This is unfortunate that even after keeping a good oral hygiene you have crowns on all teeth due to cavities in them..Do visit a dentist after every atleast 5-6 months to get them checked properly to avoid further complications..Have balanced diet with less intake of sweet or sticky food..Rinse after every meal alongwith use of dental floss and mouthwash daily..

maintaining  good oral hygiene is necessary  for you .visit physician or ent surgeon for sinus problem  which will help you to improve mouth breathing

Its very unfortunate that you have this problem but I would like to advise you to keep regular follow up of ur Dentist and just try to eat balanced diet and try to avoid sticky food stuff to stay away from propability of getting cavity.

Hello mam, some people are more prone to dental caries than others even though you try to maintain your hygiene properly. Wash your mouth after each meal or snack. Whenever you feel like you have cavity or see discoloration on your tooth visit your Dentist and get it treated without delay.