The aim of this retrospective study was to evaluate the influence of various predictors on healing outcomes after direct pulp capping (DPC) using either mineral trioxide aggregate (MTA) or calcium hydroxide (CH) as a pulp-dressing agent. The present study included 172 mature asymptomatic permanent teeth with carious-exposed pulp. The teeth were treated with DPC, using either MTA or CH, and the treatment outcome was evaluated clinically and radiographically. The effect of potential clinical variables on the treatment outcome of DPC was evaluated clinically and radiographically during a 24-72-month follow-up. In order to assess the cumulative successes of CH and MTA after DPC, Kaplan-Meier survival analysis and log-rank test was used. The subgroups were compared by means of the log-rank test. Also, univariate Cox regression analysis was used to determine hazard ratio of clinical variables. One hundred and fifty-two teeth of 172 capped teeth were available for follow-up, with an overall recall rate of 87.6% for MTA vs 89.3% for CH. The mean period of follow-up was 37.3 (±17.2) months. Overall success rates of 85.9 and 77.6% in the MTA and CH groups were observed, respectively. The cumulative success rate of both materials was not statistically different when analysed by the Cox proportional hazard regression analysis (P=0.282). The Kaplan-Meier survival curves revealed that 2-year overall pulp survival was 91.4%, while the 4- and 6-year survival rates were 84 and 65%, respectively. None of the clinical variables had a considerable influence on the outcome of DPC (p>0.05). MTA-capped teeth demonstrated a slightly higher success rate than CH, revealing that it can be recommended as a reliable direct pulp-capping material. None of the clinical variables investigated significantly affected posttreatment healing. DPC with MTA is a straightforward procedure with favourable outcome of 24- to 72-month follow-ups in vital mature asymptomatic permanent teeth with cariously exposed pulp, and it may be considered a realistic alternative therapy to RCT.