Porcelain teeth do not cause bad breath, they are made of the same material as other crowns, they are just different and do not cause bad breath, but if the internal bonding material is not tight, it may cause bad breath.
Porcelain teeth are made in almost the same way as other metal crowns and all-porcelain crowns, which are wrapped around the tooth, only the materials are different, and like crowns made of other materials, they do not cause bad breath in the mouth. If you suspect that porcelain teeth cause bad breath, it may be that the adhesive bonding between the porcelain tooth and the natural crown has loosened and micro-leakage has occurred, and food debris can enter the gap and ferment and develop a foul odor.
Porcelain tooth crowns themselves do not produce bad odor. If you have bad breath, check to see if the crowns are loose or the teeth are decayed causing bad breath, and consult a medical professional for advice.