Are invisible aligners an effective orthodontic treatment?


All orthodontic treatment is built around the principle that teeth are in constant motion just not at a rate that would be noticed during the course of a day. Teeth are always slightly pushed out of position and then return to their original alignment with every meal.

If a force is applied to a tooth, it will migrate in the direction of the force and not have the necessary time to return to its original position. This can be used therapeutically with teeth in a sub-optimal position being pushed into a better one, improving not only the appearance but also how the teeth mesh together forming an effective and even bite. The only practical way to do this is by having a device that sits in the patient’s mouth to coax teeth into new locations. These devices are collectively known as orthodontic tools.

woman wearing invisalign

Braces vs. clear aligners

In dentistry, the two most common orthodontic tools are traditional metal braces and clear aligners, sometimes referred to as invisible braces.

They are orthodontic tools that both consistently and effectively move teeth but in slightly different ways. A brace is placed onto the teeth and must be adjusted regularly by a dentist during checkups. During these checkups or tightenings, the dentist will look at how your teeth are moving, how quickly they move and in which direction. Then they will adjust parts of the brace in order to accelerate or decelerate that motion, taking the teeth into alignment over many months; 4 to 12 being a normal treatment schedule. What is actually being tightened during these checkups is the archwire that is connected to the brackets, which are close to the teeth. It is the force stored in the archwire that is slowly and consistently applied to the teeth, which moves them into new positions.

Clear aligners like Invisalign Leicester approach the problem from a different direction; they are a whole series of thin clear plastic mouth forms that can be worn over the teeth. They feel very snug; some patients described them as feeling tight, but over the course of two weeks, they will begin to feel looser. This is because the patient’s teeth have adopted new positions encouraged by the form. The force that is being applied to the teeth is generated from the elastic deformation of the not quite fitting form. Although this is a system that allows brackets and other bulky inconvenient components to be done away with, it is only effective at relatively low levels of force and over very short distances. This is why a series is required, each one taking the teeth only a few millimetres towards their eventual goal before passing on to the next aligner like a baton in a relay race.

Effectiveness in clinical practice

Metal braces have a very long history and have proven themselves effective in a wide range of cases. Clear aligners have only been around for about 30 years and have shown excellent potential when used under the supervision of a trained professional but can have very mixed results when used at home without medical supervision. This led the British Orthodontic Society to endorse aligners only when used with clinical oversight.

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