Effects of Fiber Prestrain on Shape Change of Shape Memory Alloy Fiber Embedded Denture Base Resin Matrix Smart Composite after Crack Healing

Abstract

Shape memory alloy fibers were embedded into a denture base resin to produce a smart composite for "smart denture". The effects of fiber prestrain and heat treatment (HT) for curing were discussed. Although the fiber without prestrain deformed randomly in the matrix during embedding, the fiber with prestrain could keep straight after embedding. Fiber prestrain was, therefore, effective for denture esthetics. Small pores were observed at the end of embedded fibers with prestrain in some specimens. They were formed with fiber shrinkage in the matrix before curing. Such specimens with pores showed small shape change after repair of the composite. In contrast, other specimens of the same HT did not include any pores and showed large change. The HT affected the frequency of the pore formation and, thus, affected the average shape change. Optimization of HT was necessary to minimize the shape change after repair.