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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
Original article / research
Full Version
Comparative Evaluation of Flexural Strength of Heat Polymerised Polymethyl Methacrylate Provisional Fixed Restorative Resin Reinforced with Different Percentages of Silanised Zirconium Oxide Nanoparticles: An In-vitro Study
Correspondence Address :
Dr. Vaishnavi Banode,
Postgraduate, Department of Prosthodontics, Room No. 205, VSPM Dental College and Research Centre, Hingna, Nagpur, Maharashtra, India.
E-mail: vaishnaviangel06@gmail.com
Introduction: The purpose of providing a provisional restoration includes immediate replacement of missing teeth, for protection of pulp and maintenance of periodontal health, to maintain occlusal stability, to preserve the position of the teeth and for masticatory efficiency. Provisional restorations fabricated from heat processed acrylic resin have been used successfully. Incorporation of inorganic nanoparticles into Polymethyl Methacrylates (PMMA) resin has been shown to improve its physical properties.
Aim: To evaluate and compare the flexural strength of heat polymerised PMMA provisional restorative resin reinforced with different percentages of silanised zirconium oxide nanoparticles.
Materials and Methods: This is an in-vitro study performed in the Department of Prosthodontics, VSPM’s Dental College and Research Centre, Nagpur, Maharashtra, India, from June 2018 to February 2020. A die was used to create sixty heat-cured PMMA resin specimens, which were then divided into four groups: group A includes controls with conventional heat Polymerised Provisional Restorative Resin (PMMA) and groups B, C and D conventional heat polymerised provisional restorative resin reinforced with different percentages of silanised zirconium oxide nanoparticles (1 wt%, 2.5 wt%, 5 wt%, respectively), having 15 specimens in each group. Three point bending tests were conducted on all samples using a universal testing machine. The flexural strength of each specimen was calculated. Mean value of flexural strength of each group was used for statistical analysis. One-way analysis of variance test was used to find out the mean value of flexural strength of each group.
Results: The mean flexural strength for control group was 53.76±2.97 MPa. For group B (1% Zirconium oxide) it was 58.14±4.86 MPa, for group C (2.5% Zirconium oxide) was 63.29±4.22 and for group D (5% Zirconium oxide) it was 59.02±3.99 MPa. Statistical analysis showed that maximum strength was obtained by reinforcement with 2.5% silanised zirconium oxide nanoparticles.
Conclusion: Polymethyl methacrylate reinforced with silanised 2.5% of zirconium oxide nanoparticles promises to be better material in terms of flexural strength.
Acrylic resin, Fixed partial denture, Reinforcement of provisional restorations, Temporary restorations
The fundamental component of fixed prosthodontics, which includes tooth and implant supported restorations, is provisional Fixed Dental Prostheses (FDPs) (1). The purpose of providing a provisional restoration includes immediate replacement of missing teeth, for protection of pulp and maintenance of periodontal health, to maintain occlusal stability, to preserve the position of the teeth and for masticatory efficiency (2). Currently, available provisional materials can be divided into four groups namely- Polymethyl Methacrylate (PMMA), polyethyl methacrylates, bis-acryl composite resins and visible light cure resin (3). PMMA are relatively inexpensive, with good colour stability, excellent polishability and good marginal adaptation (4). Provisional restorations fabricated from heat processed PMMA have been used successfully (5),(6).
However, in certain clinical cases where there is increased parafunction, abnormal jaw relationships, cases of raised vertical dimension, long span bridges, forces acting on provisional restoration are far more than normal. Also, where provisional materials are used for extended periods of time like full mouth rehabilitation its strength assumes paramount importance (7). The incorporation of inorganic nanoparticles of titanium dioxide, zirconium oxide and silicon dioxide into PMMA has been shown to improve its physical properties (8),(9),(10). The characteristics of polymers nanocomposites depend on the types of nanoparticles, their dimensions, as well as the concentration and interaction with polymer matrix (11). Tetragonal zirconium oxide nanoparticle powder has been reported to improve the properties of PMMA, as it is a biocompatible material that possesses high fracture resistance, improves flexural strength and fracture toughness of resin denture base (12). Zirconium Oxide (ZrO2) ceramic material is designated as 3Y-TZP i.e., 3 mol% Yttria stabilised Tetragonal Zirconium Polycrystal. It includes a variety of mechanical qualities, including good mechanical strength, fracture toughness, hardness, wear resistance, chemical resistance, good thermal stability and micro crack propagation during toughening [13,14]. The percentages 1%, 2.5% and 5% of zirconium oxide are selected as they are found effective in improving its flexural strength in auto-polymerised provisional acrylic resins (15).
Silanes can bond inorganic substances like metal and metal oxides to organic resins, improving mixing, improving bonding and boosting matrix strength (14). Limited amount of data is available in literature regarding the effect of silanisation as well as varying different percentages of zirconium oxide nanoparticles on flexural strength of heat polymerised PMMA (12),(14). Therefore, the aim of this study was to investigate and compare the flexural strength of heat polymerised PMMA provisional restorative resin reinforced with different percentages of silanised zirconium oxide nanoparticles. The null hypothesis was that there is no significant difference in the flexural strength between the groups.
This was an in-vitro study was carried out in the Department of Prosthodontics, VSPM’s Dental College and Research Centre, Nagpur, Maharashtra, India. It was approved by Institutional Ethics Committee no. ECR/885/Inst/MH/2017 and study period was during June 2018-Feb 2020.
Sample size calculation: Sample size was calculated on OpenEPI calculator considering flexural strength as the main outcome measure. Mean±Standard Deviation (SD) in control group and experimental group=85.54±1.145 and 116.04±3.028, respectively (16), by keeping confidence 95% and power 80% and significance at p-value ≤0.05. Formula for calculating sample size was n={(Zα/2+Zβ)2×(2(σ)2)}/(μ1-μ2)2. There was one control and three experimental groups, n=15 (in each group). Hence, total samples were 60 specimens (Table/Fig 1).
Study Procedure
The materials used were heat polymerised acrylic resin, zirconium oxide nanoparticles, die stone, silane coupling agent, toluene and cold mould seal. Three brass metal dies of dimension 65 mm in length, 10 mm in width, and 3 mm in height (Table/Fig 2) were fabricated (ISO 1567 standard) (17). Gypsum was moulded with uniform mould gaps, and sample replica blocks were fabricated.
For sample preparation of group B, group C and group D, the salinisation of metal oxide fillers is done as follows: in toluene solution, tetragonal zirconium oxide nanoparticles were mixed and then sonicated for 20 minutes after which the silane coupling agent i.e., Trimethoxysilylpropylmethacrylate (TMSPM) were added. The mixtures were stirred separately with magnetic stirrers for 30 minutes after which the toluene was completely evaporated using a vacuum rotary evaporator. The silanised metal oxide nanoparticles 7were well dispersed in monomer by weight of the polymer of heat polymerised PMMA provisional restorative material with the help of an ultrasonicator until a homogeneous mixture is obtained (13). The samples were created by combining heated PMMA powder with the appropriate modified and unmodified monomer, and processing was carried out in accordance with the manufacturer’s instructions (Table/Fig 3).
Each sample for measuring flexural strength was to be stored in distilled water at room temperature for one week before testing. Using a Universal testing device, a three-point bending test was performed on the samples at a 5.0 mm/minute crosshead speed (18). At the point of fracture, the amount of force and defection were recorded.
Flexural strength will be recorded using the following formula (19):
FS=3PI/2bd2
Where, FS=Flexural strength (N/mm2), P=Load of fracture (N), b=Width of the sample (mm), d=Thickness of the sample (mm) and I=Distance between the supporting wedges (mm).
Statistical Analysis
The statistical calculations were performed using the software Statistical Package for the Social Sciences (SPSS) for Windows (SPSS Inc. 1999, New York) software version 19.0. Descriptive statistics including mean and standard deviation were calculated. Statistical analysis using one-way Analysis of Variance (ANOVA) test and Tukey’s posthoc test were performed so as to facilitate interpretation of data. The p-value <0.05 was considered statistically significant.
The mean flexural strength of group C (63.29 MPa) was the highest when compared to other groups (Table/Fig 4). Statistical difference was found between the groups when ANOVA was applied (p-value <0.001). There was statistically significant difference (p-value=0.003) between flexural strength between group A and group B (p-value=0.00041). Statistically significant difference (p-value=0.02) existed between group A and group D (p-value=0.004). It is to be noted that statistically significant difference (p-value <0.021) was found between group B and group C (p-value=0.005) along with group C and group D (p-value=0.028). Statistically highly significant difference was found between group A and group C (p-value=0.0005). While, no statistically significant difference (p-value=0.04) was observed between group B and group D (p-value=0.935) (Table/Fig 5).
The null hypothesis was rejected as flexural strength of PMMA provisional fixed restorative resins reinforced with different percentages of silanised zirconium oxide nanoparticles was significantly different from the others. Asopa V et al., used zirconium oxide as a filler in the high impact acrylic resin resulted in increase in transverse strength as compared to the control group (20). They stated that zirconium oxide, possesses strong ionic interatomic bonding, giving rise to its desirable material characteristics. Addition of zirconia nanofillers to acrylic resin was found to improve mechanical properties (21). In addition to that ZrO2 is known to have excellent biocompatibility and white colour which was less likely to alter esthetics. A study by Zuccari AG et al., concluded that the provisional restorative resin enhanced with zirconium oxide particles demonstrated the significant improvements in elasticity modulus, transverse strength, toughness and hardness (22).
A study by Ihab NS et al., concluded that increase in the transverse strength occurred with addition of 2-5 wt% ZrO2 nanoparticles due to good distribution of the very fine size of nanoparticles (12). However, due to nano-ZrO2 agglomeration, increasing the percentage of modified nano-ZrO2 to 7 wt% decreased the impact strength and transverse strength. Hence, ZrO2 in the percentage of 1 wt%, 2.5 wt%, 5 wt% percentages were selected in the present study. The hydrophilic ionic nature of the inorganic filler particles typically causes them to display high surface energy. But due to difference in surface energy, the hydrophobic polymer does not wet or interact with the filler particles (23). Therefore, it is important to modify the filler surface for better dispersion and improve surface wetting, thereby improving the physical properties of the composites (24). Hence, in this study, zirconium oxide nanoparticles were treated with TMSPM to improve adhesion of nanoparticles to the resin matrix (25). The role of silanisation has been postulated as an agent which increases resin matrix strength, decreases resin component water intake, and enhances the bonding of colour or fillers to resin and reduction in polymerisation shrinkage (14).
According to present study the average values of flexural strength of heat polymerised acrylic resins is 53.76±2.97 MPa. The mean flexural strength obtained for group A (control) was 53.76±2.97 MPa, group B was 58.14±4.86 MPa), group C was 63.29±4.22 MPa and group D was 59.02±3.99 MPa. The maximum increase in the flexural strength was obtained when PMMA was reinforced with silanised 2.5% of zirconium oxide nanoparticles.
These results are in accordance with the study done by Alhavaz A et al., on untreated zirconia nanoparticles who concluded that highly significant increase in the flexural strength occurred with the incorporation of 2.5 wt% zirconium oxide nanofiller than unreinforced controls (2). Explanation for enhanced flexural strength is by the incidence of interstitial ZrO2 filling in acrylic resin matrix, which interferes with fracture propagation (26). The decline in the flexural strength values above 2.5 wt% concentration are in accordance with study by Raouf L et al., who concluded that flexural strength decreases significantly above 3 wt% of ZrO2 nanoparticles concentration. Possible explanations for reduction in strength with increasing in percentage could be stress concentration as a result of too many filler particles and due to nanoparticles agglomeration (27).
Limitation(s)
Provisional restorations are exposed varying forces in different directions in the oral cavity. The same situation could not be simulated in the present in-vitro study. Scanning Electron Microscopy (SEM) examination of the samples to evaluate the adhesion of zirconium oxide nanoparticles to the surface of PMMA was not performed.
Within the constraints of this research, it may be stated that reinforcement with silanised zirconium oxide nanoparticles increased the flexural strength of heat polymerised PMMA provisional restorative materials. The maximum increase was found with 2.5 wt% concentration zirconium oxide nanoparticles. The flexural strength declined with increasing the zirconium oxide nanoparticles concentration to 5 wt%. It is highly recommended to reinforce the provisional fixed restoration with 2.5 wt% silanised zirconium oxide especially when long term provisional are given to the patient.
DOI: 10.7860/JCDR/2023/60021.17713
Date of Submission: Sep 06, 2022
Date of Peer Review: Oct 19, 2022
Date of Acceptance: Jan 13, 2023
Date of Publishing: Apr 01, 2023
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. NA
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