Objective To observe the application effect of iRoot BP Plus direct pulp capping under dental operating microscope in the minimally invasive treatment of deep caries with pulp exposure in permanent teeth. Methods A total of 90 patients with deep caries and pulp exposure in permanent teeth admitted to our hospital from January 2023 to December 2024 were selected as the research subjects, and they were divided into control group A, control group B and observation group by the random number table method, with 30 patients in each group. Control group A was treated with calcium hydroxide pulp capping, control group B was treated with MTA pulp capping, and the observation group was treated with iRoot BP Plus direct pulp capping. The pain intensity, treatment success rate, calcified bridge formation rate, tooth discoloration and treatment satisfaction were compared among the three groups. Results The VAS score of the observation group after operation was lower than that of control group A and control group B (P<0.05). The treatment success rate and calciffed bridge formation rate of the observation group at 3 and 6 months after operation were higher than those of control group A and control group B, while the incidence of tooth discoloration was lower than that of control group A and control group B (P<0.05). The treatment satisfaction rate of the observation group (93.33%) was higher than that of control group A (66.67%) and control group B (73.33%) (P<0.05). Conclusion The application of iRoot BP Plus direct pulp capping under dental operating microscope in the minimally invasive treatment of deep caries with pulp exposure in permanent teeth has a good effect. It can improve the treatment success rate and calciffed bridge formation rate, reduce the patient's pain intensity and the incidence of tooth discoloration, and the patient's treatment satisfaction is relatively high.