关键词: 桩核, 超声, 共振

Abstract: Post-core crown is a common method to repair residual roots and crowns in clinical practice. However，in non-surgical root canal retreatment，the post-core should be removed to clean and reform the root canal. During the process of removing the post-core，the residual tooth tissue should be protected and tooth fracture should be avoided. Because of its safety and high efficiency，ultrasonic instrument has become an important means to remove metal post-core. This paper briefly introduces research progress in the factors influencing the efficiency of ultrasonic removal of metal post core.

Key words: post-core, ultrasound, resonance