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. Vitality of teeth can be assessed through various means.
Tasimelteon, sold under the brand name Hetlioz, is a medication approved by the U.S. Food and Drug Administration (FDA) in January 2014, for the treatment of non-24-hour sleep–wake disorder (also called non-24, N24 and N24HSWD). In June 2014, the European Medicines Agency (EMA) accepted an EU filing application for tasimelteon and in July 2015, the drug was approved in the European Union for the treatment of non-24-hour sleep-wake rhythm disorder in totally blind adults, but not in the rarer case of non-24 in sighted people. The most common side effects include headache, somnolence, nausea (feeling sick) and dizziness. Medical uses
In the United States, tasimelteon capsules are indicated for the treatment of non-24-hour sleep–wake disorder (Non-24) in adults and for the treatment of nighttime sleep disturbances in Smith-Magenis Syndrome (SMS) in people sixteen years of age and older. Tasimelteon oral suspension is indicated for the treatment of nighttime sleep disturbances in SMS in children from 3 to 15 years of age.In the European Union, tasimelteon capsules are indicated for the treatment of non-24-hour sleep–wake disorder (Non-24) in totally blind adults.The capsule and liquid suspension forms of tasimelteon are not interchangeable.Tasimelteon is a selective agonist for the melatonin receptors MT1 and MT2, similar to other members of the melatonin receptor agonist class of which ramelteon (2005), melatonin (2007), and agomelatine (2009) were the first approved. As a treatment for N24HSWD, as with melatonin or other melatonin derivatives, the patient may experience improved sleep timing while taking the drug.