Objective To explore the application effect of fluid resin and glass ionomer combined with composite resin filling in adult patients with moderate wedge-shaped defects. Methods A total of 90 adult patients (90 teeth) with moderate wedge-shaped defects admitted to 903 Hospital from September 2022 to December 2023 were randomly divided into group A and group B, with 45 patients in each group. Group A was filled with fluid resin+composite resin, and group B was filled with glass ionomer+composite resin. The repair effect, filling state, aesthetic effect and periodontal index were compared between the two groups. Results There was no significant difference in the total effective rate of repair between the two groups (P >0.05). The marginal fit satisfaction of group A was higher than that of group B, and the tooth sensitivity satisfaction was lower than that of group B (P <0.05). The probing depth of periodontal pocket and gingival index in group A were higher than those in group B (P <0.05). The probing depth of periodontal pocket and gingival index in group A were higher than those in group B (P <0.05). Conclusion In the treatment of moderate wedge-shaped defects in adults, fluid resin and glass ionomer have their own advantages and disadvantages. The former has high marginal fit, while the latter can prevent tooth sensitivity and improve periodontal health. It should be selected according to the actual needs of patients.