Is there any research showing success of teaching with smell? Cognitive science holds that smell is the sense that has the strongest ability to trigger memories. It is discussed in awe. 

We see anecdotes such as the sudden striking memory of sitting in your grandmothers kitchen when you were 6 - because you have just smelled the same scent of the food she cooked (30 years later). Has anyone been using scent timed with instruction to improve performance? I am only seeing studies of the effect of certain smells (peppermint, cinnamon, etc) on the neural activity of lab rats being watched with fMRI. 

Is there any research in which a control group (no smells) performed worse than an experimental group (had smells during learning and testing?)
I am a bit amazed, but there is, at least for scent as a memory retrieval cue:

Aggleton and Waskett (1999):


  This study determined the extent to which re-exposure to the unique combination of odours present in a museum (the Jorvik Viking Centre in York) aids the recall of a previous visit to the museum, which had typically taken place several years earlier. To test this, three groups of participants completed questionnaires about the contents of the museum, but in different conditions. One group completed the questionnaire in the presence of exactly the same distinctive odours as those present in the museum at the time of their original visit. Those in two other groups were given either a different (control) set of odours or no odours at all. After a brief delay, the same questionnaire was presented again to participants in all three groups. Those who had initially been given a novel (control) set of odours were now tested in the presence of the genuine Jorvik museum odours, while the group that had received the Jorvik odours were now tested with the control odours. The third group received no odours on either test. Only the novel odour-Jorvik odours condition led to a highly significant improvement in performance. This interaction showed that the museum odours could act as effective retrieval cues for this incidentally acquired, real-world episode. 



Wow 1: The average time since the last museum visit was 6.7 years!
Wow 2: At the time of writing, the paper has been cited more than 120
times according to Google Scholar! 
Wow 3: Vikings!


References

Aggleton, J. P., &amp; Waskett, L. (1999). The ability of odours to serve as state-dependent cues for real-world memories: Can Viking smells aid the recall of Viking experiences? British Journal of Psychology, 90, 1–7.