This article focuses on the principles of porcelain dentistry, contraindications to porcelain dentistry, and why porcelain dentistry is not appropriate for patients who grind their teeth at night. There are various types of porcelain teeth, and the principle is to form a hard bone covering the affected area on the patient’s oral model, and then sinter ceramics with a lower melting point and a color close to that of natural teeth on the bone. These artificial teeth are strong and look great, and their stability and biocompatibility are excellent. In fact, there are contraindications to having porcelain teeth, and people who suffer from nighttime teeth grinding are not suitable for porcelain teeth. Bruxism is the behavior of grinding or clenching the upper and lower teeth against each other while a person is asleep or awake. Because teeth grinding is often accompanied by the sound of gah, gah, gah, usually also called clenching, but also because it occurs in the night time sleep, also known as nocturnal teeth grinding. Nocturnal teeth grinding causes teeth to strongly knock together, and no food buffer, upper and lower teeth in direct contact, not only the force is large, and lasts for a long time, resulting in excessive wear and tear of the enamel on the surface of the teeth, so that the dentin under the protective material is exposed, it will be cold, hot, sour, sweet and other stimuli feel uncomfortable, and even tooth necrosis, but also lead to bleeding of the dental bed, tooth looseness or even fall off. Night grinding will cause serious wear and tear of the tooth tissue, porcelain teeth will be more than its stress range of pressure will appear broken porcelain. And night grinding to bite force is too large, repeated stress is easy to cause chipping. In addition, people with severely overlapping teeth or tight bites are also not suitable for porcelain teeth.