The formation of a strong and long-lasting adhesive force between dental tissue and restorative materials is crucial for oral adhesive repair. The adhesion of dentin relies on the formation of a mixed layer structure, but existing full acid etching adhesion systems and self acid etching adhesion systems can form defect zones and nano leaks at the bottom of the mixed layer, causing some dentin collagen to lose the protective effect of the adhesive and be exposed, easily degraded by moisture and various proteolytic enzymes, leading to the degeneration of the dentin adhesion interface. Therefore, how to effectively improve the cross-linking degree of dentin collagen fibers and reduce collagen exposure is the main means to improve the durability of dentin bonding interface. Low temperature atmospheric pressure plasma is an emerging surface treatment technology in recent years, which can generate a large number of charged particles, various ions, free radicals, reactive oxygen species and other active substances. Moreover, it has a weak heating effect on the surrounding environment during energy conversion, so it can maintain a low temperature, making plasma technology applicable to biological tissues with high thermal sensitivity.

Plasma is the fourth form of matter after gas, liquid, and solid. It is a gas cluster that is electrically neutral and has high ionization degree when gas is subjected to high-frequency and high-voltage electric fields. Contains a large number of active substances such as charged particles, various ions, free radicals, reactive oxygen species, ultraviolet radiation, visible light, etc. These highly active plasma groups can react with the surface of the material to clean, etch, or form a thin layer of plasma coating on the material surface, thereby changing the surface properties of the material. At present, research on low-temperature plasma technology in the field of oral healthcare includes sterilization, surface modification of restorative materials, tooth whitening, periodontal treatment, and oral bonding technology.

Plasma treatment can significantly improve the immediate bonding strength between dentin and the fully etched bonding system, while maintaining a relatively stable bonding durability. The specific mechanism is related to the following aspects: ① Plasma treatment can improve the hydrophilicity and wettability of the dentin surface, reduce the contact angle of the dentin surface, and thus improve the permeability of the adhesive at the dentin bonding interface; ② Plasma treatment can introduce functional groups such as carboxyl or carbonyl groups into collagen fibers, and an increase in carbonyl content on the surface of dentin can enhance the hydrogen bonding interaction between collagen fibers and adhesives; ③ The electric repulsion generated by the increase in the number of carbonyl groups temporarily causes collagen fibers to dissociate into smaller fiber aggregates, even individual fibers, improving the penetration of the adhesive into collagen fibers; ④ The antibacterial effect of plasma plays a certain role, and residual bacteria after tooth preparation can survive at the dentin bonding interface for up to two years. Plasma treatment can reduce microbial mediated degradation at the bonding interface.