ANTIMICROBIAL PROPERTIES OF SEVERAL TYPES OF ENDODONTIC SEALERS; A SYSTEMATIC REVIEW

1. Consultant Endodontist, Member of the Scientific Council, Saudi Board of Endodontics, Swedish Board in Endodontics, Fellowship in Endodontic Microsurgery, Jeddah Specialty Dental Centre, Ministry of Health. 2. Dental Intern, Riyadh Elm University, KSA. 3. Dental Intern, Imam Abdulrahman University, KSA. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History Received: 01 April 2020 Final Accepted: 05 May 2020 Published: June 2020

When an individual is suffering from distinct pulpal diseases, sealers with desirable antimicrobial activities should be selected because of their capability to reduce and avoid the remaining bacteria's growth and development. Therefore, for the treatment of endodontic illnesses to be successful, the microbial load must be entirelyeradicated by chemo-mechanical preparation of root canal (Gholamhoseini et al. 2018, p. 261).The primary roles of the sealers are usually to fill voids, form a connectionbetween the wall of the root canal and the filling material's core, and to act as a lubricant during the treatment procedure (Al-Haddad, A., Ab Aziz, C. and Zeti 2016, p. 1).Al-Haddad et al.
(2016, p. 1) explain that in most cases, sealers are grouped based on their main chemical components: bioceramicbased, resin, silicone, glass ionomer, calcium hydroxide, and zinc oxide eugenol. These categories suggest that various kinds of sealers with different constituents and bases that offer multiple antimicrobial properties exist (Gholamhoseini et al. 2018, p. 261).Their existence has been aroused the interest of numerous scholars and ISSN: 2320-5407 Int. J. Adv. Res. 8(06), 36-44 37 researchers who desire to determine suitable sealers that can be used during endodontic treatment procedures to prevent infections.
Even so, little research has been performed to investigate the antimicrobial properties of these different types of endodontic sealers. Although Al-Haddad et al. (2016, p. 1) claim that sealers of the root canal have been reviewed across several examinations either based on their constituents or collectively, the studies are not extensive enough. Most importantly, specific types of sealers like the ones based on bioceramicshave only been used during endodontic treatments for the past three decades (Al-Haddad et al. 2016, p. 1). Their popularity can be attributed to the improved utilization of bioceramic technology in dentistry and medicine. Nevertheless, an extensive investigation or review of those particular sealers is yet to be undertaken. In this regard, this systematic review focuses on analyzing the antimicrobial properties of not only the bioceramic-based sealers but also of the other types of endodontic sealers.

Materials and Methods:-
This section is a crucial aspect of systematic reviews (SRs), and itshould conform to the PRISMA guidelines.Selçuk (2019, p. 57)highlights that PRISMA rule, which stands for Preferred Reporting Items for Systematic Reviews and Meta-Analyses, is a 27-item checklist and a four-phase flow chart that defines the process of identifying, screening, and showing the eligibility of the reports to beincorporated into the analysis. This rule can help with organizing SRsin the required formatand surveying the quality of the investigation. As much asDijkers (2017, p. 1) proposes that the PRISMA rule is more of a detailing guide than a quality-assessment system, its significance in SRs cannot be refuted. In this regard, this SR included its PRISMA chart that portrays the different stages of the review, as can be seen in figure 1 below.

Registration and Protocol
In most cases, undertaking and registering the SR's protocol is often the regular and desirable occurrence. A significant number of scholars and researchers who perform SRsoftenregister the stepwise procedures they employed in their reviews into various databases. Registering the protocols of SRs ensures that the reportis accurately orchestrated and explicitly chronicled before the survey starts. Consequently, it propels unwavering quality in conduct for the analysis group and supports the obligation, dependability, and straightforwardness of the ultimatelyfinished SR (Jahan, Naveed, Zeshan, and Tahir

Identification
Articles from other sources (n = 7) Results after duplications removal (n = 25) Screening records (n = 25) Removed articles (n = 10) Eligibility records (n = 15) Removed articles due to various reasons (n = 5) Studies encompassed in the SR (n = 10) 38 As already mentioned, numerous databases exist that can be utilized to register protocols. For instance, Jahan et al. (2016, p. 4) outline that the Cochrane Database of Systematic Reviews and PROSPERO stand apart as well known databases utilized for enrolling examination questions and methodology, and they search for previous existing duplicate investigation procedures and inquiries. The PROSPERO is a worldwide database for registering protocols and increasing the transparency of reviews(Page, Shamseer, and Tricco 2018, p. 32). Even so, this review's protocol was not registered. Therefore, it does not have an enlistment number as is consistently the standard in many registered SRs. Regardless, if this protocol is utilized by any invested individuals to undertake a comparable examination, the outcomes will no doubt be the equivalent or fundamentally the same.

Search Strategy
A distinct strategy was utilized to search for articles and studies that could be incorporated into this SR. Almost all of the publications included in the review usually act as evidence or educational tools to answer the research question or support claims made as part of the investigation topic. In this case, the search strategy was initiated by identifying and determining the databases that could be used to retrieve the studies of interest. The databases that were utilized include Google Scholar, NCBI, PubMed, and EBSCO-host, and they enabled the retrieval of a broad scope of publications and studies that could be used as sources in this SR.
After deciding on the databases, the second step was to categorize and determine the keywords and medical subject headings (MeSHs) that could be used to drive the search and retrieval of the articles already mentioned above. MeSHs are terms assigned to definite articles to portray what theyinvolve(Baumann 2016, p. 171). As for the keywords, they often improve the effectiveness of an article by allowing easy and fast retrieval and recognition of that particular publication. Some of the MeSHs and keywords employed in this SR include sealers, endodontic sealers, antimicrobial sealers, antimicrobial properties, and types of endodontic sealers.They were used to retrieve articles published between 1 st January 2016 and 15 th March 2020.

Eligibility Criteria
After the search described above, and the retrieval of various studies, the eligibility criteria were used to select the most suitable articles that could be incorporated into the review. In most cases, the most desirable publications are those that attempt to respond to the investigationinquiry or satisfy the requirement of the inquiry topic. Even so, not all reports with this qualityare usually included in an SR; hence, the use of the eligibility criteria. Pussegoda et al.
(2017, p. 131) depict that the eligibility criteria underscore which studies to be used in an SR and the ones to be excluded from the review, thereby necessitating the establishment of an inclusion criterion and exclusion criterion, respectively.In this SR, the inclusion criterion requires that the studies are all published in English, of any design, conducted in any region of the world, and focus on the topic of interest, which is evaluating antimicrobial properties of several types of endodontic sealers. On the same note, the exclusion criterion requires that the articles published in non-English languages and do not concentrate on the topic of interest should be excluded from the review.

Process of Selecting the Studies
With the help of the eligibility criteria explained above, some of the retrieved articles were selected via a stepwise process and included in the SR.The first step was the random selection of the publications that were retrieved from the databases. The technique was utilized to eliminate or lessen the danger of predisposition that may be experienced suppose a particular rule was utilized to shape or decide the investigations to be retrieved from the databases.After the random selection, the second step encompassed assessing the abstracts and titles of the retrieved articles to define their suitability to be incorporated into the review. This progression empowered the removal of all duplicates. The last step was assessing the reports' full texts to determine whether or not their contents were in line with the SR's topic of interest. The articles that were in line with the research topic were included in the SR while the others with no direct link to the primary concern of the review were excluded. This last step was undertaken in cases where the abstracts and titles of the studies did not give enough data to decide their qualification to be incorporated into the SR.

Extracting Information
Before any data analysis is done in an SR, information is often extracted from the publication retrieved from the databases and included in the review. Extracting data from the articles included in the SR usually encompasses perusing the examinations and gathering the vital information pertinent to the subject of intrigue. In this SR, extraction of information was performed physically. Those particular articles were read, and explicit data that was considered significant to the subject of intrigue was recovered and recorded in a table. Since the outcomes were not 39 by any means the only significant parts of the articles, other data were likewise acquired from the studies. For instance, the names of the authors, years of publications, designs of the studies, and their outcomes were collected from the articles included in the review. The outcomes section highlighted above refers to the results of the studies regarding the antimicrobial properties of several kinds of endodonticsealers.

Analysis of Information
After the information is extracted from the publications included in the review, it was then analyzed. Ali and Bhaskar (2016, p. 662) explain thatanalyzing the information is a technique that can be utilized to offer importance to the data collected from those particular articles by empowering the identification of vital facts gained from the studies included in the review. Even though several analysis strategies and procedures exist, this SR utilized a table to evaluate the information retrieved from the reports. The table was partitioned into four sections, every one of which was showing specific facts from the publications incorporated into the SR. This procedure empowered examinations of results in the articles to be made, thereby supporting the completion of the outcomes section of this SR.

Risk of Bias Assessment
When undertaking an SR, the endeavor is inclined continuously to potential predispositions that may affect the outcomes of the review and subsequent conclusions. Predisposition regularly happens if imperfections or limitations in conduct, analysis, or design of an SR distort its results. Therefore, assessing the bias risk involved in conducting an SR is often crucial. Numerous instruments exist that can be utilized to attempt the evaluation referenced. Page, McKenzie, and Higgins (2018, p. 6)highlight that some of those tools can be based on domains, checklists, or scales.
The most common instrument in use is the Cochrane technique, which assesses biases in the methodologies, results, conclusions, and other sections of SRsby using judgments of low risks, unclear risks, and high risks on various axes (Cote et al. 2016, p. 533).This SR utilized the Cochrane approach to assessing the inclination hazard in the various reports that were incorporated into the SR.

Results:-Summary
As evident in the PRISMA chart, the first results obtained in the review were from the literature search. Searching the literature from different databases resulted in identifying and retrieving thirty articles. The reference pages of those thirty publications were utilized to get other seven sources. Therefore, the total number of reports acquired from the exploration of the databases already mentioned earlier was thirty-seven. The thirty-seven articles were exposed to different checks to empower the identification and determination of those that could be used in the review as sources. Their titles and abstracts were checked, and twelve duplicates were pinpointed, which were removed. In this regard, only twenty-five articles remained and were subjected to the other checks.
For instance, the twenty-five publications were screened. During the screening, the abstracts and titles of the twentyfive reports were assessed to decide their qualification to be incorporated into the SR. Ten of the reports failed to meet the qualification standards; hence, they were omitted from the SR.Only fifteen articles remained after this second check. The fifteen publications were subjected to the last check, which was a full-content evaluation. It excluded only fivereports that did not meet the eligibility criteria. Ultimately, only tenpublications were encompassed in the review because they met the inclusion criterion.

Characteristics of the Studies
The features of the studies of interest were authors, years of publication, design, and outcomes. There was more than one author who undertook the reportsincorporated into the review and published their methodologies and results. Therefore, when considering this characteristic, more than one author wrote100% of the reports that were used in the SR as sources. Those particular reports were published in different years. For instance, 10%, 30%, 30%, and 30% of the articles were published in 2016, 2017, 2018, and 2019, respectively. As for the designs of the studies, the majority of them used the experimental technique, representing 90% of the publications incorporated into the SR. The other 10% of the articles were systematic reviews. This information is illustrated in Appendix A.The last feature of the studies was their outcomes. This section is discussed in detail in the subsequent section of the review.
Apart from the four main characteristics mentioned above, each of the reports included in the SR presented a specific level of bias as can be seen in Appendix B. From the table in Appendix B;three variables were utilized to evaluate the quality of the publications: low risk, high risk, and unclear risk. Precise symbols were employed to 40 denote each of the three variables. Low risk was denoted by (+), high risk by (-), and unclear risk by (?). As evident in Appendix B, these variables were assigned to each report based on seven distinct measures. The outcomes suggest that all the articles included in the review have a low reporting bias risk and high-performance bias risk. When considering the other measures of the Cochrane method, the reports illuminated low bias risk. Therefore, the publications' quality warranted their inclusion in the review.

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From the information underscored above, it seems that several scholars and researchers agree with the antimicrobial properties of a significant number of endodontic sealers. Shin

Conclusion:-
The reports included in this review were essential in ensuring the paper's objective was met. All the articles focused on highlighting the antibacterial properties of several types of sealers. From theirfindings, it is apparent that various types of endodontic sealers possess antimicrobial activity against numerous oral bacteria. However, it should be noted that the level and effectiveness of their bactericidal effect differ. Some sealers function better and are more effective than others against specific bacteria than others. Therefore, more research should be undertaken to determine the antimicrobial properties and effectiveness of specific endodontic sealers against precise oral bacteria to enable a proper comparative analysis.