Two-year Follow-up Study of Class V Glass-ionomer Restorations

Objectives: To evaluate the longevity and clinical performance of glass ionomer cement (GIC) and resin-modified glass ionomer cement (RMGIC) class V restorations placed by dental students.
Methods: GIC (Fuji IX) and RMGIC (Fuji II) class V restorations placed by dental students were followed over a 2-year period. Restorations were assessed according to the modified United States Public Health Service criteria by two independent investigators. Failures were established as those restorations that were lost or fractured prior to evaluation, or those that required replacement due to poor marginal adaptation or secondary caries. The type of lesion (carious vs. non-carious cervical lesion), the type of ionomer-based material (GIC vs. RMGIC), and the use of polyacrylic acid conditioner were recorded. Restoration retention was calculated using the Kaplan-Meier algorithm, and restoration failure rates were compared using the Fisher’s exact test (p<0.05).
Results: 36 patients were assessed, for a total of 96 restorations. At the 2-year evaluation, restorations ranged in age from 2.5 to 3.5-years-old. Estimated retention for all restorations (GIC and RMGIC) was 94.6% at 1 year, and 78.6% at 2 years. In total, 26 restorations failed during the study period. The failure rate of GIC restorations at 2 years was significantly higher than that of RMGIC restorations (GIC: 40.9%, RMGIC: 17.6%, p=0.0104). The major reasons for restoration failure were loss of restoration for GIC (17.9%), and secondary caries for RMGIC (12.2%).
Conclusions: This study revealed limitations in the clinical performance of GIC and RMGIC class V restorations placed by dental students, with RMGIC demonstrating better overall performance at 2-years of follow-up. Further investigations are required to evaluate the long-term clinical performance of GIC and RMGIC restorative materials in class V restorations.