Abstract: The integrity of the remaining tooth structure affects the long-term preservation of the tooth after root canal treatment. Retaining more healthy tooth tissue is important for improving the flexural performance and the prognosis of the tooth. Related studies have found that the retention of peri-cervical dentin (PCD) structure plays an important role in the biomechanical properties of the remaining teeth and long-term repair and preservation. This article will review the definition, the function, the research methods and the problems still existing in the current study of the peri-cervical dentin, and the way to preserve it.

Key words: Peri-cervical dentin, Fracture resistance, Preservation of tooth structure