RESUMO
AIM: To compare the clinical and radiographic success rates of an antibiotic mix consisting of metronidazole, minocycline and ciprofloxacin (3Mix-MP) and another mix where minocycline was replaced with clindamycin (3Mix-MP-R) in non-instrumentation endodontic treatment (NIET) of necrotic primary molars and to determine the effect of root resorption on the success of the treatment. MATERIALS AND METHODS: Forty-two necrotic mandibular primary molars from 22 healthy children were randomly assigned to either mixture. Blinded clinical evaluation was conducted after 1, 3, 6 and 12 months by the operator, and blinded radiographic evaluation was conducted at 6 and 12 months follow-ups by other two investigators with inter-examiner reproducibility of 0.95. RESULTS: Overall success rates of 3Mix-MP and 3Mix-MP-R were 80.96% and 76.20% respectively, with no statistically significant difference. Radiographically, resorption of more than one third of the root length had a lower failure rate with no statistically significant difference (p<0.5). CONCLUSION: Primary teeth with necrotic pulp can be treated with 3Mix-MP or 3Mix-MP-R irrespective of the degree of root resorption.