Objective To evaluate the effect of root canal therapy combined with calcium hydroxide preparation on periodontal indicators in patients with dental pulp disease. Methods A total of 94 patients with dental pulp disease admitted to Daxing District Caiyu Town Central Health Center from January to October 2023 were selected, and they were divided into the control group and the observation group by the random number table method, with 47 patients in each group. The control group received conventional root canal therapy, and the observation group used calcium hydroxide preparation as intracanal medication on the basis of the control group. The treatment effect, pain intensity, periodontal indicators, oral function and aesthetic indicators were compared between the two groups. Results The total effective rate of the observation group (97.87%) was higher than that of the control group (82.98%) (P<0.05). The score of NRS in the observation group after treatment was lower than that in the control group (P<0.05). The BI, PLI and CAL of the observation group after treatment were lower than those of the control group (P<0.05). The scores of abutment health, masticatory function, dental aesthetics and dental occlusion in the observation group were higher than those in the control group (P<0.05). Conclusion The application of root canal therapy combined with calcium hydroxide preparation in the treatment of dental pulp disease can enhance the overall treatment effect, relieve patients' pain, improve the health status of periodontal tissues, and promote the recovery of overall oral function and health level.