In endodontically treated teeth, the incidence of apical periodontitis is 41.3% (1). Non surgical root canal retreatment eliminates filling materials, debris, and microorganisms through proper cleaning, reshaping, and refilling of the root canal system (2),(3),(4). Solomonov M et al., root canals are considered effectively cleaned when only 0.5% of the root canal-filling material remains (5). Treatment outcomes may be influenced by incomplete removal of filling materials because obturation prevents the contact of irrigation solutions with persistent microorganisms (4),(5),(6). Endodontic retreatment can be influenced by the morphology of the root canal system, status of the periapical tissues, material and technique of obturation, and type of endodontic sealers used [7,8]. Retreatment enables access to the root canal system and the removal of filling material to allow for effective disinfection (9). After retreatment, the remaining filling material may harbour bacteria that are resistant to antimicrobial agents, potentially triggering apical periodontitis (9). The presence of hydroxyapatite crystals can be detected at the interface between dentin and calcium silicate-based sealers. However, removing these crystals from the dentinal wall and tubules can pose a challenge. Additionally, the ability of the sealer to penetrate into dentin may impact its retrievability. Dentin penetration does not impede canal retreatment. However, deep material penetration and dentin tubule blockage can complicate canal retreatment. Additionally, residual material can impair the adhesion of the new root canal-filling material to the radicular dentin, leading to retreatment failure (10). The chemical composition of the root canal sealers and techniques used for obturation can influence the effectiveness of root canal-filling material removal (11). The type of endodontic sealer used influences the ability to retreat the root canal system (12),(13). Removal of bioceramic root canal sealers during retreatment concerns clinicians who have recently become interested in exploring new methods and techniques. Thus, the present paper aimed to review the techniques and materials used to remove BCS from the main root canal walls, evaluate the time required to remove the filling material, and establish foramen patency.
Literature Search
Article selection: A literature search was conducted based on the following criteria: articles retrieved in PubMed, Web of Science, Scopus, Science Direct, and Google Scholar using the following keywords: “BCS” and “calcium silicate-based sealer” and “retreatment” and “retreatability” and “micro-CT” and “SEM”; articles in the English language; and articles published between January 2009 and July 2023.
The article titles and abstracts underwent screening based on predetermined inclusion and exclusion criteria, with the removal of any duplicates. Articles not sufficiently related to the review’s subject, based on the abstract and title, were excluded. Ex-vivo studies in English assessing the retrievability of BCS in mature human permanent teeth using micro-CT and SEM were included. Clinical studies, unpublished articles, narrative reviews, book chapters, conference abstracts, and expert opinions in other languages including animals, artificial teeth, or endodontic training blocks, and those deploying Cone Beam Computed Tomography (CBCT), optical microscopy, stereomicroscopy, or dental operating microscopy were excluded. In total, 638 articles were identified. A total of 46 articles met the inclusion criteria (13),(14),(15),(16),(17),(18),(19),(20),(21),(22),(23),(24),(25),(26),(27),(28),(29),(30),(31),(32),(33),(34),(35),(36),(37),(38),(39),(40),(41),(42),(43),(44),(45),(46),(47),(48),(49),(50),(51),(52),(53),(54),(55),(56),(57),(58).
Analysis of remaining root canal filling materials: Research in these areas is better carried out using micro-CT and SEM, based on quantifying the remaining filling materials, cleanliness of the root canal system, and removal of filling materials. Eight studies (14),(15),(16),(17),(18),(19),(20),(21) used SEM to evaluate the BCS remaining after retreatment, whereas 36 studies (13),(22),(23),(24),(25),(26),(27),(28),(29),(30),(31),(32),(33),(34),(35),(36),(37),(38),(39),(40),(41),(42),(43),(44),(45),(46),(47),(48),(49),(50),(51),(52),(53),(54),(55),(56) used micro-CT. One study used micro-CT and SEM (57), and another used micro-CT, SEM, CBCT, and digital microscopy (58).
None of them showed that conventional retreatment techniques were unable to completely remove the BCS. Micro-CT is non destructive, repeatable, and can quantitatively measure remnants with minimal operational control. The same sample can be used for several tests without destruction (59), allowing evaluation of the volume before and after instrumentation, quality of root canal obturation, and material removal from the root canal (retreatment). Additionally, micro-CT facilitates repeat scanning (60) and image manipulation using specific software. However, it cannot be used for in-vivo studies because it exposes live samples to high radiation levels. Furthermore, micro-CT allows the investigation of specimens of limited size, which limits some analyses. Despite its low resolution, CBCT can be used in patients (61). The nature of the remaining materials is not disclosed by CBCT. According to digital microscopy, it was observed that the prevalent residual materials consisted of calcium silicate sealers, along with minor volumes of gutta-percha residue (58).
Obturation techniques used: Gutta-percha was utilised as the core obturation material, and the various obturation techniques are described in (Table/Fig 1) (13),(14),(15),(16),(17),(18),(19),(20),(21),(22),(23),(24),(25),(26),(27),(28),(29),(30),(31),(32),(33),(34),(35),(36),(37),(38),(39),(40),(41),(42),(43),(44),(45),(46),(47),(48),(49),(50),(51),(52),(53),(54),(55),(56),(57),(58).
Ma J et al., found that the continuous wave of condensation group had a larger mean volume of remaining material than the cold lateral condensation group, particularly in the apical part of the root canal system (p<0.05) (22).
The ease of retrieval for Endoseal MTA, EndoSequence BCS, and AH Plus sealers in single and double-rooted canals did not exhibit any significant differences. Conversely, significant remnants were present in the C-shaped root canals that were obturated with Endoseal MTA, followed by AH Plus and EndoSequence BCS (29). Teeth filled using the thermoplasticized technique exhibited a significant increase in the amount of remaining filling material (p<0.05) (26).
Retreatment Technique Solvent
Solvents used during the retreatment of canals filled with BCSs are described in (Table/Fig 2) [16,20,22,24]. The use of chloroform and rotary instruments resulted in more residual root canal-filling material than rotary instruments alone (16). Using 10% FA, 20% HCl, and chloroform may achieve patency for most cases obturated with gutta-percha and EndoSequence BCS (20). The BCS group that underwent retreatment with chloroform exhibited a significant decrease in sealer when compared to the BCS group without chloroform (24). Contrastingly, the time to reach the WL in the solvent group (chloroform) was significantly shorter than that in the groups without solvents (p<0.05). However, less time was needed to achieve satisfactory gutta-percha removal and root canal refinement in the non-solvent group than in the solvent group (p<0.05) (22).
Reciprocating and rotary systems: A total of 32 studies used continuous rotary files during retreatment (13),(14),(15),(16),(17),(18),(19),(20),(21),(22),(24),(27),(29),(30),(34),(36),(38),(39),(40),(41),(42),(43),(45),(48),(49),(51),(52),(53),(57),(58). Eleven studies used reciprocating files during retreatment (23),(32),(33),(35),(37),(44),(46),(47),(50),(55),(56), and three studies compared continuous nickel-titanium rotary and reciprocation systems during retreatment (28),(31),(54) as described in (Table/Fig 3).
No significant differences (p≥0.05) in gutta-percha and sealer removal were found between Trushape and Reciproc files (RC). The reciprocating file allowed for faster filling removal than the Trushape files (p<0.05) (23). In all groups, there was a significant decrease in the amount of filling material after retreatment with ProTaper Universal rotary instruments (Maillefer, Baillaigues, Switzerland) (p<0.05). The MTA Fillapex group showed the highest reduction (p<0.001), and there was no difference between the EndoSequence BCS and the AH Plus groups (p=0.608) (23). Specifically, rotary motion instruments were compared with reciprocal motion instruments, and reciprocal motion instruments reportedly removed a greater amount of filling material from the root canal, especially from the apical third (28). ProTaper and Gates Glidden (GG) showed a higher mean value than RC (p=0.023). These findings indicated that RC files remove more filling materials than ProTaper and GG with H files (31). Reciproc and Reciproc Blue (RB) are suitable for treating severely curved root canals that have been filled with either bioceramic- or resin-based sealers (32).
The effectiveness of the one curve rotary file in removing the filling materials did not show any improvement (43). R25 Reciproc instruments (VDW, Munich, Germany) were more effective in removing BCSs than epoxy resin-based sealers (44). A significant reduction in the amount of remaining filling material in the apical third was observed after the additional apical preparation when using ProDesign Logic 50/0.01 (PDL RT; Easy Equipamentos Odontológicos, Belo Horizonte, Minas Gerais, Brazil) (p<0.05) (47). Calcium silicate-based sealer fillings were found to be more efficiently removed by endodontic reciprocation systems, albeit at a slightly longer duration compared to rotary systems (54). The BCS group exhibited a significantly higher volume of residual filling material compared to the AH group (p=0.035) following instrumentation with the Reciproc R40 (55).
Regaining apical patency and re-establishing Working Length (WL): Only six studies mentioned regaining apical patency and re-establishing WL (14),(17),(20),(24),(34),(35). In 70% of the samples, the WL was not achieved when the BCS/master cone was short of the WL. However, patency was re-established in 80% of samples with the BCS/master cone to the WL (14). Furthermore, the utilisation of 10% FA in combination with mechanical instrumentation proved to be the most effective approach in eliminating the obturation material from the root canal. This method successfully achieved a removal rate of over 95% for both gutta-percha and bioceramic-coated versions, in addition to the achievement of patency and re-establishment of WL (34). Another study compared three different sealers: Gutta-percha (GP)/AH26, GP/TotalFill BCS, and GP/BioRoot RCS. No significant differences were found in the WL and patency recovery among the sealers. Residual debris was observed in all samples, regardless of the sealer used. All sealers were similarly removed, and the WL and patency were re-established with all types of sealers (17). Achieving patency in teeth obturated with EndoSequence BCS was found to be more successful when utilising 20% HCl compared to 10% FA and chloroform. Regardless of the solvent utilised, patency could be achieved in the majority of cases where GP and EndoSequence BCS were used for obturation (20). All procedures continued until the Reciproc R40 file reached the WL, and foraminal patency could be maintained with a #15 K-type file (35). Canals obturated with GP/BCS and retreated using chloroform, WL and patency were successfully re-established in 93% of teeth. However, only 14% of these cases were able to regain patency, which showed a significant difference compared to the other groups (p<0.0001) (24).
Time: Bioceramic-based sealers formed hydroxyapatite with the root dentin, which may pose challenges in removing these sealers during retreatment procedures (13).
A total of 14 studies included the time taken for retreatment of the BCS-filled teeth (14),(15),(20),(22),(23),(26),(30),(32),(36),(38),(52),(53),(54),(58). The time required to remove the filling materials using the Tango-Endo (3.7 min), Fanta-AF-One (4.1 min), and R-Motion (4.1 min) systems was shorter than that required by the RB (5.4 min) and WaveOne-Gold (4.9 min) systems (54). TotalFill bioceramic required less retreatment time than AH Plus; however, the difference was not statistically significant {44.38 (±13.73) versus 53.93 (±23.34) s} (p=0.418) (52). The mean time to complete retreatment of canals filled with BioRoot RCS and GuttaFlow Bioseal was not significantly different (25.52 and 21.56 min, respectively) (p>0.05) (30). Hess D et al., found that using BCS with a single GP master cone placed to the full WL resulted in a longer retreatment time compared with when the master GP cone was trimmed to fit approximately 2 mm short of the WL.
Simsek N et al., found that there was no significant difference in the time required to remove the AH Plus, iRoot SP, or MM Seal (p>0.05) (15). The time to reach the WL was significantly shorter in the solvent groups than in the non-solvent groups (p<0.05) (22). Moreover, no significant difference was found in the time to achieve patency between chloroform and 10% FA. The median time to achieve patency for the chloroform and FA groups was 28.2 and 33.2 seconds, respectively (p>0.05). However, there was a significant difference between chloroform and HCl. The median time to achieve patency for the chloroform and HCl groups was 28.2 and 14.8 seconds, respectively (p<0.05). The median time to achieve patency for the 10% FA and 20% HCl groups was 33.2 and 14.8 seconds, respectively (p<0.05) (20). For the retreatment of roots filled with BCS, the time taken was 180.0±22.5 sec using the Reciproc file and 253.3±31.5 sec with the Trushape file. It was longer than roots filled with a pulp canal sealer and retreated using the Reciproc file (133.4±14.9 sec) and Trushape file (199.2±18.8 sec) (p<0.05) (23). Moreover, a significantly shorter retreatment time was required for the AH Plus group than for the BioRoot RCS group (p<0.05) (36). Retreatment of canals filled with BCS was more time-consuming than that of canals filled with AH Plus sealer. Moreover, the retreatment time for the AH Plus/Reciproc group was significantly shorter than that for the BCS/Reciproc, BCS/RB, and AH Plus/RB groups (p=0.004) (32). Total Fill bioceramic required less retreatment time than AH Plus, albeit with no statistical significance 44.38±13.73 versus 53.93±23.34 S (p=0.418) (52).
The mean time to complete the retreatment of canals filled with BioRoot RCS and GuttaFlow Bioseal was not significantly different (25.52 minutes and 21.56 minutes, respectively) (p>0.05) (30). The Dia-ProSeal group had considerably less retreatment time than the TotalFill BCS group (p<0.05) (53). Additionally, the time is affected by the obturation technique. Significantly less time was required for retreatment in teeth obturated with the lateral condensation technique (p≤0.05) than for teeth obturated with warm vertical compaction and thermoplasticized injectable techniques (26). The time taken to remove the filling material was longer in the warm vertical compaction group than in the Single Cone Obturation (SCO) group (38). The motion of NiTi files also affected time. The time required to achieve the full working length was significantly higher with the Protaper Universal Retreatment and Protaper Universal Retreatment followed by the use of XP-Endo Finisher, as compared to D-Race or D-Race followed by the use of XP-Endo Finisher R, respectively (p<0.05) (58).
Supplementary Techniques for Retreatment
According to Schirrmeister JF et al., it is crucial to completely remove any previous obturation materials as the presence of necrotic tissue and bacteria within the remaining Gutta-percha (GP) and sealer can potentially lead to post-treatment disease (12). Many new techniques are expected to allow greater removal of the remains of GP and sealers. Supplementary techniques were used in 25 of the included articles and are described in (Table/Fig 4) (13),(15),(19),(21),(23),(25),(27),(30),(35),(36),(37),(38),(42),(45),(48),(49),(50),(51),(52),(53),(54),(55),(56),(57),(58). Supplementary techniques such as ultrasonic-assisted irrigation (15),(19),(23),(30),(35),(36),(37),(45),(54),(55) and laser-activated irrigation (25),(56), ultrasonic-assisted irrigation, and laser-activated irrigation (48),(49),(50),(51),(57).Significantly improved gutta-percha with BC sealer removal was observed when incorporating UI and LI adjuncts into NiTi rotary retreatment techniques. However, the efficacy of surfactants remained unaltered (51). The Shock Wave-enhanced Emission Photoacoustic Streaming (SWEEPS) mode of the Er:YAG laser, UAI, and Syringe Needle Technique (SNI) all demonstrated comparable effectiveness in eliminating residual filling remnants (49). The additional application of PIPS resulted in a significant decrease in the quantity of root fillings when compared to the PUI and Conventional Syringe Irrigation (CSI) techniques (p<0.05) (57). Interestingly, all supplementary techniques observed enhanced cleanliness of the root canal walls during endodontic retreatment procedures. Supplementary techniques enhanced the retrievability of the root canal-filling material compared to the primary technique.
Dentinal Microcracks
Only a few comparative studies on dentinal microcracks exist. Three articles investigated dental microcracks during the retreatment of root canal systems filled with a BCS (33),(40),(48). Almeida A et al., removed a root canal filling with two different sealers using RC and RB (33).
The use of AH Plus and EndoSequence BCS, as well as the removal of the filling material using RC and RB instruments, did not induce dentinal defects. In contrast, Luciana da Cruz RJ et al., utilised GP and total fill BCS to fill the canal (40). They then employed rotary ProTaper Retreatment files to eliminate the filling material. Interestingly, the presence of silicate-based root canal-filling material in the mesial roots of mandibular molars did not impact the development of dentinal microcracks. Barakat RM et al., revealed a significant increase in the number of cracks following the implementation of post-retreatment protocols, particularly in the coronal and middle thirds of the canals, compared to both pre- and post-instrumentation (p=0.0001) (48). However, the utilisation of ultrasonic or laser-activated irrigation did not result in a significant increase in crack formation (p=0.345). Conversely, the use of D-Race NiTi rotary instruments for root canal retreatment was associated with a substantial increase in dentinal microcracks.
Despite the introduction of various sealers in the market, their retreatability remains unknown. Moreover, the efforts to develop an ideal sealer have predominantly prioritised achieving complete obturation of the root canal, rather than retreatability. Recently, BCS materials have become increasingly popular as sealer filling materials due to their biocompatibility, antibacterial properties during the setting process, and minimal shrinkage upon setting (29). The chemical bonding of BCS with tooth structures is facilitated by the formation of tags along dentinal tubules, rendering retreatability challenging (24).
The type of GP affects retreatability; BC-coated GP is more challenging compared to conventional GP endodontics (21). Moreover, the sealer influences retreatability (52). The apical third had significantly more filling material debris (p<0.05) (26). However, only the apical third of the BCS/Reciproc group presented a significantly greater reduction in residual filling material compared to the BCS/Reciproc Blue (32). Additionally, in both the mesiobuccal and distobuccal canals, the tricalcium silicate-based material was removed as rapidly as the zinc oxide-eugenol sealer (62).
The SCO technique is recommended with calcium silicate-based sealers according to the manufacturer’s recommendations. The obturation technique during the initial treatment affected the residual material amount independently of the sealer type, and the remaining root canal-filling material was between 15% and 24%. Moreover, the obturating technique also influenced the retreatment time (26). A possible explanation for this result may be that the continuous wave compaction technique fills the canal in 3-D obturation, whereas the cold lateral condensation and single cone do not.
More time may be required when retreating canals filled with BCS (32). Warm vertical compaction takes longer retrieval time than SCO (38). Retrieval of a single GP master cone placed to the full WL took longer using EndoSequence than using the master GP cone trimmed to fit approximately 2 mm short of the WL (14). There was no significant difference in the time to reach the WL between AH Plus, iRoot SP, or MM Seal (p>0.05) or the time from starting the removal to the completion of the cleaning process using R-Endo versus ultrasonic tips (p>0.05) (15). For teeth obturated with the lateral condensation technique, significantly less time was required for retreatment (p≤0.05) compared to warm vertical compaction and thermoplasticized injectable techniques. A possible explanation for this might be differences in the retreatment files, the tooth morphology, the obturation technique, and the period between the initial treatment and retreatment (26).
Different instrumentation protocols can be applied to effectively remove filling materials from the root canal system, although not entirely. The use of solvents enhances the penetration of files, but it can also impede the cleaning process of the root canal. To facilitate the removal process and minimise the chances of altering the original canal shape, straightening, or perforation, it is recommended to utilise a solvent to soften the GP (63),(64),(65). However, a greater amount of root canal-filling material remained with the use of chloroform (16). The ability of four commonly used endodontic solvents was compared to chloroform, Endosolv R (Septodont, Saint-Maur, France), Endosolv E (Septodont), or eucalyptol to soften GP and MTA Fillapex to allow for the re-establishment of apical patency. The result showed that all solvents used effectively softened GP and MTA Fillapex, thereby assisting in the re-establishment of apical patency. The observed decrease in these studies when using solvents implicates that dissolving GP can increase the adherence of GP and sealer to the canal wall; however, as mentioned above, using solvents allows the re-establishment of patency and reaching the full WL (66).
Cutting capacity is a crucial characteristic of instruments, particularly for the removal of filling materials. Various factors influence the cutting ability, including the helical angle, rake angle, and cross-sectional design. The helical angle is the angle formed between the cutting edge and the longitudinal wall of the dentin. Sizes of the preparation affect the removal of root canal-filling (67),(68). Excessive enlargement of the root canal should be avoided, as this may predispose the root to fractures (67). The amount of remaining filling materials after using rotary systems (10.1%) was higher than that after using reciprocating systems (3.8%) (p<0.001) (54).
The utilisation of reciprocating systems proved to be more efficient in the removal of a combination of BCS and bioceramic GP from the canal (44). There are several possible explanations for these results. The alternating movement of the reciprocating files could better dislodge the filling material, particularly the hard-set MTA-sealer, from the root canal walls, improving its removal coronally if the instrument design (cross-sectional shape and the helical angle) allowed such removal. Moreover, reciprocating systems have better centring ability than rotary systems (69),(70).
Regaining WL and patency in retreatment cases is regarded as significant indicators of success in root canal retreatment (68),(71) and shown to substantially improve the periapical healing rates (71). Retreatment may be compromised if WL and/or patency cannot be regained, as it hinders the proper cleaning and shaping of the apical canal space, which may harbour bacteria [14,24]. The time needed to attain apical patency in root canals can be impacted by the operator’s expertise, regardless of the filling material used or the type of canal (62).
The WL and patency were re-established sufficiently in AH26, TotalFill BCS, and BioRoot RCS (17). Patency could be re-established in canals filled with BCS in 84.4% of cases (23). This may be explained by the capacity of small hand files to navigate through voids within the BCS or bypass the sealer in a canal with an irregular shape. The hardness of bioceramics upon setting makes it unlikely for files to penetrate the BCS, although there are cases where unset sealers may be penetrable. The remaining BCS sealer, due to its hardness upon setting, is nearly impenetrable by NiTi files, thus impeding the proper cleaning and shaping of the apical canal space (62).
In recent years, researchers have investigated a variety of approaches to remove the remaining GP and sealer. The complex root canal anatomy is one of the challenges during retreatment due to the difficulty in engaging the rotary instruments in the apical root region, as well as the filling material lodging into the canal irregularities, making it difficult to remove during retreatment. All the included studies using supplementary techniques showed a significant reduction in the filling remnants and sealer compared with the settings not involving supplementary techniques. PIPS showed a significant reduction in the filling remnants with EndoSequence BCS, MTA Fillapex, and AH Plus sealer (p<0.05) (25).
A significantly smaller volume of root-filling remnants of BioRoot RCS was achieved by using Tornado brush and UAI compared with syringe irrigation (p<0.05) (30). The removal of SCO using EndoSequence BCS was efficiently removed by the combined use of XP-endo Shaper (XPS) and XP-endo Finisher R (XPFR) instruments (p<0.05) (13). The six-month group exhibited a significantly higher percentage volume of the filling material removed after the initial retreatment and XPFR cleaning compared to the 2-week groups (p<0.05) (38). The amount of material removed following ultrasonic and diode laser was significantly greater than that following manual irrigation (p<0.0001) (51). XP Finisher R and XP Finisher had better cleaning ability compared with PUI in all thirds of each root canal (p<0.001) (19). Regardless of the sealer type, the efficacy of removing filling materials was significantly improved through additional preparation with XP-Endo Finisher (p<0.05) (27). The efficacy of XPR in removing the filling material in mandibular premolars with oval canals was found to be superior to that of both UAI and EAI methods (35). However, there were no statistically significant differences in efficacy between the SWEEPS mode of the Er:YAG laser, UAI (Irri S, 25/25, VDW), and conventional SNI. Similar effectiveness was observed among all tested techniques in the removal of the remaining filling remnants (49).
None of the articles included in the present study could completely remove the GP and BCS from the root canal system. Researchers conducted a systematic review of laboratory studies utilising micro-CT to evaluate the residual filling materials. The findings indicated that none of the instruments were able to achieve total removal of GP and sealer from root canals. The mean percentage of residues was less than 10% (68). The presence of residual sealer material creates an environment conducive to bacterial colonisation, impeding the formation of an effective seal with the new filling material and resulting in failure during subsequent retreatment (29).
The absence of dentinal defects was noted following the use of AH Plus and EndoSequence BCS, along with the utilisation of RC and RB instruments for the elimination of filling material from the mesial root of mandibular molars (33). The formation of dentinal microcracks was not affected by the utilisation of ProTaper Universal Retreatment during the retreatment process of mesial roots in mandibular molars filled with a silicate-based root canal-filling material (40). However, retreatment of single canal teeth using D-Race NiTi rotary instruments showed an increased number of cracks after retreatment protocols, particularly in the coronal and middle third of the canal, compared with those at pre-treatment and post-treatment (p=0.0001) (48). Using supplemental irrigation such as 17% Ethylenediaminetetraacetic acid (EDTA) and 10% FA applied for five minutes did not damage the dentine but affected the structural integrity of the sealer (34).
The differences in these results could be attributed to the differences in methodologies (i.e., different retreatment files and tooth types). Numerous authors have reported that the formation of dentinal defects can be attributed to various factors, such as tip design, cross-section geometry, constant or progressive taper design, constant or variable pitch, and flute form (72),(73). One limitation of the present review is the absence of clinical studies evaluating the effects of the remaining BCS on retreatment outcomes. Thus, future research should aim to investigate this issue.
The results of the studies varied significantly owing to differences in methodologies. Initial obturation techniques affected the remaining GP during retreatment. Both rotary and reciprocating systems can effectively remove root-filling material. However, reciprocating systems required more retreatment time compared to the use of rotary files. The use of supplemental techniques can enhance the cleanliness of the root canal during retreatment. Solvents helped establish patency and reach the WL. Overall, this review revealed that no techniques or methods can completely remove BCS during retreatment, as complete sealer removal was not observed in any of the studies.
The author would like to thank the Deanship of Scientific Research at Majmaah University for supporting this work under Project Number No R-2024-980.
Authors’ contribution: FA: Conceptualisation; Data curation; Formal analysis; Funding acquisition; Investigation; Methodology; Project administration; Resources; Software; Supervision; Validation; Visualisation; Roles/Writing-original draft; and Writing-review and editing. ORCID ID: 0000-0003-0417-8001.
DOI: 10.7860/JCDR/2024/69247.19509
Date of Submission: Dec 23, 2023
Date of Peer Review: Jan 14, 2024
Date of Acceptance: Mar 09, 2024
Date of Publishing: Jun 01, 2024
AUTHOR DECLARATION:
• Financial or Other Competing Interests: None
• Was informed consent obtained from the subjects involved in the study? No
• For any images presented appropriate consent has been obtained from the subjects. NA
PLAGIARISM CHECKING METHODS:
• Plagiarism X-checker: Dec 4, 2023
• Manual Googling: Jan 24, 2024
• iThenticate Software: Mar 08, 2024 (26%)
ETYMOLOGY: Author Origin
EMENDATIONS: 6
- Emerging Sources Citation Index (Web of Science, thomsonreuters)
- Index Copernicus ICV 2017: 134.54
- Academic Search Complete Database
- Directory of Open Access Journals (DOAJ)
- Embase
- EBSCOhost
- Google Scholar
- HINARI Access to Research in Health Programme
- Indian Science Abstracts (ISA)
- Journal seek Database
- Popline (reproductive health literature)
- www.omnimedicalsearch.com