A lesion that appears dark brown and shiny suggests dental caries were once present but the demineralization process has stopped, leaving a stain. Active decay is lighter in color and dull in appearance.As the enamel and dentin are destroyed, the cavity becomes more noticeable. The affected areas of the tooth change color and become soft to the touch. Once the decay passes through the enamel, the dentinal tubules, which have passages to the nerve of the tooth, become exposed, resulting in pain that can be transient, temporarily worsening with exposure to heat, cold, or sweet foods and drinks. A tooth weakened by extensive internal decay can sometimes suddenly fracture under normal chewing forces. When the decay has progressed enough to allow the bacteria to overwhelm the pulp tissue in the center of the tooth, a toothache can result and the pain will become more constant. Death of the pulp tissue and infection are common consequences. The tooth will no longer be sensitive to hot or cold but can be very tender to pressure. Dental caries can also cause bad breath and foul tastes. In highly progressed cases, an infection can spread from the tooth to the surrounding soft tissues. Complications such as cavernous sinus thrombosis and Ludwig angina can be life-threatening. Cause
Four things are required for caries to form: a tooth surface (enamel or dentin), caries-causing bacteria, fermentable carbohydrates (such as sucrose), and time. This involves adherence of food to the teeth and acid creation by the bacteria that makes up the dental plaque.
Tumors that demonstrate neural differentiation by light microscopy, immunohistochemistry, or electron microscopy have been traditionally labeled PNETs, and those that are undifferentiated by these analyses have been diagnosed as Ewings sarcoma." PNET of the CNS
PNET of the CNS generally refer to supratentorial PNETs. In the past medulloblastomas were considered PNETs; however, they are genetically, transcriptionally and clinically distinct. As such, "infratentorial" PNETs are now referred to as medulloblastoma. Pineoblastomas are embryonal tumours originating in the pineal gland and are likely distinct from supratentorial PNETs. Treatment
The approach to management of a CNS PNET is first to obtain detailed imaging through MRI, as well as additional scans of the patients body (X-ray, CT, PET, even bone marrow biopsies) to look for metastasis or other associated malignancies. The tumor will then need to be biopsied to confirm the diagnosis. After the diagnosis of a CNS PNET is confirmed, management includes neoadjuvant chemotherapy and radiation (to reduce tumor size burden), complete surgical resection with confirmed negative margins, and/or additional adjuvant post-surgical chemotherapy. CNS PNET is aggressive and must be managed as so. Palliative care services should also become involved in the patients care team when the diagnosis is made. See also
Medulloblastoma
Ependymoma
Ewing family of tumors


== References ==