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What is Screening for oral cancer comes under which level of prevention? and explain in detail?
Secondary prevention: 

Secondary prevention is defined as an action which halts the progress of the disease at its incipient stage and prevents complication.
The specific interventions are early diagnosis and adequate treatment.
The earlier a disease is diagnosed and treated, the better it is from the point of view of prognosis and preventing further complications or long term disability.
Strictly speaking, early diagnosis and treatment cannot be considered as prevention, since the disease process has already started.

Advantages:
-  Important in reducing the high mortality and morbidity of certain diseases like hypertension.
Disadvantages: 
- Expensive.
- Patient is already subjected to pain and suffering and the community to loss of **
Soben Peter 
Essentials of preventive and community dentistry 
4th edition