Objectives: To compare the longevity and cariostatic effects of resin-modified (RMGIC) and conventional glass ionomer (GIC) restorations in primary teeth in the Danish Public Dental Health Service.
Methods: The sample consisted of 543 RMGIC and 451 GIC restorations in all cavity types in the primary teeth of 640 children, aged 3.0-17.5 years. The restorations were in contact with 480 unrestored surfaces. The restorations and the adjacent surfaces were followed until exfoliation/extraction of the teeth, repair/replacement of restorations or operative treatment of adjacent surfaces. Survival analyses supplied with multivariate analyses were performed to assess the influence of different factors on the longevity of restorations, occurrence of prevalent failures, and caries treatment of adjacent surfaces.
Results: After 8 years, 2% of the restorations were still in function and 37% of the RMGIC and 44% of the GIC restorations had been repaired or replaced. Fracture and loss of retention predominated as the reasons for failure of restorations in both materials. The 50% survival time for restorations was 55 months for RMGIC and 48 months for GIC (p = 0.01). Progression of caries lesions required operative treatment on 20% of the surfaces in contact with RMGIC and on 14% of surfaces adjacent to GIC restorations. The 75% survival time was 35 months for surfaces in contact with both materials (p = 0.37).
Conclusions: RMGIC and GIC showed similar cariostatic effects on restored teeth and adjacent tooth surfaces, but RMGIC should be preferred for class II restorations in the primary dentition, and class III/V restorations should be made in GIC due to enhanced longevity.