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Dr Mohan Z Mani

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Department of Dermatolgy,
Believers Church Medical College,
Thiruvalla, Kerala
On Sep 2018




Prof. Somashekhar Nimbalkar

"Over the last few years, we have published our research regularly in Journal of Clinical and Diagnostic Research. Having published in more than 20 high impact journals over the last five years including several high impact ones and reviewing articles for even more journals across my fields of interest, we value our published work in JCDR for their high standards in publishing scientific articles. The ease of submission, the rapid reviews in under a month, the high quality of their reviewers and keen attention to the final process of proofs and publication, ensure that there are no mistakes in the final article. We have been asked clarifications on several occasions and have been happy to provide them and it exemplifies the commitment to quality of the team at JCDR."



Prof. Somashekhar Nimbalkar
Head, Department of Pediatrics, Pramukhswami Medical College, Karamsad
Chairman, Research Group, Charutar Arogya Mandal, Karamsad
National Joint Coordinator - Advanced IAP NNF NRP Program
Ex-Member, Governing Body, National Neonatology Forum, New Delhi
Ex-President - National Neonatology Forum Gujarat State Chapter
Department of Pediatrics, Pramukhswami Medical College, Karamsad, Anand, Gujarat.
On Sep 2018




Dr. Kalyani R

"Journal of Clinical and Diagnostic Research is at present a well-known Indian originated scientific journal which started with a humble beginning. I have been associated with this journal since many years. I appreciate the Editor, Dr. Hemant Jain, for his constant effort in bringing up this journal to the present status right from the scratch. The journal is multidisciplinary. It encourages in publishing the scientific articles from postgraduates and also the beginners who start their career. At the same time the journal also caters for the high quality articles from specialty and super-specialty researchers. Hence it provides a platform for the scientist and researchers to publish. The other aspect of it is, the readers get the information regarding the most recent developments in science which can be used for teaching, research, treating patients and to some extent take preventive measures against certain diseases. The journal is contributing immensely to the society at national and international level."



Dr Kalyani R
Professor and Head
Department of Pathology
Sri Devaraj Urs Medical College
Sri Devaraj Urs Academy of Higher Education and Research , Kolar, Karnataka
On Sep 2018




Dr. Saumya Navit

"As a peer-reviewed journal, the Journal of Clinical and Diagnostic Research provides an opportunity to researchers, scientists and budding professionals to explore the developments in the field of medicine and dentistry and their varied specialities, thus extending our view on biological diversities of living species in relation to medicine.
‘Knowledge is treasure of a wise man.’ The free access of this journal provides an immense scope of learning for the both the old and the young in field of medicine and dentistry as well. The multidisciplinary nature of the journal makes it a better platform to absorb all that is being researched and developed. The publication process is systematic and professional. Online submission, publication and peer reviewing makes it a user-friendly journal.
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I wish JCDR a great success and I hope that journal will soar higher with the passing time."



Dr Saumya Navit
Professor and Head
Department of Pediatric Dentistry
Saraswati Dental College
Lucknow
On Sep 2018




Dr. Arunava Biswas

"My sincere attachment with JCDR as an author as well as reviewer is a learning experience . Their systematic approach in publication of article in various categories is really praiseworthy.
Their prompt and timely response to review's query and the manner in which they have set the reviewing process helps in extracting the best possible scientific writings for publication.
It's a honour and pride to be a part of the JCDR team. My very best wishes to JCDR and hope it will sparkle up above the sky as a high indexed journal in near future."



Dr. Arunava Biswas
MD, DM (Clinical Pharmacology)
Assistant Professor
Department of Pharmacology
Calcutta National Medical College & Hospital , Kolkata




Dr. C.S. Ramesh Babu
" Journal of Clinical and Diagnostic Research (JCDR) is a multi-specialty medical and dental journal publishing high quality research articles in almost all branches of medicine. The quality of printing of figures and tables is excellent and comparable to any International journal. An added advantage is nominal publication charges and monthly issue of the journal and more chances of an article being accepted for publication. Moreover being a multi-specialty journal an article concerning a particular specialty has a wider reach of readers of other related specialties also. As an author and reviewer for several years I find this Journal most suitable and highly recommend this Journal."
Best regards,
C.S. Ramesh Babu,
Associate Professor of Anatomy,
Muzaffarnagar Medical College,
Muzaffarnagar.
On Aug 2018




Dr. Arundhathi. S
"Journal of Clinical and Diagnostic Research (JCDR) is a reputed peer reviewed journal and is constantly involved in publishing high quality research articles related to medicine. Its been a great pleasure to be associated with this esteemed journal as a reviewer and as an author for a couple of years. The editorial board consists of many dedicated and reputed experts as its members and they are doing an appreciable work in guiding budding researchers. JCDR is doing a commendable job in scientific research by promoting excellent quality research & review articles and case reports & series. The reviewers provide appropriate suggestions that improve the quality of articles. I strongly recommend my fraternity to encourage JCDR by contributing their valuable research work in this widely accepted, user friendly journal. I hope my collaboration with JCDR will continue for a long time".



Dr. Arundhathi. S
MBBS, MD (Pathology),
Sanjay Gandhi institute of trauma and orthopedics,
Bengaluru.
On Aug 2018




Dr. Mamta Gupta,
"It gives me great pleasure to be associated with JCDR, since last 2-3 years. Since then I have authored, co-authored and reviewed about 25 articles in JCDR. I thank JCDR for giving me an opportunity to improve my own skills as an author and a reviewer.
It 's a multispecialty journal, publishing high quality articles. It gives a platform to the authors to publish their research work which can be available for everyone across the globe to read. The best thing about JCDR is that the full articles of all medical specialties are available as pdf/html for reading free of cost or without institutional subscription, which is not there for other journals. For those who have problem in writing manuscript or do statistical work, JCDR comes for their rescue.
The journal has a monthly publication and the articles are published quite fast. In time compared to other journals. The on-line first publication is also a great advantage and facility to review one's own articles before going to print. The response to any query and permission if required, is quite fast; this is quite commendable. I have a very good experience about seeking quick permission for quoting a photograph (Fig.) from a JCDR article for my chapter authored in an E book. I never thought it would be so easy. No hassles.
Reviewing articles is no less a pain staking process and requires in depth perception, knowledge about the topic for review. It requires time and concentration, yet I enjoy doing it. The JCDR website especially for the reviewers is quite user friendly. My suggestions for improving the journal is, more strict review process, so that only high quality articles are published. I find a a good number of articles in Obst. Gynae, hence, a new journal for this specialty titled JCDR-OG can be started. May be a bimonthly or quarterly publication to begin with. Only selected articles should find a place in it.
An yearly reward for the best article authored can also incentivize the authors. Though the process of finding the best article will be not be very easy. I do not know how reviewing process can be improved. If an article is being reviewed by two reviewers, then opinion of one can be communicated to the other or the final opinion of the editor can be communicated to the reviewer if requested for. This will help one’s reviewing skills.
My best wishes to Dr. Hemant Jain and all the editorial staff of JCDR for their untiring efforts to bring out this journal. I strongly recommend medical fraternity to publish their valuable research work in this esteemed journal, JCDR".



Dr. Mamta Gupta
Consultant
(Ex HOD Obs &Gynae, Hindu Rao Hospital and associated NDMC Medical College, Delhi)
Aug 2018




Dr. Rajendra Kumar Ghritlaharey

"I wish to thank Dr. Hemant Jain, Editor-in-Chief Journal of Clinical and Diagnostic Research (JCDR), for asking me to write up few words.
Writing is the representation of language in a textual medium i e; into the words and sentences on paper. Quality medical manuscript writing in particular, demands not only a high-quality research, but also requires accurate and concise communication of findings and conclusions, with adherence to particular journal guidelines. In medical field whether working in teaching, private, or in corporate institution, everyone wants to excel in his / her own field and get recognised by making manuscripts publication.


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

Important Notice

Original article / research
Year : 2022 | Month : April | Volume : 16 | Issue : 4 | Page : ZC45 - ZC50 Full Version

Impact of Access Cavity Design and Root Canal Taper on Fracture Resistance of Permanent Mandibular Molars: An In-vitro Study


Published: April 1, 2022 | DOI: https://doi.org/10.7860/JCDR/2022/52143.16267
Nandini T Niranjan, Jwaalaa Rajkumar

1. Professor, Department of Conservative Dentistry and Endodontics, Bapuji Dental College and Hospital, Davangere, Karnataka, India. 2. Postgraduate, Department of Conservative Dentistry and Endodontics, Bapuji Dental College and Hospital, Davangere, Karnataka, India.

Correspondence Address :
Nandini T Niranjan,
Professor, Department of Conservatve Dentistry and Endodontics, Room No. 6, Bapuji Dental College and Hospital, Davangere, Karnataka, India.
E-mail: nanduendo@gmail.com

Abstract

Introduction: Minimal invasive endodontics in the form of conservative access designs and minimal root canal taper preparation have been devised to preserve tooth structure and increase fracture resistance.

Aim: To assess the influence of two different access cavity designs and two different final preparation tapers on fracture resistance of mandibular molars.

Materials and Methods: In this in-vitro study, performed over a period of two months, a total of 54 extracted human permanent mandibular first and second molar teeth with completely formed apices were selected and for infection control, the teeth were stored in 10% buffered formalin solution for two weeks before the experiment. The teeth were then randomly allocated into three groups, Group C where no tooth preparation was carried out, Group TAC in which Traditional Access Cavity design was performed and Group TREC where Truss Access Cavity was performed. The groups TAC and TREC were further subdivided into subgroup A and B with two different tapers 0.04 and 0.06 taper preparations. Mesial canals of the teeth were chosen for testing the minimal root canal taper preparations. After apical gauging the distal canals, obturation and postendodontic restoration was carried out in all teeth of both the test groups. The teeth in all three groups were subjected to fracture testing in a universal testing machine. The data were recorded. One-way Analysis of Variance (ANOVA) and Tukey’s Post-hoc test were used for statistical analysis.

Results: The fracture resistance between group C and groups TAC and TREC and their subgroups were found to be statistically significant (p<0.05). However, there was no statistically significant difference (p>0.05) observed between the two test groups TAC and TREC and their subgroups.

Conclusion: The conservative truss access design in combination with a reduced root canal taper preparation has shown to have produced better fracture resistance values in comparison to other groups and their subgroups although the results were not statistically significant.

Keywords

Conservative access preparation, Minimal invasive endodontics, Truss cavity

Teeth managed endodontically are known to be weak due to caries removal, access cavity preparation and excessive use of rotary instrumentation. Vertical root fracture is a serious clinical concern and has multiple precipitating factors. Hence, in an effort to reduce such complications minimal enlargement and flare preparation of root canal space has been recommended. Since, increased cavity sizes and access cavities increase cuspal deflection, the extent of cuspal flexure after endodontic procedures also becomes a factor to be considered for potential failure (1). A study by Clark D and Khademi J states that molar fracturing can be described as retrograde vertical root fracture and that the ultimate purpose of access must be to avoid the fracturing potential of endodontically treated teeth. Since, the traditional access design focuses more on operator needs and less on restorative needs the newer trends which lays emphasis on biologic and structural aspects for teeth in adapting to the concepts of minimally invasive dentistry have been widely acclaimed in recent times (2).

In order to maintain optimal strength and fracture resistance, the Pericervical Dentine (PCD), undermined dentine, Dentinoenamel Junction (DEJ), axial wall of DEJ, cervical enamel in physiologic young teeth which have been considered of high value with respect to tissue type becomes important. The PCD is the dentine near the alveolar crest and the critical zone identified to be roughly 4 mm above the crestal bone and 4 mm below the crestal bone is important when it comes to ferrule, fracturing and dentine tubule proximity (2).

In the endodontic domain the essence of MID could be attained by shifting to access opening designs that are crafted to preserve sound tooth structure especially cervically as loss of tooth structure in this area of the teeth could make them more susceptible to fracture and by the use of minimally tapered rotary instruments in the root canal space as an attempt to avoid straightening the canals, causing irreparable defects like cracks and stripping of the root walls (3). Although undermined enamel does not aid in reinforcing the tooth with regard to fracture potential but naturally occurring undermined dentine in the form of soffit aids in adding mechanical strength and value to the teeth (4). Since, the fracture of teeth often results in extraction it can ultimately leave the dentist and patients to question the prognosis of such endodontically treated teeth.

Although the primary objective of these newer designs is ‘directed dentine conservation’ (2) several approaches to the Contracted Endodontic Cavities (CEC) technique have been discussed and demonstrated. The ‘Ninja’ and ‘Truss’ endodontic cavities (NEC) and (TREC) designs are inclusive of such demonstrations (5). The TREC is more a strategic design where cavities are prepared over each canal orifice from occlusal surface leaving a dentine truss between the cavities. The approach also proves to be more conservative in that the entire pulp chamber deroofing is avoided (5),(6).

Although studies (4),(5) have been conducted on fracture resistance of conservative cavity designs and root canal instrumentation of increasing tapers (6) no study till date has been conducted in combination of the two in the same experimental teeth. Hence, the aim of this study was to assess the influence of two different access cavity designs and two different final preparation tapers on fracture resistance of mandibular molars. The null hypothesis is that, there is no difference in the fracture resistance of teeth with two different access cavity designs and two different root canal taper preparation.

Material and Methods

In this in-vitro study, performed over a period of two months between September and October 2020 in the Department of Conservative Dentistry and Endodontics, Bapuji Dental College and Hospital, Davangere, Karnataka, India. A total of 54 extracted human permanent mandibular first and second molar teeth with completely formed apices were selected and the teeth were stored in 10% buffered formalin solution for two weeks before the experiment. At no stage in the procedure, were the teeth allowed to dehydrate. Ethical committee clearance was obtained from the Research Development and Sustenance Committee, Bapuji Dental College and Hospital, Davangere (Ref.No.BDC/Exam/467/20018-2019).

Inclusion and Exclusion criteria: Non carious teeth with mature apices, teeth with no visible fracture lines or cracks and free of any developmental defects, teeth with similar morphology and relative coronal dimensions were included in the study. However, teeth with previous restoration or endodontic manipulation, short thin or curved roots, fused roots, fused mesial canals and canal calcifications, internal or external resorption were excluded.

The teeth where then randomly allocated into three groups. Standardised radiographs (Paralleling Technique) of each tooth in both the buccal-lingual and mesial-distal directions was taken. The anatomic crown height of the 54 teeth was measured from the occlusal surface to the CEJ on all four sides of the teeth; buccolingual and mesiodistal (MD) dimensions were measured at the occlusal surface. Tooth measurements were taken with a digital caliper (Digimatic 500). Teeth with similar dimensions were selected. Therefore, homogenous groups were created based on the averages of tooth dimensions in order to minimise the influence of size and shape variations. The specimens were randomly divided into two test groups (TAC and TREC) and one control group containing 18 teeth each. The two test groups were divided into two subgroups, Subgroup A (n=9): 0.04 taper and Subgroup B (n=9): 0.06 taper.

Study Procedure

1. A Access cavity preparation: Access cavities were performed with a size 856 diamond point and Endo z bur in a high-speed air rotor with water cooling.

In the intact group, no treatment was performed on teeth, and they remained intact until the fracture resistance test. In the TAC group, traditional endodontic access cavities were prepared following conventional guidelines (7). TRECs (Table/Fig 1) was performed by 46keeping part of the pulp chamber roof intact. Then, a single access to the mesial canals was created in the buccal-lingual direction, and another circular one was made to reach the distal canal orifice. The single oval access to the mesial canals was determined by joining the two access slots created following the perpendicular projection to the occlusal surface of the mesial canals and enlarging it up to 1.2 mm for the oval minimum diameter; the circular access over the distal canal was started with one access slot created following the perpendicular projection to the occlusal surface of the distal canal, and it was enlarged circularly to a 1.2 mm diameter. The diameters were measured and checked with a digital caliper. The two accesses on the same occlusal surface were separated by an enamel/dentine bridge (5),(8).

2. Canal instrumentation: In mesial canals of all specimens of group TAC and TREC, working length was determined by advancing a size 10 K-file into the canal until it was just visible at the foramen and then 1 mm was subtracted from this measurement. The size of the minor constriction was standardised, and any tooth where the size 15 K-file extruded beyond the apical foramen was excluded (9).

Group TAC and TREC: Subgroup A: The mesial canals of teeth were shaped with rotary instruments reaching a final continuous 0.04 taper up to tip size 25 using crown down technique, in the order of files sequence according to manufacturer instructions.

Group TAC and TREC: Subgroup B: The mesial canals of teeth were shaped with rotary instruments reaching a final continuous 0.06 taper up to tip size 25 using crown down technique, in the order of files sequence according to manufacturer instructions.

The final apical file size and taper of the distal canals of all teeth in the two test groups were determined by apical gauging. Also, instruments were used with an endodontic motor (X-Smart, Dentsply Maillefer) following the manufacturer’s instruction.

During the shaping p rocedure, a #10 K-file was taken to the working length to check patency, and intermittent irrigation with 5.25% NaOCl was performed with disposable syringes of 5 mL with 27 G needles.The final flush was done using 17% EDTA and saline. The root canals were then dried using paper points.

3. Obturation: Master cone was selected and obturation was then carried out using cold lateral compaction technique and AH Plus sealer with all canals. The orifices were sealed using flowable resin composite and postendodontic core build up was done using resin composite.

4. Fracture resistance testing: The 54 specimens were mounted in self-curing resin (SR Ivolen; Ivoclar Vivadent, Schaan, Lichtenstein) with the roots embedded up to 2 mm apical to the CEJ as reported in a previous study (4).The specimens were then placed in the Hounsfield universal testing machine (Table/Fig 2) equipped with a 500 N cell load that applied a continuous compressive strength force at a crosshead speed of 1 mm/min. The teeth were positioned vertically and a cylindrical hardened steel rod attached to the upper crosshead was lowered until the cone shaped point of the rod rested on the teeth. The universal load-testing machine was then connected to a microsoft based Qmat Pro that collected all the information and indicated the load at which each mandibular molar tooth fractured. The load at which the fracture occurred was then measured in kilogram force.

Statistical Analysis

The values obtained from samples were analysed using R software version 4.0.2. The descriptive statistics, including Mean and Standard Deviation (SD) were calculated for each group tested. The data was normally distributed hence, One-way ANOVA (Analysis of Variance) was used for intergroup and repeated ANOVA was used for intragroup analysis data for significant differences. Pair-wise comparison between the groups were done using Tukey’s Post-hoc test. A p<0.05 was considered statistically significant.

Results

The descriptive statistics between the three groups have been shown in (Table/Fig 3) and the mean and SD of intact tooth group was found to be higher than the two test groups. (Table/Fig 4) reveals that The intact teeth have maximum fracture resistance with a Mean±SD of 262.9±58.75 kilograms force.

(Table/Fig 5) reveals that intact teeth group in comparison to TAC and Truss group showed statistical significance (p<0.05). However, 47TAC group was found to show statistically significant difference in comparison to intact teeth group (p<0.05) but showed statistically non significant difference in comparison to Truss group. Similarly, the Truss group showed statistically significant difference (p<0.05) in comparison to intact teeth. However, it did not show statistically significant difference when compared to TAC group.

(Table/Fig 6) shows multiple comparisons between the groups and subgroup. The intact teeth group was found to produce statistically significant difference when compared to TAC (Subgroup A), TAC (Subgroup B), Truss (Subgroup A) and Truss (Subgroup B) with (p<0.05).

The traditional (Subgroup A) showed statistically significant difference when compared to intact teeth with (p<0.05). It did not show statistically significant difference when compared to Traditional (Subgroup B), Truss (Subgroup A), and Truss (Subgroup B).

Also, Traditional (Subgroup B) was found to give a statistically significant difference with intact teeth group with (p<0.05) and did not show statistically significant difference with the remaining group.

Similarly, Truss (Subgroup A) and Truss (Subgroup B) groups also showed statistically significant difference only with intact teeth group (p<0.05) and not with other groups.

Discussion

The present study was aimed to understand if minimal invasive access design in combination with reduced taper root canal preparation 0.04 and 0.06 taper has increased the fracture resistance of teeth in comparison to traditional access design with similar taper root canal preparation and intact control group.

The minimal invasive endodontics approach has gained popularity in current times as it aids in maintaining a balance in functional, biological, adhesive, mechanical and aesthetic parameters through maximum preservation and conservation of tooth structure (3),(10).

In the present study, a statistically significant result was obtained between the intact teeth group and the two test groups TAC and Truss endodontic access design. It is important to understand, however, that restoring teeth after access cavity preparation has been shown to enable teeth to regain 72% of their fracture resistance (11),(12) and that, it is not the cavity design per se. The traditional access design based on GV Black’s extention for prevention and the Truss design based on the concept of directed dentine as described by Clark D and Khademi J (2) that highlights preserving PCD and a portion of coronal pulp chamber, the soffit are not the main reason for reduced fracture resistance but rather the loss of mesial and distal ridges as observed by Corsentino G et al., and Silva AA et al., (5),(13).

In this study irrespective of tapers, Truss access design has performed better than the traditional access design, however, a statistically significant difference could not be obtained and this could be attributed to smaller samples in each of the groups and their subgroups. The better performance can to a certain extent attributed to dentine preservation as claimed by Clark D and Khademi J, Plotino G et al., (2),(14). However, several studies that followed to test this proposition as tabulated in (Table/Fig 7) did not report any statistically significant difference in fracture resistance of contracted/conservative cavities in comparison to TAC. The results of the present study is in accordance with these studies (5),(6),(12),(15),(16),(17),(18).

However, several other studies that followed to test this proposition such as Moore B et al., where CEC showed mean failure loads at (1703-558 N; range, 1205-3021 N) and TEC that showed failure loads at (1384-377 N; range, 966-2381 N) (12), Chlup Z et al., where mean failure loads for mandibular premolars where 1079.0±383.2 N for CEC and for TEC was 946.6±384.1 N, Ivanoff CS et al., (CEC-601.7±307.9 N and TEC- 600.9±360.3 N), Rover G et al., (18) (CEC-996.30-490.78 N and TEC 937.55-347.25 N), Corsentino G et al., (TEC 1149.8 N/mm2 and TREC-1237.1 N/mm2) and Ozyurek T et al., (CEC and TEC with class 11 cavities restored with Ever X Posterior and SDR (TEC+EverX Posterior-971.03±114.28 N, CEC+EverX Posterior -1008.25±216.83 N, TEC+SDR-1451.92±205.39 N, CEC+SDR- 1674.07±238.36 N), Sabeti M et al., (Conservative access cavity- 1705.691250 (591.51) N, Traditional access cavity-1471.113125 (435.34) N) did not report any statistically significant difference in fracture resistance of contracted/conservative cavities in comparison to TEC (5),(6),(13),(16),(17),(18),(19). The results of the present study (Mean fracture resistance values expressed as break force- {TAC - 167.4 Kg and TREC - 184.8 Kg) are in accordance with these studies.

Similarly between Traditional 0.04 and 0.06 tapers and Truss 0.04 and Truss 0.06 tapers, 0.04 taper, in both groups has performed better than 0.06 taper but then again a statistically significant result could not be obtained because of smaller sample size.

With regard to the tapers 0.04 and 0.06 that was tested in the current study, studies by Sabeti M et al., and Zogheib C et al., have shown similar results and it was concluded by Sabeti M et al., that, increasing tapers 0.06 to 0.08 files increased stress in root dentine and reduces the fracture resistance(6),(19).

Although previous studies have emphasised that the root canals are significantly weakened by instrumentation alone (20),(21),(22). A study by Zandbiglari T et al., has shown that greater taper instruments greatly weaken the teeth (23). The amount of remaining dentine thickness and its preservation impacts the resistance of prepared root canals to fracture is henceforth a serious consideration; however, the compromised efficiency of disinfection of root canals through such minimal access preparations cannot be overlooked.

Teeth like the mandibular molars are more prone to vertical root fracture (24) and severe tooth structure loss has been proposed as an important cause for tooth fracture (2),(4),(6).The conservation of tooth structure through newer access designs and minimal canal preparation with lesser tapers and maintaining smaller apical diameters had been the focus of the present study that aimed to incorporate the minimal invasive approach in endodontics (3),(10).

Based on the results of the present study the null hypothesis is partially rejected as the intact control group (Group C) has shown statistically significant difference when compared to Traditional (0.04 taper), Traditional (0.06 taper), Truss (0.04 taper) and Truss (0.06 taper). However, although the Truss group (Group TREC) and its subgroups A and B were found to have mean values of fracture resistance slightly above the Traditional group (Group TAC) and its subgroups A and B, a statistically significant difference was not obtained, this could be attributed to smaller samples in each of the groups and their subgroups.

Limitation(s)

The limitations of the present in-vitro study are that exact oral conditions could not be simulated. Also, smaller sample size could have resulted in not producing a statistically significant difference between the test groups. Further studies with larger sample sizes and its application into clinical settings are necessary and recommended.

Conclusion

Within the limitations of the present in-vitro study and based on the results, following conclusions can be drawn. There was a statistically significant difference between the intact teeth group and the two test groups and their subgroups. There was no statistically significant difference between the test groups and their subgroups. However, the conservative Truss access design in combination with a reduced root canal taper preparation has shown to have produced better fracture resistance values in comparison to other groups and their subgroups indicating a need for more studies to be carried out with larger sample sizes.

References

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DOI and Others

DOI: 10.7860/JCDR/2022/52143.16267

Date of Submission: Aug 27, 2021
Date of Peer Review: Oct 29, 2021
Date of Acceptance: Dec 13, 2021
Date of Publishing: Apr 01, 2022

AUTHOR DECLARATION:
• Financial or Other Competing Interests: None
• Was Ethics Committee Approval obtained for this study? Yes
• Was informed consent obtained from the subjects involved in the study? NA
• For any images presented appropriate consent has been obtained from the subjects. NA

PLAGIARISM CHECKING METHODS:
• Plagiarism X-checker: Aug 28, 2021
• Manual Googling: Oct 30, 2021
• iThenticate Software: Dec 08, 2021 (17%)

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