Reduced polymerization stress through non-bonded nanofiller particles

Area of Science:

• Dental Materials Science
• Polymer Chemistry
• Biomaterials Engineering

Background:

• Confined placement of dental composites can lead to polymerization stress, compromising marginal seal integrity.
• Untreated nanofiller particles in dental composites may result in lower stress levels.
• Understanding factors influencing polymerization stress is crucial for improving dental restoration longevity.

Purpose of the Study:

• To evaluate the effect of nanofiller surface treatment on polymerization stress in dental composites.
• To investigate the impact of filler type (nanofillers vs. mini-fillers) and concentration on stress generation.
• To assess the influence of resin matrix composition, specifically monomer molecular weight, on polymerization stress.

Main Methods:

• Three types of nanofillers (functional silane, non-functional silane, no coating) were incorporated into dimethacrylate resins at varying volume percentages.
• Resins were also filled with mini-filler particles to clinically relevant levels.
• Polymerization stress was measured using a mechanical testing machine during confined curing.
• Resin formulations with varied co-monomer levels were prepared to study the effect of monomer molecular weight.

Main Results:

• Reductions in polymerization stress of up to 31% were observed in both nanofilled and mini-filled composites.
• The use of functional silane-coated nanofillers contributed to stress reduction.
• Higher levels of diluent monomer in the resin formulations significantly increased polymerization stress.

Conclusions:

• Minor modifications in dental composite chemistry, such as functionalizing nanofillers, can significantly reduce polymerization stress.
• Optimizing filler treatment and resin composition is key to mitigating stress and improving marginal seal in dental restorations.
• These findings offer a pathway to developing more durable and reliable dental composite materials.