Effect of denture cleansers on color stability and surface roughness of denture bases fabricated from three different techniques: Conventional heat‐polymerizing, CAD/CAM additive, and CAD/CAM subtractive manufacturing

Abstract

PurposeDenture base materials are commonly exposed to different denture cleansers which can affect their essential properties. This study aimed to assess the effect of 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.Materials and MethodsIn this in vitro study, 24 disc‐shaped specimens were fabricated by the mentioned methods for each group. The initial color and surface roughness of specimens were recorded. The specimens were randomly divided into three subgroups (n = 8): a control subgroup (distilled water), and two experimental subgroups of bioactive oxygen tablet (Corega) and 1% sodium hypochlorite solution. Then they were immersed in the solutions simulating 180 days of clinical use. Color change (∆E) was measured by a spectrophotometer according to the CIE L*a*b* color space and the American National Bureau of Standards (NBS = 0.92 × ∆E). Final surface roughness was recorded by a profilometer and its change was calculated. The Kruskal–Wallis test followed by the Wilcoxon signed rank test were used for statistical analyses (α = .05).ResultsThe conventional and CAD/CAM subtractive groups showed an increase in surface roughness following immersion in hypochlorite solution (p < .05). After immersion in the solutions, the highest surface roughness was noted in the conventional group, and the lowest in the CAD/CAM additive group. The CAD/CAM additive group experienced a significant color change in hypochlorite solution (p < .05) and showed the highest color change while the CAD/CAM subtractive group showed the lowest color change in all denture cleanser solutions.ConclusionAlthough the CAD/CAM additive denture base resins had the lowest surface roughness after exposure to denture cleanser solutions, they showed significant color change, which should be taken into account. Using hypochlorite as a denture cleanser should be cautioned due to its negative effects on the surface roughness and color stability of denture base materials.

Effect of various staining beverages on the color stability of CAD/CAM PMMA denture teeth: An in vitro study

“…Coffee, red tea, and cola were assessed in the current study as they are the most consumed staining beverages in the daily diet (Al-Shami et al, 2023;Aydın et al, 2020), and distilled water was selected as Takhtdar et al, 2023) which considered an optimal period to obtain a cumulative effect. In addition, according to Aydin et al ( 2020), 30 days of exposure to certain beverages would reproduce 2.5 years of regular consumption, and a day of exposure would reproduce 30 days of consumption.…”

“…The samples were immersed in the medium for a day, 7 days, and 30 days. The maximum duration of immersion was 30 days, according to many studies (Al‐Shami et al, 2023 ; Takhtdar et al, 2023 ) which considered an optimal period to obtain a cumulative effect. In addition, according to Aydin et al ( 2020 ), 30 days of exposure to certain beverages would reproduce 2.5 years of regular consumption, and a day of exposure would reproduce 30 days of consumption.…”

“…The color change ( ) was assessed using a spectrophotometer (VITA Easyshade® V, VITA North America) using a white background (Takhtdar et al, 2023 ). The Kappa coefficient of intraexaminer reliability was >0.8.…”

“…It was evaluated at four‐time points: at the baseline (t 0 ), on the 1st day (t 1 ), on the 7th day (t 2 ), and on the 30th day (t 3 ) of immersion (Aydın et al, 2020 ), and repeated measurements were standardized in a positioning jig (Positioning Jigs, MISUMI). Before each measurement, a white calibration plate (Labsphere's Spectralon®, Labsphere, Inc.) was used (Takhtdar et al, 2023 ). was calculated using the following formula: where , , and indicate lightness, green/red coordinate, and blue/yellow coordinate, respectively (Al‐Shami et al, 2023 ).…”