Influence of the Adhesives and Pigment on the Physical and Optical Properties of Acrylic Resin

Abstract Acrylic resin is widely used in manufacturing removable implant-supported prostheses. To evaluate the influence of pigment addition and the application of different adhesives (Equate, Fixodent, and Poligrip) on the physical and optical properties of thermopolymerizable acrylic resins. A total of 160 samples were prepared for each test group (dimensional stability, detail reproduction, color, roughness, and surface microhardness), where 80 samples of each size, with and without pigment addition, were divided into 16 subgroups, including a control group with equate fixative, Poligrip, and Fixodent, with n = 10 samples. The samples were stored in an oven at 37°C, immersed in distilled water, and the adhesives were reapplied every 3 days for 2 months. Dimensional stability showed a significant difference only for pigment before and after aging (p < 0.01). Detail reproduction remained unchanged, with grooves and angles preserved regardless of adhesive. Color change was significant for pigment (p < 0.01). Aging significantly affected the properties of control (p ≤ 0.041), Equate (p ≤ 0.038), and Fixodent (p ≤ 0.034) adhesives, regardless of pigment, whereas Poligrip showed significant changes only in pigmented samples (p = 0.021). Surface microhardness differed significantly only after aging (p < 0.001), independent of other factors. The addition or absence of pigment caused changes in physical and optical properties after 2 months of aging, except in detailed reproduction and with the application of adhesives.