Journal of Prosthetic Dentistry
Research and Education|Articles in Press

Level of evidence and characteristics of clinical studies published in leading prosthodontics journals


      Statement of problem

      Data on the level of evidence and the characteristics of studies published in peer-reviewed prosthodontic journals are lacking.


      The purpose of this study was to investigate the characteristics and level of evidence (LOE) scores of studies published in 3 leading peer-reviewed prosthodontic journals.

      Material and methods

      Clinical studies published in the Journal of Prosthetic Dentistry (JPD), the Journal of Prosthodontics (JP), and the International Journal of Prosthodontics (IJP) in 2013 and 2020 were included in the analysis. Abstracts, letters to the editor, book reviews, and animal and laboratory studies were excluded from the investigation. For each study, design, type and LOE scores (Levels 1 to 5), publication year, impact factor (IF) of the journals, geographic origins of the first and corresponding authors, and funding status were recorded. Level 1 and Level 2 were defined as high evidence (HE), and Level 3, Level 4, and Level 5 were defined as low evidence (LE). Descriptive statistics and logistic regression analysis were performed (α=.05).


      Among the 439 studies included in the analysis, the proportion of HE and LE studies was 14.1% and 85.9%, respectively. According to univariate and multivariate analysis results, year of publication (P=.010 and P=.029), geographic origin of the corresponding author (P<.001), and funding status (P<.001 and P=.002) were significantly associated with the LOE of a study. However, the journal IF was not associated with LOE (P=.328).


      Although the number of HE studies in 3 leading prosthodontic journals has increased over time, the total number was still limited compared with LE studies. A further improvement in the overall LOE of clinical studies in prosthodontics is needed.
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        • Ismail A.I.
        • Bader J.D.
        Evidence-based dentistry in clinical practice.
        J Am Dent Assoc. 2004; 135: 78-83
        • Sackett D.L.
        Evidence-based medicine.
        Spine. 1998; 23: 1085-1086
        • Dumbrigue H.B.
        • Al-Bayat M.I.
        • Ng C.C.
        • Wakefield C.W.
        Assessment of bias in methodology for randomized controlled trials published on implant dentistry.
        J Prosthodont. 2006; 15: 257-263
        • Howe M.S.
        What is the methodological quality of published dental implant guidelines?.
        Evid Based Dent. 2017; 18: 35-36
        • Kloukos D.
        • Papageorgiou S.N.
        • Doulis I.
        • Petridis H.
        • Pandis N.
        Reporting quality of randomised controlled trials published in prosthodontic and implantology journals.
        J Oral Rehabil. 2015; 42: 914-925
        • Lieber R.
        • Pandis N.
        • Faggion C.M.
        Reporting and handling of incomplete outcome data in implant dentistry: a survey of randomized clinical trials.
        J Clin Periodontol. 2020; 47: 257-266
        • Yaffe J.
        • Montgomery P.
        • Hopewell S.
        • Shepard L.D.
        Empty reviews: a description and consideration of Cochrane systematic reviews with no included studies.
        PLoS One. 2012; 7e36626
        • Brighton B.
        • Bhandari M.
        • Tornetta P.
        • Felson D.T.
        Hierarchy of evidence: from case reports to randomized controlled trials.
        Clin Orthop Relat Res. 2003; 413: 19-24
        • Sprague S.
        • McKay P.
        • Thoma A.
        Study design and hierarchy of evidence for surgical decision making.
        Clin Plast Surg. 2008; 35: 195-205
        • Wright J.G.
        • Swiontkowski M.F.
        • Heckman J.D.
        Introducing levels of evidence to the journal.
        J Bone Joint Surg Am. 2003; 85: 1-3
        • Hussain N.
        • Yankanah R.
        • Wright J.G.
        The validity of level of evidence ratings of articles submitted to JBJS.
        J Bone Joint Surg Am. 2015; 97: 1-5
        • Amiri A.R.
        • Kanesalingam K.
        • Cro S.
        • Casey A.T.
        Level of evidence of clinical spinal research and its correlation with journal impact factor.
        Spine J. 2013; 13: 1148-1153
        • Harbour R.
        • Miller J.
        A new system for grading recommendations in evidence based guidelines.
        BMJ. 2001; 323: 334-336
        • Lau S.L.
        • Samman N.
        Levels of evidence and journal impact factor in oral and maxillofacial surgery.
        Int J Oral Maxillofac Surg. 2007; 36: 1-5
        • Nabil S.
        • Samman N.
        Levels of evidence and journal impact factor in oral and maxillofacial surgery: a 15-year follow-up.
        Int J Oral Maxillofac Surg. 2021; 50: 1394-1399
        • Garfield E.
        Citation indexes for science; a new dimension in documentation through association of ideas.
        Science. 1955; 122: 108-111
        • Callaway E.
        Beat it, impact factor! Publishing elite turns against controversial metric.
        Nature. 2016; 535: 210-211
        • Amin M.
        • Mabe M.A.
        Impact factors: use and abuse.
        Medicina (B Aires). 2003; 63: 347-354
        • Kanavakis G.
        • Dombroski M.M.
        • Malouf D.P.
        • Athanasiou A.E.
        Demographic characteristics of systematic reviews, meta-analyses, and randomized controlled trials in orthodontic journals with impact factor.
        Eur J Orthod. 2016; 38: 57-65
        • Patsopoulos N.A.
        • Analatos A.A.
        • Ioannidis J.P.
        Relative citation impact of various study designs in the health sciences.
        JAMA. 2005; 293: 2362-2366
        • Kanavakis G.
        • Spinos P.
        • Polychronopoulou A.
        • Eliades T.
        • Papadopoulos M.A.
        • Athanasiou A.E.
        Orthodontic journals with impact factors in perspective: trends in the types of articles and authorship characteristics.
        Am J Orthod Dentofacial Orthop. 2006; 130: 516-522
        • Alhajj M.N.
        • Al-Sanabani F.A.
        • Alkheraif A.A.
        • Smran A.
        • Alqerban A.
        • Samran A.
        Bibliometric analysis and evaluation of the Journal of Prosthetic Dentistry from 1970 to 2019.
        J Prosthet Dent. 23 June 2021; ([Epub ahead of print])
        • Praveen G.
        • Chaithanya R.
        • Alla R.K.
        • Shammas M.
        • Abdurahiman V.T.
        • Anitha A.
        The 100 most cited articles in prosthodontic journals: a bibliometric analysis of articles published between 1951 and 2019.
        J Prosthet Dent. 2020; 123: 724-730
        • Cappell M.S.
        • Davis M.
        A significant decline in the American domination of research in gastroenterology with increasing globalization from 1980 to 2005: an analysis of American authorship among 8,251 articles.
        Am J Gastroenterol. 2008; 103: 1065-1074
        • Rahman M.
        • Sakamoto J.
        • Fukui T.
        Japan's contribution to nuclear medical research.
        Ann Nucl Med. 2002; 16: 383-385
        • Rahman M.
        • Fukui T.
        Biomedical publication--global profile and trend.
        Public Health. 2003; 117: 274-280
        • Vioque J.
        • Ramos J.M.
        • Navarrete-Munoz E.M.
        • Garcia-de-la-Hera M.
        A bibliometric study of scientific literature on obesity research in PubMed (1988-2007).
        Obes Rev. 2010; 11: 603-611
        • Falagas M.E.
        • Papastamataki P.A.
        • Bliziotis I.A.
        A bibliometric analysis of research productivity in Parasitology by different world regions during a 9-year period (1995-2003).
        BMC Infect Dis. 2006; 6: 56
        • Michalopoulos A.
        • Falagas M.E.
        A bibliometric analysis of global research production in respiratory medicine.
        Chest. 2005; 128: 3993-3998
        • Rosenzweig J.S.
        • Van Deusen S.K.
        • Okpara O.
        • Datillo P.A.
        • Briggs W.M.
        • Birkhahn R.H.
        Authorship, collaboration, and predictors of extramural funding in the emergency medicine literature.
        Am J Emerg Med. 2008; 26: 5-9
        • Birkhahn R.H.
        • Van Deusen S.K.
        • Okpara O.I.
        • Datillo P.A.
        • Briggs W.M.
        • Gaeta T.J.
        Funding and publishing trends of original research by emergency medicine investigators over the past decade.
        Acad Emerg Med. 2006; 13: 95-101
        • Barao V.A.
        • Shyamsunder N.
        • Yuan J.C.
        • Knoernschild K.L.
        • Assuncao W.G.
        • Sukotjo C.
        Trends in funding, internationalization, and types of study for original articles published in five implant-related journals between 2005 and 2009.
        Int J Oral Maxillofac Implants. 2012; 27: 69-76
        • Alonso-Arroyo A.
        • Tarazona-Alvarez B.
        • Lucas-Dominguez R.
        • Penarrocha-Oltra D.
        • Vidal-Infer A.
        The funding sources of implantology research in the period 2008-2017: a bibliometric analysis.
        Clin Implant Dent Relat Res. 2019; 21: 708-714
        • Buchkowsky S.S.
        • Jewesson P.J.
        Industry sponsorship and authorship of clinical trials over 20 years.
        Ann Pharmacother. 2004; 38: 579-585
        • Peppercorn J.
        • Blood E.
        • Winer E.
        • Partridge A.
        Association between pharmaceutical involvement and outcomes in breast cancer clinical trials.
        Cancer. 2007; 109: 1239-1246
        • Thornton K.
        • Lee D.J.
        • Yuan J.C.
        • Knoernschild K.L.
        • Campbell S.D.
        • Sukotjo C.
        An analysis of prosthodontic research productivity: geographic, economic, and collaborative perspective.
        J Prosthodont. 2012; 21: 73-78
        • Lee D.J.
        • Yuan J.C.
        • Prasad S.
        • Barao V.A.
        • Shyamsunder N.
        • Sukotjo C.
        Analysis of abstracts presented at the prosthodontic research section of IADR General Sessions 2004-2005: demographics, publication rates, and factors contributing to publication.
        J Prosthodont. 2012; 21: 225-231
        • Yuan J.C.
        • Lee D.J.
        • Knoernschild K.L.
        • Campbell S.D.
        • Sukotjo C.
        Authorship characteristics in prosthodontic literature: proliferation and internationalization. A review and analysis following a 10-year observation.
        J Prosthet Dent. 2010; 104: 158-164
        • Barao V.A.
        • Shyamsunder N.
        • Yuan J.C.
        • Lee D.J.
        • Assuncao W.G.
        • Sukotjo C.
        Authorship, collaboration, and funding trends in implantology literature: analysis of five journals from 2005 to 2009.
        Implant Dent. 2011; 20: 68-75
        • Chen Y.
        • Hua F.
        • Mei Y.
        • Thiruvenkatachari B.
        • Riley P.
        • He H.
        The characteristics and level of evidence of clinical studies published in 5 leading orthodontic journals.
        J Evid Based Dent Pract. 2019; 19: 273-282
        • Wu X.
        • Hu Q.
        • Yan Q.
        • et al.
        Trends in the level of evidence and impact of clinical studies published in leading oral implantology journals: 2008-2018.
        Clin Oral Implants Res. 2020; 31: 980-991
        • Meng Z.
        • Xiang Q.
        • Wu X.
        • Hua F.
        • Dong W.
        • Tu Y.K.
        The level of evidence, scientific impact and social impact of clinical studies in periodontology: a methodological study.
        J Clin Periodontol. 2020; 47: 902-911