Purposes: The purposes of this prospective trial were to: (1) compare the clinical and radiographic outcomes of three restorative methods -modified atraumatic restorative treatment (mART), the Hall technique (HT), and stainless steel crown (SSC)-in primary molars with multi-surface curious lesions; and (2) assess child behavior throughout these treatments. Methods: In this randomized controlled trial (RCT), 123 primary molars in four- to nine-year-old children were randomly divided into treatment groups (HT, mART, and SSC). Variables, including signs of failure, treatment time, child's discomfort, child's behavior, and canine overbite relationship in HT; were recorded immediately after the treatment and at six- and 12-month recalls. Results: Failures occurred most significantly for mART at all recalls (P=0.001). The treatment time was significantly higher in SSC. There was no significant difference in the child-assessment of discomfort (P=0.814). The child's behavior, us evaluated by the dentist, however, was significantly better for the SSC group. Alterations to the canine overbite relationship of HT decreased significantly during recalls (P<0.001). Conclusions: The high success and shorter treatment time of the Hall technique support its consideration us an alternative to the conventional technique for the treatment of curious primary teeth with multisurface lesions. The results for modified utraumatic restorative treatment were not as satisfying.