Here is another article which delves deeper into the properties of
the different oils and gives more info on *why* the oil works.
I offer a few blurbs but if you read the article, you will find
much inspiration and testimonials~~
Adding some peppermint oil one drop when adding to the sunflower oil will reduce or neutralize the toxins whenever bacteria are killed. This would have reduce any negative problems experience by the oil pulling. Drinking ACV + baking soda before oil pulling, say 2 tablespoon of ACV plus 1/4 baking soda plus 1/2 glass of water will also neutralize many toxins if bacteria and microbes do get killed and the negative effects from oil pulling should be lessened.
The point in oil pulling and what oils to use is the components of the anti-microbial activities found in the oils itself. The second properties lies in its ability to remove heavy metals, but most oils seem to share this. So most of the issues that we have to look at is the component. Olive oil's anti-microbial activities, especially extra virgin oil is the polyphenols and oleic acid being the major components.
The most active anti-microbial properties of sunflower is found in the linoleic acid and the oleic acid. It is therefore, in terms of oil, excluding polyphenols, that sunflower is more wider spectrum in its anti-microbial properties. While on the other end of the spectrum is safflower oil which has the highest amount of linoleic acid.
Coconut oil is most unusual, it has monolaurin, or lauric acid, which is considered antiviral rather antibacterial. While fish oils is also known to have antibacterial powers.
Often it is the middle chain fats, which is the oleic, linoleic, and lauric component giving the best properties in killing various microbes, bacteria and virus. So it would seem the "verdict" imperfect as it is would be a mixture of coconut oil and sunflower oil.
You might ask how about sesame seed oil? Sesame seed oil has both oleic acid and linoleic acid as same as sunflower oil. So theoretically speaking they are of equal in antimicrobials. However, in practice, sesame seeds, at least where I live they use stainless steel rollers to squeeze out the oil and during this process it might acquire some heavy metals. While sunflower, the refined oil anyway are of lower quantities.