1, the hardness of porcelain teeth is greater than human enamel, and it is fragile, which can cause wear on jaw teeth, and its internal crown is metal internal crown.

2. The hardness of all-ceramic teeth is softer than that of porcelain teeth, and the enamel is similar, which will not cause wear on jaw teeth. The inner crown is an all-ceramic inner crown.

Second, the biocompatibility is different.

1. All-ceramic teeth contain no metal, will not be corroded by acid and alkali substances, and will not cause allergies.

2. Porcelain teeth are based on metal, so they are easily corroded by acid and alkali.

Third, the appearance is different.

1. All-ceramic teeth are transparent and more like real teeth.

2. The opacity of the metal crown of porcelain-fused-to-metal teeth requires opaque porcelain to cover the metal base, which affects the transparency of the restoration, making the porcelain-fused-to-metal teeth appear obviously chalk-colored, pale and false after cosmetic treatment, and the "black source line" caused by the metal base of the tooth neck affects the appearance.

The above contents refer to Baidu Encyclopedia-porcelain teeth and Baidu Encyclopedia-all porcelain teeth.