Dental Sedation advice needed, Please help?

Hi I need to know if dentists sedate patients for only certain treatments or all? I am extremely phobic and have not been to a dentist since 1995/6, my teeth are in a seriously bad way & I know the only way forward for treatment for me is sedation. Do they sedate for fillings? Filing down teeth for crowning? or just extraction? I cannot bare the drill, the noise the smell. I want to be out of it for any procedure I need. What's my chances?