Publication of statistically significant research findings in prosthodontics & implant dentistry in the context of other dental specialtiesby Spyridon N. Papageorgiou, Dimitrios Kloukos, Haralampos Petridis, Nikolaos Pandis

Journal of Dentistry

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Year
2015
DOI
10.1016/j.jdent.2015.08.005
Subject
Dentistry (all)

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Accepted Manuscript

Title: Publication of statistically significant research findings in prosthodontics and implant dentistry in the context of other dental specialties

Author: Spyridon N. Papageorgiou Dimitrios Kloukos

Haralampos Petridis Nikolaos Pandis

PII: S0300-5712(15)30030-0

DOI: http://dx.doi.org/doi:10.1016/j.jdent.2015.08.005

Reference: JJOD 2510

To appear in: Journal of Dentistry

Received date: 15-4-2015

Revised date: 15-7-2015

Accepted date: 11-8-2015

Please cite this article as: Papageorgiou Spyridon N, Kloukos Dimitrios, Petridis

Haralampos, Pandis Nikolaos.Publication of statistically significant research findings in prosthodontics and implant dentistry in the context of other dental specialties.Journal of Dentistry http://dx.doi.org/10.1016/j.jdent.2015.08.005

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Title Page

Publication of statistically significant research findings in prosthodontics & implant dentistry compared to in the context of other dental specialties

Spyridon N. Papageorgiou a,b, Dimitrios Kloukos c, Haralampos Petridis d,*, Nikolaos Pandis c,e a Department of Orthodontics, School of Dentistry, University of Bonn, Bonn 53111, Germany b Department of Oral Technology, School of Dentistry, University of Bonn, Bonn 53111, Germany. c Department of Orthodontics and Dentofacial Orthopedics, School of Dental Medicine, Medical

Faculty, University of Bern, Bern 3010, Switzerland. d Prosthodontic Unit, Department of Restorative Dentistry, UCL Eastman Dental Institute, London

WC1X 8LD, UK. ePrivate Practice, Corfu 49100, Greece.

Short title: Significance in oral / prosthetic dentistry *Corresponding author: Dr. Nikolaos Pandis 29P. Zafiropoulou Str, Corfu, Greece email: npandis@yahoo.com

Keywords: publication bias, dentistry, prosthodontics, dental implant, statistical significance, reporting bias

Abstract word count: 250

Total word count (Abstract to Acknowledgemetns): 2772

Total number of tables & figures: 8

Number of references: 40

Blinded Manuscript

Publication of statistically significant research findings in prosthodontics & implant dentistry compared to in the context of other dental specialties

Abstract

Objectives: To assess the hypothesis that there is excessive reporting of statistically significant studies published in prosthodontic and implantology journals, which could indicate selective publication.

Methods: The last 30 issues of 9 journals in prosthodontics and implant dentistry were handsearched for articles with statistical analyses. The percentages of significant and non-significant results were tabulated by parameter of interest. Univariable/multivariable logistic regression analyses were applied to identify possible predictors of reporting statistically significance findings.

The results of this study were compared with similar studies in dentistry with random-effects meta-analyses.

Results: From the 2323 included studies 71% of them reported statistically significant results, with the significant results ranging from 47% to 86%. Multivariable modeling identified that geographical area and involvement of statistician were predictors of statistically significant results.

Compared to interventional studies, the odds that in-vitro and observational studies would report statistically significant results was increased by 1.20 times (OR: 2.20, 95% CI: 1.66-2.92) and 1.35 times (OR: 1.35, 95% CI: 1.05-1.73), respectively. The probability of statistically significant results from randomized controlled trials was significantly lower compared to various study designs (difference: 30%, 95% CI: 11%-49%). Likewise the probability of statistically significant results in prosthodontics and implant dentistry was lower compared to other dental specialties, but this result did not reach statistical significant (P>0.05).

Conclusions: The majority of studies identified in the fields of prosthodontics and implant dentistry presented statistically significant results. The same trend existed in publications of other specialties in dentistry.

Publication of statistically significant research findings in prosthodontics & implant dentistry compared to in the context of other dental specialties 1. Introduction

Statistical significance seems to influence the attractiveness and consequent publication of research.1 Albeit the commonality of this approach, it is accepted that interpretation based solely on P-values can be misleading2 and is usually made at the expense of other more meaningful measures, such as the effect size and the associated confidence intervals.3-5 The authors’ perception of the ‘attractiveness’ of the results can lead to selective reporting of study findings (reporting bias).

The wider family of reporting bias includes, but is not limited, to time lag bias, multiple (duplicate) publication bias, location bias, citation bias, outcome reporting bias and publication bias.6

Publication bias is defined as the selective publication of studies based on the nature and direction of their results.7 There is empirical evidence that studies with statistically non-significant results are more likely to be published with delay or not at all compared to studies with significant results. The discrepancy in the probability of publication between studies with significant vs. nonsignificant results has been associated with the unwillingness of researchers to submit “nonappealing” studies8 to journals and/or the predilection of reviewers and journal editors to accept for publication studies with positive or significant results.6 It has also been shown that trials with significant results, especially those with external financial support, are published sooner than nonsupported studies.9 Selective publication of studies may jeopardize the validity of systematic review estimates and consequently healthcare recommendations, as they are based on only a subsample of existing studies.