There have been extravagant claims in the media and within parts of the dental profession on the virtues and potency of what are called orthopaedic or functional appliances. This page aims to place these useful appliances in perspective.

Jaw development (widening) techniques
The technique of jaw widening (orthodontists call it expansion) has been in use for over a hundred years. Dental arches were routinely widened so that crowded teeth could be accommodated without any extractions. However, many patients needed to be re-treated on the basis of dental extractions because the teeth didn't stay in their widened positions and crowding returned. Additionally, in some cases, the appearance was too 'toothy' and there were problems of receding gums.

As a reaction, treatment based on dental extractions became widespread in the 1950s, 60s and 70s. More recently, there has been renewed interest in jaw widening techniques. However, properly conducted scientific research shows that whilst a small amount of widening can be stable in selected cases, indiscriminate use of this form of treatment leads to relapse in many cases, just as in the early 1900s.

Functional / orthopaedic appliances
There are many types of functional appliances, mainly to treat underdeveloped lower jaws. Some are fixed to the teeth but most are removable by the patient for cleaning and in some cases for eating. They all work by holding the lower jaw in a forward position for around 9 to 12 months.

These appliances are very effective at changing the way the teeth bite together. But this does not signify that the process is necessarily one of stimulating extra growth in the jawbone. Many studies have been carried out that show that the longterm change in the bite is mainly due to a backward movement of the upper teeth and a forward movement of the lower teeth in relation to the jawbone. A smaller proportion of the change in the bite is due to an effect on the growth of the bones of the face. Nevertheless, Dr Kirschen and Dr Harris use 'Twinblock' functional appliances for many patients but it is inappropriate to make extravagant claims about them.

Early treatment
Early treatment, at 7 to 9 years of age, is appropriate for certain problems when it should be undertaken for a period of 3 to 12 months with specific but limited aims. An example would be the correction of a condition known as 'crossbite'. (See page on removable braces).

For problems such as underdeveloped jaws, a study in the US has shown that early treatment followed by a second stage some time later (so-called 'two stage' treatment) does not yield any better long term results than treatment carried out from 11 to 13 in a single stage. An early start to treatment does not mean that treatment finishes earlier, but usually means a longer period of treatment at higher cost.

In cases where an initial functional appliance phase to correct a bite discrepancy is appropriate, followed by fixed appliances to fine tune the alignment of the teeth, we prefer to begin treatment in the final year of the mixed dentition (when there is a mixture of primary and permanent teeth). This ensures that the two phases of treatment can take place one after the other, without pause. This shortens the overall duration of treatment, reduces costs and is preferred by patients.

Despite the comments above, early treatment is appropriate, even desirable, where the upper front teeth protrude in such a way that the risk of accidental damage is increased or when the young patient is suffering from being teased.