Much like the debate of folding versus scrunching or showering in the morning versus at night, whether you should brush your teeth before or after brekkie is a topic of much contention.
On one hand, if you brush before breakfast you're getting rid of those godawful bacteria responsible for you being a walking oral stink bomb. On the other hand, if you brush afterward you're removing food particles, as well as the built up bacteria.
So, which time is the best?
First, let's take a look at what's actually happening in the mouth while we're sleeping -- and why morning breath is a (terrible) thing.
"Your mouth is the same as the rest of your body during the night -- things slow down," Marc Tennant, Winthrop Professor and director of International Research Collaborative Oral Health and Equity at The University of Western Australia, told The Huffington Post Australia.
"The main change in your mouth is the amount of spit, or saliva, you produce which is substantially less at night than it is in the day. For example, somewhere between 80-90 percent of your total daily spit production is during the day, and just 10 or 15 percent is through the night. That has a bundle of consequences."
Saliva is critical to maintaining the health of your gums and teeth as it acts to protect your tooth surfaces. This reduced saliva flow at night means your teeth and gums are at much higher risk of decay and infections, respectively.
"What happens is that the bacteria in your mouth are opportunistic in a sense -- when the saliva isn't there they breed and grow and that's why you often wake up in the morning with bad breath."
Sugar can also encourage bad bacteria, so Tennant recommends not having too many sweets right before bedtime.
"You are low of saliva in the evening, so if you then eat lots of sugar, which feeds your bacteria, you are at very high risk of ending up with decay," he said. "It's really important not to get into the lollies and sugar just as you're going to bed because you are feeding the bacteria of your mouth and they are going to end up damaging your teeth and gums."
Now, fast forward to the morning when you've just woken up. Is it best to brush your teeth as soon as you're up, or wait until after breakfast?
According to Tennant, it's totally up to you.
"It depends on what makes you feel happy. If you feel happy brushing your teeth before you eat, fine, do it. If you feel happy doing it after, do it," he said.
"The reality about brushing is it's breaking up the growing bacteria on your teeth and it's disrupting the bad bacteria and giving the good bacteria a chance, so to speak. The main mission is: just do it."
If the taste of a night's worth of bacteria bothers you or affects the taste of your breakfast, pre-meal brushing might be for you. If you like the ultra clean, smooth feeling of brushing after breakfast, stick to that.
However, if your breakfast is highly acidic, for example a big orange and pineapple juice, it might be a good idea to wait a bit before brushing.
"If you've eaten something quite acidic, to give a little time for the surface of your enamel to stabilise again is a really good thing," Tennant told HuffPost Australia. "The food you're eating at the same time as drinking will help stabilise the acidity level of the juice.
"The real risk is if you've vomited -- that's some of the strongest acid that gets in your mouth. The tip is to get some toothpaste on your finger and rub it around on your teeth, but wait 20-30 minutes and brush then. Don't abrade your teeth while they're at risk with the acid. That's more important than having an orange juice at breakfast."
Regardless of the time, type of toothbrush or what you've eaten, the most important thing regarding brushing teeth is "just do it".
"Brush your teeth at least a couple of times a day with toothpaste and get to every tooth surface and where the tooth meets the gum -- do it in whatever fashion you like and with whichever kind of toothbrush you can effectively get to every tooth surface," Tennant told HuffPost Australia.
Tips you might not know about tooth brushing:
1. Don't go to town on your teeth while brushing
"Sometimes people think if they scrub them with absolute brutal force that's better, but that's not the case. You can actually damage the surfaces of your teeth by being harsh with your brushing method," Tennant said.
"The idea is to brush them but not so your partner in the other room can hear the bristles going across your teeth."
2. Brushing 2-3 times a day is enough
"In terms of the frequency, there's no rule. The usual is a couple of times a day, sometimes three times a day, which is fine.
"If you're doing it six, eight or ten times a day then there's other things you could be doing with your time. Just be careful and not overly forceful."
3. Only use a pea-sized amount of toothpaste
"One thing about toothpaste is you only need an amount the size of a pea, you don't need to use a megalitre of it," Tennant said.
4. Don't rinse after brushing
"One of the best tips we have is at the start and end of the day, give your teeth a good brush and then spit out -- don't rinse," Tennant said.
"Rinsing the toothpaste out after you brush your teeth doesn't leave you with the added protection that toothpaste has in it. That's why I say take the cup or glass in the bathroom and throw it in the rubbish or put it back in the kitchen where it belongs.
"Spitting out, and not rinsing, all the toothpaste after you've brushed is a very positive event for your teeth. At night when you're going into what I call a 'risk phase' it's a bonus."