Evaluation of a glaze polishing technique for pigmented denture acrylic resin submitted to thermocycling and disinfection

Abstract

Aims: Compare the mechanical and physical properties of two polishing techniques for acrylic resins under the influence of disinfection. Materials and Methods: Two hundred and eight circular samples (10 mm diameter × 3 mm height) were manufactured, with 160 for the color stability, hardness, surface roughness, and wettability (n = 10) analyses, and 48 for the scanning electron microscopy and atomic force microscopy evaluation (n = 1). Two brands of prosthesis acrylic resin, Onda Cryl and Lucitone, were used to manufacture the samples. Half of the samples were intrinsically pigmented with a purple acrylic pigment (Policor) at 7% of the total weight in powder; half of those received the mechanical polish with sand paper under constant water irrigation in a universal polishing machine at 300 rpm (control), and half received a uniform coat of a photopolymerized glaze (Megaseal) to be tested. The samples were kept immersed in distilled water for 24 h before the initial measurements (T0), afterward, they were divided into two disinfection procedures; half were disinfected through microwave energy and half through cleaning tablets (Efferdent) for 60 days (T1). Results: The glaze polished groups presented inferior chromatic stability and the pigments prevented discoloration for the glaze polish. The disinfectant solutions promoted a superficial degradation of the acrylic resin for both polishing techniques. Lucitone presented higher hardness values than Onda Cryl (P < 0.001) and the glaze technique had higher hardness values than the mechanic polish. Conclusion: The photopolymerized glaze improved some characteristics of the acrylic resin, such as the surface hardness and roughness suggesting it is an adequate polish for acrylic resins.