Posterior composite and glass ionomer/composite laminate restorations: 2-year clinical results

The purpose of this investigation was to evaluate and compare the clinical performance of two posterior composite materials, and two placement techniques, unlaminated and laminated to glass ionomer base. Forty Class II carious lesions were randomly assigned for restoration with one of two composites: Status or Ful-Fil; and using one of two techniques: with and without a glass ionomer base. In the 20 restorations using the laminate technique, the glass ionomer base covered the dentin and extended to the cavosurface in the gingival third of the proximal box. The restorations were evaluated clinically at 24 hours, 6 months, 12 months and 24 months. The clinical parameters used for the examination were: anatomic form, marginal adaptation, color, secondary caries, marginal discoloration and contact. Bitewing radiographs were taken at 24 hours and at 24 months to evaluate gingival margin discrepancy. Impressions of the restorations were made for fabrication of stone dies. Of the 40 restorations, 38 (95%) were available for evaluation at 24 months. For both materials there was a deterioration in anatomic form, in marginal adaptation, and in marginal discoloration. Anatomic form was significantly worse with Status (P less than 0.05). Of the 20 restorations placed using the laminate technique, two had observable loss of the glass ionomer material. Radiographic radiolucencies were observed for both materials and with both techniques. For the laminate technique, all radiolucencies were between the glass ionomer and the composite. The radiographic observations did not change after the initial evaluation. All the restorations were functioning well at 24 months, but longer observation will be required to determine whether there is a clinically significant difference between the two placement techniques.