There have been a variety of different theories to explain the
pathogenesis of ORN. In 1926, Ewing first recognized and reported
the bone changes associated with radiation therapy and described
this disease state as ‘‘radiation osteitis”.5 Later, in 1938 Watson and
Scarborough described ‘‘radiation osteitis” as being caused by radiation,
trauma, and infection.6 It was believed that trauma to the
soft tissue overlying bone in the oral cavity permitted bacteria to
enter into the underlying demineralized bone, leading to osteomyelitis.
In 1972, Daly challenged the role of trauma in ORN.7 More
recently, it has become clear that micro-organisms only play a surface
contaminant role and are not the true etiological cause of
ORN.