Lucena et al. assessed the quality of the statistical methodology used in Endodontic leakage studies. Of 209 papers published during 2001-2010 in dentistry; oral surgery and medicine; materials science; and biomaterials, and having the descriptors root filling, microleakage, dye penetration, dye leakage, polymicrobial leakage, or fluid filtration, potential pitfalls in statistical methodology, study design, data management or data analysis, were searched.

No statistical test was used in 2% of the papers, and in 41% of the cases, the chi-square test or parametric methods were inappropriately selected. In 99% of cases, a statistically significant or not significant effect was reported as the main finding. Only 1% of the papers also presented an effect estimate.

When appropriate statistical methods were applied in the studies with inappropriate data analysis, the conclusions changed in 19% of the cases.

The authors conclude that statistical deficiencies in leakage studies “may affect their results and interpretation and might be one of the reasons for the poor agreement amongst the reported findings. Therefore, more effort should be made to standardize statistical methodology.”


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 2013;46:323-331.