Claims and denials of clinically relevant effects of, in particular, non-surgical periodontal treatment on markers of diabetic control have not only led to a surge of new randomized clinical trials and systematic reviews thereof. If anybody had hope that the current frenzy has found a happy end with the updated and very comprehensive Cochrane review by Simpson et al. (2015) (s)he has been mistaken. In the June issue of the Australian Dental Journal, Botero et al. (2016) report on an umbrella review in which they systematically reviewed all systematic reviews on the subject, be it with or without meta-analysis, published between 1995 and 2015. The paper has been accepted for publication on January 20, 2016. It has to be emphasized that using the term “umbrella review” is somewhat misleading. In a strict sense, an umbrella review assembles together several systematic reviews on the same condition in the presence of many treatments or many important outcomes.