One of the most common reason for this problem is hyperacidity or excessive drinking of preservative based drinks e. g. sport drinks or packed juices
Then next major cause is progressive wearing of natural teeth structure
This is a complex problem and restoration of teeth needs to planned
Next Steps
Consult a dentist who has expertise in full mouth rehabilitation
Health Tips
Conservative veneers & ONLAYS (Direct Composite or Indirect Ceramic) should be opted as per your affordability.
Crowns (caps) should avoided as far as possible.