Regulatory mechanisms and regeneration strategies of the soft–hard tissue interface in the human periodontium

The soft-hard tissue interface of the human periodontium is responsible for periodontal homeostasis and is essential for normal oral activities. This soft-hard tissue interface is formed by the direct insertion of fibrous ligaments into the bone tissue. It differs from the unique four-layer structure of the fibrocartilage interface. This interface is formed by a combination of physical, chemical, and biological factors. The physiological functions of this interface are regulated by different signaling pathways. The unique structure of this soft-hard tissue interface has inspired scientists to construct biomimetic gradient structures. These biomimetic systems include nanofiber scaffolds, cell sheets, and hydrogels. Exploring methods to repair this soft-hard tissue interface can help solve clinically unresolved problems. The present review examines the structure of the soft-hard tissue interface of the periodontium and the factors that influence the development of this interface. Relevant regulatory pathways and biomimetic reconstruction methods are also presented to provide ideas for future research on interfacial tissue engineering.