Flossing could be given the flick by the New Zealand Dental Association (NZDA) after the US government dropped the practice from its own recommendations.
The latest US guidelines issued by the Departments of Agriculture and Health and Human Services contain no mention of flossing - despite dentists around the world recommending that patients do so daily.
NZDA spokesman and Otago University periodontology professor Warwick Duncan said the change appeared to be in response to a report by the Associated Press, which reviewed the evidence for flossing and found much of it was weak.
NZDA was now reviewing its own guidelines but recommended people continue to floss in the meantime, Dr Duncan said.
The American Academy of Periodontology published a statement confirming that research done over the years was often substandard.
"Much of the current evidence does not utilise a large sample size or examine gum health over a significant amount of time," the Academy said.
"Additionally, many of the existing studies do not measure true markers of periodontal health such as inflammation or clinical attachment loss."
However, patients should continue to floss until there was quality evidence to the contrary, it said.
Flossing research had been questioned over the years, Dr Duncan said.
"If you look into the systematic reviews, it's apparent that some of that research is not very robust."
A lot of that was down to the age of the research, he said.
"It's not uncommon in most areas of medicine ... to find that the older research is criticised as being too small, not enough people in it, not long enough, quite often funded by industry so potentially biased - various things that could create flaws."
That did not mean the evidence was incorrect - just that new, more robust research needed to be done, Dr Duncan said.
Systematic reviews had found small brushes for cleaning between teeth, and irrigators such as water-picks, worked well.
"So the story that comes out really is that having bacteria between your teeth is bad, we do need to remove it, there are some devices out there for which the evidence is quite strong ... and then there's the evidence for flossing which is not as convincing and really needs to be repeated," he said.
"It probably is effective if you're as good as a professional - talk to your dentist or your hygienist and make sure you're using it properly."
The Guardian reported that Britain's NHS was also reviewing its flossing guidelines.