Marginal gaps / microleakage leading to sensitivity
What it is
A restoration is placed with imperfect marginal adaptation or seal, creating microscopic gaps at the tooth–restoration interface. Fluids and bacteria can penetrate (microleakage), which is associated with post-operative sensitivity, marginal staining, and recurrent caries risk. Microleakage and marginal gap formation are widely studied outcomes in resin composite restorations.
Why it happens
• Inadequate bonding to enamel/dentin (contamination, wrong etch/bond handling, poor solvent evaporation) → weak hybrid layer and gap formation under function/thermal cycling. • Polymerization shrinkage stress (especially in high C-factor cavities) pulling composite away from the margin → marginal gap/microleakage. • Under-curing or curing from poor angle/distance → lower conversion at the interface and reduced properties, worsening marginal integrity over time. • Deep proximal/cervical margins (dentin/cementum margins are harder to seal than enamel; moisture control and access are more difficult).
The full clinical mistake entry includes
- How to avoid it — the prevention protocol
- The clinical tip experienced clinicians use
- The documented reference behind the mistake
More clinical mistakes
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