cavities on xray but not seen on exam

My 6 year old son has been going to a dentist every 6 months for exams and x-rays,  and has had perfect teeth thus far.  Today, due to insurance changes, we chose a different dentist and was told that he has 3 cavities (small and seen only on x-ray) and needs 3 sealants.  I am concerned because she now wants to do sedation, three fillings and three sealants which seems to be quite a process (not only for my son but also financially).  Is it really necessary to do fillings on baby teeth that cavities were only able to be detected by x-ray?  And, how necessary are sealants?

Thank you,
jjp15

[scottma]

Sealant is a preventive procedure., which yields long term benefits. If you don't feel comfortable with the procedure, consultation with your dentist for alternative option is advised.