A Comparative Evaluation of Class II Composite Restoration Techniques: A Systematic Review on Incremental Layering versus Bulk-Fill Approaches

Abstract

This systematic review of 112 RCTs (n=89,712) compared incremental versus bulk-fill placement techniques for direct Class II composite restorations in permanent posterior teeth over ≥6 months. Meta-analyses found no significant differences between groups for retention, recurrent caries, marginal adaptation, fracture, postoperative sensitivity, surface roughness, color match, or anatomic form (p>0.05 for all). Bulk-fill had less marginal staining (p=0.01). Clinical performance correlated more with materials and protocols than placement technique. Challenges like microleakage and wear persisted long-term. Neither incremental nor bulk-fill demonstrated clear superiority across clinical outcomes over up to 7 years. Both can provide durable posterior restorations. Practitioners should use professional judgment in technique selection based on clinical factors. Further long-term RCTs are warranted to reinforce these conclusions that neither placement technique showed superior clinical performance for direct Class II composite restorations.