If you share a house with a teenager, you have probably heard about at least one of these: closing a gap with rubber bands, reshaping your jawline with tongue posture, or straightening your teeth with aligners ordered online. Some of it is harmless fun. Some of it genuinely worries us as specialists, because we see what happens when it goes wrong. So here is the honest version, trend by trend.

The rubber band gap trend: please do not try it

The most viral DIY straightening trend involves wrapping a small elastic or hair tie around two front teeth to pull a gap closed. It looks convincing on camera, and that is exactly the problem. The American Association of Orthodontists has formally warned against moving teeth with rubber bands, floss or anything else bought off the internet, and for good reason.

• An elastic squeezed between teeth tends to slide up under the gum, where you cannot see it or remove it.
• Once there, it can strangle the blood supply to the roots and damage the bone that holds the teeth in.
• Teenagers overseas have lost front teeth permanently this way. Not crooked teeth. Lost teeth.

The frustrating part is that a small gap is often one of the simpler things we treat. Closed properly with clear aligners or braces, the roots move with the crowns and the result actually holds. A rubber band tips the crowns together while the roots stay put, so even in the lucky cases the gap comes straight back.

Mewing: does it actually reshape your jawline?

Mewing is the practice of pressing your tongue against the roof of your mouth in the hope of sharpening your jawline over time. It is enormously popular with teenage boys, and the honest answer is that there is no scientific evidence it works. The American Association of Orthodontists reviewed the research and found no peer-reviewed studies showing mewing changes jawlines, cheekbones or tooth alignment.

For an adult, gentle tongue posture is harmless. The concern is teenagers forcing it. Jaws are still growing in the teenage years, and sustained, uneven pressure from the tongue can shift teeth and change a developing bite. The AAO has warned that aggressive mewing can contribute to loosened teeth, bite problems and even speech changes, which can take genuinely complicated treatment to undo. If your teen is worried about their jaw or profile, that is exactly the kind of thing a specialist assessment can answer properly, for free in our case.

Mail order aligners: the quiet risk

Aligners posted to your door after a home impression kit look like a bargain next to specialist treatment. What is missing is everything you cannot see in a selfie: x-rays, root positions, gum health, and how your bite actually fits together. Moving teeth is a medical procedure. Done without diagnosis, teeth can be pushed out of the bone that supports them, and nobody is checking along the way.

We regularly meet people partway through treatment that has drifted off course, and fixing it usually costs more than doing it properly would have. If you are weighing up an online aligner offer, we are happy to give you a second opinion before you commit. No hard feelings either way.

What we tell Auckland parents and teens

• Most TikTok dental content is entertainment, not treatment advice, and that is fine as long as everyone knows it.
• If a trend involves putting force on teeth, it can move them. Unplanned movement is the whole problem.
• Gaps, crowding and bite issues all have safe fixes, and they are almost always simpler and cheaper than repairing DIY damage.
• For children, we recommend a first orthodontic check around age seven, so anything brewing can be caught early. More on that on our children's orthodontics page.

Straight answers cost nothing here. A free Smile Assessment at our Newmarket clinic or on Zoom will tell you honestly whether anything needs doing at all. If treatment does make sense, a full work-up with your written plan and exact quote is $390, every fee is all-inclusive, and interest-free weekly payment plans are available. Book online or phone (09) 520 1880.

Milk Orthodontics is a specialist orthodontic practice in Newmarket, Auckland, with an Albany clinic opening in August 2026. Every treatment is planned and delivered by Dr Shaz MacAvoy, a registered specialist orthodontist with the Dental Council of New Zealand.