Effects of disinfection procedures on surface roughness of hard chairside relining and denture base acrylic resins: An in vitro study

Abstract

Objective: There is a concern that disinfection procedures may adversely affect the surface roughness of relining and acrylic denture base resins. Hence, this in vitro study was conducted to evaluate the effect of chemical and microwave disinfection on surface roughness of commonly used hard chairside relining (Ufi Gel hard and Kooliner) and acrylic denture base resins (Lucitone 199). Materials and Methods: Powder (polymer) and liquid (monomer) were mixed according to manufacturer’s instructions to prepare 20 specimens from each material. Specimens were divided into two control and two test groups. Surface roughness measurements (Ra, μm) were made after polymerization and water immersion (control groups) and after chemical and microwave disinfection (test groups). Measurements of roughness were statistically analyzed. Result: When compared with control groups, the surface roughness of all three types of materials evaluated were significantly increased (P ≤ 0.05) by both chemical disinfection (Ufi Gel hard, from 0.16 to 0.28 μm; Kooliner, from 0.18 to 0.29 μm; and Lucitone 199, from 0.14 to 0.26 μm) and microwave disinfection (Ufi Gel hard, from 0.16 to 0.26 μm; Kooliner, from 0.18 to 0.25 μm; and Lucitone 199, from 0.14 to 0.23 μm). For all three types of materials, specimens disinfected in microwave (Ufi Gel hard, 0.26 μm; Kooliner, 0.25 μm; and Lucitone 199, 0.23 μm) showed lower mean surface roughness values than those that were chemically disinfected (Ufi Gel hard, 0.28 μm; Kooliner, 0.29 μm; and Lucitone 199, 0.26 μm) but the difference was significant only for Kooliner (P = 0.015). Conclusion: The result of this in vitro study favored the use of microwave disinfection method as it had less adverse effect on surface roughness of materials compared to that of chemical disinfection.