12 - Fibre-reinforced composites (FRCs) as dental materials

Abstract

Fibre-reinforced composites (FRCs) are a novel group of dental materials characterized by fibrous fillers. The function of the fibres is to transfer loads from the weaker polymer phase to the more durable reinforcing fibres. In dentistry, the use of glass fibres is justified because of their good cosmetic–aesthetic properties and because they can be correctly bonded to the resins using silane coupling agents, which is impossible with polyethylene fibres. The quality of the FrC used is particularly critical in small dental appliances. Factors influencing FRCs that should be considered, include: fibre properties versus polymer matrix properties, impregnation of fibres in the resin, adhesion of fibres to the polymer matrix, quantity and direction of fibres, and location of the fibre-rich phase in construction. The most commonly used applications of FRCs are in removable dentures, minimally invasive fixed partial dentures, periodontal splints, root canal posts and orthodontic devices. Minimally invasive prosthodontics aims to preserve the remaining tooth substance. Certain design principles must be followed when minimally invasive fixed partial dentures are constructed, including occlusal rests against vertical forces, pontic reinforcements against veneer delamination, and additional bonding wings against dislodgement of the fixed partial denture. The use of large amounts of FRC in the coronal part of the root canal opening creates a highly durable post-and-core system which cannot be obtained by the current prefabricated and standard-sized fibre posts.