Radiopacity and Porosity of Bulk-fill and Conventional Composite Posterior Restorations-Digital X-ray Analysis

To compare radiopacity and porosity as expressed by the presence of voids in restorations carried out using bulk-fill and incremental filling techniques to restore large mesio-occlusal-distal (MOD) cavities.

Fifty-five molars with MOD preparations were incrementally filled with Filtek Z-350XT (Z350XT) or bulk-fill composite: Filtek Bulk Fill/Z-350XT (FBF/Z350XT), Venus Bulk Fill/Charisma Diamond (VBF/CHA), SDR/Esthet-X HD (SDR/EST-X), Tetric EvoCeram Bulk Fill (TEC). Digital radiographic images (Vistascan scanner) were taken of restored molars and analyzed at the gingival and isthmus floors. Radiodensity measurements were performed using standardized points symmetrically distributed over each region of composite and tooth structure. Three calibrated evaluators visually assessed the presence of voids. Confidence intervals were calculated, and data were analyzed using analysis of variance and χ² tests.

TEC and VBF/CHA showed significantly higher radiodensities, while the lowest values were observed for FBF/Z350XT and Z350XT. Radiodensity at the cervical regions tended to be greater than that found at the isthmus floor. The lowest incidence of voids was found for VBF/CHA, whereas the incremental insertion technique resulted in the highest rate of voids.

Bulk-fill composite resin demonstrated an adequate level of radiodensity and a reduced presence of voids compared with the incremental filling technique.