Dr. Thiessen was a member of two National Research Council panels and is an international expert in risk assessment. About Dr. Thiessen: http://www.orrisk.com/thiessen_bio.html
Cherrypicking data is the hallmark of the fluoridationist studies, like Calgary. That was the accusation in the 1950s, too, which has been supported by both the international 2000 York and 2015 Cochrane panels who did meta-analysis of all the fluoridationist literature. They agreed, that there is no safety data and only evidence of small benefit from low quality studies in which the prestigious panels had low confidence. 

"It is particularly worrying then that statements that mislead the public are made in press releases..... The evidence did not show water fluoridation to be safe. The quality of the research was too poor to establish with confidence whether or not there are potentially important adverse effects in addition to the high levels of fluorosis." - Prof Trevor Sheldon, chair of York Review Advisory