Objective To analyze the effect of plastic fiber post and prefabricated fiber post on dental function and periodontal indexes in patients undergoing oral restoration. Methods A total of 60 patients who underwent oral restoration and were admitted to Pucheng County Maternal and Child Health Care and Family Planning Service Center from January 2023 to January 2024 were selected as the research subjects. According to the random number table method, they were divided into the control group and the experimental group, with 30 patients in each group. The control group was treated with plastic fiber post, and the experimental group was treated with prefabricated fiber post. The clinical efficacy, dental function, periodontal indexes and adverse reactions were compared between the two groups. Results The total effective rate of treatment in the experimental group was 96.67%, which was higher than 80.00% in the control group (P <0.05). The scores of masticatory efficiency, occlusal force and gingival index in the experimental group at 1 and 3 months after discharge were better than those in the control group (P <0.05). After treatment, the BI, PLI, PD and mobility in the experimental group were lower than those in the control group (P <0.05). The incidence of adverse reactions in the experimental group was 3.33%, which was lower than 20.00% in the control group (P <0.05). Conclusion Both plastic fiber post and prefabricated fiber post can achieve good treatment effects in oral restoration. However, the treatment effect of prefabricated fiber post is more prominent. It can effectively improve the dental function and periodontal health of patients, and reduce the the risk of adverse reactions, which is worthy of clinical application.