Design: A split-mouth randomised controlled trial (RCT) was conducted. Intervention: Standard noncarious pulp exposures were treated with either enamel matrix derivative (EMD) or calcium hydroxide and restored with a preformed metal crown (PMC). Patients were followed up at 1, 6 and 12 months. Outcome measure: The appearance of any of the following was considered to signify treatment failure: internal dentin resorption, spontaneous pain, gingival abscess (sinus tract), external root resorption, or pathologic mobility. Results: In total, 90 direct pulp capping (DPC) treatments were performed (45 in the experimental group and 45 in the control group) and followed for 12 months. There were 88 successful treatments at the end of this period, with only two failures (one in each study group)ConclusionsBoth capping materials showed a similar effectiveness in this pulp procedure with a postoperative observation time of 12 months. On the basis of this study, we recommend the use of DCP treatment on primary molars as a standard technique.