To analyze the clinical effect of zirconia all-ceramic crown restoration in patients with dental defect. Methods A total of 48 patients with dental defect admitted to Midu County People's Hospital from January 2021 to December 2022 were selected as the research objects. According to different treatment methods, they were divided into control group and observation group, with 24 patients in each group. The control group was treated with cobalt-chromium alloy porcelain crown restoration, and the observation group was treated with zirconia all-ceramic crown restoration. The periodontal health, aesthetic effect and adverse reactions were compared between the two groups. Results The plaque index and gingival index of the observation group were lower than those of the control group after 6 months of treatment, and the differences were statistically significant (P<0.05).The pink esthetic score (PES) and white esthetic score (WES) in the observation group were higher than those in the control group after 6 months of treatment, and the differences were statistically significant (P<0.05). The incidence of adverse reactions in the observation group was 4.17%, which was lower than 33.33% in the control group, and the difference was statistically significant (P<0.05). Conclusion The effect of zirconia all-ceramic crown restoration for patients with dental defects is good, which can effectively improve the periodontal health, and is conducive to improving the aesthetic effect of teeth. Meanwhile, the risk of adverse reactions is low, and the safety and effectiveness are high.