Comparison of the color stability and surface roughness of 3-unit provisional fixed partial dentures fabricated by milling, conventional and different 3D printing fabrication techniques

Effect of aging on optical behavior and color of 3D printing resin-based dental restorative materials

OBJECTIVES

To evaluate the influence of aging on color and optical properties of 3D printing resin-based dental restorative materials.

METHODS

Four 3D printing resin-based dental restorative materials (DFT- Detax Freeprint Temp; FT- Formlabs Temporary CB; FP- Formlabs Permanent Crown; and GCT- GC TempPrint) were evaluated. The structures were printed using digital light processing (DLP) (DFT and GCT groups) and stereolithography (SLA) (FT and FP groups) technologies. Samples (10 × 10 × 1 mm; n = 3) were printed in light (L) and medium (M) shades and at 0° and 90° and then polished to a thickness of 1.00 ± 0.01 mm with silicon carbide (SiC) sandpapers under water cooling. Artificial aging followed the ISO 4892-2 standard. 1) Color differences were evaluated using CIEDE2000 and perceptibility and acceptability thresholds (PT00 and AT00), 2) spectral reflectance (R%) and transmittance (T%) were measured and scattering (S) and absorption (K) coefficients, light reflectivity (RI), infinite optical thickness (X∞) pre- and post-aging were calculated using Kubelka-Munk method and Root Mean Square Error (RMSE) and Goodness of Fit (GFC) were used as performance optical behavior.

RESULTS

1) All 3D-printed dental resins evaluated, irrespectively of the printed angles, showed mean ΔE00 values above AT00 (.ΔE00>1.8), and FT-M and FP-M showed the least color changes among the evaluated materials, 2) GFC<0.999 and RMSE >2 % values were found between pre and post aging for R%, T%, S, K, RI and X∞ properties.

CONCLUSIONS

This study showed poor spectral match and comparative spectral values of R%, T%, S, K, RI and X∞ between after and before aging, resulting in unacceptable color changes. Printing orientation does not influence the change of the optical behavior of the evaluated materials after aging.

CLINICAL SIGNIFICANCE

Aging causes significant changes on the spectral optical behavior for the 3D-printed resin-based restorative materials studied, resulting in clinically unacceptable color changes.

Shade variability and stability in interim and definitive tooth-colored resin-based restorative materials: Comparing manufacturer-claimed shades to a universal shade guide

PURPOSE

To evaluate the shade variability and stability of interim and definitive tooth-colored restorative materials by comparing manufacturer-claimed shades to a universal shade guide before and after thermocycling.

MATERIALS AND METHODS

Eight commercially available tooth-colored restorative materials were tested, including conventional, milled, and 3D-printed types. Each material was categorized into three shade subgroups (A1, A2, and A3), with 10 samples per subgroup. The color differences (ΔE00) between the materials' shades and a universal shade guide (VITA classical A1-D4) were measured using a digital spectrophotometer before (ΔE00-R1) and after (ΔE00-R2) thermocycling. A higher ΔE00 indicated higher variability between the manufacturer-claimed shade and a corresponding universal shade guide. The ΔE00 was analyzed using the CIEDE2000 formula, and statistical analysis was performed to evaluate the effects of materials, shades, and thermocycling. In addition, the ΔE00 was compared against 50%:50% perceptibility threshold (PT) and 50%:50% acceptability threshold (AT) using one-sample t-tests (α = 0.05).

RESULTS

The observations from descriptive statistics showed that the milled Aidite group exhibited the lowest ΔE00. In addition, shade A1 showed higher ΔE00 than A2 and A3 within each group; however, the ΔE00 between shade types A2 and A3 was similar. The three-way interaction among materials, shades, and thermocycling was significant (p < 0.0001), highlighting their combined effect on ΔE00. No significant interaction between shade and thermocycling was observed (p = 0.6239), suggesting that thermocycling did not significantly affect ΔE00 among shade subgroups. Comparison of ΔE00-R1 and ΔE00-R2 against 50%:50% PT (0.8) and 50%:50% AT (1.8) revealed significant color differences beyond both thresholds for most study groups.

CONCLUSIONS

Color variability in dental restorative materials is influenced by material, shade, and thermocycling. Most samples showed significant discrepancies from manufacturer-specified shades (A1, A2, and A3) when compared to the VITA classical A1-D4 guide. Clinicians might consider using a custom shade guide that is fabricated from the same material as the prostheses to improve shade matching outcomes.

Effect of polydopamine surface treatment on the mechanical properties of zirconia and resin occlusal veneers fabricated using additive and subtractive manufacturing: An in vitro study

OBJECTIVES

To evaluate the influence of polydopamine (PDA) treatment on bond strength, fracture, and wear resistance of occlusal veneers (OVs) fabricated using additive (AM) and subtractive manufacturing (SM) techniques.

METHODS

Three hundred twenty 0.5 mm-thick OVs were fabricated through AM and SM and from four groups of materials (n = 80): AM ceramic-filled resin (AM-C), AM zirconia (AM-Z), SM nano-ceramic resin (SM-C), and SM zirconia (SM-Z). Each group was further divided into PDA-treated and untreated subgroups (n = 40). Specimens were cemented onto resin dies using self-curing resin cement (Multilink N; Ivoclar Vivadent) and subjected to five million chewing cycles with thermal cycling. Fracture and wear resistance were assessed using a load-to-failure test and 3D surface analysis, respectively (n = 20). Additionally, bond strength was evaluated using a pull-out test (n = 20). Data were analyzed using three-way ANOVA to assess the main and interaction effects of material, manufacturing technique, and PDA treatment (α=0.05).

RESULTS

Significant main effects of manufacturing technique, material type, and PDA treatment were found for all outcomes (p<.001), along with significant manufacturing × PDA interactions. PDA notably improved fracture resistance and bond strength in AM-Z and AM-C (p<.05), but had minimal effect on SM groups. Wear was significantly reduced in AM groups following PDA (p<.001), while SM-C showed a slight increase (p=.021). Among all groups, untreated AM-C demonstrated the weakest overall mechanical performance.

CONCLUSIONS

PDA treatment enhanced fracture and bond strength in AM materials, with limited effect on SM ceramics. Milled zirconia showed the best overall performance, while untreated AM-C consistently performed the worst.

CLINICAL RELEVANCE

Polydopamine surface treatment enhances the mechanical performance of occlusal veneers fabricated by additive manufacturing, particularly improving bond strength and fracture resistance. This approach may increase the clinical reliability of 3D-printed restorations, especially in thin, conservative designs.

Stainability of 3D-printed resins for denture base and artificial teeth

BACKGROUND

The 3D-printed resins for denture bases and artificial teeth are susceptible to staining from the colorants. The purpose of the study is to evaluate the color stability of 3D-printed denture base and artificial teeth resins submitted to staining by beverages for the simulated periods of 3, 6 and 12 months.

METHODS

Discs (15 × 3 mm) of denture bases resins [Lucitone 550 (n = 50), Cosmos Denture (n = 50) and NextDent Denture 3D+ (n = 50)] and artificial teeth resins [Duralay (n = 50) and Cosmos Temp (n = 50)] were manufactured. A spectrophotometer evaluated color stability after immersion in: instant coffee, cola, tea, red wine and distilled water, simulating periods of 3, 6 and 12 months of consumption. The data (ΔE00) were submitted to Generalized Estimating Equations (GEE) and Bonferroni post-test (α = 0.05). The perceptibility and acceptability thresholds of color change was set at PT/AT: ΔE00 = 1.7/4.1.

RESULTS

The Cosmos Denture resin showed greater color change after immersion in coffee and red wine for most periods at unacceptable levels, in comparison to Lucitone and NextDent. The ΔE00 values for NextDent and Lucitone resins were similar to each other regardless of the beverage and the period evaluated. For artificial teeth resins, Cosmos Temp predominantly reached unacceptable levels of staining in most cases, showing visible color changing due to exposure to instant coffee and red wine. Duralay and Cosmos Temp exhibited a time-dependent discoloration.

CONCLUSIONS

It was concluded that the Cosmos Denture resin presented the greatest changes in color stability in relation to other denture base resins for coffee and red wine. The 3D-printed denture base resin NextDent showed similar behavior of color change in relation to the conventional heat-polymerized denture base resin, irrespective of the beverage and immersion period. The Cosmos Temp artificial teeth resin showed unacceptable color stability compared to Duralay when immersed in coffee and red wine, irrespective of the period.

Does Cigarette Smoke Affect Permanent Resin-Based Crown Materials?

OBJECTIVE

The purpose of this study was to investigate how cigarette smoking affects the surface roughness (Ra) and stainability of additively and subtractively manufactured resins.

MATERIALS AND METHODS

Two additively manufactured definitive resins (Dentafab, DF and Formlabs, FL) and a subtractively manufactured resin nanoceramic (Cerasmart, CS) were used to fabricate 60 specimens (14 × 12 × 1 mm). After taking baseline Ra and color measurements (ΔE00), they were divided into two groups (n = 10). Using a programmable cigarette smoking simulation device, the study groups smoked 10 cigarettes a day for 30 days. The control groups were kept in artificial saliva for 30 days. The Ra and ΔE00 were performed again. Scanning electron microscope images were taken. Kruskal-Wallis test, Mann-Whitney U, Bonferroni, and Wilcoxon Signed Rank tests were used for statistical analyses (α = 0.05).

RESULT

Significantly less discoloration was observed in the FL group compared with the other groups (p < 0.001). The Ra of the DF study groups was statistically significantly higher than the control groups (p = 0.005).

CONCLUSION

All the tested materials had moderately unacceptable color change when previously reported threshold values were considered. There was not found to be any linear correlation between the Ra of materials and smoking-induced discoloration.

CLINICAL SIGNIFICANCE

The discoloration and surface roughness of three-dimensional (3D)-produced SLA definitive resin because of smoking are at acceptable levels. Optimized physical and chemical properties of definitive resins are clinically important to extend the life of the restoration. The application of 3D definitive resin can be recommended in clinical practice.

Influence of 3D printing system, postpolymerization and aging protocols on resin flexural strength and dimensional stability for printing occlusal splints, models and temporary restorations

OBJECTIVES

Investigate the effect of different postpolymerization protocols, aging, and 3D printing systems on the flexural strength (σ), dimensional stability, and roughness of resins used to fabricate occlusal splints, dental models, and temporary restorations.

MATERIAL AND METHODS

180 bars (25 × 2 x 2 mm-ISO 4049) of each type of resin (T-Temporary/Cosmos Temp, Yller; OS-Occlusal splint/Cosmos Splint, Yller; MO - Models/ Cosmos Model, Yller) were printed and divided into 12 groups (n = 15) according to the factors: "Postpolymerization" (Ctr - Control; UV - Ultraviolet oven and MW - Microwave); "Printer" (SLA- stereolithography (Forms 2/Formslab); LCD- liquid crystal display (FlashForge Foto 6.0/FlashForge)) and "Aging" (TC - 10,000 thermocycling cycles and Without). Each bar was measured with a digital caliper at 11 points before and after postpolymerization to evaluate dimensional stability. The samples were subjected to the σ test (100Kgf;1 mm/min). Data was evaluated using Three- and Two-way ANOVA, and Tukey's test (5%). Weibull analysis, Scanning Electron Microscopic and optical profilometry was performed.

RESULTS

LCD printing system and UV oven postpolymerization exhibited the highest σ (P < .05). The groups printed in SLA and post-polymerized in microwave ovens showed the greatest variations in their dimensions, for the occlusal splint resin, the OS-SLA-MW group (-4.29 ± 3.15)A showed a shrinkage of 40.2%. The resins for models (3.31 ± 0.66)A and temporary (-2.06 ± 1.52)A showed a shrinkage of 33% and 20.6%, respectively.

CONCLUSIONS

LCD printing with UV light postpolymerization was the most effective method for resins used in occlusal splints, dental models, and temporary restorations. SLA printing with UV postpolymerization showed the most significant dimensional changes, leading to shrinkage in occlusal splint resins, while model resins and temporary restorations expanded.

CLINICAL RELEVANCE

Resins for 3D printing should ideally be post-polymerized with UV light and printed using LCD technology, as this approach results in better mechanical properties and less dimensional change compared to microwave oven post-polymerization.

Evaluation of the Colour Stability and Surface Roughness of Polymethylmethacrylate and Indirect Composites With and Without Ageing: An In-Vitro Study

BACKGROUND

Indirect restorations are a staple restorative option in dentistry due to their versatility, exceptional aesthetics, and desirable strength and longevity. Metal ceramics and all ceramics are the material of choice for permanent restorations but come with certain disadvantages, such as chipping, fracture, and wear of the antagonist tooth or restoration. Polymethylmethacrylate (PMMA) and indirect composite resins are commonly used materials due to their favourable properties for temporary restorations, but lately, they have been chosen as the restorative material of choice for implant-supported full-mouth rehabilitations. This study aimed to evaluate and compare the colour stability and surface roughness of PMMA and indirect composite resins under both ageing and non-ageing conditions. This would greatly help a clinician in choosing materials depending on the clinical scenarios.

AIM

This study aims to evaluate the colour stability and surface roughness of PMMA and indirect composite resins with and without ageing.

METHODS

Specimens of PMMA and indirect composite resins were fabricated and subjected to an ageing process involving thermocycling in the TW-C4.4 (Tae-Won Tech, Incheon, Korea) and immersion in a staining solution. Colour stability was assessed using a spectrophotometer (SpectraMagic NX, RM2002QC, Konica Minolta Corp., Ramsey, Japan), and surface roughness was measured using a stylus profilometer (Mituyoto, Mituyoto Corporation, Kawasaki, Japan). Statistical analysis was performed using IBM SPSS Statistics for Windows, Version 24 (Released 2016; IBM Corp., Armonk, New York) to determine significant differences between materials and ageing effects.

RESULTS

PMMA exhibited significantly higher colour changes and increased surface roughness post-ageing compared to indirect composite resins. The findings underscored PMMA's susceptibility to discolouration and surface degradation under thermal stress conditions.

CONCLUSION

PMMA demonstrates inferior colour stability and increased surface roughness following thermocycling compared to indirect composite materials, suggesting careful consideration in material selection for provisional restorations. Further research should explore additional ageing processes and materials to enhance understanding and improve clinical outcomes.

Assessment of color stability and translucency of various CAD/CAM ceramics of different compositions and Thicknesses: An in vitro study

Background

Translucency and optical characteristics significantly affect the aesthetics of ceramic restorations. The introduction of new virgilite crystals to novel ceramic advanced lithium disilicate through a matrix firing process enhances the material's strength and aesthetic quality according to the manufacturer.

Materials and Methods

Four types of CAD/CAM ceramics; lithium disilicate (LD), leucite reinforced (LR), advanced lithium disilicate (ALD), and zirconia-reinforced lithium silicate (ZLS) exposed to different staining solutions (tea, cola, coffee, and distilled water). Each ceramic type had 120 specimens, divided into subgroups based on thickness (0.5 mm, 1 mm, and 1.5 mm). Color changes (ΔE00) and translucency parameters (TP00) were measured after thermocycling, and spectrophotometry was employed to evaluate ΔE00 and TP00 after 1, 7, and 30 days of exposure to the staining solutions.

Results

ZLS exhibited the lowest color stability, while lithium LD and ALD displayed the highest. Thickness significantly affected color stability, with 0.5 mm thickness showing the least change. The duration of exposure also impacted color changes, with 30 days causing the most significant shift. LD demonstrated the highest translucency. Coffee and tea induced more pronounced reductions in translucency and color stability compared to the control group.

Conclusions

Material structure, thickness, staining solution, and exposure duration significantly influenced the color stability and translucency of CAD/CAM ceramics, with LD and ALD demonstrating superior color stability and LD exhibiting the highest translucency.

Effect of milling procedures in CAD-CAM systems on the color changes of CAD-CAM polymethyl methacrylate resin material as interim material

PURPOSE

This study aimed to investigate the effects of new and used burs on CAD-CAM PMMA resin color changes following thermocycling.

MATERIALS AND METHODS

Twenty disk-shaped specimens (10 × 2 mm) were made using a single brand of CAD-CAM polymethyl methacrylate resin (Polident) for the color test. Group N consisted of half of the specimens that were machined using the new tungsten carbide bur set, and Group U consisted of the specimens that were milled using the used bur set (500 machining time). A color test was performed on the specimens both before and after thermocycling. For the statistical analysis, the Kruskal-Wallis and Dunn Pairwise Comparison tests were employed.

RESULTS

The ∆E* value of specimens (2.057) milled with the used bur was higher than those of specimens milled with the new bur (0.340), but this value is within clinically acceptable limits. After thermocycling, specimens milled with the utilized burs had the greatest L* (93.850) and b* (5.000) values. After thermocycling, statistically significant differences were discovered between Group N and Group U as well as between specimens milled with the utilized bur before and after thermocycling.

CONCLUSION

Thermocycling process have an effect on the mean ∆E values of specimens milled with the used carbide bur, but these ∆E* values were not statistically significant.

CLINICAL SIGNIFICANCE

The color and clinical performance of CAD-CAM restorations may be affected by variations in CAD-CAM milling bur properties, particularly those related to their frequent use.

Color stability of CAD-CAM hybrid ceramic materials following immersion in artificial saliva and wine

PURPOSE

To examine the color stability of 3D-printed and milled, interim, and definitive, restorative materials after immersion in artificial saliva and wine for 1, 3, and 6 months.

MATERIAL AND METHODS

The study used a 2 × 5 factorial design with 10 subgroups, including 2 immersion liquids (artificial saliva and wine) and 5 manufacturing technology and restorative material combinations (n = 10). Color measurements were taken using a contact-type digital spectrophotometer (CM-2600d Spectrophotometer; Konica Minolta Healthcare Americas Inc) before immersion and at 1 month (T1), 3 months (T3), and 6 months (T6) after immersion. The CIE2000 system was used to calculate quantitative measurements of color differences in ΔE00, and comparisons were made to the acceptability threshold (AT) and perceptibility threshold (PT). Repeated measures of ANOVA (α = 0.05) were used to compare differences in color changes between manufacturing technology/restorative material-immersion liquid combinations at T1, T3, and T6.

RESULTS

To compare the effect of immersion liquid and time on the manufacturing technology/restorative material groups, the ΔE00 values were compared to the PT of 0.8 and the AT of 1.8. Wine caused significant color changes in ΔE00 values beyond the PT and AT values in all groups at all time intervals, except for the AT value of milled definitive crowns (hybrid nano-ceramic material). Wine immersion caused significant ΔE00 for all manufacturing technology/restorative material groups at all time intervals (1 month, 3 months, and 6 months) when compared to artificial saliva immersion (all p < 0.001).

CONCLUSION

Upon exposure to artificial saliva, 80%-100% of samples from all groups remained within the acceptable and perceptible color change thresholds. The wine had significant chromogenic effects on all tested restorative materials, however, the milled definitive crowns (hybrid nano-ceramic material) showed the greatest color stability. For patients with heavy wine consumption, 3D-printed definitive crowns (hybrid ceramic-filled material) may show discoloration exceeding acceptable and perceptible color change limits.

Influence of printing orientation on mechanical properties of aged 3D-printed restorative resins

OBJECTIVE

To evaluate the influence of printing orientation on flexural strength (σf) and elastic modulus (E) of different 3D printing dental restorative resins.

METHODS

Bar-shaped specimens (n = 20) were fabricated from two SLA-printed resins (FT- Formlabs Temporary, and FP- Formlabs Permanent) and two DLP-printed resins (DFT- Detax Freeprint Temp, and GCT- GC Temporary) using two building orientations (0º and 90º). The 3D-printed structures were aged (14 d) before submitted to three-point bending in 37ºC distilled water at a crosshead speed of 1.0 ± 0.3 mm/min until fracture to calculate the σf and the E values. The fractured surfaces were evaluated using stereomicroscopy and scanning electron microscopy (SEM) following fractography principles. Data were statistically analyzed using two-way ANOVA and Tukey post-hoc (α = 0.001).

RESULTS

FP and FT showed significantly higher E values than DFT and GCT, irrespectively of printing orientation (p < 0.001). There was no statistical difference between the building orientations (0º and 90º) for the mean σf and E values for the resin materials evaluated. Fractographic characteristics were similar for the surface fracture from all the materials evaluated, showing typical brittle fracture behavior.

SIGNIFICANCE

Printing orientation did not influence of flexural strength and elastic modulus values for the 3D-printed resin structures evaluated. Surface topography was mostly governed by the 3D printer type.

Effect of thermocycling on the mechanical properties of permanent composite-based CAD-CAM restorative materials produced by additive and subtractive manufacturing techniques

BACKGROUND

The aim of the study was to determine and compare the biaxial flexural strength (BFS) and Vickers hardness (VHN) of additive and subtractive manufactured permanent composite-based restorative materials, before and after thermal aging.

METHODS

A total of 200 specimens were prepared; 100 disc-shaped specimens (diameter 13 × 1.2 mm) for the BFS test and 100 square specimens (14 × 14 × 2 mm) for the VHN test. The specimens were made from various materials: two subtractive composite-based blocks (Cerasmart 270 [CS], Vita Enamic [VE]), two additive composite-based resins used for two different vat polymerization methods (digital light processing [DLP]; Saremco Print Crowntec [SC] and stereolithography [SLA]; Formlabs Permanent Crown Resin [FP]), and one feldspathic glass-matrix ceramic block (Vita Mark II [VM]) as the control group. Specimens of each material were divided into two subgroups: thermal cycled or non-thermal cycled (n = 10). BFS and VHN tests were performed on all groups. Data were analyzed with two-way ANOVA and post hoc Tukey test (α = 0.05).

RESULTS

The type of restorative material used for the specimen had a statistically significant influence on both BFS and VHN values. However, thermal cycling did not affect the BFS and VHN values. After thermal cycling, the results of the BFS test were ranked from best to worst as follows: CS, FP, SC, VE, then VM. For the VHN values, the order from best to worst was as follows: VM, VE, CS, FP, then SC.

CONCLUSIONS

3D printed and milled composite groups showed higher BFS than feldspathic ceramics. When the VHN results were examined, it was seen that the 3D resin groups had the lowest VHN values. Furthermore, it was observed that the thermal cycle had no effect on BFS or VHN.

Comparing the physical and mechanical properties of different biocompatible three-dimensional resin materials in possible use of dental appliances: An in vitro study

OBJECTIVE

This study aimed to assess the colour stability, water sorption, microhardness and water contact angle of two different 3D printing systems (SLA and DLP) in a possible use of producing paediatric and orthodontic dental appliances.

MATERIALS AND METHODS

SLA and DLP printer systems produced a total of 160 disk samples with a diameter of 15.00 mm and a height of 2.00 mm. Colour changes of 64 samples were assessed in distilled water, coffee, coke and cherry juice and Vicker's microhardness tests were also conducted. Solubility and water sorption were held following the water contact angle assessment. Statistical analyses were performed using the SPSS software. Mann-Whitney-U test, Friedman test and Bonferroni post hoc Multiple Comparison Test were performed.

RESULTS

In DLP and SLA groups, coffee had a statistically significant colouring effect regarding the assessment periods (P = .001, 20.09 ± 2.96, 22.09 ± 3.51, respectively), and the discolouration effect of coffee was higher in the SLA group at all endpoints (P < .05). At the same time, DLP was more affected by coke solution in T0-T1 and T0-T7 (P < .05). The values of water sorption showed statistically significant differences in the group of DLP compared to the SLA (P = .01, 121.11 ± 10.54, 92.78 ± 8.70, respectively). No statistical significance was detected between the solubility values and water contact angle of SLA and DLP groups. The SLA printer's microhardness values revealed statistically significantly higher values than the DLP group (P = .001) and a decrease was detected following the immersion period in the microhardness values of the SLA group (P = .022).

CONCLUSION

The compared groups exposed to staining solutions revealed colour changes above the clinically acceptable values at all periods (ΔE00  = 2.25).

Comparison of the Surface Properties of 3D-printed Permanent Restorative Resins and Resin-based CAD/CAM Blocks

OBJECTIVE

This study aimed to investigate the surface roughness, microhardness, and color changes of resin-based computer-aided design/computer-aided manufacturing (CAD/CAM) blocks and 3D-printed permanent resins in different beverages.

METHODS AND MATERIALS

Resin-based CAD/CAM blocks (Cerasmart 270 and Grandio Blocs) and 3D-printed permanent restorative resins (Crowntec and Permanent Crown) were used in this study. A total of 96 specimens were prepared from CAD/CAM blocks and 3D-printed permanent resins. The initial surface roughness, microhardness, and shade value of the specimens were measured. Then, the specimens prepared from each material were divided into three subgroups (n=8) and immersed in tea, coffee, and distilled water for 30 days. After the specimens were immersed in the beverages, the surface roughness, microhardness, and tone values were measured again. The data were statistically analyzed using a two-way analysis of variance test (p<0.05).

RESULTS

No statistically significant difference was found in the surface roughness values of the resin-based CAD/CAM blocks and 3D-printed resins (p<0.05). Resin-based CAD/CAM blocks showed statistically significantly higher microhardness than 3D-printed permanent resins (p<0.05). Although the color changes in 3D-printed resins in tea and coffee were similar to those in resin-based CAD/CAM blocks on the first and seventh days, more color changes appeared in the 3D-printed resins after 30 days. The surface roughness and microhardness values of the specimens submerged in tea, coffee, and distilled water showed no statistically significant changes (p<0.05).

CONCLUSIONS

Although the surface roughness of 3D-printed permanent resins was similar to that of resin-based CAD/CAM blocks, they had a lower microhardness value. Moreover, 3D-printed permanent resins showed more color changes in tea and coffee.