The temporomandibular joint and the disc-condyle relationship after functional orthopaedic treatment: a magnetic resonance imaging study

Causative correction of Class II skeletal malocclusions may be achieved through bite jumping by various means. Numerous animal experiments have yielded evidence of remodelled temporomandibular structures after mandibular protrusion. However, the mode and extent of structural and/or topographic changes of the disc-condyle relationship after functional orthopaedic treatment is still unresolved. A problem exists in defining the physiological position of the condyles and disc-condyle relationship, which is tentatively determined by various methods particularly in magnetic resonance tomographic studies. Despite the high resolution provided, the results have to be interpreted with caution, as osseous resorption and apposition cannot be assessed by visual evidence. This investigation examined the impact on the temporomandibular joints (TMJ), i.e. the condylar shape and position, and the disc-condyle relationship, of the bionator plus extra-oral traction in combination with vertical elastics. The underlying reactions were studied by means of magnetic resonance images (MRI) obtained from n = 15 successfully treated patients (mean age 11.6 years).