Porosities and voids in Class I restorations placed by six operators using a packable or syringable composite

Objectives: The aim of the study was to investigate the influence of two resin composites with different handling properties and application techniques on the homogeneity of a restoration placed in small and large cavities. Furthermore, the operator-effect on the restorative procedure was studied. Methods: Standardized Class I cavities of two sizes were prepared in artificial lower first molars. The cavities were restored with two resin composites (Surefil and Ecusit) using either a packing or an injection technique. Six operators were involved in the study, five general practitioners and one final-year dental student. Each operator restored 40 preparations, ten in each group. After finishing, the restorations were sectioned and inspected for the presence of voids and porosities. Results: 240 restorations were placed and 480 sections were available for evaluation. Only 143 sections were totally free of porosities. For both the small and large preparation design the Ecusit composite used with the injection technique resulted in significantly less porosities in the restoration. Differences between operators were evident, but none of the operators achieved significantly better results with the packing technique than with the injection technique. Significance: The use of a syringable resin composite results in a better adaptation of the restoration compared to a packable resin composite.