Effect of Fibers on Fracture Toughness at the Silicone/Acrylic Resin Interface for Implant-Retained Maxillofacial Prostheses
Authors: Russell Wang, Kevin Wang, and Xiaofeng Wang
Abstract: Purpose. Clinical failures at the silicone/acrylic resin interface are the second most common reason for remaking a new facial prosthesis. The minimum adhesive bond strength for silicone/acrylic resin system required for implant-supported maxillofacial prostheses has not been established. This purpose of the study was to determine the fracture toughness of a commonly used clinical silicone material bonded to an acrylic resin as a function of fiber reinforcement and surface conditioning of the acrylic resin.
Methods. Eighty specimens were separated into 10 equal groups. The adhesive fracture toughness of silicone/acrylic resin specimens under various conditions was determined based on uni-axial tensile testing. Failure modes were evaluated by total separation of silicone material from acrylic resin plates; subsequently, fractured surfaces were analyzed by scanning electron microscopy. ANOVA based on a general linear model was performed to compare the effect of fracture toughness on bonding methods, fibers, and orientations.
Results. Textile fibers led at 45° had the highest fracture toughness. The control groups without fiber reinforcement showed the lowest values of fracture toughness at the silicone/acrylic resin interface. Fibers parallel to the pulling direction did not improve the resistance to interfacial fracture. Small diameter textile fibers performed better than larger diameter polypropylene fibers.
Clinical Significance. The use of textile fibers incorporated at the silicone/acrylic resin interface--particularly at a 450 angle to pulling forces provides significant improvement in resisting to interfacial fracture for implant-supported maxillofacial prostheses.