see YouTube video here
I have already mentioned some of the consequences of orthodontic treatment such as facial damage and root resorption but there are other longer-term risks such as re-crowding and some such as gum damage which have only recently been recognised. Because patients prefer to avoid extractions Orthodontists currently go to great effort to avoid extracting teeth where possible. Some orthodontists and many general dentists use a screw appliance or an ‘ALF’ to expand the upper jaw to provide enough space for all the teeth. However this does not usually provide room for the wisdoms which they may say are unnecessary.
These are a simple way of avoiding extractions but the teeth usually re-crowd a few years later. This is avoided by many clinicians who give the patient a retaining appliance or attach fixed wires to their teeth either permanently or until they brake or are removed. Other clinicians avoid extractions for a while by pushing the side teeth back to make room for the front teeth but this tends to result in a flat looking face, it is then more likely that the wisdom teeth will become impacted and have to be extracted which can involve complex surgery.
Few if any orthodontists seem to use the Orthotropic method of lengthening the jaw as well as widening it. This makes much more room for the teeth and provided it is done by the age of 8 or 9 should always provide room for the permanent teeth including the wisdoms. This of course also takes the whole upper jaw forward improving the appearance of the cheek bones, sometimes dramatically. See the picture below.
Another long-term problem is gum damage which has more recently become recognised as a matter of concern. As we explained earlier the teeth and their supporting bone are normally supported by the tongue, lips and opposing teeth. But if the teeth are moved and held in a different position for a long time, such as with a retainer, the bone around them remains unstable and tends to resorb. The blood supply to the gums is carried through the bone and if it resorbs the gum often recedes or dies leaving what are called ‘fenestrations’ or holes which can severely shorten the life of the teeth.
see YouTube video
The subject has been debated since the times of the ancient Greeks and often generates more emotion than logic. I am constantly amazed that so many orthodontists are prepared to provide treatment without a clear understanding of what has caused the particular problem they are facing. To fail to do so, risks treating the symptoms of malocclusion rather than the cause. Is it genetic, environmental or both and if the last, in what ratio? It would seem essential to answer this question before contemplating how any malocclusion should best be treated.
Gross et al (1994) found 63% of five year olds left their mouth open for long periods and that those with “High levels of open mouth posture manifested significantly smaller growth of the upper jaw (maxilla)”, this in turn restricts the growth the lower jaw resulting in too little room for the teeth.
When I ask clinicians what has caused a particular malocclusion they will often answer like this “this malocclusion is due to a combination of an undersized maxilla and a retruded mandible”, but they will not explain why this discrepancy has occurred. The inference being that it has a genetic cause. Most clinicians would agree that congenital defects and Trauma are responsible for less than 5% of all malocclusions so what causes the rest?
In 1938 Brodie measured a number of X-rays and announced “The most startling find was the apparent inability to alter anything beyond the alveolar process”. This led to a generalised belief amongst orthodontists that the facial bones are inherited and cannot be changed more than a millimetre or two. However it is known that Bones remodel considerably during growth, for instance, as the maxilla enlarges the front of the sinus moves forward while the posterior wall moves back relative to the general forward movement of the bone. As a result of this and other growth changes, the landmarks that are used to overlay consecutive X-rays move, making it impossible to make accurate superimpositions.
Modern computer enhanced X-rays show very sharp 2 dimensional images but we must remember that these are based on rather fuzzy shadows of a three dimensional skull with inevitable slight tilt, differential enlargement and rotation distorting the superimposition often by several millimetres. This strongly affects the landmarks not on the midline which is why X-rays alone must be a less than certain means of determining the movements that actually take place. Hopefully the situation will become clearer as modern scanning techniques improve.
Overall the evidence is not as conclusive as some would suggest and there are clear differences of opinion amongst accepted leaders in the field. Above all, we are left with no explanation for the fact that many mono-zygote twins have substantially different facial form. Clearly it is impossible for these to be genetic if both individuals have the same genes. See the illustration below, by permission of Tom Graber.
see YouTube video here
Many clinicians from different disciplines offer explanations and cures for TMJ and it is widely assumed that there is no ‘One Size Fits All Treatment Guarantee’. However when part of the body goes wrong there is usually only one direct cause, although by coincidence two or possibly three causes could occur simultaneously. Most of the other factors are either, resultant, coincident, predisposing, or unrelated, but not causative. It is wise therefor to consider each one separately and then try to select the real culprit.
My research in anthropology convinced me that the jaw joints of our ancient ancestors rarely showed any signs of damage, so why does this joint cause so much trouble now? Things have changed since then and many jaw bones are now set back as much as 20 to 30mm from where they were back then. Most TMD clinicians agree that this distalization, causes pressure on the joint but there are few suggestions about how to improve it and surgery has not so far proved a reliable cure.
There are many recommended treatments but about 20% of patients continue to suffer whatever is done. Good cures usually surface quickly and the single most effective treatment appears to be a dental splint (orthotic) which separates the teeth somewhere between 1 to 8 millimetres. While the relief can be dramatic, and permanent the problems often return after a few weeks or months. This suggests to me that the splint may rest the joint in the short-term but the underlying cause remains. This explanation fits the fact that thickening the splint often provides a further period of relief but again the problem returns. Splints can also have side effects such as intruding teeth and despite what is done 20% or so of patients continue to suffer.
Other cures exist such as physiotherapy which can be almost as effective as splints, but again they seem ineffective for about 20% of patients. A number of clinicians and patients consider changes in the content and consistency of our diet is important, but ‘cures’ on this basis are rather unspecific and it not appear to have a high ratio of success.
With orthotropics we try to reverse the life-style changes because we believe that modern living has encouraged many children to leave their mouths open and also to swallow with their tongue between their teeth. Research shows that this is a major reason for both jaws failing to grow forward which in turn disrupts the way the teeth and jaws meet and effects the position and form of the TMJ. Orthotropic treatment is based on the ‘Tropic Premise’ which says “correct oral posture is with the tongue resting against the palate, the lips sealed and the teeth in light contact for about six hours a day”. Orthotropic treatment aims to train children to keep their mouths closed which increases forward growth improving the teeth and face. This seems to reduce their susceptibility to TMJ problems later but is only fully effective with growing children. However adopting the Tropic Premise can often cure TMD pain in young adults possibly reaching that last 20%. see the picture below.
See YouTube video here
Estimates of the number of British children and young adults receiving orthognathic surgery have varied widely over the last twenty years. Previously it was thought to be less than 1000 a year but in 1999 a survey suggested that 7% of a consultant Orthodontist’s workload was related to Orthognathic treatment. In 2009 it was estimated that 1.5 million people would warrant orthognathic treatment. I think that this change in treatment selection has been driven by the difficulty in correcting class II malocclusions by non-surgical means.
Twenty years ago most overjets treated by surgery were over 7 millimetres but currently many cases are less than 5 millimetres. This may be due to the realisation that correction by functional and dental-orthopaedic appliances is uncertain even when the overjets are small. There are few accurate figures to tell us what the current number might be and anyway the figure is distorted by the number of children who are advised to have surgery but who are too frightened to accept. These may outnumber those accepting surgery by two to one, leaving many children with disfigurement that no one can cure satisfactorily.
Information about orthognathic surgery is largely supplied by individuals who publish successful cases but of course this is always slightly unsatisfactory as one is left wondering what might have happened had another method been used. As a result there is little evidence to show if some methods get better results than others. Although modern surgery is very safe there is always the chance that things can go seriously wrong and certainly surgery should always be avoided if possible.
Most orthognathic surgery these days it a sequence of orthodontic treatment using fixed appliances and surgery, usually in that order but sometime with a second cycle of orthodontics. This can make overall treatment quite a lengthy process. Non-surgical methods such as Fixed, Functional and Herbst Appliances have been used but there is a risk of only partial improvement as a result of unattractive facial lengthening (Faure, J. 1998). Some success has been reported using Orthotropic treatment on cases previously recommended for surgery suggesting that it could be an effective alternative (see below).
Although these cases have been shown to the GDC they have said orthodontists need not “inform a patient of alternative treatments which, in the dentist’s opinion would not be appropriate”. Some readers might think that patients should be informed about all realistic alternatives especially if they can avoid invasive surgery so they are able to decide for themselves.
see YouTube video here
The Tongue: What Part does it Play?
It is hard to comprehend the full difference between the correct and incorrect action/posture of the tongue. The teeth are resistant to short-term force during biting or swallowing but they are very sensitive to light long-term force/posture, including the touch of the tongue. If you place a blob of resin on the lingual side of an unopposed molar it will move away from the light contact of the tongue because it is continuous while the strong push from the tongue during swallowing lasts barely a second and so has little influence.
The shape of the dental arch is determined primarily by the tongue but also by the cheeks and lips, all of which have far more influence than the genes. That is why the arch shape of all animals and our primitive ancestors reflects the shape of the tongue. That does not apply to people who have any malocclusion because all of them have displaced tongues. Usually children from industrialised countries rest their tongue to a greater or lesser extent between the teeth. In fact about 95% of civilised children do this, leaving the teeth and lips apart for varying periods which of course is why malocclusion is endemic.
William Profit’s research at South Carolina, showed very clearly that teeth erupt when out of contact and intrude when in contact (Proffit et al 1993). From this research it is obvious that teeth need to be in contact 4 to 8 hours a day for them all to meet evenly with the face the correct height. But if the tongue rests between the teeth this balance is distorted.
The problem has been that few clinicians who work in the mouth have realised how influential the tongue is for the growth and development of the jaws and face. This includes many Dentists, Ear Nose and Throat Specialists, Orthodontists, Speech Therapists, Orthognathic Surgeons, Oral Myologists and to some extent Beauty Specialists and Plastic Surgeons all of whom are involved in the shape and function of the facial skeleton. We could also include Anthropologists who study the historical shape of the face as well as the Cranial Osteopaths, and Chiropractors who treat internal deformation of the skull. Many of them visualise the tongue as a soft structure which adapts to the form of the tissues around it, rather than seeing it as the large powerful muscle it is.
Orthotropists believe that the natural growth and appearance of the face is largely guided by the position of the tongue, but no one has yet found an accurate way of measuring tongue posture and so this suggestion is as yet hypothetical. It is theorised that the forward growth of the maxilla (the mid face) depends to a large extent on support from the tongue but although there is incidental evidence to support this concept it is not widely accepted by orthodontists. Sadly because it can’t be measured, university researchers have shown little interest in tongue posture so we have little idea whether it is crucial or unimportant.
The illustration below shows the effect of enlarging the maxilla and taking it forward.
YouTube video here
The big majority of orthodontics in Britain is carried out with fixed appliances this achieves excellent alignment of the teeth but is often followed by relapse. I think orthodontists are embarrassed about relapse but believe that by retaining the result afterwards they remove the problem.
To prevent re-crowding, the teeth must be held in position by one of the many types of retention available, and the British Orthodontic Society has recently recommended that every orthodontic patient should be advised that they will need to wear a retention appliance for the rest of their life. This can require more work than the treatment itself. There are also concerns about food retention and gum damage with fixed wires, especially if subsequent restorative work is required. Experience suggests that removable retainers are usually dis-guarded within a decade or two. There are clearly problems ahead and who will pay for this?
Concern has recently been expressed recently by periodontists (ref if poss) about the consequences of long-term retention of expanded dental arches. Many orthodontists do this to avoid extractions. The teeth are held in position but the soft tissue forces of the tongue, lips and cheeks remain unchanged resulting in progressive clefting and fenestration of the teeth and bone. Because this type of expansion is now widespread, it is likely to become a major problem, not only for the patients but also of course for the dental insurance companies, which may be why it is rarely discussed.
Orthotropics does not need any retention hence there is little risk of gum damage.
see YouTube video here
The big majority of orthodontics in Britain is carried out with fixed appliances which achieve excellent alignment of the teeth but several scientific papers have suggested the possibility of adverse facial changes (Battagel 1996). I think orthodontists are embarrassed about this but believe that by avoiding discussing the subject, the public will not be worried.
The father of the girl shown below was a medical doctor and asked for non-extraction treatment for his daughter hoping this would avoid damage. After a year of retractive Headgear there was little change and she then had 4 teeth extracted. After another year the orthodontist said she would need jaw surgery. The picture below shows the change to her face at that point.
The next patient (below) received a nice improvement from Biobloc Orthotropic treatment but then decided to have the alignment improved with fixed appliance. See the vertical growth that followed.