Objective To investigate the effect of minimally invasive crown lengthening combined with nano-resin in the repair of subgingival wedge-shaped defects. Methods A total of 180 patients with subgingival wedge-shaped defects admitted to our hospital from May 2019 to May 2023 were selected as the research objects. They were divided into control group and study group by random number table method, with 90 patients in each group. The control group was treated with conventional crown lengthening combined with nano-resin, and the study group was treated with minimally invasive crown lengthening combined with nano-resin. The repair effect, periodontal health level, pain degree and aesthetic satisfaction were compared between the two groups. Results The excellent and good rate of the study group was 95.56%, which was higher than 80.00% of the control group (P <0.05). The PD level of the study group was lower than that of the control group at 3 months after operation, and the AL level was higher than that of the control group (P <0.05 ). The BI and MD levels of the study group were higher than those of the control group 3 months after operation, but the difference was not statistically significant (P >0.05). The NRS scores of the study group at 1 d, 3 d and 7 d after operation were lower than those of the control group (P <0.05). The aesthetic satisfaction of the study group was 95.56%, which was higher than 81.11% of the control group (P <0.05). Conclusion Minimally invasive crown lengthening combined with nano-resin repair has definite clinical effect in patients with subgingival wedge-shaped defects, which can improve periodontal health, pain degree and aesthetic satisfaction, and is worthy of clinical application.