牙体预备超过釉牙本质界时,牙本质小管被切断并损伤其中的造牙本质细胞突起,牙本质被切开的部位,应看作是牙髓面周围的创伤,实行相应的防护措施。措施之一,减少对牙髓的机械性和物理性损伤。转速高的切割器械只用于磨削釉质,随着向釉牙本质界的接近,转速应该减慢,磨削牙本质时用低速。因为高速转动的器械与牙齿接触的部位会产生负压,切割牙本质小管时,在负压的影响下,造牙本质细胞核被吸入牙本质小管内,细胞被破坏,以 When the tooth preparation exceeds the enamel dentin boundary, the dentinal tubules are severed and the process of dentin protuberance is damaged. The site of dentin incision should be regarded as the trauma around the pulp surface and the corresponding protective measures should be taken. One of the measures to reduce the mechanical and physical damage to pulp. High-speed cutting instruments are only used to grind the enamel, with the enamel to dentin boundaries approaching, the speed should be slow, low-speed grinding dentin. Because high-speed rotating parts of the instrument and the teeth will produce negative pressure, cutting dentin tubules, under the influence of negative pressure, dentin nuclei are inhaled dentin tubules, the cells are destroyed to