iran is home to one of the world s oldest civilizations in southern and western asia .
the 18th - largest country in the world in terms of area at 1,648,195 km , iran has a population of around 79 million . while the publication of scientific results is the main aim of research activity , scientometric methods ( the study of research output in the form of scientific articles ) and the resulting citations
universal databases , which are being used in such studies include the thomson - reuter institute of scientific information / web of science database ( isi ) , pubmed , scopus and google scholar .
pubmed , as a trouble - free , fast and open database , has indexed 5,650 journals since 1950 and has become one of the most reliable web based resources for clinicians as well as researchers in biomedical / dental sciences .
biomedical / dental research as the leading science has had great impact on researchers , health professionals and policy makers ; these sciences weigh heavily on the measurements of national competitiveness . over the past 30 years
, iran has invested profoundly on its research infrastructure in many fields of science and technology i.e. medicine / dentistry / pharmacology , space sciences , nanotechnology , biotechnology and nuclear technology ; in the new millennium , iran has experienced a remarkable growth in the field of biomedical / dental research . while less than 1% of iran s gross domestic product ( gdp ) was allocated to research until 2011 ,
the objective of the present study was to investigate the quantity as well as the quality of pubmed - indexed published dental articles originnated from iran .
the number of articles and contributors , patterns of research designs , most selected scientific journals for each subspecialty , research output of various scientific groups / universities , characteristics of frequently cited papers and scopus / google scholar citation for each subspecialty were evaluated .
in order to access published articles by the iranian authors in pubmed - indexed journals , a limited search of affiliations was conducted using the following keywords : dental or endodont * or orthodont * or periodont * or pedodont * or prosthodont * or oral or dentistry .
finally , using advanced search , the above results were combined and the articles that had been published by june 31 , 2015 were extracted . the abstracts ( and full texts where necessary )
were reviewed , and articles in which at least one iranian author from an iranian university or institute had contributed were selected and then analyzed .
the following data were extracted from each article and transferred to microsoft excel : year of publication , field of study , name of journal , affiliation of the first / corresponding author , number of authors , scopus / google scholar citation and study design .
the field of study of each article was determined twice , i.e. according to i ) affiliated department of the first author and ii ) that of corresponding author . in case
any of these were not available or were not relevant to the fields of dentistry , title and content of the article were used .
from a total of 1,257,305 dental publications , 3,835 publications were included according to the selection criteria .
overall , the most frequent fields of study were endodontics and orthodontics , whilst the least frequent fields of study were dental materials , community oral health ( coh ) and oral radiology ( fig .
unknown  considering the affiliation of the first author and corresponding author for grouping , respectively .
this group consisted of studies that could not be categorized into one specific field ( of study ) based on the previously mentioned criteria .
( a ) distribution of articles according to related scientific group ( based on the affiliation of the first author ) ; ( b ) trend of publications of four scientific groups as well as the average of all scientific groups ( based on the affiliation of the first author ) ; ( c ) distribution of iranian dental articles according to research design ; ( d ) the number and trend of articles with zero citation in google scholar and scopus the number of publications in each field was categorized according to the year of publication in the past 10 years ( table 1 ) .
the average growth in the number of dental publications indicated a positive trend ; the results in relation to the number of dental publications in the field of endodontics indicated a decline from 2010 to 2011 ( fig .
the publications in each field were presented according to the title of journal , and table 2 shows the three journals with the highest number of publications in each field . the impact factor ( if ) of the journals in 2014
is also presented ;  iranian endodontic journal  and  journal of endodontics  had the highest number of articles and if , respectively ( table 2 ) .
overall , the most frequent study design belonged to the  others group , which included letter to editor , epidemiological studies , descriptive studies , diagnostic accuracy studies , the introduction of a new method , health education , hypothesis and cross sectional studies ; meta - analysis and systematic review studies were the least frequent study designs ( fig .
number of articles according to related scientific group in the recent 10 years c= corresponding author , f= first author ; r = rank ; n = total number of articles three most selected journals by scientific groups c= corresponding author , f= first author ; r = rank ; no= number of published articles ; if= journal s impact factor ( 2014 ) table 3 presents the three articles with the highest number of citations according to google scholar in each subspecialty .
table 4 shows the top 10 universities with the highest number of dental publications and their three most active scientific groups .
the universities of tehran , shahid beheshti and mashhad had produced the highest number of dental publications amongst all medical universities in iran .
three most cited articles in google scholar ( gs ) according to related scientific group c= corresponding author , f= first author ; r = rank ; s = scopus ; = not indexed in scopus top ten dental schools and top three disciplines that had the highest scientific paper production .
c= corresponding author , f= first author ; r = rank ; n= total number of articles the number of authors varied from one to 16 ; the majority of articles were written by four authors ( table 5 ) .
the number and percentage of citations of iranian dental articles in google scholar and scopus are presented in table 6 ; figure 1d shows a sharply increasing trend for articles with no previous citations in google scholar and scopus .
number and percentage of authors per article number and percentage of citations of iranian dental papers in google scholar and scopus = number of citation in google scholar ; = number of citation in scopus
scientometric markers are progressively used to assess the patterns of research performed by scientists / researchers , universities / institutes and countries .
objective scientometric indices have been specified for such assessments during the previous six to seven decades .
the application of scientometric techniques / rankings based on various indices has led to more inter - regional competition among the europe and the united states , west and east and the forthcoming asian countries .
our results demonstrated that the number of pubmed - indexed dental publications originating from iran had an increasing trend in the recent years .
the past three decades have been marked by near constant tensions in the middle east , including the imposed iraq - iran war , after which iraq s scientific system progressively collapsed and not until recently has it displayed any signs of recovery .
in contrast , iran has displayed one of the fastest growth rates in scientific production that the world has witnessed .
iran has progressed successfully in its agenda to improve its ( inter ) national profile in biomedical research by continuously increasing the quantity / quality of publications in peer reviewed scientific pubmed - indexed journals .
a recent study reported that iran performed higher than the expected level in six out of the 62 subfields of life sciences ; these include andrology , dentistry , oral surgery and medicine , ecology , entomology , mycology and orthopedics .
in addition , andrology is the sole subfield in life sciences in which iran has performed above the global average .
the growth rates in the subfields of dentistry , oral surgery and medicine are in the second place and may pass the global trend in the near future .
the positive trend in dental research output from iran can be attributed to the focus on research by policy - makers , a national commitment by research policy change and a drastic rise in research resources .
the research budget allocated to the health sector doubled from 1997 to 2005 , and there was a significant growth in the number of health / medical / dental researchers .
the number of dental research centers in the country increased from one in 1995 to 20 in 2012 .
such achievements were a result of a national movement in iran to develop research in a broad - spectrum .
research productivity is the amount of research performed by scientists within a certain time span .
research productivity evaluation is a critical issue because it serves to verify the existing knowledge in an institution , determine the efficiency in addition to the quality of their research and discover less frequently researched subjects ; this evaluation provides a basis for promotion decisions , funding allocations and educational reform ; it lately serves as an indicator of university quality as well .
our results revealed that endodontic researchers had the highest number of publications , particularly in the  iranian endodontic journal  .
furthermore , endodontic groups were the most frequently rated active research groups in the top ten dental schools .
it has been demonstrated that endodontic research productivity in iran is positive and is favorable in comparison to other regional countries [ 9,15 , 16 ] , which is in accord with the current results .
our results demonstrated that 3.73% of the articles were written by one author , while the majority of them ( 46% ) were written by three or four authors .
iranian researchers in the fields of dentistry , oral surgery and medicine have collaborated well with each other domestically .
this may be due to several factors , including the nature of their research , availability of the internet and e - mail correspondence as well as communication between graduate students and their advisers . in relation to this
randomized clinical trials , systematic reviews and meta - analyses provide the highest level of evidence .
they have a remarkable role in scientific grading thus being useful for decision making , treatment planning , practical guidelines and health policy decisions .
our results similar to previously reported results showed that systematic reviews and clinical trials constituted 9% of all dental publications from iran .
higher number of articles with high level of evidence indicates higher quality of publications , and such a low proportion of high quality publications is not a phenomenon limited to dentistry ; it may be related to the challenges / difficulties in designing / conducting such trials / studies .
moreover , 51% of all dental articles from iran had zero citation in scopus , which may be interpreted as an inferior quality of such publications ; however , as demonstrated in fig .
1d , these articles were mainly published in the recent years and because of the increasing trend of publications , they may be cited in the near future .
the authors of the articles were categorized based on the department of first author and corresponding author .
reporting the department of the author is not a gold standard method for reporting this variable since an author may have some articles in the fields other than his department field especially in dental materials and dental education .
considering the results of iranian pubmed - indexed publication analysis in the field of dentistry , iranian dental research output was promising and showed an increasing trend in the recent years .
 objectives : scientometric methods and the resulting citations have been applied to investigate the scientific performance of a nation . 
 the present study was designed to collect the statistical information of dental articles by iranian authors published in pubmed.materials and methods : we searched the pubmed database for dental articles of iranian authors until june 31 , 2015 . 
 all abstracts were manually reviewed in order to exclude false retrievals . 
 the number of articles per dental subspecialties , distribution of research designs , scopus / google scholar citation of each article , number of authors and affiliation of the first / corresponding author were extracted and transferred to microsoft excel . 
 the data were further analyzed to illustrate the related scientometric indicators.results:a total of 3,835 articles were retrieved according to the selection criteria . 
 the number of pubmed - indexed publications between 2008 and 2015 showed a seven - fold increase . 
 the majority of articles were written by four authors ( 24.56% ) . 
 systematic reviews and clinical trials constituted 9.20% of all publications . 
 the number and percentage of articles with 4 citations from google scholar ( n=2024 ; 52.78% ) were higher than those from scopus ( n=1015 ; 26.47% ) . according to affiliated departments of the first authors , the top three dental subspecialties with the highest number of publications belonged to endodontics ( 19.82% ) , orthodontics ( 11.13% ) and oral and maxillofacial surgery ( 10.33% ) . 
 moreover , the majority of articles originated from shahid beheshti- ( 14.47% ) , tehran- ( 13.72% ) and mashhad- ( 12.28% ) university of medical sciences.conclusions:analysis of pubmed - indexed dental publications originating from iran revealed a growing trend in the recent years . 
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
CONCLUSION