The effect of denture cleansers on color stability of denture base materials produced by different techniques

Digital developments have enabled the use of computer-aided design and computer-aided manufacturing (CAD/CAM) technology in the design and production of complete dentures. Prostheses produced with CAD/CAM offer more clinical advantages than conventional methods. Denture base materials are commonly exposed to different denture cleansers which can affect their essential properties. This study aimed to assess the effect of coffee and denture cleansers on color stability and surface roughness of poly methyl methacrylate (PMMA) denture bases fabricated from different techniques: Conventional heat‐polymerizing, CAD/CAM additive and CAD/CAM subtractive. In this in vitro study, 60 disc‐shaped specimens were fabricated by the mentioned methods for each group. The initial color and surface roughness of the specimens were recorded. The specimens were randomly divided into six subgroups (n = 10): a control subgroup (distilled water), and five experimental subgroups of Corega, 1% sodium hypochlorite solution, Coffee, Coffee+Corega, and Coffee+1% sodium hypochlorite solution. Then they were immersed in the solutions simulating 180 days of clinical use. Color change (ΔE00) was measured by a spectrophotometer according to the CIEDE2000. Final surface roughness was recorded by a contact profilometer and its change was calculated. The data were analyzed using ANOVA. In this study, The 3D Printed group showed lowest color stability in the groups kept in denture cleaners after coffee exposure. The color change in heat-polymerized PMMA and prepolymerized CAD/CAM PMMA was similar and there was no significant difference (p>0.05). Except for the Coffee + Corega and Coffee + 1% Sodium Hypochlorite subgroups of the 3D printed group (ΔE00=3.78 and ΔE00=2.38, respectively), the other color changes are below the detectable threshold (ΔE00=1.72). Surface roughness values are below the threshold value of 0.2 μm for all groups. As a conclusion and within the conditions of this study, it was observed that using denture cleaners after coffee did not provide sufficient stain removal efficiency on 3D printed denture base materials. Keywords: CAD/CAM, 3D printing, additive manufacturing, subtractive manufacturing, acrylic resin, complete denture, denture cleanser