Objective To explore the effect of IPS e.max Press cast ceramic on periodontal health and marginal adaptation in patients with posterior tooth defect. Methods A total of 70 patients with posterior tooth defect admitted to Guilin Stomatological Hospital from January 2022 to December 2023 were selected as the research subjects, and they were divided into the control group and the observation group by the random number table method, with 35 patients in each group. The control group was treated with alloy inlay, and the observation group was treated with IPS e.max Press cast ceramic. The gingival crevicular fluid inflammatory factors, periodontal health status and marginal adaptation were compared between the two groups. Results After treatment, the levels of IL-17 and IL-6 in the observation group were (13.24±2.18)ng/ml and (7.41±2.12)pg/ml, respectively, which were lower than those in the control group [(14.88±2.35)ng/ml and (8.93±2.31)pg/ml] (P <0.05). The scores of PLI, SBI and GI in the observation group after treatment were lower than those in the control group (P <0.05). The marginal adaptation of grade A, B and C in the observation group was 97.14%, which was higher than 77.14% in the control group (P <0.05). Conclusion The application of IPS e.max Press cast ceramic in the treatment of patients with posterior tooth defect can effectively reduce inflammatory reaction, improve periodontal health, and enhance marginal adaptation.