RESUMEN
BACKGROUND: Although reciprocating instrumentation has been extensively studied for permanent teeth, stronger evidence for its use in primary teeth is lacking. AIM: The aim of this randomized clinical trial was to compare the efficacy of endodontic treatment in primary molars using reciprocating (RECIP) and manual (MAN) instrumentation techniques after 24 months. DESIGN: Primary molars with indication of endodontic treatment were randomly divided into two groups: MAN and RECIP. Treatments were performed, and root canals were filled with calcium hydroxide and iodoform paste. Teeth were later restored with bulk-fill composite resin and re-evaluated after 6, 12, 18, and 24 months. The primary outcome was the success of the endodontic treatment evaluated by Cox regression analysis adjusted by cluster and success rate after 24 months in the intention-to-treat (ITT) population. Instrumentation time, discomfort, postoperative pain, and quality of root canal filling were also evaluated as secondary endpoints. RESULTS: A total of 151 primary win 107 children were included, and 137 were followed up for 24 months. Success rate of teeth allocated to the MAN group was 57.3% and 55.3% for RECIP (p = .792); MAN instrumentation, however, was more time-consuming (p = .005). CONCLUSION: The efficacy of endodontic treatment in primary molars using reciprocating and manual instrumentation is similar after 24 months.