Title : The coordinated triad of spatial temporal and biomechanical strategies managing the where when and how of shrinkage stress in bulk fill resin composite restorations
Abstract:
Background: Polymerization shrinkage and the resultant shrinkage stress at the tooth–restoration interface both remain principal causes of marginal gap formation, postoperative sensitivity, and early failure of direct composite restorations.
Objective: Present a pragmatic Triad Framework (Spatial - Temporal - Biomechanical) to manage polymerization shrinkage stress in direct posterior bulk-fill resin composite restorations and show how semi-split placement technique and delayed gap closure approach described by Hassan & Khier integrate into this Triad framework.
Methods: Synthesis of mechanistic principles and clinically applicable placement strategies organized into three pillars with a practical chairside workflow.
Results: Coordinated application of (1) spatial segmentation to reduce local effective C-factor, (2) temporal modulation of polymerization (gap closure delay and stress-relaxation curing) to permit viscous flow before gelation, and (3) biomechanical reinforcement and load management to avoid functional magnification of residual stresses appears to reduce interfacial stress concentration, pulpal floor gap formation, and early marginal breakdown.
Conclusions: The Triad Framework provides a conceptually simple and clinically applicable pathway for stress management in large/deep occlusal bulk-fill resin composite restorations when combined with Hassan & Khier’s semi-split placement technique and delayed diagonal gap closure approach.
Clinical significance: Applying spatial, temporal, and biomechanical modulation in an integrated fashion can reduce postoperative sensitivity and improve short- and potentially long-term integrity of direct posterior composite restorations.
