The 3.5-year survival rates of primary molars treated according to three treatment protocols: a controlled clinical trial

Abstract

This study aimed to test the hypothesis that there is no difference in the survival rates of molars treated according to the conventional restorative treatment (CRT) using amalgam, atraumatic restorative treatment (ART) using high-viscosity glass ionomer, and ultraconservative treatment (UCT) protocol after 3.5 years. Cavitated primary molars were treated according to CRT, ART, and UCT (small cavities were restored with ART and medium/large cavities were daily cleaned with toothpaste/toothbrush under supervision). Molar extractions resulting from toothache, sepsis, or pulp exposure were failures. The Kaplan-Meier method was used to estimate the survival curves. The numbers of treated teeth, among the 302 6-7-year-old children, were 341 (CRT), 244 (ART), and 281 (for UCT group: 109 small ART, 166 open cavities, and 6 combinations). Protocol groups were similar at baseline regarding gender and mean decayed missing filled tooth score, but not regarding age and type of surface. The numbers of molars extracted were 22 (CRT), 16 (ART), and 26 (UCT). Fistulae were most often recorded. After 3.5 years, the cumulative survival rate ± standard error for all molars treated was 90.9 ± 2.0 % with CRT, 90.4 ± 2.4 % with ART, and 89.0 [corrected] ± 1.9 % with UCT (p = 0.13). Only a type of surface effect was observed over the 3.5-year period: survival rates for molars were higher for single- than for multiple-surface cavities. There was no difference in the cumulative survival rates of primary molars treated according to the CRT, ART, and UCT protocols over a 3.5-year period. Keeping cavities in primary molars biofilm-free might be another treatment option alongside restoring such cavities through conventional and ART protocols.