The causes of orogenic bad breath are usually carious roots, crowns, bad restorations and bleeding gums in the mouth. Bad breath after all-ceramic dental treatment is closely related to the fit of the crown to the tooth. Normal all-ceramic restorations do not cause bad breath, and the treatment uses non-water-soluble materials with good fit for crown bonding, in order to try to ensure the fit of the crown edge. When the crown and tooth edges do not fit tightly, it can cause infection and caries in the abutment teeth, which can produce decaying and necrotic material and cause bad breath.