Qualitative Enhancement of the Tooth-Filling Interface Using Cold Atmospheric Plasma

Objective: To evaluate the effects of cold atmospheric plasma (CAP) on adhesive bonding in Class II composite restorations in vitro. Methods: Forty-eight standardized Class II cavities were assigned to six groups (n = 8), varying in phosphoric acid conditioning, CAP treatment (1.5 W or 3 W), composite filling, and thermo-mechanical loading (TML). Evaluations included dye penetration, adhesive layer morphology, resin tag length, and hybrid layer thickness. Results: CAP combined with phosphoric acid (H₃PO₄) significantly increased hybrid layer thickness and resin tag length (p < 0.006). The lowest dye penetration was observed in Groups 1 and 4. Conclusions: CAP in combination with phosphoric acid improved the adhesive interface in Class II cavities. CAP alone showed limited benefits, and higher power levels may negatively affect bonding.