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Mystery and controversy are directly proportional

27 August, 2012

By Dr Rohan Wijey, BOralH, Grad Dip Dent.

The less we know about a topic, the more clamorous are the polemics and the sharper the schism is between them. The orthodontic tradition is no different and has seen a familiar quarrel rumbling for more than a century.

In broad terms, two faculties of thought have evolved. The first, traditional school (Angle 1907) works under the premise that certain skeletal dimensions are intransigent (Cross 1977), and uses fixed appliances to render predominately dentoalveolar movements.

The second, historically European school (Andreson & Haupl 1936), is predicated on the belief that muscle function affects the size of jaws and dental arches, and that functional appliances can fix form by treating dysfunction.

This article will not subscribe to the heavily flogged corpse that is the debate between the two sides.

It is simply unscientific to enlist ourselves to either cause; rather, we must be directed by the flow of evidence, and be willing to jettison past beliefs in favour of new evidence.

Traditionalism exhumed, progress buried?
“Providing early orthodontic treatment for children with upper front teeth is no more effective than providing one course of orthodontic treatment when the child is in early adolescence” (Cochrane Review 2007).

Turpin (2007) claims this news “will help the clinician feel less pressure to begin early correction of this malocclusion.”

It must be noted, however, that the Review’s conclusion was based simply on overjet, peer assessment rating (PAR) scores and ANB angle; the first and second criteria concern dentoalveolar relationships, while the third describes how the maxilla and mandible approximate to each other, and not to the rest of the cranium.

There is no assessment of soft tissue profile, and these scores are simply not indicative of how the face looks.

Moreover, there is no mention of such complications as root resorption (Ballard et al. 2009), incisor trauma (Justus 2008), white spot lesions (Willmot 2008) and damaging of facial profiles with premolar extractions that are all associated with later intervention.

“Whenever there is a struggle between muscle and bone, bone yields” (Graber 1963)

The role of muscles in fashioning bone and dental arches is an immutable fact. Many studies have shown that masticatory muscle function increases sutural growth in the craniofacial complex and stimulates bone apposition (Kiliaridis 2006). Furthermore, it is not simply mastication but the whole spectrum of muscle function that influences bone, such as deglutition, respiration, sucking and speech.

Electromyographical studies have also revealed that muscles have the power to remodel bone and arches even at postural resting position, as compensatory myofunctional alterations for structural discrepancies (de Souza et al. 2008).

The studies have cast a retrospective glow on Graber’s prescient 1963 sentiment that any hope of a stable result rests on restoring the myofunctional balance of the stomatognathic system.

This overwhelming evidence clearly indicates the need for treatment to be geared toward correcting function, because it is function that affects form.

Evidence-based orthodontics
Since the epidemiologist Sackett (1986) observed that orthodontics was on par with scientology in terms of scientific legitimacy, the industry has made a concerted effort to transform itself. More orthodontists are embracing this paradigm-shift toward the weight of evidence, which rests firmly with early treatment and treating muscle function.

A case in point is this 9 year old girl with a narrow, retrusive maxilla and mandible, crowding of the upper arch and anterior flattening of the lower arch. An expansion appliance was used for the maxilla to create enough room for the tongue to posture correctly in the palate, together with a myofunctional appliance. By simply treating function, after only 4 months the overbite has reduced significantly, the lost lower right c-space has begun to re-open and the dental alignment has also improved. Obviously, the myofunctional phase of treatment is yet incomplete and the dental phase has not even begun, however, the improvement in the facial profile is already remarkable.

There is always going to be an important place for fixed appliances, because it is still the most efficient way to move a tooth. However, the two worlds are far from mutually exclusive: We can shorten the time needed for braces and greatly improve the stability of the result and fullness of the face if we intervene early with myofunctional therapy.

A new dawn is breaking in the industry, one in which we can now use the best of both worlds for better faces as well as teeth.

This story is tagged: malocclusion, orthodontics, tongue, alignment, early treatment, muscle,

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