Some cases of chronic osteomyelitis stimulate sclerosis of the surrounding bone. This sclerosis may be localized or diffuse. Within the jaws, several subtypes of chronic osteomyelitis have been described, which are characterized by varying degrees of sclerosis, rarefaction, and/or periosteal hyperplasia. These subtypes include diffuse sclerosing osteomyelitis, focal sclerosing osteomyelitis (condensing osteitis), proliferative periostitis, primary chronic osteomyelitis, and secondary chronic osteomyelitis. In addition, some authors use the term diffuse sclerosing osteomyelitis descriptively in reference to the radiographic appearance of several disease subtypes. The differential diagnosis for diffuse sclerosis of the jaws also includes florid cemento-osseous dysplasia; however, this condition is primarily a fibro-osseous condition, with infection and osteomyelitis sometimes developing secondarily in late stages of the disease.
Diffuse opacification of the anterior and left posterior mandible.(from Color Atlas of Oral and Maxillofacial Diseases)
Condensing osteitis (focal sclerosing osteomyelitis, focal sclerosing osteitis) presents as a localized area of bone sclerosis that forms in response to a low-grade inflammatory stimulus. The inflammation usually arises from a tooth with pulpitis (caused by a large carious lesion or deep restoration) or pulpal necrosis. The condition occurs over a broad age range, with a predilection for young patients and the premolar/ molar region of the mandible. Clinically, no expansion is evident. Radiographic examination shows an area of opacification surrounding the apex of the inflamed tooth. No radiolucent rim is evident; this feature aids in distinction from focal cemento-osseous dysplasia. In addition, there may be concurrent widening of the periodontal ligament. Treatment requires elimination of the underlying odontogenic infection, usually by extraction or endodontic therapy. Following appropriate treatment, there is usually partial or total resolution of the lesion over time.
Periapical opacification in association with a nonvital mandibular first molar. (from Color Atlas of Oral and Maxillofacial Diseases)
Proliferative periostitis (periostitis ossificans or so-called “Garrè’s osteomyelitis”) represents a periosteal reaction to the presence of inflammation. This condition exhibits a marked predilection for children and young adults. Gnathic cases often are caused by underlying odontogenic infection, especially originating from a mandibular molar. In addition, the condition may arise in association with traumatic jaw fracture, tooth extraction, periodontal disease, inflamed cysts, third molar pericoronitis, dental follicles, developing unerupted teeth, and neoplasms (e.g., Langerhans cell histiocytosis, Ewing sarcoma, osteosarcoma). Radiographic examination shows an area of cortical bone thickening produced by parallel layers of new periosteal bone formation. Although not always evident, the classic “onion-skinning” pattern may be best demonstrated by occlusal radiographs. Other possible radiographic findings include cortical consolidation with fine, radiating trabeculae or coarse trabeculae. The original cortex and contour of the bone may or may not be evident. Clinically, the patient exhibits a bony, hard swelling that may be asymptomatic or tender. Treatment involves addressing the underlying inflammatory stimulus. Infected teeth typically require extraction or endodontic therapy. Over time, bone remodeling gradually produces a normal bone contour. If no infection is evident, then biopsy should be performed to rule out underlying neoplasia or other conditions.
New periosteal bone formation (arrow) along the inferior border of the right posterior mandible. The underlying inflammatory stimulus was infection of the right mandibular first molar. (from Color Atlas of Oral and Maxillofacial Diseases)