Influence of mouthwashes on the physical properties of orthodontic acrylic resin

ABSTRACT

AIM: The aim of this study was to evaluate the influence of acrylic resin immersion in different mouthwashes on hardness, roughness and color. METHODS: Specimens of an orthodontic self-cured acrylic resin (Orto Clas(r)) were produced and immersed in five mouthwashes Plax(r) Classic (Colgate(r)); Plax(r) alcohol-free (Colgate(r)); Listerine(r) (Johnson & Johnson(r)); Periogard(r) (Colgate(r)) and Periogard(r) alcohol-free (Colgate(r)). Nine different immersion times were studied 1, 2, 4, 6, 8, 10, 12, 24 h and 7 days, totalizing 45 groups. The specimens were evaluated before and after immersion by Knoop microhardness (n=5), roughness in Ra parameter (n=5), and colorimetric analysis, CIElab (n=3). RESULTS: All mouthwashes softened the acrylic resins after 7 days of immersion. PlaxÒ alcohol-free showed no statistically significant difference of softening between the immersion times. Listerine(r) showed softening after immersion at all times. Plax(r) alcohol-free and Listerine(r) showed significantly increased values of roughness after 12 h of immersion (p<0.05). Listerine(r) presented a significant increase in color variation after 12 h of immersion. CONCLUSIONS: Immersion in mouthwashes could influence acrylic resin hardness, roughness and color...