Lucena et al. (1) assessed the quality of the statistical methodology in studies on leakage in Endodontics, i.e.  ‘root filling’ ‘microleakage’, ‘dye penetration’, ‘dye leakage’, ‘polymicrobial leakage’ and ‘fluid filtration’, published during 2001-2010 in journals within the categories ‘Dentistry, Oral Surgery and Medicine’ and ‘Materials Science, Biomaterials’ of the Journal Citation Report.

In all, 209 articles were reviewed. The statistical methods used were appropriate, but in 41% of the cases, the chi-square test or parametric methods were inappropriately selected. In 2% of the papers, no statistical test was used, and in 99% of cases, a statistically ‘significant’ or ‘not significant’ effect was reported as a main finding. Only 1% presented an estimation of the magnitude of the effect. When the appropriate statistical methods were applied in the studies with originally inappropriate data analysis, the conclusions changed in 19% of the cases.

The authors conclude that statistical deficiencies might be one of the reasons for the poor agreement amongst the reported findings, and that  more effort to standardize statistical methodology should be made.


Lucena C, Lopez JM, Pulgar R, Abalos C, Valderrama MJ. Potential errors and misuse of statistics in studies on leakage in endodontics. Int Endod J 2012 Jul 24. [Epub ahead of print]