First of all you, you have not written your complete problem. From what you have written, I understand that you have a bad tooth with a cavity. For that you have two options, either go for Root Canal Treatment, which your dentist can tell you after taking xrays and clinical examination or you can get it pulled out. If the tooth can be saved with Root Canal Treatment, it is always better and cheaper. For more info on Root Canal Treatment, you can check the following link in our website... http://www.identalhub.com/articlecategory-root-canal-therapy-17.aspx