Effect of Bulk/Incremental Fill on Internal Gap Formation of Bulk-Fill Composites
I bulk fill almost 1005 of my posterior restorations with Kerr's Sonicfill. MJ
Available online 27 January 2014
To examine the effects of composite type (bulk-fill/conventional) and placement (4-mm bulk/2-mm increments) on internal marginal adaptation of Class I preparations.
Cylindrical, Class I, 4 × 4-mm preparations were made on 50 recently extracted human molars and restored using either a bulk-fill (SureFil SDR Flow (SDR), Quixx (QX), SonicFill (SF), Tetric EvoCeram Bulk (TEC)), or a conventional composite designed for 2-mm increments (Filtek Supreme Ultra (FSU)). Restorations were placed in 1 or 2 increments using the manufacturer's bonding agent and curing light (n = 5). Dye was placed on the margin and visually examined by 3 observers. Gap-free marginal lengths were analyzed within three different regions of the sectioned tooth: enamel, mid-dentin, and pulpal floor.
Marginal integrity was unaffected by placement method. Bulk-placement demonstrated significantly fewer gap-free margins at the pulpal floor than in enamel, for all materials except SDR. Greater percentages of gap-free margins were found within the mid-dentin than at the pulpal floor for FSU. QX had more gap-free margins in enamel compared with the mid-dentin. Proportion of gap-free margins within enamel and mid-dentin was not significantly different for any incrementally placed product. Excluding FSU, gap-free margins within enamel were significantly greater than at the pulpal floor. Notably, significantly more gap-free margins were found within mid-dentin than at the pulpal floor for SF.
No significant differences in gap-free margins were found between placement method within a given product per location. Except for SDR, percentage of gap-free margins was significantly lower at the pulpal floor interface than at the enamel interface for bulk-fill.