Vital pulp therapy (VPT) has recently been reported as an effective approach for preventing and treating carious pulp injury in permanent teeth. Compared with root canal treatment (RCT), which involves complete removal of the pulp tissue, VPT effectively maintains pulp vitality and retains the physiological functions of the pulp. In the research pool, large-scale randomized controlled trials evaluating the treatment outcome of VPT using calcium silicate cements and RCT in cariously exposed permanent teeth are lacking. Here, we present a monocentric clinical protocol to compare the effects of VPT using iRoot BP Plus (Innovative Bioceramix, Vancouver, BC, Canada) as a pulp-capping material with RCT. The proposed trial is an open-label, single-centre, randomized, controlled, noninferiority trial. In total, 462 patients will be included in this trial according to the following criteria: adult patients (18-50years old), pulp exposure during the treatment of deep caries in mature permanent teeth, a diagnosis of reversible or partially irreversible pulpitis without apical translucency on X-ray, without periodontitis or systemic disease. Patients with signed informed consent forms will be enrolled and randomly divided into two groups (VPT and RCT) with a balanced treatment allocation (1:1). Clinical evaluations will be conducted at baseline and at 3, 6, 12, and 24months after treatment, with the potential for extension. The primary outcome measure will be the duration of success. The secondary outcomes will include the success rate at the 1-year follow-up and any adverse reactions. The Kaplan‒Meier method and log-rank test will be used to compare the duration of success of both treatments. For other outcomes, the χ2 test or Fisher's exact test will be used for categorical variables, and the t test or Mann‒Whitney U test will be used for continuous variables to assess the differences between groups. The results of this trial will provide a clinical reference for selecting treatments for carious pulp injuries in permanent teeth. ClinicalTrials.gov ChiCTR2100051369. The study has been registered in the Chinese Clinical Trial Registry (ChiCTR) ( www.chictr.org.cn ). Registered on 21 September 2021.