A gleaming smile with perfectly straight teeth might look nice and be highly desirable in our image-conscious world, but it’s not normal.
Most attractive but untreated “natural” smiles exhibit some degree of irregularity in the alignment of the teeth. What one person might consider “crooked and unsightly” another might simply regard as “character” - it really is all in the eye of the beholder.
When we straighten teeth with orthodontic braces or clear aligners we are creating an artificially perfect outcome - a better than normal “bite” or smile for that person – and one that is potentially unstable unless we act to hold the teeth in their new, corrected positions . In orthodontics these holding devices are called retainers. They are used to prevent orthodontic relapse.
The core problem is that teeth are like houses built on shifting sand. Tooth root ligaments and the supporting bone they connect to remain in a dynamic relationship throughout life, so the exact position of teeth can alter according to the balance of forces acting upon them over time. They are a bit like shape shifters.
Essentially teeth like to occupy a neutral zone between the force of the lips and cheeks pulling inwards and the tongue pushing upwards and outwards. Those muscles, and many others around them, are active every time we eat, swallow and talk. The way we breathe – whether it’s mostly nasal or mouth breathing – directly influences resting tongue posture, which can also change that balance. It is quite likely that small increments of jaw growth and changes in muscle tone as we get older, our habitual head and body posture at work, rest and play, the types of food we like to chew – even the language we speak – can all result in subtle and unpredictable muscular influences which may change the positions of our teeth!
So how do we prevent relapse after orthodontic treatment?
Well, retainers can be simple removable plates or clear guards that are worn at night, or fixed-in wires that are bonded, out of sight, on the back surfaces of the (front) teeth. Sometimes both are needed.
Removable retainers are usually slipped in over the teeth at bedtime and removed in the morning, so they don’t hinder brushing or flossing, but the patient must be reliable enough to wear them as directed, otherwise they don’t work at all! Some people will find they need to wear retainers every single night to keep their teeth perfectly straight while others might find once every week or so is enough to prevent unwanted movement – each case is different and must be carefully assessed. Removable retainers can be lost or accidentally damaged and they can wear out over time so there is an ongoing maintenance cost – like eyeglasses.
Fixed retainers have become more popular in recent years. They don’t rely on patient compliance to be effective because they’re stuck in permanently but they require extra diligence with brushing and flossing otherwise gum inflammation and even tooth decay can become a problem. An innovative “zig-zag” style retainer, one that enables conventional flossing between the teeth, has made home care with fixed retainers much easier. Often a fixed retainer is only fitted to the lower front teeth, which is the area most prone to relapse, while a removable retainer is worn overnight to keep the upper teeth in position. There are many factors that need to be considered before deciding what is best for each individual.
And how long do we need to retain the teeth for, after orthodontics?
In years past retainers were typically worn for just a year or two after treatment but now that we have a better understanding of how relapse can happen at any age the general recommendation these days is that retention be “open-ended”. In other words, you need to have some type of retainer fitted or agree to wear a removable one - even if it’s just once-a-week to check for tight spots - for as long as you want to keep your teeth looking nice and straight.
Maybe one day researchers will develop an easy way of “freezing” teeth in their newly-corrected positions…we can only hope. In the meantime, long-term retainer use must be considered an essential part of achieving a successful and enduring orthodontic treatment result. And if that open-ended commitment to retention seems a bit unrealistic or too difficult then perhaps we should be more accepting about some normal smile “character” creeping back in.
Remember, your teeth will be moving for as long as you are!