Cyclic Imide Monomers Reduce Polymerization Shrinkage in Dental Composites
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Solution Overview
Problem
Polymerization-based stress in dental composites due to volumetric shrinkage leads to issues like cracking, reduced durability, and residual internal stress, which existing methods have not fully addressed.
Innovation Solution
Incorporating cyclic imide monomers as addition-fragmentation agents in dental compositions, which fragment and add to the polymeric network during curing, thereby reducing polymerization shrinkage and stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional polymerizable dental compositions are used, then the material provides structural integrity and bonding, but polymerization shrinkage causes volumetric contraction leading to cracking, reduced durability, and residual internal stress
Solution Approach 1:
The patent changes the chemical parameters of the polymerization system by introducing cyclic imide monomers with specific molecular structures and reactivity characteristics. These monomers have lower polymerization shrinkage parameters compared to conventional monomers, thereby reducing the volumetric contraction and associated stresses while maintaining the crosslinked network structure for structural integrity
Solution Approach 2:
The patent creates a composite polymer system by combining cyclic imide monomers with conventional dental monomers (such as bis-GMA, TEGDMA). This composite approach allows the cyclic imide component to reduce shrinkage stress while the conventional monomers provide adequate bonding and structural properties, achieving a synergistic effect that resolves the contradiction between strength and shrinkage stress
2Object-generated harmful factors
If addition-fragmentation agents are incorporated to reduce shrinkage stress, then polymerization-based stress is reduced, but the complexity of the composition increases
Solution Approach 1:
The cyclic imide monomers function as temporary structural elements during polymerization that fragment after serving their stress-reduction purpose. These monomers are designed to be consumed during the curing process, providing shrinkage mitigation during the critical polymerization phase while not requiring permanent presence in the final restoration, thus simplifying the overall composition design
Solution Approach 2:
The patent optimizes the concentration parameters of cyclic imide monomers to achieve effective stress reduction at relatively low levels (e.g., 5-20 wt% of total monomer content). By adjusting this parameter, the composition complexity is minimized while still achieving the desired reduction in polymerization stress, avoiding the need for complex multi-component systems
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The use of cyclic imide monomers significantly reduces polymerization-based stress in dental composites, maintaining mechanical properties and improving the longevity of dental restorations.
Implementation Method 1
Incorporating cyclic imide monomers as addition-fragmentation agents in dental compositions, which fragment and add to the polymeric network during curing, thereby reducing polymerization shrinkage and stress
Implementation Method 2
Polymerizable dental compositions that include addition-fragmentation agents have been described
Data Source
AI summary
A dental composition is provided. The dental composition includes at least one monomer comprising at least two ethylenically unsaturated groups; and an addition-fragmentation agent comprising at least one cyclic imide monomer comprising an α, β-unsaturated carbonyl.