ORTHO TRIBUNE | FEBRUARy SUPPLEMENT Industry 13 Mystery and controversy are directly proportional The less we know about a topic, the more clamorous are the polemics and the sharper the schism is between them AD By Rohan Wijey BOralH, Grad Dip Dent T he 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 appli- ances 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 favor 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 softtissue 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. g OT page 14