Important Dental Fiber-Reinforced Composite Molding Compound Breakthroughs.

Fiber-reinforced composite (FRC) molding compounds with micromechanic requirements for fiber lengths longer than critical length (Lc) are now the most important breakthrough in Dentistry since the amalgam. The Lc is a measure of the minimum perfectly aligned fiber length dimension needed before maximum fiber stress transfer starts to occur within the cured resin [1-3]. Mechanical properties tested on flexural strength, yield strength, modulus, resilience, work of fracture (WOF), critical strain energy release (SIc), critical stress intensity factor (KIc) and Izod impact toughness for FRCs using pure quartz fibers have shown large statistically significant increases over the dental particulate-filled composites (PFCs) as 3M Corp. Z100® and Kerr Corp. Herculite® [4-10] and a PFC with microfibers that cannot satisfy Lc as Alert® from Jeneric Pentron [5-8,10]. In addition, FRCs have shown large statistically significant increases for all mechanical properties tested except modulus when compared to a widely used amalgam alloy Tytin® from Kerr Corp. [9,10]. Further, FRCs have shown other greatly improved properties for wear less than enamel [10,11], significantly increased condensing packability force with significant larger interproximal contacts [10,12] and ability to incorporate the antimicrobial triclosan without PFC sticky glueyness [10]. Industrially FRCs are accepted as high-performance molding compounds that can pack with control to form into intricate geometric cavities and used extensively in the electrical and automotive industries so that FRC development for Dentistry can proceed on firm dedicated principles.