The Journal of Biomedical Materials Research Part B: Applied Biomaterials is retracting a 2010 paper by Turkish dental researchers for “unattributed overlap.”
We’re pretty sure that’s a euphemism for plagiarism we haven’t heard before — and it raises the question, could you have acceptable, attributed overlap?
The study has been cited three times, according to Thomson Scientific’s Web of Knowledge, including by the retraction notice:
The following article from Journal of Biomedical Materials Research Part B: Applied Biomaterials, “Push-out bond strengths of two fiber post types bonded with different dentin bonding agents” by Fulya Toksoy Topcu, Ugur Erdemir, Gunes Sahinkesen, Emre Mumcu, Esra Yildiz, and Ibrahim Uslan, published online on January 20, 2010, in Wiley Online Library (www.wiley onlinelibrary.com <http://www.wiley onlinelibrary.com>), DOI: 10.1002/jbm.b.31590, and in Volume 93(2), pp. 359–366, has been retracted by agreement between the authors, the journal Editor-in-Chief, Jeremy L. Gilbert, and Wiley Periodicals, Inc.
While the hypothesis, materials and methods, and results of this work have not been called into question, the paper contained unattributed overlap with Akgungor G, Akkayan B. Influence of dentin bonding agents and polymerization modes on the bond strength between translucent fiber posts and three dentin regions within a post space. J Prosthet Dent. 2006 May;95(5):368–378.
This error was not identified by the authors prior to publication and does not have a direct impact on the merits of the experimental work described.
That’s not surprising, considering that the researchers appear to have published much, if not all, of these findings in another journal (more on that in a moment). We note that the 2006 paper came from Istanbul University, where at least some of the authors of the retracted paper have appointments.
Back to that bit about duplicate publication. We found a strikingly similar study by the same group in Dental Materials Journal, a publication of the Japanese Society for Dental Materials and Devices, that appeared in May of 2010. Here’s the abstract from the retracted article (we bolded the money sentences):
The aim of this study was to evaluate the regional push-out bond strengths for two fiber-reinforced post types using three different dentin bonding agents. Sixty single-rooted extracted human first premolar teeth were sectioned below the cemento-enamel junction, and the roots were endodontically treated. Following standardized post space preparations, the roots were divided into two fiber-post groups (Glassix(R) and Carbopost(R)), and further divided into three subgroups of 10 specimens each for the bonding systems self-etching dentin bonding agents (Clearfil SE Bond and Optibond(R) all-in-one), and total-etching dentin bonding agent (XP Bond). A dual-cure resin luting cement (Maxcem) was then placed in the post spaces and posts were then seated into the root canals polymerized through the cervical portion. The roots were then cut into 3-mm thick sections. Push-out tests were performed at a crosshead speed of 0.5 mm/min. The data were analyzed with multivariate ANOVA (alpha = 0.05). The morphology of interface between different dentin bonding agents from the cervical sections were analyzed with SEM. Glass fiber-reinforced posts demonstrated significantly higher push-out bond strengths than carbon fiber-reinforced posts (p < 0.001). Bond strength values decreased significantly from the cervical to the apical root canal regions (p < 0.001). Self-etching dentin adhesive Clearfil SE Bond and total-etching dentin adhesive XP Bond demonstrated similar bond strengths values and this was significantly higher compared with the Optibond(R) all-in-one in cervical root canal region. In conclusion, in all root segments, the glass fiber-reinforced posts provided significantly increased post retention than the carbon fiber-reinforced posts, regardless of the adhesive used.
And here’s the abstract from the paper in Dental Materials Journal:
By means of a micro push-out test, this study compared the bond strengths of two types of fiber-reinforced posts cemented with luting cements based on two currently available adhesive approaches as well as evaluated their failure modes. Sixty extracted single-rooted human maxillary central incisor and canine teeth were sectioned below the cementoenamel junction, and the roots were endodontically treated.Following standardized post space preparation, the roots were divided into two fiber post groups and then further into three subgroups of 10 specimens each according to the luting cements. A push-out test was performed to measure regional bond strengths, and the fracture modes were evaluated using a stereomicroscope. At the root section, there were no statistically significant differences (p>0.05) in push-out bond strength among the tested luting cements. Nevertheless, the push-out bond strength values of glass fiber-reinforced posts were higher than those of carbon fiber-reinforced posts, irrespective of the adhesive approach used. On failure mode, the predominant failure mode was adhesive failure between dentin and the luting cement.
Why are we not surprised that the May 2010 article references neither the January 2010 paper nor the article from which it misappropriated information?