Journal of Clinical and Diagnostic Research, ISSN - 0973 - 709X

Users Online : 306124

AbstractMaterial and MethodsResultsDiscussionConclusionReferencesDOI and Others
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

Dr Mohan Z Mani

"Thank you very much for having published my article in record time.I would like to compliment you and your entire staff for your promptness, courtesy, and willingness to be customer friendly, which is quite unusual.I was given your reference by a colleague in pathology,and was able to directly phone your editorial office for clarifications.I would particularly like to thank the publication managers and the Assistant Editor who were following up my article. I would also like to thank you for adjusting the money I paid initially into payment for my modified article,and refunding the balance.
I wish all success to your journal and look forward to sending you any suitable similar article in future"



Dr Mohan Z Mani,
Professor & Head,
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.
As an experienced dentist and an academician, I proudly recommend this journal to the dental fraternity as a good quality open access platform for rapid communication of their cutting-edge research progress and discovery.
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 : January | Volume : 16 | Issue : 1 | Page : ZC08 - ZC12 Full Version

Comparative Evaluation of Flexural Strength and Surface Roughness of Three Different Commercially Available Provisional Restorative Materials: An In-vitro Study


Published: January 1, 2022 | DOI: https://doi.org/10.7860/JCDR/2022/51527.15830
Rashmi Rajput, Anurag Hasti, Ashish Choudhary, Surabhi Duggal, Sheeba Ali

1. Postgraduate Student, Department of Prosthodontics, School of Dental Sciences, Sharda University, Greater Noida, Uttar Pradesh, India. 2. Professor, Department of Prosthodontics, School of Dental Sciences, Sharda University, Greater Noida, Uttar Pradesh, India. 3. Professor and Head, Department of Prosthodontics, School of Dental Sciences, Sharda University, Greater Noida, Uttar Pradesh, India. 4. Assistant Professor, Department of Prosthodontics, School of Dental Sciences, Sharda University, Greater Noida, Uttar Pradesh, India. 5. Assistant Professor, Department of Oral Pathology and Microbiology, School of Dental Sciences, Sharda University, Greater Noida, Uttar Pradesh, India.

Correspondence Address :
Dr. Rashmi Rajput,
Sharda University, Knowledge Park III, Greater Noida-201310, Uttar Pradesh, India.
E-mail: dr.rashmi3091@gmail.com

Abstract

Introduction: Provisional restorative materials require good mechanical properties for long term restorations. Provisional restorative materials are continuously being updated and improved upon for these mechanical, biological and esthetic properties.

Aim: To determine and compare the surface roughness and the strength of three different commercially available provisional restorative materials at different periods.

Materials and Methods: This in-vitro study involved 120 samples of a stainless steel mould fabricated and equally divided. The study was carried out for one year in the Department of Prosthodontics and Crown & Bridge, School of Dental Sciences, Sharda University between June 2020 to June 2021. Materials compared were Dental Products of India (DPI) heat cure acrylic, Protemp 4 and Revotek LC. Each group was further categorised into four groups to measure the flexural strength (after 24 hours, storage in artificial saliva for seven days and 30 days) and surface roughness. A Universal Testing Machine determined the flexural strength and Perthometer for surface roughness. Statistical analysis was done using a one-way Analysis of Variance (ANOVA) test followed by a post-hoc test.

Results: In the three types of materials studied, flexural strength after 24 hours, 7 days, and 30 days was statistically significantly higher (p-value=0.001) in DPI than Protemp 4 and Revotek LC whereas, DPI exhibited a decrease in surface roughness when compared to Protemp 4 and Revotek LC (p-value=0.002).

Conclusion: Within the limitations of the study it was found that DPI demonstrated a higher flexural strength at 24 hours than Protemp 4 and Revotek LC. After storage in saliva for 7 days and 30 days, there was a decrease in the flexural strength of three commercially available provisional materials. The mean surface roughness of Revotek LC was more than DPI and Protemp 4.

Keywords

Bisphenol glycidyl methacrylate, Perthometer, Polymethyl methacrylate, Urethane dimethacrylate, Universal testing machine

Prosthodontic management of partially edentulous individuals usually requires continual planning of provisional restorations which helps the clinician analyse the success of the final restoration in its mechanical, aesthetic, and functional aspects (1). Biologically, provisional restorations help in pulp protection, prevent tooth fracture, help in the maintenance of periodontal health, oral hygiene, and occlusal compatibility. Mechanically they help in retention, strength, and inter abutment alignment. In addition to this, provisional restorations must also be aesthetically stable in colour and translucent (2).

Since the 1930s, provisional restorative materials have changed greatly from acrylics and prepared crowns (first generation) to modern bisacryl materials and heat cure Polymethyl Methacrylate (PMMA) blocks that are being used for Computer Aided Design/Computer Aided Manufacturing (CAD/CAM) restorations (1),(2). The history of provisional restorations dates back to the 1930s. In 1937 Walter introduced PMMA heat cure resin. Auto polymerising acrylic resin was introduced in 1947 and prefabricated aluminum and celluloid crowns in 1959. Polycarbonate resin was introduced in 1973 by Charles et al., Weiner in 1983 described a technique that uses silicon putty impression material for fabrication of provisional restorations. Visible light-cured microfilled composite resin was also used by some researchers and finally provisional restorations were introduced in implant dentistry in 1987 (3).

Interim restorative substances can be categorised into four following constitutions: (a) PMMA; (b) Polyethyl or Butyl methacrylate; (c) Microfilled bisphenol A Glycidyl Methacrylate (Bis-GMA) composite resin; and (d) Urethane Dimethacrylate (UDMA) (light-polymerising resins) (4),(5). PMMA resins are comparatively economical, have good colour stability, good marginal accuracy, and superior ability to be polished. However, the main drawback of this type of resin is high polymerisation shrinkage, an exothermic reaction, low strength and wear resistance as well as pulpal irritation due to surplus free monomer (1).

Latest bis-acryl materials have resolved the disadvantages related to traditional acrylic. In the 1960s Bowen developed Bis-GMA, the backbone for most composite resins used to date. It also paved the way for bis-acryl self-cured composites. Although available in a wide variety of shades, including bleach, bis-acrylate comes in a convenient syringe applicator having a low exothermic reaction, decreased shrinkage and less odour. A drawback is ease in breakage when placed under areas of stress, but they are easy to repair (2).

The UDMA is available in an adaptable putty consistency and is light-cured. It offers a good marginal fit in addition to a polished surface, exhibiting low shrinkage and no exothermic reaction. It can be fixed with flowable and hybrid composites, provides good transverse strength, and is relatively abrasion resistant. A disadvantage is its availability in a single shade. UDMA is well suited for immediate load implant prostheses (5).

Clinicians have many choices while fabricating provisional restorations that are being updated and improved upon for their aesthetic, biological and mechanical properties. Out of these properties, flexural strength and surface roughness are important for the success of any provisional restoration. Flexural strength might have an impact on the integrity of the restoration during use making it of accurate significance in long span restorations as well as in patients with parafunctional habits (5).

The surface roughness of restorative materials is important for the periodontal health of the teeth. Rough surfaces on provisional restorations develop conditions for the multiplication of microorganisms, especially those responsible for caries and periodontal disease (1).

There still exists a lacuna of information in the literature, even though research on the impact strength of various provisional restorative materials has been performed. Hence, this study was done to assess the flexural strength and surface roughness of three commonly used provisional restorative materials (DPI heat cure tooth moulding acrylic resin, Bis-GMA, and UDMA) in simulated intraoral conditions (Wet mouth Artificial saliva, ICPA Health Products Ltd., Mumbai). A paucity of research in the literature regarding UDMA and the comparison of its result with different existing provisional restorative materials makes this study novel.

Material and Methods

This in-vitro study was conducted in the Department of Prosthodontics and Crown & Bridge, School of Dental Sciences, Sharda University, Uttar Pradesh, India between June 2020 to June 2021. Before the commencement of the laboratory study, the study design was approved by the Institutional Ethical Review committee (Ref. No. SU/SMS&R/76-A/2018/120).

Procedure

A total of 120 samples were made and equally divided into three groups. Further, each group was subdivided into four subgroups (Table/Fig 1),(Table/Fig 2).

The study was divided into two parts: Part I- Preparation of test samples and part II- Evaluation of test samples.

Preparation of test samples includes: a) Preparation of acrylic resin (DPI tooth moulding resin: polymer and monomer, Dental product of India: The Bombay Burmah Trading Corporation Ltd.,) test samples (represented as PF1, PF2, PF3, PF4). b) Preparation of Protemp 4 (Bis GMA) (3M Deutschland GmbH Batch no 41453- Neuss-Germany) test sample (represented as BF1, BF2, BF3, BF4). c) Preparation of Revoteck LC (Urethane Dimethacrylate) (GC Dental Products Corp. Tokyo Japan) test samples (represented as UF1, UF2, UF3, UF4). Evaluation of test samples includes: a) Evaluation of test samples for flexural strength and b) Evaluation of test samples for surface roughness.

Part I- Preparation of Test Samples

a) Preparation of acrylic resin test samples (n=40)

Preparation of gypsum mould to obtain the test samples: A standardised mild stainless steel mould (according to International Standards Organisation Specification No. 27) was used for fabrication of the master die measuring 25 mm long, 2 mm wide and 2 mm thick (Table/Fig 3) for flexural strength (6),(7). For surface roughness, the dimensions were calculated up to 20 mm long, 10 mm wide, and 3 mm thick (Table/Fig 4) (8).

A mould of the master die was created into which molten modeling wax was poured to obtain wax blocks followed by the traditional process of flasking to obtain the acrylic resin samples which were further finished and polished.

Finishing of samples (1),(3),(8): For flexural strength tungsten carbide burs WL-B2 and WL-B11 attached to the lathe were used for finishing. For surface roughness tungsten carbide burs were used along with emery sandpaper no. 100, 400, 800 and 1200 together with polishing using pumice and buff.

b) Preparation of Bis-GMA test samples (n=40): Sample moulds were fabricated by duplicating the master die to make Protemp 4 restorative material. Gun dispenser was used to fill in the moulds and shaped using a plastic filling instrument. As instructed by the manufacturer, the material was allowed to auto-cure for 5-7 minutes and then retrieved.

Finishing of samples (9),(10): An oxygen inhibition layer was formed on the surface of test samples during self-cure which was removed by gauze soaked in alcohol after polymerisation of the material. Red-coded tungsten carbides were used for finishing of samples. For surface roughness: After tungsten carbide super finishing bur, the Shofu super snap composite polishing kit was employed for polishing to measure surface roughness.

c) Preparation of urethane dimethacrylate test samples (n=40): The sample moulds obtained after duplication were packed with Revotek LC packable consistency in small increments and adapted well. According to the manufacturer’s instructions, a light cure unit (Ivoclar Vivadent Bluephase N LED) was used for curing for 30 to 60 seconds, henceforth retrieval.

Finishing of sample (1),(3),(8): For flexural strength the set of test samples were finished with tungsten carbide super finishing bur. For surface roughness: Samples were finished with carbide super finishing bur and polished using shofu super snap composite polishing kit.

The samples thus obtained were divided into groups mentioned earlier and were stored in artificial saliva for seven days and 30 days respectively.

PART II- Evaluation of Test Samples

a) Evaluation of test samples for flexural strength: Flexural strength determination of test samples was done using a universal testing machine (UTEST Material testing Equipment, Model No. WAW-2000Y) (Table/Fig 5) of 1 mm/min crosshead speed. The progressive load was applied and reading was recorded on the software at the fracture of the test samples (Table/Fig 6).

b) Evaluation of test samples for surface roughness: Test samples were subjected to surface roughness evaluation immediately. Quantitative judgment was done with the aid of a Perthometer (Mahr Perthometer PGK plus). The stylus Perthometer utilises a probe to identify the surface. It is moved along the surface to analyse the surface height. A feedback loop monitors the force from the sample that pushes up against the probe (Table/Fig 7).

Statistical Analysis

The data obtained were tabulated and subjected to statistical analysis using the IBM Statistical Package for the Social Sciences software for Windows version 23.0 (Armonk, NY: IBM Corporation. Released 2015). The significance level was fixed at 5% (α=0.05). Parametric tests namely one-way ANOVA and the post-hoc test were used to analyse the data. Statistical significance was set at p-value<0.05. One-way ANOVA is dedicated to comparing means of two or higher groups to determine any statistical evidence. In this study, one-way ANOVA test was used to compare the mean values of surface roughness (postfinishing of the samples) between the three subgroups. The Post-hoc test form an important component of ANOVA. However, ANOVA results do not signify particular differences between means that are significant. Post-hoc tests revealed differences between means of multiple groups while controlling the error rate.

Results

The mean flexural strength of the subgroups PF1, BF1, UF1 after 24 hours (Table/Fig 8) demonstrate a higher flexural strength for PF1 (377.11 MPa) than BF1 (320.85 MPa) and UF1 (215.96 MPa) and it was statistically significant (p-value=0.001).

Mean flexural strength after 7 days (Table/Fig 9) was least for UF2 (155.43 MPa), followed by BF2 (284.25 MPa) and the highest for PF2 (307.23 MPa) (p-value=0.001).

Following 30 days (Table/Fig 10), the mean flexural strength was maximum for PF3 (342.37 MPa) and the lowest for UF3 (160.31 MPa) (p-value=0.001).

(Table/Fig 11) depicts the surface roughness values for subgroups PS4, BS4 and US4. Surface roughness values for PS4 (0.23 Ra) specimens were found to be lower than the BS4 (0.24 Ra) and US4 (0.30 Ra) specimens (p-value=0.002).

Discussion

Stability as a mechanical property of provisional crown materials is essential to avoid failure of restorations from the start till the end. It must be protected to the pulp, positionally stable, easy to clean, have accurate margins, resistant to wear, and dimensionally stable (2).

It can be predicted that interactions between saliva, food components, beverages in the oral environment, and these materials impair and deteriorate dental restorations (11). Flexural strength is thus a relevant characteristic property for a provisional restorative material to long term provisionalisation. They are a crucial diagnostic aid for the success of fixed prosthodontic treatment (2). For treatment planning of complex cases when the final prosthesis is delayed, the long term dimensional stability of provisional restorations in the oral environment is desirable. The clinically acceptable critical value for a hard surface in the oral environment is 0.2 microns, above which bacterial colonisation takes place. This substantiates the need for a smooth and glossy surface. Also, greater the surface smoothness of a restorative material, lower the capability to retain microorganisms and dental biofilm formation [2,6].

A study conducted by Sharma SP et al., in 2013 showed that the flexural strength of PMMA is finer than UDMA (12). Also, PMMA proves as a better provisional material for a long period, in patients with parafunction. Yanikog???lu N et al., evaluated the flexural strength of temporary restorative materials stored in different solutions of one methacrylate based resin and three bis-acryl resin provisional materials (11). Protemp 4 displayed the highest fracture strength amongst the bis-acryl materials during the 14 days inspection interval. Hence, this study was organised with the intent to determine which provisional restorative material would fulfill most requirements of long term provisionalisation.

Lang R et al., tested Polymethylmethacrylate (PMMA) and composite based Fixed Partial Denture (FPD) for their resistance to fracture (13). They found that PMMA materials showed, low mechanical fracture behaviour because of deformation during oral stimulation. While in this study the mean flexural strength of DPI was higher at 24 hours than post 7 days and 30 days. A reason for this result could be the breaking down of the resultant cross-linking chain after water absorption that leads to degradation of the mechanical properties of PMMA. Another reason might be the polar properties of the resin molecules, which can act as plasticisers hence decreasing the fracture strength of the materials (5).

In this experiment, the average flexural strength of Bis-GMA obtained was greater at 24 hours than after 7 days and 30 days. The reason for this could be credited to the swelling of bis-acrylate and the breaking of cross-link groups after water absorption. The Bis-GMA based polymer is vulnerable to swelling and softening by organic solvent covering a spectrum of the solubility parameter. The microvoids within the subsurface damaged region of the solvent treated specimens are believed to be caused by leaching out of unreacted monomer, in addition to the swelling process (5). In 1984 Wu W et al., studied the subsurface damage layer of composite restoration by testing three materials of bis-acrylate (Adaptic, Profile, Concise) via an optical microscope (14). They concluded that Bis-GMA based polymers are highly susceptible to softening by organic solvents. Binalrimal SR et al., studied the flexural strength of immediate and aged provisional restorative materials and observed that Integrity was significantly higher than Jet and Tuff-Temp Plus, while Jet was higher than Tuff-Temp Plus. Integrity has two methacrylate groups (bi-functional) one group is used to form a polymer, other for cross-linking. Cross-link group breakdown in the oral environment depends on the storage of period (15).

The study demonstrates a higher strength in flexion of Revotek LC at 24 hours than after 7 days and 30 days. The reason for this result can be absence of phenol rings in Revotek LC (UDMA), because of which the material is soft and after water absorption, it becomes more rubber like. The composition of Revotek LC includes dimethacrylate and crystalline silica powder as filler. The minimal amount by weight of fillers is found in interim composites when compared to normal composites (9). This might be the reason for the decreased strength of the material. The fillers eventually leach out in the presence of saliva, indicating the reduction in mechanical properties of the interim composite after storage (5). This result is similar to a study done by Poonacha V et al., in 2013 wherein the authors studied the flexural strength and elastic modulus of three provisional crown materials (DPI self-cure India, Protemp-2 Germany, Revotek GC Dental product, Japan) used in fixed prosthodontics and found that the methacrylate resin exhibited excellent flexural strength when compared to light polymerised and bis-acrylic composite (7). They also studied the mechanical properties of provisional restoration and made a note of methacrylate resin which again displayed superior flexural strength in comparison to the other materials used (7).

Gujjari AK et al., examined the colour stability and flexural strength of PMMA and bis-acrylic resins subjected to beverages and food dye. They observed that PMMA is a better provisional restorative material than bis-acrylate (16). Koumjian JH and Nimmo A studied the fracture resistance of resins used for provisional restoration and summarised that dissimilarities in flexural strength appearance were material specific even without the evidence of data to compare the filler content of bis-acrylic composite materials (17).

The present study showed a higher flexural strength of DPI when compared to Bis-GMA and UDMA. This is in correlation with the study conducted by Binalrimal SR et al. Authors studied the flexural strength for determination of immediate and aged provisional restorative materials and observed that Integrity was significantly higher than Jet and Tuff-Temp Plus. The monomer in Tuff-Temp Plus has no phenol rings. As a result, UDMA has low mechanical strength and higher flexibility so it is called rubberised urethane resin (15). The reason for a decrease in the flexural strength of Bis-GMA and UDMA in the present study is attributed to the two molecules of Bis-GMA and post water absorption cross-linking molecules breakdown thus a decrease in its mechanical properties. Bis-acryl polymers are more polar than PMMA polymers and absorb water at a higher rate because of a high diffusion coefficient in comparison to PMMA based resins. PMMA was more resistant to damage in the oral environment as related to bis-acrylate material (5),(18).

The results of the present study depicted a lower surface roughness for DPI in comparison to Protemp 4 and Revotek LC. This is not per the study performed by Tupinambá ÍVM et al., (10). Authors concluded that bis-acrylic resins displayed a considerably smoother surface than acrylic resins. But in this study, no significant differences were found between Protemp (Bis-GMA) and DPI (PMMA). The reason can be the mixing of appropriate quantities and the curing procedure of PMMA that leads to less surface roughness in comparison to Bis-GMA and UDMA (5).

Due to reduced exothermic and polymerisation shrinkage as well as ease in handling of Bis-acrylic resins they have gained popularity. This novelty has lead to decreased roughness values of the bis-acryl resins (18).

As per the study conducted by Mehrpour H et al., on flexural strength of UDMA, Methyl methacrylate, Bis-acryl, and Vinyl ethyl methacrylate, it was seen that Bis-acryl material for provisional restoration showed the highest flexural strength (6), whereas the study carried out by Poonacha V et al., revealed that methacrylate resin bagged the maximum flexural strength postfabrication and storage in artificial saliva for seven days while bis-acrylic composite resin displayed the minimum (7). In a study done by Kumar GV et al., comparison between various provisinal restorative materials showed that Protemp had minimal porosities and surface roughness followed by Tempofit and DPI (8). Previous studies on surface roughness and porosity of various provisional restorative materials conducted are compared with the present study in (Table/Fig 12) (3),(8),(12),(16),(18).

Limitation(s)

The study presents with limitations that require further research as well as studies that simulate the natural oral environment better to mimic intraoral conditions. In addition to this, scanning electron microscopy of the test samples can be taken into account for surface roughness and to demonstrate excellent results. Future studies can also include different polishing systems for finishing and polishing the samples.

Conclusion

Within the constraints of this in-vitro study, it can be concluded that the mean flexural strength of DPI was highest at 24 hours when compared to its flexural strength at seven days and 30 days. In addition to this after storage in saliva for seven days it was observed that there was a decrease in the flexural strength of all the three commercially available provisional materials. DPI exhibited the highest mean value in addition to a statistically significant difference. Also, after storage in saliva for 30 days, there was a decrease in the flexural strength of all the three commercially available provisional materials. Furthermore, the mean surface roughness of Revotek LC was found to be better than DPI and Protemp 4.

Future outlook involves assessment of colour stability of different provisional restorations, impact strength and marginal fit assessment in a bridge. More number of commercially available provisional restorative materials can be taken into consideration in further studies as well as studies on CAD-CAM generated provisional restorations can be carried out.

References

1.
Hiramatsu DA, Moretti-Neto RT, Ferraz BFR, Porto VC, Rubo JH. Roughness and porosity of provisional crowns. RPG Rev Pós Grad. 2011;18(2):108-12.
2.
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of fixed prosthodontics. 3rd ed. Chicago: Quintessence Pub. Co.; 1997.
3.
Kadiyala KK, Badisa MK, Anne G, Anche SC, Chiramana S, Muvva SB, et al. Evaluation of flexural strength of thermocycled interim resin materials used in prosthetic rehabilitation- an in vitro study. J Clin Diag Res. 2016;10(9):ZC91-95. [crossref] [PubMed]
4.
Yanikoglu ND, Bayindir F, Kürklü D, Besir B. Flexural strength of temporary restorative materials stored in different solutions. Open Journal of Stomatology and Scientific Research. 2014;4:291-98. [crossref]
5.
Karaokutan I, Sayin G, Kara O. In vitro study of fracture strength of provisional crown materials. J Adv Prosthodont. 2015;7(1):27-31. [crossref] [PubMed]
6.
Mehrpour H, Farjood E, Giti R, Ghasrdashti AB, Heidari H. Evaluation of the flexural strength of interim restorative materials in fixed prosthodontics. J Dent (Shiraz). 2016;17(3):201-06.
7.
Poonacha V, Poonacha S, Salagundi B, Rupesh PL, Raghavan R. In vitro comparison of flexural strength and elastic modulus of the provisional crown materials used in fixed prosthodontics. J Clin Exp Dent. 2013;5(5):e212-17. [crossref] [PubMed]
8.
Kumar GV, Devi R, Anto N. Evaluation and comparison of the surface roughness and porosity of different provisional restorative materials: An in vitro study. CODS J Dent. 2016;8(1):39-45. [crossref]
9.
Sen D, Göller G, Issever H. The effect of two polishing pastes on the surface roughness of bis-acryl composite and methacrylate-based resins. J Prosthet Dent. 2002;88(5):527-32. [crossref] [PubMed]
10.
Tupinambá ÍVM, Giampá PCC, Rocha IAR, Lima EMCX. Effect of different polishing methods on surface roughness of provisional prosthetic materials. J Indian Prosthodont Soc. 2018;18(2):96-101. [crossref] [PubMed]
11.
Yanikogšlu N, Bayindir F, Kürklü D, Besir B. Flexural strength of temporary restorative materials stored in different solutions. Open Journal of Stomatology. 2014;4:291-98. [crossref]
12.
Sharma SP, Jain AR, Balasubramanian R, Alavandar S, Manoharan PS. An in vitro evaluation of flexural strength of two provisional restorative materials light polymerised resin and autopolymerised resin. J Dent and Med Sciences. 2013;6(5):05-10. [crossref]
13.
Lang R, Rosentritt M, Behr M, Handel G. Fracture Resistance of PMMA and resin matrix composite-based interim FPD materials. Int J Prosthodont. 2003;16(4):381-84.
14.
Wu W, Toth EE, Moffa JF, Ellison JA. Materials science subsurface damage layer of in vivo worn dental composite restorations. Journal of Dental Research. 1984;63(5):675-80. [crossref] [PubMed]
15.
Binalrimal SR, Yaman P, Dennison JB, Jin Q. Flexural strength evaluation of immediate and aged repair of provisional restorative materials. J Dent Oral Health. 2018;5:01-07.
16.
Gujjari AK, Bhatnagar VM, Basavaraju RM. Colour stability and flexural strength of poly (methyl methacrylate) and bis-acrylic composite based provisional crown and bridge auto-polymerising resins exposed to beverages and food dye: An in vitro study. Indian J Dent Res. 2013;24(2):172-77. [crossref] [PubMed]
17.
Koumjian JH, Nimmo A. Evaluation of fracture resistance of resins used for provisional restorations. J Prosthet Dent. 1990;64(6):654-57. [crossref]
18.
Jo LJ, Shenoy KK, Shetty S. Flexural strength and hardness of resins for interim fixed partial dentures. Indian J Dent Res. 2011;22:71-76. [crossref] [PubMed]

DOI and Others

DOI: 10.7860/JCDR/2022/51527.15830

Date of Submission: Jul 23, 2021
Date of Peer Review: Sep 06, 2021
Date of Acceptance: Oct 30, 2021
Date of Publishing: Jan 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? No
• For any images presented appropriate consent has been obtained from the subjects. No

PLAGIARISM CHECKING METHODS:
• Plagiarism X-checker: Jul 24, 2021
• Manual Googling: Oct 28, 2021
• iThenticate Software: Nov 25, 2021 (10%)

ETYMOLOGY: Author Origin

JCDR is now Monthly and more widely Indexed .
  • 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
  • Google
  • Popline (reproductive health literature)
  • www.omnimedicalsearch.com