0.3 Orthodontic relapse – Is it a problem? by Prof John Mew

Before and After Orthodontic Treatment
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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.

0.5 Can orthodontics damage faces?

Before and After Orthodontic Treatment
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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.

0.1 Root resorption – Does it matter? by Prof. John Mew

Tooth Root Resorption X-Ray
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Root Resorption – Does it Matter?

Most orthodontics in Britain is carried out with fixed appliances and is usually associated with some root resorption. I think most orthodontists are embarrassed about this resorption but accept it as unavoidable. However we are left with little idea of its consequence in old age.

Some persistent researchers are very concerned about it and when you read their figures you can understand why. Kurol for one found that “root resorption is an early and frequent iatrogenic consequence of orthodontic treatment, even after application of a force below what is often used in other clinical situations”.  “93% of teeth showed some root resorption but none of this could be seen on periapical radiographs”.

Perhaps we should consider the physiological aspect, the periodontal membrane is about ⅛ mm thick and has evolved like a sling to take the load of biting. However the fibres do not withstand lateral loads very well and if a side movement exceeds ⅛ mm the narrow line of contact between the root and the socket the surrounding membrane becomes compressed and therefor ischaemic. If this lasts for any length of time the cells die causing the pain that many children suffer following adjustment of their orthodontic appliances.

Unfortunately this is routine whenever a fixed or removable spring device is adjusted. As we might expect intermittent forces are more healthy as they allow the blood flow to be re-established at intervals but orthodontists have found these difficult or impossible to apply (Kento et al 2017).

An alternative method might be to use a rigid removable appliance which applies exactly 1/16th mm movement to each side of the maxillary arch each day so that the membrane which is ⅛th mm thick is never crushed. This precise rate might provemore effective at moving teeth and bone with little or no damage.

It is known that there is little root resorption if patients are treated young before their root apices have closed so that apical resorption is unlikely to take place (Mavragani et al 2002). The illustration below shows that orthodontic treatment is sometimes associated with root resorption.