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What is Phoenix abscess and explain in detail?
A phoenix abscess is an acute exacerbation of a chronic periapical lesion. It is a dental abscess that can occur immediately following root canal treatment. Another cause is due to untreated necrotic pulp (chronic apical periodontitis). It is also the result of inadequate debridement during the endodontic procedure. Risk of occurrence of a phoenix abscess is minimised by correct identification and instrumentation of the entire root canal, ensuring no missed anatomy.
Treatment involves repeating the endodontic treatment with improved debridement, or tooth extraction. Antibiotics might be indicated to control a spreading or systemic infection.

Causes
Phoenix abscesses are believed to be due to a changing internal environment of the root canal system during the instrumentation stage of root canal treatment, causing a sudden worsening of the symptoms of chronic periradicular periodontitis. This instrumentation is thought to stimulate the residual microbes in the root canal space to cause an inflammatory reaction. These microbes are predominantly facultative anaerobic gram-positive bacteria, such as Streptococcus, Enterococcus and Actinomyces species. Another cause of a phoenix abscess is a decrease in a patients resistance to these bacteria and their products.

Signs & Symptoms
Clinical Features
PainA common clinical feature is exacerbated and exaggerated pain. There may or may not be associated with pus & suppuration. The signs & symptoms are similar to that of an acute periradicular abscess, but with a periradicular radiolucency present as well.
Loss of VitalityThe problematic tooth will have a non-vital pulp with no previous symptoms