Mandibular nonunion - TMJ Dysfunction

TMJ dysfunction may be caused by  Malocclusion. Malocclusion may be caused by nonunion. Nonunion is the lack of bone healing in the period of 8 weeks or longer until the time of surgical decision. Traditionally the terms pseudoarthrosis or fibrous union have also been used to describe nonunion.

The diagnosis is made by the presence of mobility at the fracture site. Pain may also be present in cases of nonunion.

Nonunion cannot be diagnosed at an early stage by radiographs or CT scans alone. At a later stage the fracture margins will show irregular radiolucency with mottled fracture ends (looking like elephant feet) and/or hardware loosening.

Nonunion of fractures do not necessarily present with mobility after 8 weeks because of the stability provided by the fixation system. However, the fixation system will most likely fail at some point leading to mobility.

In patients submitted to closed treatment under MMF, the diagnosis can only be made after MMF is released.

Besides the routine patient history and health status, the examiner should obtain details on previous treatment(s) (eg. dates, procedures and complications).

Physical examination should focus on facial asymmetries, limitation of mandibular movements, malocclusions, mobility of the non-union site, and the presence of infection.