Inflammatory Lesions of the Teeth and Jaws
nflammatory lesions are one of the most common lesions in the jaws. There are many ways for infectious and inflammatory agents to invade the bone and cause pathological condition through dental caries and periodontal diseases. The inflammatory response by the body destroys the walls of the lesion and initiates the repair mechanism. There is balance between bone resorption and bone deposition under normal circumstances. However, during and inflammation process, inflammatory mediators such as cytokines and prostaglandins disturb this balance in favor of either bone resorption or deposition.
Inflammatory lesions regardless of the causing agent; should not be considered as separate entities rather a continuum of the same process that varies depending on the site, size, duration and severity. Periapical inflammation is the term used when the infection is restricted to the periapical area of the affected tooth, if the infection extends beyond that; the condition now is called osteomyelitis. Periodontitis is the term used to describe an infection to the bone from periodontal source while pericoronitis is an inflammation that develops around the crown of partially erupted tooth.
Inflammation can be characterized by five cardinal signs: redness, heat, swelling, pan, and loss of function. Inflammatory lesions can be classified according to their onset into two types: acute and chronic. Acute inflammation is short on onset and usually associated with pain and swelling. Chronic inflammation is prolonged in duration and it may be associated with swelling or mild pain, it may not produce any symptoms at all.
Inflammatory lesions have different radiographic appearance which can be radiolucent when there is bone resorption around the apex of the tooth to radiopaque when there is bone formation or a combination of both. The boundaries of inflammatory lesions are usually ill-defined and they blend smoothly with normal surrounding trabecular bone with or without sclerosis. Osteomyelitis can have sequestra which are islands of dense non-vital bone surrounded a radiolucent margin.
If the inflammation is originated in the pulp of an infected tooth then usually the epicenter of the lesion will be in the apex of the tooth. It can also be long the pulp of tooth due to the presence of accessory canals or perforation during therapy or root fracture. Periodontal lesions start at the level of the alveolar cortex and they can involve the furcation area of the posterior teeth in case of moderate periodontitis and in severe cases, the lesions can affect the apex of teeth. When there is an infection of bone or bone marrow, it is called osteomyelitis.
Inflammatory lesions can cause widening of the periodontal space usually around the apex of the tooth. Root resorption can occur in chronic inflammatory conditions and can be associated with loss of cortical boundaries at the apex of the tooth. The periosteum of the bone can be affected causing new layers of bone to be deposited which run parallel to the root surface.