Edge-strength of flowable resin-composites

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Restorative Dentistry

Background:

• Flowable composites are widely used in dental restorations.
• Understanding their mechanical properties at critical interfaces is crucial for clinical longevity.
• Edge-strength is a key factor influencing the performance of dental restorative materials.

Purpose of the Study:

• To investigate the in vitro failure forces of flowable composites at varying distances from an interface edge.
• To assess the relationship between distance from the edge and the fracture resistance of flowable composites.
• To determine if filler content correlates with edge-strength in these materials.

Main Methods:

• Seven flowable composite materials were tested using an edge-strength testing instrument (CK10).
• Disc-shaped specimens were prepared and light-cured, with measurements taken at 0.1mm intervals from 0.4mm to 1.0mm from the edge.
• Failure forces and modes (cracking, chipping) were analyzed using ANOVA and Tukey post-hoc tests.

Main Results:

• Failure forces varied significantly among materials, with Grandio flow exhibiting the highest and Filtek flow the lowest at 0.5mm.
• A strong correlation (r²=0.95-0.98) was observed between decreasing failure force and increasing distance from the edge for all composites.
• No correlation was found between failure force and the weight percentage of filler content.

Conclusions:

• Edge-strength testing effectively differentiates flowable composite materials.
• The findings suggest that flowable composites exhibit lower fracture resistance near the margins compared to their centers.
• This data can help predict clinical margin performance and guide material selection in restorative dentistry.