Denture wearers are advised to follow the protocol of using both mechanical and chemical hygiene methods. In this study, the in-vitro color stability of heat-cured, light-cured and newly developed pre-polymerized CAD/CAM acrylic resin base materials were evaluated after exposure to mechanical brushing and chemical denture cleansers. Two polymethyl methacrylate (PMMA) (heat-cured, and pre-polymerised CAD/CAM) and one urethane dimethacrylate based resin denture base material were subjected to mechanical brushing, followed by immersion in chemical denture cleansers (Corega, 5.25% Sodium hypochlorite (NaOCl), and 0.2% chlorhexidine gluconate (CHG)) and thermal-cycling to simulate one-year of normal prosthesis use. Baseline and final color measurements were determined and the difference in color was calculated using bench-top UV light visible spectrophotometer. The highest (29.69 ± 1.84) and lowest (19.03 ± 8.78) mean ΔE was observed with light-cured and CAD/CAM materials immersed in 0.2% CHG, respectively. Tukey’s post-hoc test showed that heat cured and light-cured resins immersed in either of the denture cleansers showed no significant differences (p > 0.05) in the mean ΔE values. On the contrary, CAD/CAM materials immersed in either of the denture cleansers demonstrated significant differences in the mean ΔE values (p ≤ 0.05). A statistically significant interaction between the combination of materials and denture cleansers (F = 4.890; p = 0.001) was observed. The color stability of the pre-polymerized CAD/CAM acrylic discs is comparatively better than the conventional acrylic resin materials. The changes in the color values of all the tested materials were above the clinically acceptable range, regardless of the type of denture cleanser used.

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Objective Conservative approaches to esthetically treat stained arrested caries lesions (s-ACLs) have not been explored in clinical studies. This study aims to investigate the efficacy of in-office dental bleaching agent, as a conservative approach, to esthetically treat s-ACLs. Materials and Methods Twelve patients (n = 46) presented with s-ACLs were treated with 40% hydrogen peroxide (in-office bleaching protocol; 20 minutes × 3). Color values were measured using a spectrophotometer (CIE L*a*b*), aided with digital photography to assess visual color change clinically. Measurements were taken for each specimen at baseline and immediately after bleaching. Statistical Analysis The color change calculated before and after bleaching for each dental substrate was analyzed using paired t-test (α = 0.05). Results The bleached s-ACLs had a significant increase in L* values (p < 0.001), and a significant decrease in both a* (p = 0.001) and b* (p = 0.007) values, indicating lighter color improvement (bleaching efficacy). The baseline mean L*, a*, and b* values were 61.5, 2, and 15.4, respectively, and after bleaching were 67.7, 1.4, and 13.3, respectively, with a mean increase in ∆E of >7.9, which resulted in a visible clinical stain improvement as orange/light brown stains were removed completely, while gray/black stains improved to a lesser extent. Conclusion Significant color improvement was observed when the in-office bleaching protocol (40% hydrogen peroxide) was used in orange/brown s-ACLs. However, it showed lesser improvement in gray/black s-ACLs.

Oral dentures are subjected to mechanical and chemical cleansing processes. However, these processes alter the physical and mechanical properties of denture acrylic resins. This study analyzes the surface roughness of conventional heat-cured (HC) polymethacrylate, light-cured (LC) urethane dimethacrylate, and prepolymerized computer-aided design/computer-aided manufacturing (CAD/CAM) dental acrylic resins. The materials were subjected to combined surface treatment of mechanical brushing, thermal cycling, and immersion in chemical disinfectants (corega, chlorhexidine gluconate [CHG], and sodium hypochlorite) to simulate 1 year of clinical use. The surface roughness of the resin specimens before and after surface treatment was evaluated using a noncontact profilometer. Statistical tests based on analysis of variance revealed significant interactions between resin type and disinfectants, indicating that the effects of these two factors were interdependent. The highest and lowest surface roughness was observed in HC resins immersed in CHG and CAD/CAM resins immersed in sodium hypochlorite. Among the materials, HC resins demonstrated the overall highest mean roughness, followed by LC and CAD/CAM resins. Regarding the disinfectant use, the highest mean roughness was observed in disks immersed in CHG, followed by those immersed in corega and sodium hypochlorite. The prepolymerized CAD/CAM acrylic resin demonstrated superior surface quality following combined surface treatments. The HC and LC resins exceeded the roughness threshold and the reported roughness values for acrylic resins following surface treatments. Among the disinfectants tested, sodium hypochlorite produced overall low roughness values.