Purpose: To evaluate how different polishing techniques and coffee thermal cycling affect the surface roughness and stainability of additively and subtractively manufactured resins used for definitive prostheses.Materials and Methods: Two additively manufactured composite resins (Crowntec, CT and VarseoSmile Crown Plus, VS) and a subtractively manufactured resin nanoceramic (Cerasmart, CS) were used to fabricate 90 rectangular‐shaped specimens (14 × 12 × 1 mm) (n = 30). After baseline surface roughness (R_a) measurements, specimens were divided into three groups based on the polishing technique; conventional polishing with a 2‐stage polishing kit (CP) and surface sealant application (Optiglaze, OG or Vita Akzent LC, VA) (n = 10). After polishing, specimens were subjected to 10,000 cycles of coffee thermal cycling. R_a and color coordinate measurements were performed after polishing and after coffee thermal cycling. Color difference (ΔE₀₀) was calculated. Scanning electron microscope images were taken at each time interval. Kruskal–Wallis or 1‐way analysis of variance (ANOVA) were used to evaluate R_a of materials within each polishing‐time interval pair and different polishing techniques within each material‐time interval pair, while Friedman or repeated measures ANOVA were used to evaluate R_a at different time intervals within each material‐polishing pair. ΔE₀₀ was assessed with 2‐way ANOVA (α = 0.05).Results: Other than VA‐after polishing (p = 0.055), tested materials had significantly different R_a within each polishing‐time interval pair (p ≤ 0.038). When R_a differences among different polishing techniques within each material‐time interval pair were considered, CS had differences after coffee thermal cycling, CT had differences before polishing and after coffee thermal cycling, and VS had differences within each time interval (p ≤ 0.038). When R_a differences among different time intervals within each material‐polishing pair were considered, significant differences were observed among all pairs (p ≤ 0.016), except for CS‐VA (p = 0.695) and VS‐VA (p = 0.300). ΔE₀₀ values were affected by material and polishing technique interaction (p = 0.007).Conclusions: R_a of CS was similar to or lower than the R_a of other materials, regardless of the time interval or polishing technique. CP mostly led to lower R_a than other polishing techniques, whereas VA resulted in a high R_a regardless of the material‐time interval pair. Polishing reduced the R_a, while coffee thermal cycling was found to have a small effect. Among tested material‐polishing pairs, only CS‐VA had moderately unacceptable color change when previously reported threshold values were considered.

Three-dimensional (3D) printing is increasingly used to fabricate denture base materials. However, information on the effect of simulated brushing and thermocycling on the surface roughness and color stability of 3D-printed denture base materials is lacking. The aim of this study was to evaluate the effect of brushing and thermocycling on the surface roughness and color stability of 3D-printed denture base materials and to compare with those of milled and heat-polymerized denture base resins. Disk-shaped specimens (Ø 10 mm × 2 mm) were prepared from 4 different denture base resins (NextDent Denture 3D+ (ND); Denturetec (SC); Polident d.o.o (PD); Promolux (CNV)) (n = 10). Surface roughness (R_a) values were measured before and after polishing with a profilometer. Initial color coordinates were measured by using a spectrophotometer after polishing. Specimens were then consecutively subjected to simulated brushing (10,000 cycles), thermocycling (10,000 cycles), and brushing (10,000 cycles) again. R_a and color coordinates were measured after each interval. Color differences (ΔE₀₀) between each interval were calculated and these values were further evaluated considering previously reported perceptibility (1.72 units) and acceptability (4.08 units) thresholds. Data were analyzed with Friedman, Kruskal–Wallis, and Mann–Whitney U tests (α = 0.05). R_a (p ≥ 0.051) and ΔE₀₀ (p ≥ 0.061) values among different time intervals within each material were similar. Within each time interval, significant differences in R_a (p ≤ 0.002) and ΔE₀₀ values (p ≤ 0.001) were observed among materials. Polishing, brushing, and thermocycling resulted in acceptable surface roughness for all materials that were either similar to or below 0.2 µm. Color of ND printed resin was affected by brushing and thermocycling. All materials had acceptable color stability when reported thresholds are considered.

Purpose: To evaluate the surface roughness, optical properties, and microhardness of additively or subtractively manufactured CAD‐CAM materials after simulated brushing and coffee thermal cycling.Material and methods: Two additively manufactured resins (Crowntec, CT and VarseoSmile Crown Plus, VS) and 3 subtractively manufactured materials (a reinforced composite (Brilliant Crios, BC), a polymer‐infiltrated ceramic network (Enamic, VE), and a feldspathic ceramic (Mark II, VM)) were used to fabricate disk‐shaped specimens (Ø10×1‐mm) (n = 10). Surface roughness, Vickers microhardness, and color coordinates were measured after polishing, while surface roughness was also measured before polishing. Specimens were then subjected to 25000 cycles of brushing and 10000 cycles of coffee thermal cycling, and measurements were repeated after each time interval. Color difference (ΔE₀₀) and relative translucency parameter (RTP) were calculated. Robust analysis of variance test was used to evaluate surface roughness, ΔE₀₀, and RTP data, while generalized linear model analysis was used for microhardness data (α = 0.05).Results: Material type and time interval interaction affected tested parameters (p ≤ 0.002). In addition, material type affected all parameters (p < 0.001) other than surface roughness (p = 0.051), and time interval affected surface roughness and microhardness values (p < 0.001). Tested materials mostly had their highest surface roughness before polishing (p ≤ 0.026); however, there was no clear trend regarding the roughness of materials within different time intervals along with ΔE00 and RTP values within materials or time intervals. VS and CT had the lowest microhardness regardless of the time interval, while the remaining materials were listed as VM, VE, and BC in decreasing order (p < 0.001). Coffee thermal cycling only reduced the microhardness of VM (p < 0.001).Conclusions: Tested additively manufactured resins can be considered more susceptible to simulated brushing and coffee thermal cycling than the other materials, given the fact that their surface roughness and ΔE00 values were higher than previously reported acceptability thresholds and because they had the lowest microhardness after all procedures were complete.

The aim of this study was to evaluate the effects of sandblasting and different chemical bonding agents on shear bond strength of zirconia and conventional resin cement. In this study, 35 zirconia specimens were treated as follows: Group I: control; Group II: sandblasting; Group III: sandblasting + Monobond S; Group IV: sandblasting + Monobond Plus; Group V: sandblasting + Z-Prime Plus. The specimens in each group were bonded with conventional composite resin cement Variolink II. After cementation, specimens were stored in distilled water (at 37 °C) for 24 h and shear test was performed. The highest shear bond strength values were observed in Groups IV and V. The lowest shear bond strength values were observed in Group I. Using 10-methacryloyloxy-decyl dihydrogenphosphate monomer-containing priming agents, e.g. Monobond Plus and Z-PRIME Plus, combined with sandblasting can be an effective method for resin bonding of zirconia restorations.