In adhesive dentistry, C Factor is defined as.

In adhesive dentistry, C Factor is defined as.

• A. The ratio of bonded to unbonded surfaces
• B. The rate of polymerization
• C. The modulus of elasticity
• D. The thermal conductivity

Answer: (A)

C-factor, or configuration factor, measures how constrained the resin is during polymerization. It is defined as the ratio of bonded surfaces to unbonded (free) surfaces inside the prepared cavity. The more surfaces the resin is bonded to, the higher the C-factor, and the less room there is for shrinkage to relieve itself by flow. That means greater polymerization shrinkage stress at the bonded interfaces, which raises the risk of marginal gaps, debonding, or postoperative sensitivity. For example, a closed cavity with several walls bonded to the resin has a high C-factor because there are many bonded surfaces and relatively few free surfaces for the material to flow toward as it sets. A cavity with more free surface area and fewer bonded walls has a lower C-factor, allowing better relief of shrinkage stresses.

C-factor, or configuration factor, measures how constrained the resin is during polymerization. It is defined as the ratio of bonded surfaces to unbonded (free) surfaces inside the prepared cavity. The more surfaces the resin is bonded to, the higher the C-factor, and the less room there is for shrinkage to relieve itself by flow. That means greater polymerization shrinkage stress at the bonded interfaces, which raises the risk of marginal gaps, debonding, or postoperative sensitivity.

For example, a closed cavity with several walls bonded to the resin has a high C-factor because there are many bonded surfaces and relatively few free surfaces for the material to flow toward as it sets. A cavity with more free surface area and fewer bonded walls has a lower C-factor, allowing better relief of shrinkage stresses.