Patients who have had their jaws irradiated as part of management of head and neck malignancy are at risk of osteoradionecrosis (ORN) following tooth extraction. Thirty-seven patients with a history of irradiation to the jaws were managed during a four year period. Twenty-nine patients received hyperbaric oxygen therapy (HBO) consisting of 20 treatments before surgery and ten treatments a f t e r. Only one (4 per cent) developed ORN. Seven patients who did not have HBO and one who did (15 per cent) developed ORN. The need for prophylactic treatment with HBO is discussed. It is recommended that prophylactic HBO is used prior to surgery for irradiated facial bones.Key words: Osteoradionecrosis, hyperbaric oxygen, surgery.(Received for publication July 1998. Accepted September 1998.) i rr a d i ated bone, which fails to heal without intervention'.3 The usual first presentation is pain with subsequent exposure of bone into the mouth. This m ay progress to wide exposure of bone both i n t o the mouth and through the skin. M o r e advanced stages are associated with constant pain, s e q u e s t r at i o n , p at h o l o gic fracture, m a l o d o u r , deformity and discharge. 4 Radiology is not usually helpful in the early stages of ORN 5 and even in its advanced stages does not necessarily relate to the imaging features.6 Described r a d i o graphic features range from normal appearance, to localized areas of osteolysis to extensive osteolysis, sequestra and fracture. Extraction sockets will often remain visible for more than twelve months after surgery.Computerized tomography (CT) is more valuable in determining the boundaries between norm a l and non-viable bone.5 Nuclear medicine scans, usually with technetium 99, will delineate between vascularized and inflamed areas versus non-viable s e g m e n t s. 7 Magnetic resonance imaging has a limited role.Concepts of the pathogenesis of ORN have undergone change over the last decade. For much of this century ORN was considered primarily an infection,that is,the irradiated bone was injured and became infected. 8 Common traumatic events which breached the overlying mucosa and thus allowed ingress of bacteria were biopsies, cancer surgery, tooth extraction and denture irritation.Hence treatment of ORN followed the classical principles of infection management; removal of the cause, debridement, drainage and antibiotics.This concept was challenged by Marx in the early 1980s. He presented the view that ORN was p ri m a rily a non-healing wound secondary to endarteritis.1 The effect of irradiation on the bone Introduction Osteoradionecrosis (ORN) of the facial bones, particularly of the mandible, is a known serious complication of therapeutic radiotherapy for head and neck cancer. ORN is painful, debilitating and frequently refractory to treat m e n t .

No abstract

Rotational drift of mandibular third molar teeth is a challenge for clinicians to predict and manage. Evidence on the incidence and degree of rotation is sparse. As the factors influencing rotation are not defined, prediction is impossible. A series of four cases with lower third molar rotation are presented and discussed. Significant rotation can alter the degree of difficulty for an extraction. A lack of well-documented cases has hindered investigation of this phenomenon. Further research is required to identify the aetiology, incidence and increase in risk factors caused by such rotational drift.

This paper reviews all 17 cases of facial bone osteoradionecrosis (ORN) which were treated in Adelaide, South Australia, in a nine-year period (1987 1996). This was 1.2% of all cases of head and neck cancer treated with radiotherapy (RT). Fourteen cases received treatment following the Marx principles of staging and the protocols of hyperbaric oxygen plus or minus surgery. The three exclusions were two patients who died of recurrent cancer before treatment was complete and one who declined treatment. The eleven cases of mandibular ORN occurred within a few years of the initial RT treatment. All except one occurred after surgical trauma, with dental extractions being the factor in nine cases. All responded to HBO, with or without surgery depending on stage. The three cases of temporal bone ORN were all of late spontaneous onset. All were stage I and all responded to HBO alone. This study shows that the incidence of ORN in Adelaide is low, probably through use of conservative doses of RT and good preventative protocols. The treatment with HBO plus or minus surgery was effective.