Question

All of the following statements regarding self cure as compared to heat cure are true, except:

• A. Self cure has lower molecular weight
• B. Self cure has higher residual monomer content
• C. Self cure is more porous
• D. Self cure has more transverse strength

Hint:

Self-cure resins typically have lower strength compared to heat-cure resins, but their advantages lie in their ease of use and ability to cure without additional heat.

Answer 1

The Correct Option is D

To solve this question, we need to evaluate the given statements about self-curing and heat-curing dental materials, particularly focusing on properties like molecular weight, residual monomer content, porosity, and transverse strength.

1. Self cure has lower molecular weight: Self-curing resins are known to have lower molecular weight compared to heat-cured resins. This is due to the fact that the polymerization process is less complete in self-cure resins as they are cured at room temperature, resulting in shorter polymer chains.
2. Self cure has higher residual monomer content: Self-curing resins typically have a higher residual monomer content. Since the polymerization is conducted at room temperature and potentially less efficiently, more unreacted monomers remain in the final product.
3. Self cure is more porous: Self-curing materials tend to be more porous. The lack of external heat and pressure leads to a less densely packed structure, allowing for more voids or pores to be present in the material.
4. Self cure has more transverse strength: This statement is incorrect. Self-curing materials generally have less transverse strength compared to heat-cured ones. Heat-cured resins benefit from elevated temperatures and pressure during the curing process, leading to stronger and more durable polymer networks.

Therefore, the incorrect statement here, regarding self-cure versus heat-cure, is: "Self cure has more transverse strength." This contradicts the general understanding that heat-cured materials possess greater transverse strength due to more robust polymerization.