18-month outcomes of three caries management strategies in primary molars: a randomized split-mouth trial

The Hall Technique (HT), a minimally invasive restorative approach involving the placement of stainless-steel crowns without local anaesthesia, tooth preparation, or carious tissue removal, is considered one of the most reliable options for managing carious primary molars. The aim of this study was to compare the 18-month clinical and radiographic success of three caries management strategies in children—Hall Technique (HT), ammonia-free water-based 38% silver fluoride (AgF), and conventional restorations (CR)—and to evaluate pain perception, behavior, and treatment acceptability. In this split-mouth randomized controlled trial, 60 children aged 4–8 years received HT ( n = 60), AgF ( n = 60), and CR ( n = 60). Clinical outcomes were assessed using ICDAS and Nyvad criteria, while radiographic evaluation was performed using bite-wing radiographs. Pain perception was evaluated with the Visual Analog Scale of Faces and behavior with the Frankl scale. Statistical analyses included Fisher’s exact, ANOVA, Kruskal–Wallis, Friedman, Dunn’s post hoc, Cochran’s Q, Kaplan–Meier, log-rank, and Cox regression tests ( p < 0.05). At 18 months, 55 participants (165 teeth) were available for evaluation. Clinical and radiographic success rates were 100% for HT, 63.6% for AgF, and 90.9% for CR ( p < 0.001). HT showed no failures, whereas AgF and CR demonstrated higher minor and major failure rates ( p < 0.05). Behavioral responses were similar among groups. HT and AgF required significantly shorter treatment times than CR, and AgF produced lower pain scores than HT ( p < 0.05). Occlusal vertical dimension scores increased immediately after HT treatment and returned toward baseline after 1 month ( p < 0.001). HT demonstrated the highest success over the 18-month follow-up period, followed by CR, whereas AgF showed good short-term caries arrest but lower stability during the 18-month follow-up period. Trial Registration : ClinicalTrials.gov, NCT07447583. First registered on 20 February 2026. Retrospectively registered.