Purpose To investigate the influence of reducing material thickness on flexural properties of computer‐aided design and computer‐aided manufacturing (CAD‐CAM) denture base resins. Materials and methods Four CAD‐CAM denture base acrylic resin materials were selected; two were made via the subtractive method (AvaDent and IvoCad) and two were made with the additive method (FormLabs and NextDent). One heat‐polymerized denture base material was used as a control. Specimens were fabricated with varying thicknesses (n = 10/group): 3.3 mm, 2.5 mm, 2 mm, or 1.5 mm. Flexural strength was evaluated via a three‐point bending test. One‐ and two‐way ANOVA were used for data analysis along with Tukey's post hoc comparison (α = 0.05). Results Reducing the thickness of materials made via the subtractive method did not influence flexural strength up to 2 mm (p > 0.05). However, the difference was significant at a 1.5 mm thickness (p ˂ 0.001). For materials made via the additive method, NextDent specimens had no significant decrease in flexural strength when the thickness was reduced to 2 mm (p = 0.58). FormLabs specimens showed a significant decrease (p ˂ 0.001), although the values of flexural strength were clinically acceptable. During testing, specimens manufactured via the additive method at a 1.5 mm thickness bent without fracturing and were therefore excluded. All materials showed a reduction in elastic modulus as the thickness decreased (p ˂ 0.001). Conclusion Heat‐polymerized, AvaDent, and IvoCad materials may be used for denture base fabrication at a minimum thickness of 1.5 mm. FormLabs and NextDent may be fabricated at a 2 mm minimum thickness, with clinically acceptable flexural properties.

Purpose To evaluate the effect of ageing process and brushing on the color stability and surface roughness of white spot lesions treated with resin infiltration or remineralization. Patients and Methods Artificial white spot lesions were created on the facial surface of extracted bovine teeth. Specimens were divided into three main groups based on treatment received: resin infiltration (Icon), MI Paste Plus (MI) or no treatment (control). Specimens underwent pH cycling for 7 days, followed by brushing with toothbrush simulator. Specimens were then immersed in three different solutions (water, cranberry juice, or coffee) for 7 days. Surface roughness (SR) and color stability (CS) assessments were performed at baseline and after each test. One-way and two-way ANOVA were used to calculate the statistical comparisons between the groups and significance considered at P <0.05. Results Icon group had the least color change after pH cycling, while MI showed the least color change after brushing test. Immersion in coffee produced the highest color change in all groups, followed by cranberry juice. Icon group had the best color stability when immersed in cranberry juice or coffee. Control and the MI treated specimens showed gradual increase of SR after pH cycling and brushing test, while Icon group had improved surface properties. Brushing test alone produced less color change in comparison with immersion in cranberry juice and coffee; however, brushing increased SR. Conclusion Icon treatment showed superior color stability and surface roughness, compared to the control and the MI treated teeth. Brushing had less influence on color change compared to the immersion in cranberry juice or coffee.