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

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On Sep 2018




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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."



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Sri Devaraj Urs Medical College
Sri Devaraj Urs Academy of Higher Education and Research , Kolar, Karnataka
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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.
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Dr Saumya Navit
Professor and Head
Department of Pediatric Dentistry
Saraswati Dental College
Lucknow
On Sep 2018




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




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Best regards,
C.S. Ramesh Babu,
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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 : June | Volume : 16 | Issue : 6 | Page : ZC27 - ZC31 Full Version

Evaluation of the Effect of Titanium Dioxide and Silicon Dioxide Nanoparticles on Impact Strength of Two Commercially Available Heat Cure Acrylic Resins


Published: June 1, 2022 | DOI: https://doi.org/10.7860/JCDR/2022/55413.16493
Aparana Sharma, Anurag Hasti, Ashish Choudhary, Megha Chopra, Jay Vikram, Pooja Srivastava

1. Assistant Professor, Department of Prosthodontics and Crown and Bridge, Shree Bankey Bihari Dental College, Ghaziabad, Uttar Pradesh, India. 2. Professor, Department of Prosthodontics and Crown and Bridge, School of Dental Sciences, Sharda University, Greater Noida, Uttar Pradesh, India. 3. Professor and Head, Department of Prosthodontics and Crown and Bridge, School of Dental Sciences, Sharda University, Greater Noida, Uttar Pradesh, India. 4. Assistant Professor, Department of Prosthodontics and Crown and Bridge, School of Dental Sciences, Sharda University, Greater Noida, Uttar Pradesh, India. 5. Private Practitioner, Private Clinic, New Delhi, New Delhi, India. 6. Private Practitioner and Consultant, Private Clinic, New Delhi, India.

Correspondence Address :
Megha Chopra,
H.No- 1040 C, Sector 46, Faridabad, Haryana, India.
E-mail: drmeghachopra@gmail.com

Abstract

Introduction: Poor mechanical properties are among the main limitations of denture base resin. There has been a continuous attempt to improve the mechanical properties of denture base resins. Nanotechnology has evolved health care industry to a large scale and its applications are a boon to modern medicine and dental science. Nanoparticles are nowadays, extensively used in prosthodontics as they are incorporated in Polymethyl Methacrylate denture bases to alter the properties such as impact strength.

Aim: To evaluate and compare the effect of titanium dioxide and silicon dioxide nanoparticles on impact strength of two commercially available heat cure acrylic resins.

Materials and Methods: The in-vitro study was conducted in Department of Prosthodontics and Crown and Bridge, School of Dental Sciences, Sharda University, Greater Noida, Uttar Pradesh, India between April 2019 to May 2021, that involved 120 samples. Materials compared were Dental Products of India (DPI) heat cure acrylic and Trevalon heat cure acrylic. Each group was further categorized into four groups to measure the impact strength i.e, without incorporation of nanoparticles and with incorporation of nanoparticles SiO2 and TiO2 and a combination of both. Samples obtained were tested for impact strength using Izod method. Statistical analysis was done using a one-way Analysis of Variance (ANOVA), Student’s t-test and Post-hoc Bonferroni test.

Results: In the two types of materials studied, the mean impact strength of Trevalon was statistically significantly higher (p-value=0.045) than DPI. After the addition of nanoparticles, i.e; SiO2 and TiO2 the mean impact strength was higher in Trevalon (8.66 kJ/m2 without the addition of nanoparticles, 5.79 kJ/m2 addition of 1% TiO2 nanoparticles, 5.77 kJ/m2 addition of 1% SiO2 nanoparticles and 5.75 kJ/m2 when a 1% combination of both the above was added) than DPI (7.19 kJ/m2 without the addition of nanoparticles, 5.86 kJ/m2- addition of 1% TiO2 nanoparticles, 5.77 kJ/m2 addition of 1% SiO2 nanoparticles and 5.66 kJ/m2 when a 1% combination of both the above was incorporated).

Conclusion: Mean Impact strength of Trevalon was higher than mean impact strength of DPI. Incorporation of TiO2, SiO2 Nanoparticles or in combination decreases impact strength of both the commercially available heat cure denture base resin with statistically no significant difference.

Keywords

Mechanical properties, Nanotechnology, Polymethylmethacrylate

Polymethyl Methacrylate (PMMA) is one of the most frequently used material in dentistry that is commonly used for prosthetic dental applications, that includes the fabrication of artificial teeth, denture bases, dentures, obturators, orthodontic retainers, temporary/ provisional crowns, and for the repair of dental prostheses (1). Many desirable properties such as stability in the oral environment, ease of manipulation, polish ability, and fabrication with the use of inexpensive equipment has led to its extensive use in fabrication of prosthesis, and orthodontic appliances. Since its introduction there has been continuous trials to improve the mechanical properties of acrylic resins (2).

Various properties of heat cure acrylic resin like tensile strength, compressive strength, and surface hardness are important but impact strength has a significant role to play clinically. Impact strength is the ability of the material to withstand a sudden applied load and is stated in terms of energy lost per unit of thickness (1). Many studies have been carried out to improve the properties of denture base materials by adding suitable fillers into PMMA denture base that included, PMMA reinforcement with glass fibers, sapphire whiskers, aramid fibers, carbon fibers, metal wires, nylon, polyurethane fibers and zirconia that showed improved fracture resistance (3),(4),(5).

Nanotechnology has evolved health care industry to a large scale and its application are a boon to modern medicine and dental science. Futuristically, it is expected that it will pervade and further revolutionize the art and science of dentistry and will expand all the aspects of oral diseases, diagnosis, prevention and treatment. Nanomaterials are now successfully being used in caries inhibitors, antimicrobial resins, hard tissue remineralizing agents, targeted drug delivery, scaffolds, biomembranes, restorative cements, adhesion promoters and boosters, bioactive glass, tissue wires and nano composites (6).

The scientific advancements have led to the era of nanotechnology and nano-phased materials, and thus; a great attention is directed towards the use of nano-sized fillers to reinforce the denture base resins leading to the production of a polymer nanocomposite with improved mechanical and physical properties as compared to those filled with microscale particles (7).

Inorganic carriers like Titanium dioxide (TiO2) nanoparticles have been used as additives to biomaterials due to its certain characteristics such as white colour, low toxicity, antimicrobial properties, high stability and efficiency as well as availability and low cost (8). Among compounds as inorganic carriers such as apatite, zeolite and phosphate, Silicon dioxide (SiO2) is more promising due to its porous structure and adsorption properties. Nano SiO2 particle possess extremely high surface activity and adsorb various ions and molecules (8).

In literature, various advantages as well as disadvantages of TiO2 and SiO2 nanoparticles on mechanical properties, especially flexural strength of PMMA have been recorded; few studies have evaluated the combination effect of these particles (9),(10). The addition of nano-filler TiO2 improved the thermal, mechanical and viscoelastic properties of the PMMA. A study done by Alzayyat ST et al., wherein, the incorporation of SiO2 in denture base resin, led to a significant increase in the flexural strength (9). Also, in a study done by Sodagar A et al., demonstrated that the incorporation of TiO2 and SiO2 nanoparticles into acrylic resins can adversely affect the flexural strength of the final products, and this effect is directly correlated with the concentration of nanoparticles (10). As many studies done before evaluated the flexural strength therefore, the present study aimed to evaluate the and compare the effect of titanium dioxide and silicon dioxide nanoparticles on impact strength of two commercially available heat cure acrylic resins (DPI and Trevalon).

Material and Methods

This in-vitro study was conducted in the Department of Prosthodontics and Crown and Bridge, School of Dental Sciences, Sharda University, Greater Noida, Uttar Pradesh, India, between April 2019 to May 2021. The laboratory study was approved by the Institutional Ethical Review committee (Ref No. SU/ SMS&R/ 76-A/ 2017/75).

A total of 120 samples were made and divided into two groups of 60 samples each. Further each group was subdivided into four subgroups.

Preparation of Test Samples

A stainless steel master die (Table/Fig 1) of dimensions 60 mm in length, 7 mm in width and 4 mm in thickness was duplicated in putty elastomeric impression material (Zhermack Zetaplus Putty impression material) and molten modeling wax (Pyrax Polymers) was poured to prepare wax blocks. Two pour technique, was used for the flasking of wax blocks. After 15-20 minutes when the gypsum was completely set, it was placed in the dewaxing unit at 100°C for 5-7 minutes. Flask was carefully opened and clean boiling water was poured over it to completely eliminate the wax. A brush and soap solution was used to clean any traces of wax. It was allowed to cool for 10 minutes and then two layers of cold mold seal (DPI- The Bombay Burmah Trading Corporation Ltd. Cold Mold seal -batch no.- 5194) was applied all over the set gypsum. Gypsum moulds were thus, obtained (11).

I. Preparation of Samples for Group A

Appropriate amount of DPI heat cure acrylic resin (DPI-The Bombay Burmah Trading Corporation Ltd. P-5191, L-4193 was used to prepare dough in the ratio of 3:1 by volume (21 grams of powder and 10 mL of liquid) (Table/Fig 2). The gypsum moulds were filled. The flask was closed and trial closure was carried out using hydraulic press. The flask was then clamped and then pressure was maintained for 30 minutes to allow proper penetration of monomer into polymer. An overnight bench curing was done for the same.

Subgroup D1: Polymer was mixed with monomer without incorporation of nanoparticles.
Subgroup D2: 1% TiO2 (0.2 grams) nanoparticles (TiO2 Nanoparticles: Souvenier chemicals, Ultra reagents, IISN code- 2823) were incorporated in polymer and then mixed with monomer.
Subgroup D3: 1% SiO2 (0.2 grams) nanoparticles (Ultra reagents, IISN code- 2811) was incorporated in polymer and then mixed with monomer.
Subgroup D4: 1% combination of TiO2 (0.1 grams) and SiO2 (0.1 grams) nanoparticles was incorporated in polymer and then mixed with monomer.

II. Preparation of Samples for Group B

Appropriate amount of Trevalon heat cure acrylic resin (Dentsply India Pvt. Ltd. T-180414) was used to prepare dough in the ratio of 3:1 by volume (21 grams of powder and 10 mL of liquid) (Table/Fig 3). The moulds were filled. The flask was closed and trial closure was carried out using hydraulic press. The flask was then clamped and then pressure was maintained for 30 minutes to allow proper penetration of monomer into polymer. An overnight bench curing was done for the same.

Subgroup T1: Polymer was mixed with monomer without incorporation of any nanoparticles.
Subgroup T2: 1% TiO2 (0.2 grams) nanoparticles was incorporated in polymer and then mixed with monomer.
Subgroup T3: 1% SiO2 (0.2 grams) nanoparticles was incorporated in polymer and then mixed with monomer.
Subgroup T4: 1% combination of TiO2 (0.1 grams) and SiO2 (0.1 grams) nanoparticles was incorporated in polymer and then mixed with monomer (Table/Fig 4).

Curing of the Samples

The flask was immersed in an acrylizer at room temperature. The temperature was raised to 73°C, held for 1 ½ hours, then to 100°C and this temperature was maintained for half an hour. After the curing cycle, the flask was removed from the acrylizer water-bath and bench cooled for 30 minutes, immersed in cool tap water for 15 minutes preceding the deflasking (11).

Finishing and polishing of samples

The acrylic specimens were then retrieved, finished and polished. The dimension and quality of specimens were verified for any porosity, visible impurities and dimensional deformity. Finally there were two groups of 60 samples in each group (Table/Fig 5), (Table/Fig 6).

Evaluation of Samples for Impact Strength

Evaluation of test samples was done using Izod Impact Testing Machine (Saumya technocrats Model: IZB-B Sr. No.-ST-10-287). The un-notched sample was clamped vertically and hammer with 2 Joules was used to break the samples (Table/Fig 7). Breaking energy was then recorded in joules and then Impact strength was calculated in kJ/m2 (4).

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 value was p-value <0.05 (α=0.05). Parametric tests namely Unpaired t-test, one-way Analysis of Variance (ANOVA) and Post-hoc Bonferroni test were used to statistically analyze the data.

Results

The mean impact strength of Group B (6.49 kJ/m2) heat cure acrylic resin was significantly more than Group A (6.12 kJ/m2) (p-value- 0.045) (Table/Fig 8). The mean impact strength. was also compared between subgroups D1, D2, D3 and D4 and T1, T2, T3 and T4 using the one-way ANOVA test. There was a significant difference in the mean impact strength of all the subgroups (Table/Fig 9).

The intragroup comparison of mean impact strength was also done for both the groups by Post-hoc Bonferroni test. In group A the mean impact strength was significantly more for subgroup D1 (p-value <0.001). The mean difference between subgroup D1 and D2, D1 and D3 and D1 and D4 was 1.33, 1.42 and 1.53 respectively and all were significant whereas; the mean difference of subgroup D2 and D3, D2 and D4 was 0.09 and 0.21 and the mean difference of subgroup D3 and D4 was 0.11 (all were insignificant) (Table/Fig 10). In group B, similarly; the mean impact strength was significantly more in subgroup T1 (p-value <0.001). The mean difference between subgroup T1 and T2, T1 and T3 and T1 and T4 was 2.87, 2.90 and 2.92 respectively and all were significant whereas; the mean difference of subgroup T2 and T3, T2 and T4 was 0.03 and 0.05 and the mean difference of subgroup T3 and T4 was 0.02 (all were non significant) (Table/Fig 11). The mean impact strength was significantly more in subgroup T1.

The intergroup statistical comparisons (unpaired t-test) between subgroup D1 and T1 depicted the mean impact strength to be significantly more in T1 (8.66 kJ/m2) compared to D1 (7.19 kJ/m2) (p-value <0.001). The comparisons between subgroups D2 and T2, D3 and T3 and D4 and T4 were insignificant (Table/Fig 12).

Discussion

The above study was planned to evaluate and compare the effects of titanium dioxide and silicon dioxide nanoparticles individually and in combination on the impact strength of PMMA. The ideal denture base material should possess adequate physical and mechanical properties which are key attributes for the basic requirements of denture base materials like biocompatibility, good esthetics, high bond strength with available denture teeth, radiopacity and ease of repair (12). The impact and flexural strength of PMMA is not satisfactory as continuous efforts are being done to improve the same.

Fracture in an acrylic denture base is a common clinical problem. Therefore, numerous trials were done to improve the mechanical properties of PMMA, but they can be summarized in three ways: replacing PMMA with an alternative material; chemically modifying it; and reinforcing the PMMA with other materials like fibers or metals, and recently nanoparticles (13).

Acrylic specimens in size 60 mm in length, 7 mm in width and 4 mm in thickness were prepared from two different heat cure acrylic denture base resin (DPI and Trevalon). The test samples of each group were divided into four subgroups and were incorporated with 1% nano TiO2 and 1% nano SiO2 and their mixture (1:1 W/W). The test samples thus obtained were tested for Impact Strength using Izod method. The results were obtained and data was statistically analyzed.

Narendra R et al., in an in-vitro study evaluated the impact strength of conventionally heat cured and high impact heat cured polymethyl methacrylate denture base resins. They concluded that Trevalon had higher impact strength than DPI. The mean impact strength of Trevalon was found to be higher than DPI (14). B Praveen B et a., in a Scanning Electron Microscopy (SEM) study compared the impact strength and fracture morphology of different heat cure denture acrylic resins and it was concluded that the mean impact strength of Trevalon was higher than DPI. The SEM was also done to study the matrix structure. It was concluded that the impact strength of the acrylic resins was affected by the reinforcement of fibers (15).

The reason for high impact strength in Trevalon is co-polymerization of Methyl Methacrylate (MMA) and butadiene monomer molecules. The resultant polymer is further surface coated with MMA, thus enabling further cross linkage on polymerization. Due to this complex structure there is increased cross linking amongst the polymer chains resulting in rapid polymerization and increase in mechanical properties specially impact strength (16).

Some studies have also shown the adverse effect of addition of TiO2 nanoparticles (10),(17),(18). One of such examples is a study conducted by Ahmed MA et al., where it was concluded that the addition of TiO2 nanoparticles adversely affected the impact strength of conventional acrylic resin (17). The reason of decrease in the impact strength on addition of TiO2 nanoparticles in PMMA could be the lack of chemical bond between TiO2 nano particles and PMMA. Also, the TiO2 nanoparticles agglomerate into larger particles, thus acting as stress concentrating center in the matrix. This agglomeration of TiO2 nanoparticles probably gives rise to some microporosities and microcracks as structural defects resulting in loss of mechanical properties. Thus, concluding that the content of nanoparticle additives is of critical importance (17). Similarly, Han Y et al., had a similar conclusion and related the results to agglomeration of particles within the matrix, which makes them stress concentration areas (18).

Salman AD et al., studied the effect of comparative study of the effect of incorporating SiO2 nanoparticles on properties of polymethyl methacrylate denture base resin. Nanoparticles with different concentrations were incorporated and samples were tested for impact strength and surface hardness along with SEM Impact strength. The results showed adverse effects. The SEM demonstrated porous structure that comprised of mainly large sized pores. Numerous cracks were also spotted which indicated that the interaction process was not completed. The SiO2 nanoparticles form clusters by adhesion thus acting as impurity and decreasing the strength (8).

In this study the result was found to be co-related with the study mentioned previously done by Albeladi HK et al., (16). The reason of decrease in the impact strength on addition of SiO2 nanoparticles in PMMA could be because of the improper dispersion of SiO2 nanoparticles in PMMA matrix which act as impurities and unfavorably affects the reaction of monomers, leading to increased levels of unreacted monomer, which act as a plasticizer.

Kango S et al., also reviewed the surface modification of inorganic nanoparticles for development of organic-inorganic nano composites. Various methods were described to improve metal bonding between inorganic nanoparticles like TiO2 and SiO2 with PMMA. Silanization of the nanoparticles is an effective pre-treatment for improved bonding thus resulting in improved mechanical properties. The Silane coupling agent act as a mediator for formation of metallic bond between the metal nanoparticles and the polymer chains, which otherwise are not reactive and act only as impurities. This is detrimental on the mechanical properties of the resin especially the impact strength (19).

Limitation(s)

The present study has its limitation in use of single concentration of the nanoparticles. Also, there could have been a lack of visualization of dispersion of nanoparticles in the resin matrix especially at the fracture site.

Conclusion

Within the limitations of this in vitro study, it can be concluded that the mean impact strength of Trevalon was found to be the higher than the mean impact strength of DPI. Also, it was observed that the incorporation of TiO2 and SiO2 nanoparticles and their combined incorporation decreased the impact strength of both the commercially available heat cure denture base resin (though, statistically no significant difference was found). Finally to conclude, as the number of studies evaluating the effect of nanoparticles on the mechanical properties of heat cure acrylic resin are limited; the futuristic approach can aim on the pretreatment of the nanoparticles, SEM can be utilized for better understanding of dispersion of nanoparticles in resin matrix.

References

1.
Zafar MS. Prosthodontic Applications of Polymethyl Methacrylate (PMMA): An Update. Polymers. 2020;12:2299. Doi: 10.3390/polym12102299. [crossref] [PubMed]
2.
Gautam R, Singh RD, Sharma VP, Siddhartha R, Chand P, Kumar R. Biocompatibility of polymethylmethacrylate resins used in dentistry. J Biomed Mater Res B Appl Biomater. 2012;100(5):1444-50. [crossref] [PubMed]
3.
Gad MM, Al-Thobity AM, Rahoma A, Abualsaud R. Reinforcement of PMMA Denture Base Material with a Mixture of ZrO2 Nanoparticles and Glass Fibres. Int J Dent. 2019:01-12. Available from: https://doi.org/10.1155/2019/2489393. [crossref] [PubMed]
4.
Mowade TK, Dange SP, Thakre MB, Kamble VD. Effect of fiber reinforcement on impact strength of heat polymerized polymethyl methacrylate denture base resin: in vitro study and SEM analysis. J Adv Prosthodont. 2012;4(1):30-36. [crossref] [PubMed]
5.
Somani MV, Khandelwal M, Punia V, Sharma V. The effect of incorporating various reinforcement materials on flexural strength and impact strength of polymethylmethacrylate: A meta-analysis. J Indian Prosthodont Soc. 2019;19(2):101. [crossref] [PubMed]
6.
Sharan J, Singh S, Lale SV, Mishra M, Koul V, Kharbanda OP. Applications of nanomaterials in dental science: A review. J Nanosci Nanotechnol. 2017;17(4):2235-55. [crossref] [PubMed]
7.
Wang W, Liao S, Zhu Y, Liu M. Recent Applications of Nanomaterials in Prosthodontics. J Nanomat. 2015:01-11. Available from: https://doi.org/10.1155/2015/408643. [crossref]
8.
Salman AD, Jani GH, Fatalla AA. Comparative study of the effect of incorporating SiO2 nano-particles on properties of poly methyl methacrylate denture bases. Biomed Pharmacol J. 2017;10(3). [crossref]
9.
Alzayyat ST, Almutiri GA, Aljandan JK, Algarzai RM, Khan SQ, Akhtar S, et al. Effects of SiO2 Incorporation on the Flexural Properties of a Denture Base Resin: An In Vitro Study. Eur J Dent. 2022;16(01):188-94. [crossref] [PubMed]
10.
Sodagar A, Bahador A, Khalil S, Shahroudi AS, Kassaee MZ. The effect of TiO2 and SiO2 nanoparticles on flexural strength of poly (methyl methacrylate) acrylic resins. J Prosthodont Res. 2013;57(1):15-19. [crossref] [PubMed]
11.
Phillips RW. Skinner’s science of dental materials. W. B. Saunders Company, xii+ 682, 26 x 18 cm, illustrated, 1973. 1973.
12.
Prajwala N, Kumar CR, Sujesh M, Rao DC, Pavani L. Denture base reinforcing materials-A review. IP Annals of Prosthodontics and Restorative Dentistry. 2020;6(2):52-59. [crossref]
13.
Alla RK, Sajjan S, Alluri VR, Ginjupalli K, Upadhya N. Influence of fiber reinforcement on the properties of denture base resins. Journal of Biomaterials and Nanobiotechnology. 2013;14(1). Article ID:27371,7.
14.
Narendra R, Reddy NS, Reddy SD, Purna CS, Shekar MC, Balasubramanyam S. A comparative evaluation of impact strength of conventionally heat cured and high impact heat cured polymethyl methacrylate denture base resins: an in vitro study. The Journal of Contemporary Dental Practice. 2013;14(6):1115. [crossref] [PubMed]
15.
Praveen B, Babaji HV, Prasanna BG, Rajalbandi SK, Shreeharsha TV, Prashant GM. Comparison of impact strength and fracture morphology of different heat cure denture acrylic resins: An in vitro study. Journal of international oral health. 2014;6(5):12.
16.
Albeladi HK, Al-Romaizan AN, Hussein MA. Role of cross-linking process on the performance of PMMA. Int J Biosens Bioelectron. 2017;3(3):279-84. [crossref]
17.
Ahmed MA, El-Shennawy M, Althomali YM, Omar AA. Effect of titanium dioxide nano particles incorporation on mechanical and physical properties on two different types of acrylic resin denture base. World Journal of Nano Science and Engineering. 2016;6(3):111-19. [crossref]
18.
Han Y, Kiat-amnuay S, Powers JM, Zhao Y. Effect of nano-oxide concentration on the mechanical properties of a maxillofacial silicone elastomer. J Prosthet Dent. 2008;100(6):465-73. [crossref]
19.
Kango S, Kalia S, Celli A. Surface Modification of Inorganic Nanoparticles for Development of Organic-Inorganic Nanocomposites- A Review. Progress in Polymer Science. 2013;38:1232-61. Available from: https://doi.org/10.1016/j.progpolymsci.2013.02.003. [crossref]

DOI and Others

DOI: 10.7860/JCDR/2022/55413.16493

Date of Submission: Feb 03, 2022
Date of Peer Review: Feb 14, 2022
Date of Acceptance: May 03, 2022
Date of Publishing: Jun 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

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