Influence of Placement Techniques on Marginal Integrity, Wear Behavior, and Clinical Efficiency of a Bulk-Fill Resin Composite

The placement technique of resin composites may significantly influence marginal integrity, wear resistance, and operative efficiency. This in vitro study evaluated the influence of different placement techniques for a bulk-fill resin composite on marginal integrity, wear behavior, and application time. Standardized Class I cavities were prepared in extracted human molars and restored using the same bulk-fill composite (Filtek One Bulk Fill, 3M, USA) applied with four techniques: incremental placement, incremental placement with a modeling liquid (GC Modeling Liquid, GC Corp., Tokyo, Japan), bulk placement, and the stamp technique. Application time was recorded in seconds. All specimens underwent combined mechanical and thermal aging (SD Mechatronik, Germany). Marginal integrity was assessed three-dimensionally using micro-computed tomography, while surface wear was quantified through computer-based digital analysis with OraCheck software (Dentsply Sirona, Germany). Bulk placement exhibited significantly higher microleakage scores than the other techniques while demonstrating the shortest application time. Incremental placement, incremental placement with modeling liquid, and the stamp technique showed comparable microleakage results (p > 0.05). Although the use of modeling liquid did not increase microleakage, it resulted in significantly greater wear. Placement technique significantly influences marginal integrity, wear behavior, and application time of bulk-fill composite restorations.