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Journals / Uluslararası Diş Hekimliği Bilimleri Dergisi / 2026 / Cilt: 12 Sayı: 2

Dynamic Effective C-Factor Reduction via Partial-Depth Diagonal Semi-Split: A Geometric Model for Shrinkage Stress Control in Large Occlusal Bulk-Fill Resin Composite Restorations

Khamis Hassan(Global Dental Centre)0000-0002-2247-355X
Salwa Khier(Global Dental Centre)0000-0001-8866-3527
Pages
90–96
Publication Date
2026-08-31
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AI Summary & Key Takeaways

AI Insight
⚡ TL;DR(Too Long; Didn't Read)

This geometric modification provides a biomechanically plausible mechanism for reducing polymerization shrinkage stress independent of material chemistry.

📌 3 Key Takeaways

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Objective & Hypothesis:Objective: A depth-consistent biomechanical model was developed for evaluating the effect of a partial-depth diagonal semi-split technique on the effective cavity configuration factor (C-factor) and its implications for polymerization shrinkage stress in direct composite restorations.
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Key Findings & Data:An effective C-factor was derived by accounting for the internal free surfaces generated by the diagonal split.
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Conclusion & Impact:This geometric modification provides a biomechanically plausible mechanism for reducing polymerization shrinkage stress independent of material chemistry.
🔬Design:Modeling & Simulation
📍Scope:Comprehensive Sample
⚙️Variables:bulk-fill resin composite · configuration factor (C-factor) · polymerization shrinkage stress

Abstract

Objective: A depth-consistent biomechanical model was developed for evaluating the effect of a partial-depth diagonal semi-split technique on the effective cavity configuration factor (C-factor) and its implications for polymerization shrinkage stress in direct composite restorations. Methods: A standardized large Class I cavity was geometrically modeled. Bonded and unbonded surface areas were calculated for a conventional bulk-fill restoration and for a partial-depth diagonal semi-split configuration. An effective C-factor was derived by accounting for the internal free surfaces generated by the diagonal split. Relative reduction in C-factor was quantified. Results: The conventional bulk-fill configuration demonstrated a baseline C-factor of approximately 4.6. Introduction of a partial-depth diagonal semi-split generated an additional internal free surface of 35.2 mm², reducing the effective bonded area to 56.8 mm² and increasing total free surface area to 55.2 mm². The resulting effective C-factor was approximately 1.03, representing a 77.6% reduction relative to baseline. The predicted stress ratio (Ceff / Cbaseline) was approximately 0.22. Conclusion: The partial-depth diagonal semi-split technique substantially lowers the effective C-factor by increasing internal free surface area without complete segmentation of the composite mass. This geometric modification provides a biomechanically plausible mechanism for reducing polymerization shrinkage stress independent of material chemistry.

Özet

Objective: A depth-consistent biomechanical model was developed for evaluating the effect of a partial-depth diagonal semi-split technique on the effective cavity configuration factor (C-factor) and its implications for polymerization shrinkage stress in direct composite restorations. Methods: A standardized large Class I cavity was geometrically modeled. Bonded and unbonded surface areas were calculated for a conventional bulk-fill restoration and for a partial-depth diagonal semi-split configuration. An effective C-factor was derived by accounting for the internal free surfaces generated by the diagonal split. Relative reduction in C-factor was quantified. Results: The conventional bulk-fill configuration demonstrated a baseline C-factor of approximately 4.6. Introduction of a partial-depth diagonal semi-split generated an additional internal free surface of 35.2 mm², reducing the effective bonded area to 56.8 mm² and increasing total free surface area to 55.2 mm². The resulting effective C-factor was approximately 1.03, representing a 77.6% reduction relative to baseline. The predicted stress ratio (Ceff / Cbaseline) was approximately 0.22. Conclusion: The partial-depth diagonal semi-split technique substantially lowers the effective C-factor by increasing internal free surface area without complete segmentation of the composite mass. This geometric modification provides a biomechanically plausible mechanism for reducing polymerization shrinkage stress independent of material chemistry.

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Cite This Article

Hassan, K., Khier, S. (2026). Dynamic Effective C-Factor Reduction via Partial-Depth Diagonal Semi-Split: A Geometric Model for Shrinkage Stress Control in Large Occlusal Bulk-Fill Resin Composite Restorations. Uluslararası Diş Hekimliği Bilimleri Dergisi, Cilt: 12 Sayı: 2, 90–96. https://doi.org/10.21306/dishekimligi.1953189

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