Color stability of recent composite resins

Color Stability of Microhybrid Composite Resins Depending on the Immersion Medium

OBJECTIVE

 The aim of this study was to assess the color stability of two microhybrid composite resins after immersion in different coloring solutions for 4 weeks.

MATERIALS AND METHODS

 Sixty disc-shaped samples (2 mm in thickness and 10 mm in diameter) were prepared according to ISO standard 4049. Two composite resins were used: Filtek Z350 XT (3M ESPE) and Harvard Restore (Harvard Dental International GmbH). After initial color measurements, five samples of each resin were immersed in artificial saliva, Turkish coffee, lemonade, black tea, Coca-Cola 0%, and green tea for 4 weeks. The spectrophotometric measurements were carried out after 24 hours of immersion in the various solutions and then weekly, using a VITA Easyshade Advance 4.0 spectrophotometer (CIE L*a*b* system). Statistical analysis was carried out with SPSS 25.0 software.

RESULTS

 The two composite resins tested revealed discoloration after immersion in all the drinks at a variable immersion period showing different color behaviors. The one-way analysis of variance showed a significant difference in the values of brightness (L), in chromaticity from green to red (a), in chromaticity from blue to yellow (b), and in the color (ΔE) of the two materials at different time intervals. The greatest color change in all the groups was caused by coffee followed by lemonade and black tea followed by green tea, Coca-Cola 0%, and artificial saliva.

CLINICAL SIGNIFICANCE

 The importance of color stability of dental restorations is crucial for dental professionals and patients. Indeed, the quality of a restoration is considered from both a functional and esthetic points of view. The information obtained from this study should prove useful for clinicians to make informed decisions in selecting the best materials for their patients' esthetic restorations.

CONCLUSION

 The Harvard Restore showed a better colorimetric behavior compared with the Filtek Z350. Coffee, black tea, and green tea had the most marked effects on the discoloration of composites, especially on Filtek Z350. Coca-Cola 0% showed a similar behavior to artificial saliva.

Effects of post-polymerization on stainability and surface roughness of 3D printed composite resin

STATEMENT OF PROBLEM

Although the post-polymerization is a necessary step to attain the final properties and color of the 3-dimensionally (3D) printed composite resins, research on its effects on color change and surface roughness is lacking.

PURPOSE

The purpose of this in vitro study was to evaluate the effect of post-polymerization time and additional placement in boiling water on the color change and surface roughness of 3D printed composite resins after exposure to coffee for 30 days.

MATERIAL AND METHODS

Sixty disk-shaped specimens (Ø10×2 mm) were 3D printed with composite resin (Crowntec). The specimens were randomly divided into 6 groups (n=10), according to the post-polymerization process at 3 different times (2×5, 2×10, and 2×20 minutes) and depending on subsequent placement in boiling water. The color differences (ΔE00) between the baseline and each aging period (1, 7, 15, and 30 days) were determined by using a spectrophotometer. After 30-day aging period, ΔL*, Δa*, and Δb* values were calculated. The surface roughness (Ra) was measured at various aging periods (initial, 7, 15, and 30 days) by a 3D noncontact optical profilometer. The data were analyzed using 2-way repeated measures ANOVA and 1-way ANOVA tests for each aging period followed by Tukey tests (α=.05).

RESULTS

As the post-polymerization time increased, a significant decrease was found in ΔE00 values (P<.001), while no significant difference was found in Ra values (P=.554). The values of ΔE00 and Ra increased with the aging period (P<.001). Additional placement in boiling water resulted in a statistically significant decrease in both ΔE00 and Ra values (P<.001). As the post-polymerization time increased, the Δa* and Δb* values decreased, while the negative ΔL* values increased (P<.001), except for Δa* between 2×10 and 2×20 (P=.175). Additional placement in boiling water resulted in a significant decrease in Δa* and Δb* values and an increase in the negative ΔL* values (P<.001), except for Δa* in 2×20 (P=.379).

CONCLUSIONS

An increase in post-polymerization time resulted in reduced stainability, while additional placement in boiling water led to reduced stainability and roughness. When subsequently placed in boiling water, the post-polymerization time had no effect on either stainability or roughness.

The Influence of Thermocycling and Ultraviolet Aging on Surface Characteristics and the Repair Bond Strength of CAD/CAM Resin Nanoceramics

BACKGROUND

The durability of computer-aided design/computer-aided manufacturing (CAD/CAM) resin nanoceramics in the oral environment is influenced by aging factors such as thermocycling and ultraviolet (UV) exposure. This study investigates the impact of these aging processes on surface characteristics and repair bond strength.

METHODS

CAD/CAM resin nanoceramic samples were divided into the following five groups: control (non-aged), 1-year and 5-year thermocycling, and 1-year and 5-year UV aging (n = 12). For the thermocycling procedure, the parameters employed were a temperature range of 5-55 °C with dwell times of 20 s per bath and 10,000 and 50,000 cycles; for the ultraviolet aging process, the parameters were established at a wavelength of 340 nm, an intensity of 0.55 W/m², and durations of 300 h and 1500 h. Surface roughness, microhardness, and repair bond strength were analyzed through profilometry, Vickers microhardness testing, and shear bond strength assessment, respectively. SEM, AFM, and XRD analyses were performed for structural evaluation.

RESULTS

Both thermocycling and UV aging significantly increased surface roughness (p < 0.001) while reducing microhardness and repair bond strength (p < 0.001). UV aging had a more pronounced effect, particularly after five years, leading to the highest surface roughness (Ra: 61.77 μm; Rz: 271.57 μm) and lowest microhardness properties (63.13). EDAX analysis indicated matrix degradation and an increase in inorganic filler exposure.

CONCLUSIONS

Aging significantly affects the surface characteristics of CAD/CAM resin nanoceramics, with UV aging exhibiting the most detrimental impact. These findings highlight the necessity of considering long-term material stability in dentistry.

Evaluation of colour stability, water sorption and solubility of no-cap flowable bulk fill resin composites

BACKGROUND

The aim of this study is to investigate the colour stability, water absorption, and solubility values of low viscosity bulk fill resin composites that do not require an additional layer in comparison with high viscosity and low viscosity bulk fill resin composites used as a base.

METHODS

In the present study, four different bulk fill resin composites were used: Charisma Bulk Flow One (Kulzer), Estelite Bulk Fill Flowable (Tokuyama), X-tra Base (VOCO), Filtek One Bulk Fill (3M ESPE). The resin composites were prepared as disc-shaped samples with a diameter of 5 mm and a thickness of 4 mm, then polymerized using a LED light device (Elipar DeepCureS, 3M ESPE). The samples were kept in artificial saliva and coffee solution for 28 days to determine water absorption, solubility levels and ∆E values, with measurements taken on days 7, 14, 21 and 28. Water absorption and solubility levels were calculated based on ISO4049:2009 specification, and mean colour change values were calculated based on CIEDE2000 formula. Repeated Measures ANOVA, along with post hoc Bonferroni, Tamhane, and Adjusted Bonferroni tests, were used for the statistical evaluation of the data (p < 0.05).

RESULTS

Among all composite groups at all time intervals, Charisma Bulk Flow One composite showed the highest water absorption, solubility, and discolouration values.

CONCLUSION

The water absorption, solubility and discolouration values of the resin composites used in this study were affected by the amount of filler in the resin structure. The clinical applicability of low-viscosity bulk-fill resin composites that do not require an additional capping layer should be carefully reassessed.

Color stability of frequently used aesthetic restorative materials following in vitro exposure to chlorhexidine- and octenidine-based mouthrinses

BACKGROUND

Long-term color match is one of the most important characteristics of aesthetic restorative materials as discoloration constitutes a primary reason for otherwise unnecessary replacements. The aim of the present in vitro study was to evaluate the color stability of frequent dental materials (ceramic, composite, orthodontic adhesive) induced by common antiseptic mouthrinses taking into account black tea consumption and mechanical cleaning.

METHODS

Twenty-four disc-shaped specimens (8 × 2 mm) were made of the materials Ceram.x Spectra™ ST HV, Ceram.x Spectra™ flow, Ceramill® Zolid HT+ PS and Unitek™ Transbond™ LR. Each of the following solutions was tested on six pieces per material: Chlorhexamed forte (CHX), octenident® (OCTD), octenimed® (OCTM) and artificial saliva (control). Dental samples underwent a total of 30 discoloration cycles in which they were alternatively placed into artificial saliva, black tea and respective mouthrinse or only in artificial saliva. After every 10 cycles, discs were mechanically cleaned with toothbrush and toothpaste. After 30 cycles, dental specimens were submitted to professional polishing. Color shifts were measured at different time-points using the VITA Easyshade® V spectrophotometer and displayed as total color difference ∆E (mean ± standard error). A post-hoc Tukey test (⍺ = 0.05) was applied to the mean ∆E values after 30 cycles to determine discoloration discrepancies between various mouthrinses as well as the control. Moreover, photos of individual discs were taken at all measurement times to visualize potential color changes by eye.

RESULTS

All mouthrinses showed major color shifts in the clinically visible range compared to the control on all different dental materials tested. However, CHX caused significantly more discoloration than OCTM and OCTD. Established color changes could be almost completely removed by simple brushing and even further by professional polishing to clinically acceptable levels on all tested materials.

CONCLUSIONS

Prolonged application of antiseptic mouthrinses may cause discoloration on different restorative materials. To maintain aesthetically satisfying conditions, patients should be educated about the importance of daily mechanical tooth brushing and regular professional polishing.

Color adjustment of single-shade composites following staining, repolishing, and bleaching procedures

OBJECTIVE

This in vitro study aimed to assess the color adjustment level of single-shade composites following staining/repolishing and bleaching procedures.

MATERIALS AND METHODS

Cervical cavities in two depths (1 mm and 2 mm) were restored. Three single-shade composites (Omnichroma, OM; Essentia Universal, EU; and Charisma DiamondOne, CDO) and one group-shade composite (NeoSpectraST, NEO) were used (n = 10 for each). Following the thermal aging, half of the restorations were subjected to staining and repolishing procedures, while the other half were subjected to bleaching procedures. The color adjustments between restoration and adjacent tooth surfaces were assessed. The deemed significance was set at < 0.050.

RESULTS

According to the initial measurements, the NEO composite presented the lowest ∆E00 while the OM presented the highest (P = .005 and P = .014). Single-shade composites presented similar and clinically acceptable ∆E00 values (P ≥ .050; AT ≤ 1.8). After the staining, the ∆E00 of the OM was higher among the other single-shade composites (P = .001). Repolishing procedure decreased only the ∆E00 of the NEO composite (P = .020). The bleaching procedure provided no difference for the single-shade composites (P ≥ .050). The increase in the cavity depth decreased the initial color adjustments for the OM in both repolishing and bleaching groups (P = .041 and P = .047).

CONCLUSIONS

Re-polishing after aging and staining may not enhance the single-shade composites' color adjustment level, unlike the group-shade composites. Good color adjustment might be predicted for the single-shade composites after bleaching, unlike the group-shade composites. The effect of the cavity depth was considered composite brand dependent.

CLINICAL SIGNIFICANCE

Clinicians should understand the color adjustment behaviors of the single-shade composites well after different clinical procedures such as staining, re-polishing, and bleaching to perform a proper restorative treatment plan and to obtain better esthetic outcomes.

Surface Roughness and Color Stability of Newly Developed Resin Composites With Color Adjustment Potential After Immersion in Staining Solutions

The aim of this this study was to evaluate the surface roughness and color stability of resin composites (RCs) with color adjustment potential (CAP): Omnichroma (OM), (Tokuyama Dental, Tokyo, Japan); Neo Spectra ST (NS) (Dentsply Sirona, York, PA,USA); and Charisma Diamond One (CD) (Kulzer, Hanau, Germany), compared to a conventional RC, Filtek Z350XT (FZ) (3M ESPE, St. Paul, MN,USA), after immersion in three staining solutions, cola, coffee, and black tea, with distilled water as a control. Forty specimens (8 mm diameter x 2 mm thickness) were prepared for each RC material and divided into subgroups (n=10/group) based on the immersion solution. Surface roughness was measured at baseline and after 21 days of immersion using a non-contact optical profilometer. Color change (ΔE00) was evaluated at baseline, 1, 7, and 21 days with a spectrophotometer. The results showed that FZ demonstrated the lowest surface roughness (0.14), significantly differing from that of the other RCs with CAP (p<0.05), while no significant differences in surface roughness were observed between RCs with CAP (p>0.05). There were no significant changes in surface roughness before and after immersion in various solutions. The results for color change (ΔE00) were statistically significant. Neo Spectra ST showed the lowest tendency for color change, while Filtek Z350XT displayed a moderate potential, and Omnichroma and Charisma Diamond One showed the highest potential for color change.

3D micro-CT and O-PTIR spectroscopy bring new understanding of the influence of filler content in dental resin composites

BACKGROUND

Dental resin composites' performance is intricately linked to their polymerisation shrinkage characteristics. This study compares polymerisation shrinkage using advanced 3D micro-computed tomography (micro-CT) and traditional 2D linear assessments. It delves into the crucial role of filler content on shrinkage and the degree of conversion in dental resin composites, providing valuable insights for the field.

METHODS

Five experimental dental composite materials were prepared with increasing filler contents (55-75 wt%) and analysed using either 3D micro-CT for volumetric shrinkage or a custom-designed linometer for 2D linear shrinkage. The degree of conversion was assessed using Optical Photothermal Infrared (O-PTIR) and Fourier-Transform Infrared (FTIR) spectroscopy. Light transmittance through a 2-mm layer was evaluated using a NIST-calibrated spectrometer. Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDX) examined surface morphology and elemental distribution. Correlation between the investigated parameters was determined using Spearman correlation analyses.

RESULTS

The study found significant differences in polymerisation-related properties among different filler content categories, with volumetric shrinkage consistently demonstrating higher mean values than linear shrinkage across most groups. Volumetric shrinkage decreased with increasing curing depth, showing no direct correlation between filler content and shrinkage levels at different curing depths. The results highlighted a strong negative correlation between filler content and degree of conversion, volumetric and linear shrinkage, as well as maximum shrinkage rate. Light transmittance showed a moderate correlation with the filler content and a weak correlation with other tested parameters.

CONCLUSIONS

This study underscores the importance of considering both volumetric and linear shrinkage in the design and analysis of dental composite materials. The findings advocate optimising filler content to minimise shrinkage and enhance material performance. Integrating micro-CT and O-PTIR techniques offers novel insights into dental composites' polymerisation behaviour, providing a foundation for future research to develop materials with improved clinical outcomes.

Evaluation of Long-term colour resistance of composite materials used in aligner treatments: A comparative study

AIM

The aim of this study is to evaluate the discolouration resistance of attachments made of composites having different physical properties, filler ratios and viscosity through the simulated environment and conditions.

MATERIALS AND METHODS

Seventy-two extracted human teeth were aligned to simulate upper and lower dental arches. The attachments were prepared according to the guides determined by ClearCorrect. Three different composite groups were used for attachments preparation: Aligner Connect, G-Aenial Universal Injectable, and Tetric Prime and Tetric Evoflow combination. Dental models and aligners were kept in artificial saliva throughout the experiment of 96 weeks. The aligners were also subjected to 2308 thermal cycles and insertion and removing procedures 840 times for each period of 12 weeks. Afterwards, the models were kept in coffee and red wine solutions. Colour measurements were made with Vita Easy Shade 4.0 at 12th, 24th, 48th and 96th simulated weeks.

RESULTS

No significant difference in discolouration was observed during thermal cycle application of 12th and 24th week experimental periods. In the later periods, discolouration was observed in the composite materials, and G-Aenial Universal Injectable was less coloured than the other samples. The composite samples were more coloured in proportion to their residence time. The G-Aenial Universal Injectable was more affected by wine solution, and Tetric Prime and Tetric Evoflow combination were more affected by coffee solution.

CONCLUSIONS

Viscosity, resin matrix content and nature of inorganic filler particles of the composite materials significantly affect the colour changing properties of them due to the long-term ageing and exposure to colouring agents.

The color stability of artificial white spot lesions treated with resin infiltration after exposure to staining beverages

BACKGROUND

To evaluate the effect of staining beverages on the color-changing of resin-infiltrated artificial white spot lesions (WSLs).

METHODS

Thirty-five artificial WSLs were created by pH cycling on flat bovine teeth specimens. The WSLs were treated with resin infiltration and were divided into five groups based on staining beverages: artificial saliva, coffee, wine, green tea, and Coca-Cola. These specimens were subjected to a 28-day exposure to the respective beverages. Color stability was assessed using a spectrophotometer at different time points: baseline, after 7, 14, 21, and 28 days of exposure, and repolishing. The color difference (∆E) between each time point and the baseline was calculated. Statistical analysis was performed using two-way measures ANOVA with a significance level of p = 0.05.

RESULTS

All resin-infiltrated specimens exposed to staining beverages for 7 days exhibited more significant color changes than those exposed to artificial saliva. The color change patterns varied based on the type of beverage. The color alterations intensified with extended immersion in the wine and Coca-Cola groups, while there were no significant differences in the color of specimens after 28 days of immersion in the coffee and green tea groups. However, after cleaning with pumice powder, all specimens showed significantly reduced color changes compared to those observed after 28 days of immersion, except those immersed in coffee.

CONCLUSIONS

Exposure of resin-infiltrated bovine tooth specimens to staining beverages resulted in a significant color alteration as the immersion time increased. However, the staining effect could be minimized by cleaning with pumice powder, except for the coffee group.

CLINICAL RELEVANCE

After resin infiltration treatment, patients should be advised to minimize the consumption of colored beverages to prevent staining that could impact esthetic appearance.

Microscopic and Color Changes in Direct Dental Restorative Composite Resins upon Immersion in Beverages: Characterization by Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS)

This study aimed to evaluate the staining sensitivity and surface changes in recent composite resins (Herculite Ultra XRV (Kerr, Bolzano, Italy), G-ænial A'CHORD (GC Corp, Tokyo, Japan), and Omnichroma (Yamaguchi, Japan)) when exposed to common beverages such as coffee, red wine, and Coca-Cola. A total of 60 disk-shaped specimens were prepared from three different resin composites (n = 20 each). The specimens were exposed to coffee, red wine, and Coca-Cola for 10 days. Color measurements were taken using a spectrophotometer, and surface morphology and elemental composition were analyzed using SEM and EDS. The SEM and EDS analyses revealed significant changes in the surface morphology and elemental composition of the composites after immersion. Coffee and wine caused significant surface degradation, whereas Coca-Cola resulted in the greatest degree of surface and elemental variations. Color changes (ΔE = 4 ± 0.52) were most notable in Coca-Cola for Herculite Ultra XRV (Kerr, Italy), in red wine for G-ænial A'CHORD (GC Corp, Japan) (ΔE = 12.51 ± 0.38), and in coffee for Omnichroma (Yamaguchi, Japan) (ΔE = 10.85 ± 1.03). The tested beverages significantly affected both the surface condition and the chemical composition of the resin at the surface level. These findings highlight the importance of understanding the effects of common dietary beverages on dental composites.

Can discolored dental composites be bleached in depth?

Objectives

Previous in vitro studies determined the whitening effects of bleaching products on stained resin composite surfaces. This in vitro study aimed to verify the effectiveness of a whitening system on composite resin previously subjected to pigmentation, specifically examining the depth of whitening effectiveness within the material structure.

Materials and Methods

A commercially available nano-filled composite resin was used. Specimens were stained using a coffee-based solution and a 10% carbamide peroxide-based gel was employed as the whitening agent. The pigment's penetration and the effect of the bleaching gel were evaluated by measuring color (CieLab values) from the outer edge to the inner part of the specimens. Color measurements were taken at 14 points, starting from 0.1 mm from the external perimeter up to 3.0 mm.

Results

Analysis of variance tests showed a statistically significant difference between the Control Group (CG), Pigmentation Group, and Whitening Group. The whitening agent was effective up to 1.5 mm in depth, with Whiteness index (W) values not statistically different from those of CG up to 0.5 mm in depth.

Conclusions

Whitening agents on nano-filled resin composite previously pigmented appear effective in restoring the W to values similar to the original, particularly in the superficial layers of the sample.

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.

Quantification of Color Variation of Various Esthetic Restorative Materials in Pediatric Dentistry

Aim of study

The goal of this paper is to find an association between the staining capacity of dental restorations used in pediatric patients and food items and to develop an optimum model to predict the most informative factor that causes the highest amount of color change through machine learning algorithms.

Background

Color changes in restorative materials occur as a result of intrinsic and extrinsic factors, such as the type of restorative material, food items used, polished status of the material, and time interval.

Materials and methods

This was an "in vitro study" conducted at Aligarh Muslim University, Aligarh, Uttar Pradesh, India. The study included 200 specimens, that is, 40 in each group A (orange juice), group B (Amul Kool Café), group C (Pepsi), group D (Amul Kesar Milk), and group E (artificial saliva). The materials were glass ionomer cement (GIC), resin-modified glass ionomer cement (RMGIC), microhybrid composite resin, and nanohybrid composite resin. These were further divided into polished and unpolished groups. The optimum modeling of the prediction of color change in materials by different effective factors was done by machine learning decision tree. We applied two algorithms: Chi-square automatic interaction detector (CHAID) and classification and regression tree (CART). In prediction modeling in the decision tree by CHAID and CART, color change is taken as the dependent variable, and group (type of restorative material), food items, time interval, and polished status are taken as independent variables.

Results

The various beverages caused significant color variation due to different pigmentation agents. The agent that caused the highest color change was Kool Café. The Kesar Milk had the lowest pigmentation capacity. The greatest color variation was found on Glasionomer FX-II submerged in Pepsi and the least on Ivoclar Te-Econom Plus in Kesar Milk. The mean absolute error for the training dataset in the CART model and CHAID model is 0.379 and 0.332, and for the testing data set, it is 0.398 and 0.333, respectively. Therefore, the prediction of color change by the CHAID model is optimum, and we found that the restorative materials have a maximum predictor importance of 0.86 (86%), time interval 0.07 (7%), food items 0.04 (4%), and polished status has the least importance, that is, 0.03 (3%).

Conclusion

The staining capacity of restorative material highly depends on the material itself, the initial time interval, and least on the food items used.

Clinical significance

The clinical performance of dental restorations could be affected by various beverages consumed by children. This study thus provides important clinical insights into esthetic dentistry by offering valuable information on long-term color stability and the effect of polishing on common esthetic restorative materials used in pediatric dentistry.

How to cite this article

Varshney P, Khan SY, Jindal MK, et al. Quantification of Color Variation of Various Esthetic Restorative Materials in Pediatric Dentistry. Int J Clin Pediatr Dent 2024;17(7):754-765.

The effect of various inhaled asthma medications on the color stability of paediatric dental restorative materials

BACKGROUND

The purpose of the study is to analyse the effects of different inhaled asthma medications (IAMs) on the color change of dental restorative materials (DRMs).

METHODS

In total, 192 samples were taken from six different DRMs: [Filtek Z550 (nanohybrid composite), Fusio Liquid Dentin (Self-adhering flowable composite), Filtek Ultimate (nanofilled flowable composite), Dyract XP (compomer), Fuji II LC (resin-modified glass ionomer), Fuji IX Fast (self-cured-packable glass ionomer), (n = 32)]. After the initial color values (CIELab) of DRMs were measured by using a spectrophotometer, each sample was exposed to the same IAMs via nebulizer according to the four different inhaled therapies and measurements were repeated on the 7th & 21st days.

RESULTS

In all IAM groups, DRM with the least amount of ΔE was nanohybrid composite, while the highest ΔE was found in Fuji II LC. Among all experimental groups, only Fuji II LC which was administered the combined medication, exceeded the clinically unacceptable threshold (ΔE = 3.3) on 7th & 21st days.

CONCLUSIONS

Consequently, important factors affecting the susceptibility to color stability are the type of IAMs, the administration time-dosage, and the type of DRMs.

Assessment of physical/mechanical properties and cytotoxicity of dual-cured resin cements containing Sr-bioactive glass nanoparticles and calcium phosphate

The aim was to develop dual-cured resin cements containing Sr-bioactive glass nanoparticles (Sr-BGNPs; 5 or 10 wt%) and monocalcium phosphate monohydrate (MCPM; 3 or 6 wt%). Effects of additives on degree of monomer conversion (DC), biaxial flexural strength/modulus, shear bond strength (SBS), mass/volume change, color stability, ion release, and cytotoxicity were examined. Controls included material without reactive fillers and Panavia SA Plus (PV). Experimental cements showed higher DC than PV regardless of light activation (p<0.05). Mean SBS and color stability were comparable between experimental cements and PV. Cell viability upon the exposure to sample extracts of experimental cements was 80%-92%. High additive concentrations led to lower strength and modulus than PV (p<0.05). The additives increased mass change, reduced color stability, and promoted ion release. The experimental resin cements demonstrated acceptable mechanical/chemical properties and cytotoxicity. The additives reduced the strength but provided ion release, a desirable action to prevent recurrent caries.

Color match analysis of single-shade and multi-shade composite resins using spectrophotometric and visual methods after bleaching

The aim of this study is to evaluate the color match of the materials after the staining and bleaching procedures applied to the teeth restored with single-shade and multi-shade composite resins. Cavities prepared on the facial surface of human incisors were restored with two different composite resins. After 24 h, the color matching parameters between the initial filling-tooth of the samples were recorded. Then, the color measurements of the samples subjected to the coloring process were repeated. Each composite resin group was randomly divided into 2 subgroups and home and office bleaching methods were applied to the samples. After bleaching, color measurements were repeated. In terms of periods, a statistically significant difference was found in ΔE values 1 day and 28 days after bleaching (p<0.05). In addition, it was found that the color match between filling-tooth was generally weaker in Omnichroma material and after home bleaching.

An in vitro assessment of biaxial flexural strength, degree of monomer conversion, color stability, and ion release in provisional restorations containing Sr-bioactive glass nanoparticles

This study examined the mechanical and chemical properties of an experimental provisional restoration containing Sr-bioactive glass nanoparticles (Sr-BGNPs) compared to commercial provisional materials. The experimental material (TempS10) contained dimethacrylate monomers with added 10 wt% Sr-BGNPs. The degree of monomer conversion (DC) of self-curing (n = 5), biaxial flexural strength (BFS)/modulus (BFM) (n = 5), and color changes (ΔE*00) of materials in red wine (n = 5) were determined. Additionally, ion release (Ca, P, and Sr) in water at 2 weeks was examined (n = 3). The commercial materials tested included polymethyl methacrylate-based provisional material (Unifast) and bis-acrylic materials (Protemp4 and Cooltemp). TempS10 exhibited a comparable degree of monomer conversion (49%) to that of Protemp4 (60%) and Cooltemp (54%) (p > 0.05). The DC of Unifast (81%) was significantly higher than that of other materials (p < 0.05). TempS10 showed a BFS (126 MPa) similar to Cooltemp (102 MPa) and Unifast (123 MPa), but lower than Protemp4 (194 MPa). The immersion time for 2 weeks exhibited no detrimental effect on the strength and modulus of all materials. The highest ΔE*00 at 24 h and 2 weeks was observed with TempS10, followed by Cooltemp, Unifast, and Protemp4. Only TempS10 showed a detectable amount of Ca (0.69 ppm), P (0.12 ppm), and Sr (3.01 ppm). The experimental provisional resin restoration containing Sr-BGNPs demonstrated polymerization and strength comparable to those of bis-acryl provisional restorations but with the added benefit of ion-releasing properties. However, the experimental material demonstrated unsatisfactory color stability.

Evaluation of the color stability of attachments made with different resin composites

INTRODUCTION

Coloring solutions-such as coffee and cola, frequently consumed daily-cause coloration of attachments made with resin composites. This may reduce the motivation for clear aligner treatment, often preferred by patients with esthetic concerns. This study aimed to compare color changes of orthodontic attachments made with 3 different composite resins.

METHODS

A total of 90 premolar teeth (n = 10) extracted for orthodontic reasons were used. All teeth were embedded in plaster models to imitate the arch shape and scanned with an intraoral scanner. Horizontal rectangular attachments were placed on each tooth by printing the attachment template obtained using digital models. Three composite resins: Omnichroma, GC Aligner Connect, and Tetric PowerFlow were used to prepare the attachments. The models prepared in arc-shaped in each composite group were divided into subgroups and kept in 3 different solutions (coffee, cola, and distilled water) in the incubator at 37 ± 1°C. The models were photographed at baseline and 28 days later with the Smile-Lite MDP device. L, a, and b values were obtained with Digital Color Meter (version 5.22; Apple, Cupertino, Calif). CIEDE2000 formula (ΔE00) was used to evaluate color changes. In addition, models were scanned for color determination at baseline and 28 days later with the 3Shape intraoral scanner.

RESULTS

There were significant color differences between solutions (P <0.05).

CONCLUSIONS

Attachments can be colored easily. Patients should be warned against coloring solutions at the beginning of the treatment, and their eating and drinking habits should be regulated.

Color stability and degree of conversion of gingiva-colored resin-based composites

OBJECTIVES

To evaluate gingiva-colored resin-based composites' (GCRBC) color stability and degree of conversion (DC%).

METHODS

Eight discs (8 × 1 mm) of 20 shades of GCRBC were prepared. Color coordinates were measured against a gray background with a calibrated spectroradiometer, CIE D65 illuminant and the CIE 45°/0° geometry at baseline and after 30 days of storage in distilled water, coffee, and red wine. Color differences ( ∆ E 00 ) between final and baseline conditions were calculated. An ATR-FTIR spectrometer with a diamond tip was used to calculate DC%. The results were analyzed statistically using ANOVA and Tukey post-hoc test. The level of significance was p < 0.05.

RESULTS

DC% and color stability correlated with each other and with the GCRBC brand. DC% ranged between 43% and 96%, highest values correspond to flowable composites. All composites have experienced color changes after immersion in water, wine and coffee. However, the magnitude of the color change has varied widely depending on the immersion medium and the GCRBC. Color changes generated by the wine were, globally, greater than those induced by coffee (p < 0.001) and above the acceptability thresholds.

CONCLUSIONS

The DC% of GCRBCs is sufficient to achieve adequate biocompatibility and physicomechanical properties, but the high susceptibility to staining could compromise aesthetic long-term results.

CLINICAL SIGNIFICANCE

The degree of conversion and the color stability of gingiva-colored resin-based composites correlated with each other. All composites have experienced color changes after immersion in water, wine and coffee. Color changes generated by wine were, globally, greater than those induced by coffee and above the acceptability thresholds that could compromise aesthetic long-term results.

Effect of immersion and thermocycling in different beverages on the surface roughness of single- and multi-shade resin composites

BACKGROUND

Resin composite restorations are highly esthetic restorations, which should have and maintain high surface polish. However, esthetic restorations are subjected to different beverages at variable temperatures, which may affect their surface roughness. This study aimed to evaluate the surface roughness of single-shade (Omnichroma) and multi-shade (Filtek Z350XT) composite materials, following aging by immersion and thermocycling in different beverages, simulating one year of clinical service.

METHODS

Thirty specimens of each material were prepared and divided into 6 subgroups (n = 5). In each material, the grouping of the specimens was as follows: the first subgroup was the as-prepared specimens stored dry without immersion or thermocycling. The second, third, and fourth subgroups were immersed in saliva, tea, and red wine, respectively, for 12 days at 37 °C. The fifth and sixth subgroups were thermocycled for 10,000 cycles, in tea (the fifth between 37 and 57 °C) and in red wine (the sixth between 37 °C and12°C). The resultant surface roughness was measured by two different methods, stylus profilometer and atomic force microscopy (AFM). Intergroup comparison was performed using independent t test, while intragroup comparison was performed using one-way analysis of variance (ANOVA) followed by Tukey's post-hoc test.

RESULTS

Intergroup comparison between both composites showed no statistically significant differences in all groups using the stylus profilometer roughness measurements (P>0.05), while the AFM measurements showed significant difference (P ≤ 0.05) within all storage media except the as-prepared control (P = 0.0645), where nanofilled Filtek Z350 XT showed lower nano-roughness. Intragroup comparison data were variable, depending on the material, aging conditions, and roughness assessment tool. However, the resultant average surface roughness (R_a) values in all groups did not exceed the threshold value of R_a 0.2 μm.

CONCLUSIONS

Both resin composites attained and retained a clinically acceptable surface finish after immersion and thermocycling in different beverages.

In Vitro Evaluation of Tooth-Whitening Potential of Peroxide-Free OTC Dental Bleaching Agents

Purpose: To evaluate and compare the tooth-whitening potential of five over-the-counter (OTC), peroxide-free dental bleaching methods as well as an experimental tooth-whitening solution containing 0.1% hydrogen peroxide complexed with doping agents with a gold standard (positive control) containing 16% carbamide peroxide. Material and Methods: Eighty permanent bovine incisor teeth were randomly allocated to eight different groups. Two teeth from each group were immerged into five staining solutions represented by coffee, tea, red wine, and curry mixed in warm oil or distilled water (control group) and stored at 37 °C for 28 days in an incubator. The teeth were then reallocated to the eight groups, resulting in ten samples per group, and each group was matched with a bleaching product. The bleaching procedures were executed following the manufacturer’s recommendations. The color of each sample was assessed over a white and black background using a quantitative numerical measurement approach with a calibrated spectrophotometer. Spectrophotometric measurements were performed after exposing the teeth to the bleaching agent for 60 min (T2), 100 min (T3), and 200 min (T4), and ΔE00 was calculated. Results: When analyzed over a white background, the mean ΔE00 values ranged from 2.14 (placebo) to 6.32 (Opalescence PF). When analyzed over a black background, the mean ΔE00 values ranged from 2.31 (placebo) to 5.78 (Opalescence PF). Statistically significant ΔE00 color changes over time for the eight groups and five staining solutions at T1 and T4 were assessed for both backgrounds using repeated ANOVA followed by Fisher’s LSD post hoc test (p-value < 0.01). Conclusions: All tested over-the-counter whitening kits except one exhibited positive color variation. However, the individual performance differed vastly from one brand to the other, and the overall performance was less effective compared to the conventional carbamide-peroxide-based positive control.

Effect of two artificial aging protocols on color and gloss of single-shade versus multi-shade resin composites

The long-term color stability and gloss retention of resin composites are among the crucial factors that affect the clinical longevity of esthetic restorations, especially in anterior teeth. This study evaluated the effect of artificial aging by immersion in different storage media and thermocycling on color and gloss of dental single-shade resin composite (Omnichroma) versus multi-shade one (Filtek Z350XT). One hundred resin-composite disc-shaped specimens were used, 50 from each group, Omnichroma and Filtek Z350XT. Ten specimens from each material acted as control group (incubated in saliva). For each material, 40 specimens were divided according to the artificial-aging protocol (immersion at 37 °C for 12 days or thermocycling for 10,000 cycles) and storage media (tea, red wine). Color and gloss were measured before and after artificial aging. Color difference (∆E₀₀) was compared with perceptibility threshold and acceptability threshold. Data were statistically analyzed; independent t test was used to compare results between two tested materials, while two-way ANOVA was used to compare results among the different immersion media within the same material. Artificial aging (immersion or thermocycling) in tea and red wine led to significant color changes and gloss reduction in both materials (P < 0.05), in contrast to control group. Red wine produced highest color differences. Both dental resin-composites; the single-shade (Omnichroma) and multi-shade (Filtek Z350XT) displayed unacceptable discoloration and gloss reduction after artificial-aging in tea and red-wine by immersion or thermocycling simulating one-year clinical-service.

Evaluation of the Color Stability, Water Sorption, and Solubility of Current Resin Composites

This study aims to assess the color stability, water sorption, and solubility of 11 resin composites as commercially available dental products. Twenty samples (10 mm in diameter and 2 mm in thickness) of each material were fabricated using a customized silicone mold, followed by immersion in each of curry, coffee, wine, and distilled water for 28 days (n = 5). Baseline shade and color changes (ΔE) were measured using a reflection spectrophotometer. The CIE L*, a*, b* system was used to evaluate the color changes. Five samples of each resin composite were applied to test water sorption and solubility according to ISO 4049:2009. As a result, the ∆E values were significantly influenced by each of the three factors (composition of material, solution, time) and the interactions between them (p < 0.001). Highest resistance to discoloration was achieved by Ceram.X One Universal (CXU), followed by Magnafill Putty (MP). Generally, microhybrid composites showed fewer color changes than nanohybrid composites and giomers. DX. Universal and Filtek Z350 XT showed the highest ΔE values in all colorants. All materials tested in this study fulfilled the criteria of ISO 4049:2009; CXU and MP had the lowest water sorption and solubility. The Pearson test showed statistically significant positive correlations between water sorption and ΔE and between solubility and ΔE.

The effect of bleaching applications on stained bulk-fill resin composites

Background

The structure of bulk-fill resin composites differs from that of their conventional counterparts, but how this difference affects the color stability of the former after staining and bleaching is unclear. Accordingly, this study was aimed at investigating color change in nine bulk-fill resin composites and one nanohybrid resin composite treated with hydrogen peroxide and carbamide peroxide after staining with tea, coffee, and red wine.

Methods

Eighty specimens were prepared from each resins [Clearfil Majesty Posterior (CMP), SDR flow⁺ (SDR), Filtek^TMBulk-Fill Flowable Restorative (FBF), Reveal HD Bulk (RHD), Beautifil-Bulk Restorative (BBR), Tetric EvoCeram® Bulk Fill (TEC), SonicFill™2 (SF2), everX Posterior™ (eXP), X-tra base (XB), and Venus® Bulk Fill (VBF)]. Following baseline color measurements, the specimens were randomly divided into 4 groups according to immersion solutions and distilled water as the control. At the end of a 30-day test period, color measurements were repeated, and color change values (∆E₀₀) were calculated. Each resin group was then divided into 2 subgroups (with 10 specimens per group) on the basis of bleaching agent (Opalescence Boost 40%, Opalescence PF 16%). Following bleaching application, ∆E₀₀ and changes of whiteness (∆WI_D1 = WI_Dbleaching-WI_Dbaseline, ΔWI_D2 = WI_Dbleaching-WI_Dstaining) values were recorded. Two- and three-way analyses of variance and Tukey’s post hoc test were performed, with a P < 0.05 regarded as indicative of significance.

Results

After immersion in distilled water, tea, and red wine, the highest ΔE₀₀ values were observed in eXP (P < 0.05). Resin materials immersed in coffee and tea exhibited statistically higher ∆E₀₀ values than those immersed in red wine except for eXP, TEC, and FBF (P < 0.05). For eXP, the highest ∆E₀₀ values were recorded in distilled water. For TEC and FBF, there was no statistically significant difference among the immersion solutions and distilled water (P > 0.05). For all the resins and staining beverages, no statistically significant difference in ∆WI_D1 and ∆WI_D2 values were detected between bleaching agents (P > 0.05). All the ΔWI_D1 values were above the whiteness perceptibility threshold.

Conclusion

The bulk-fill materials were more resistant to discoloration and bleaching procedures than the conventional resin composites. Coffee and tea caused more staining than distilled water and red wine generally. The type of bleaching procedure had no effect on the whiteness of the tested materials.

Effect of different surface treatments on the microhardness and colour change of artificial enamel lesions

BACKGROUND

To investigate the effect of three different surface treatments on the microhardness and colour change of artificial enamel lesions.

MATERIALS AND METHODS

One hundred bovine teeth were randomly assigned into four groups. Artificial enamel lesions were created using demineralizing solution for all groups except the sound enamel group. Different surface treatments were then performed G1: resin-infiltrant; G2: Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP); G3: artificial saliva; G4: Sound Enamel. Each group was subdivided into three subgroups, where each subgroup was subjected to a different testing method. Subgroup 1: surface microhardness; subgroup 2: cross-sectional microhardness; subgroup 3: colour measurement. Statistical analysis was performed by ANOVA, followed by Tukey's post hoc test.

RESULTS

Sound enamel group recorded the highest surface and cross-sectional microhardness results. No significant difference was found between the resin-infiltrant group and CPP-ACP regarding surface and cross-sectional microhardness at different lesion depths. Resin-infiltrant group showed the least colour change (∆E) results compared to the other groups.

CONCLUSION

Resin-infiltrant can effectively enhance surface microhardness and enamel resistance to demineralization, additionally, reduces the staining susceptibility of white spot lesions (WSLs) after treatment. CPP-ACP application for 4 weeks seems to improve surface microhardness; however, has a limited effect in resisting staining of WSLs after treatment. © 2022 Australian Dental Association.

Stain Susceptibility of Composite Resins: Pigment Penetration Analysis

Composite resins are considered the material of choice for esthetic direct restorations, considering both their satisfying esthetic and mechanical properties. The success of composite resin restorations depends highly on their color stability. Discoloration causes color mismatch, consequent patient dissatisfaction, and eventually additional costs for correction/replacement of the restoration. The purpose of this study was to evaluate the degree of pigment penetration within the composite resins, in order to understand how discoloration can be treated properly. Two different commercially available composite resins were compared in the study: a nano-filled composite resin and a non-homogeneous micro-hybrid composite resin. A coffee solution was used to induce staining of the materials. Subsequently, the penetration of the pigments was measured by analyzing the color from the outside to the inside of the specimen. 14 levels were analyzed starting from 0.1 mm to 3.0 mm in depth. The ANOVA test demonstrated a statistically significant difference (p < 0.0001) between test and control groups up to a depth of 1.0 mm for the nano-filled composite and up to a depth of 2.0 mm for the non-homogeneous micro-hybrid composite. The two composite resin materials, subjected to pigmenting treatment, underwent a color variation with different patterns.

ANTİ-HALİTOSİS GARGARALARININ REZİN BAZLI RESTORATİF DENTAL MATERYALLERİN YÜZEY ÖZELLİKLERİ ÜZERİNE ETKİSİ

Amaç: Bu in-vitro çalışmanın amacı anti-halitosis etkili beş farklı ağız gargarasının iki farklı restoratif materyalin renk stabilitesi ve yüzey pürüzlülüğü üzerine olan etkisinin araştırılmasıdır. Gereç ve Yöntemler: Çalışmada nano-hibrit (Filtek Z550, 3M ESPE) ve giomer (Beautifill II, Shofu Dental) yapıda olan iki çeşit reçine bazlı restoratif materyal kullanılmıştır. Her iki materyalden test edilmek üzere toplam 120 adet kompozit disk üretici talimatları doğrultusunda 10x2mm ebatlarında silindir kalıplar kullanılarak hazırlanmıştır. Rastgele seçilen örnekler, 5 farklı ağız gargarası (Listerine Fresh Burst, Listerine Total Care, Colgate Plax, Oderol, Halitosil) ve 1 kontrol grubunda (distile su) bekletilmek üzere toplam 6 farklı gruba ayrılmıştır. Başlangıç renk koordinatları CIELAB renk sistemine göre spektrofotometre (Easyshade Compact) ile yüzey pürüzlülük değerleri (Ra) ise kontakt profilometre (Surtronic 25) ile ölçülmüştür. Tüm örnekler 37°C'de ağız gargaralarında 12boyunca bekletilmiş ardından renk ve pürüzlülük ölçüm prosedürleri aynı şekilde gerçekleştirilmiştir. Elde edilen veriler SPSS 24.0 programı ile Kruskal-Wallis H ve Bonferroni Post Hoc testleri kullanılarak 0.05 anlamlılık düzeyinde analiz edilmiştir. Bulgular: Bu çalışmanın sonuçları, yüzey pürüzlülük değerlerinde istatistiksel olarak anlamlı bir artış olmadığını göstermiştir. Ağız gargaralarında bekletilen Beautifil II materyallerinin tamamında CIELAB değerlerinde önemli bir değişiklik olmuştur (P

Effects of Sr/F-Bioactive Glass Nanoparticles and Calcium Phosphate on Monomer Conversion, Biaxial Flexural Strength, Surface Microhardness, Mass/Volume Changes, and Color Stability of Dual-Cured Dental Composites for Core Build-Up Materials

This study prepared composites for core build-up containing Sr/F bioactive glass nanoparticles (Sr/F-BGNPs) and monocalcium phosphate monohydrate (MCPM) to prevent dental caries. The effect of the additives on the physical/mechanical properties of the materials was examined. Dual-cured resin composites were prepared using dimethacrylate monomers with added Sr/F-BGNPs (5 or 10 wt%) and MCPM (3 or 6 wt%). The additives reduced the light-activated monomer conversion by ~10%, but their effect on the conversion upon self-curing was negligible. The conversions of light-curing or self-curing polymerization of the experimental materials were greater than that of the commercial material. The additives reduced biaxial flexural strength (191 to 155 MPa), modulus (4.4 to 3.3), and surface microhardness (53 to 45 VHN). These values were comparable to that of the commercial material or within the acceptable range of the standard. The changes in the experimental composites' mass and volume (~1%) were similar to that of the commercial comparison. The color change of the commercial material (1.0) was lower than that of the experimental composites (1.5-5.8). The addition of Sr/F-BGNPs and MCPM negatively affected the physical/mechanical properties of the composites, but the results were satisfactory except for color stability.

Color stability of resin-based composites: Staining procedures with liquids-A narrative review

OBJECTIVE

The objective of this study was to review the experimental staining procedures performed in in-vitro studies for evaluating color stability of resin-based composites used for direct restorations.

OVERVIEW

A review was performed with the purpose to identify in vitro procedures carried out to establish staining and color stability of resin-based composites used for direct restorations. A literature search was performed on four online databases (PubMed, Scopus, Embase and Web of Science) for articles published from January 1st 2001 till March 20th 2021, using a combination of free words and Medical Subject Headings (MESH) terms: "Composite Resins" AND "Color Stability" OR "Staining." Two reviewers screened titles and/or abstracts of 1728 unique studies. In total, 208 studies were selected for full-text reading, from which 178 were included in the review. The assessed variables were specimen dimensions, shape, and surface finishing; time before immersion; staining media type, dwell time, temperature and renewal interval; type of composite; color and translucency assessment parameters and measuring system. One hundred and seventy-eight articles analyzed color stability with staining liquids. Coffee was the most used staining medium (n = 102), followed by tea (n = 61), and red wine (n = 55). A disc-shaped specimen was used in most studies (n = 170) with a 2 mm thickness (n = 116). Spectrophotometers were the most used color assessment devices (n = 154), followed by colorimeters (n = 17). Color differences were quantified with ΔE (n = 154), ΔE00 (n = 23). Acceptability and or perceptibility thresholds were also taken into consideration (n = 126).

CONCLUSIONS

The large variety of staining procedure suggests the need for standardization.

CLINICAL SIGNIFICANCE

Aesthetic failure due to discoloration is a relevant clinical problem. Evaluating benefits and drawbacks of resin based composites artificial staining procedures will improve to predict materials clinical performances.

Evaluation of color stability and microhardness of contemporary bulk-fill composite resins with different polymerization properties

OBJECTIVES

To determine the color stability and microhardness of three bulk-fill composites with different polymerization characteristics, after immersion in four different solutions.

MATERIALS AND METHODS

Color measurements of three bulk fill (Viscalor (VIS), Tetric PowerFill (TPF), Fill Up! (FUP)) and a microhyrid composite resin (G-aenial posterior [GCP]) were performed after polymerization. The specimens were immersed in coffee, cola, red wine and distilled water. Discolorations were recorded after 24 h (T1), 10 days (T2) and 30 days (T3) of immersion. ΔE (CIEDE2000) values were calculated. Vickers microhardness (VHN) was measured from top and bottom surfaces at T0 and T3. Data was analyzed with Two-way ANOVA, One-way ANOVA and Tukey post hoc tests.

RESULTS

The highest discoloration was seen in wine and the lowest in distilled water and cola. At T3, there was no difference in distilled water groups, while the statistically highest ΔE₀₀ were obtained in TPF and GCP in coffee, cola and wine. VIS groups had the highest VHN values at T0 and T3 in all solutions.

CONCLUSIONS

Samples immersed in coffee and wine showed discoloration beyond clinically acceptable limits. After 30 days, discoloration occurred in all materials immersed in all solutions. At T3, VIS microhardness generally decreased, while TPF did not.

CLINICAL SIGNIFICANCE

After 30 days, all bulk-fill composites immersed in distilled water, coffee and wine showed clinically unacceptable ΔE₀₀ .

Effects of storage and toothbrush simulation on color, gloss, and roughness of CAD/CAM, hand-cast, thermoforming, and 3D-printed splint materials

Objectives

The aim was to investigate color, gloss, or roughness of splint materials after storage in liquids and toothbrush simulation.

Materials and methods

A total of 58 × 8 (n = 10 per material and group) specimens were fabricated (hand-cast, thermoforming, CAD/CAM-milled, 3D-printed materials); stored in air, water, coffee, red wine, and cleaning tablets; and investigated after fabrication, 24 h, two-, and four-week storage or toothbrushing. Color values (L*, a*, b*; ISO 11664–4:2008; CM–3500d, Konica-Minolta), gloss (ISO 2813:2014), and roughness values were determined (3D laser-scanning-microscope, KJ 3D, Keyence) before and after simulation or storage. Statistics: Levene-test, one-way ANOVA, Bonferroni post hoc test, between-subjects effects, Pearson correlation (α = 0.05).

Results

Color, gloss, and roughness altered due to contact with staining solutions/toothbrush simulation. Highest impact on color, gloss, and roughness presented the material followed by storage time (ΔE material (η2 = 0.239/p < 0.001), storage time (η2 = 0.179/p < 0.001); gloss (η2 = 0.751/p < 0.001) (η2 = 0.401/p < 0.001); Ra/Rz (η2 ≥ 0.801/p < 0.001) (η2 ≥ 0.416/p < 0.001)). Correlations were found between Rz and Ra (Pearson 0.887/p ≤ 0.001) or Rz and ΔE (0.517/p ≤ 0.001) or Ra and ΔE (0.460/p ≤ 0.001).

Conclusions

Storage and toothbrushing were accompanied by a change in color, gloss, and roughness. Almost all materials showed visible discoloration after 4 weeks of storage. Gloss values decreased as storage time increased. The initial roughness and polishability were better with harder materials.

Clinical relevance.

Milled and 3D printed splints show good color, gloss, and roughness resistance after 4-week storage or toothbrush application.

Color stability of resin composites for orthodontic attachments: an in vitro study

Objective:

The aim of the present study was to evaluate the color stability of Filtek Z350 XT, Filtek Z250 XT, Z100 resin composites and Transbond XT orthodontic resin, all used in orthodontic attachments, when immersed in popular beverages.

Methods:

Thirty disk-shaped specimens of each resin composite (2 x 5mm) were manufactured and randomly divided into six groups according to immersion solutions: coffee, red wine, white wine, regular beer, dark beer and deionized water (control). The specimens were fully immersed in each of the solutions for six days at 37°C, representing approximately six months of consumption. The color measurements were evaluated by a reflection spectrophotometer, at baseline (before immersion) and after staining. L*a*b* coordinates were measured and the color change (ΔE₀₀) was calculated using the CIEDE2000 formula. The data were analyzed by ANOVA/Tukey tests at a significance level of 0.05.

Results:

The resin composites immersed in white wine and regular beer showed either imperceptible or clinically acceptable ΔE₀₀, and no difference from the control group (p= 0.4449 and p= 0.467 respectively). Immersion in coffee and red wine were considered clinically unacceptable and were significantly different from the control group (p= 0.0028 and p= 0.0475 respectively).

Conclusion:

Based on the results of the present study, the consumption of coffee and red wine may cause color change of the resin composite attachments above the visual acceptability threshold, and impair aesthetics during treatment.

Effect of Conventional and Electronic Cigarettes Smoking on the Color Stability and Translucency of Tooth Colored Restorative Materials: An In Vitro Analysis

This in vitro study compared the effects of conventional and electronic cigarettes on the aesthetics (color stability and translucency) of two types of composite resins: micro and nano-hybrid. Methods: A total of 120 specimens from two different composite materials Filtek Z250 XT (Nano-hybrid, 3M) and Filtek Z250 (Micro-hybrid, 3M) were divided into four groups (n = 30); shade A2 was used. The samples were exposed to conventional and electronic cigarette smoke via a custom made chamber device. The color values and measurements were recorded using a spectrophotometer before and after the exposure. The color and translucency were evaluated using the three-dimensional CIE Lab. Results: There was a significant change in the color (ΔE) and the translucency parameter (TP) in all of the specimens exposed to electronic cigarettes and conventional cigarettes. The results showed that the highest ΔE mean is for the nano-hybrid composite exposed to conventional cigarettes with 1.74 ΔE while the same material is 0.64 under the electronic cigarettes and the difference is significant with (p < 0.05). The micro-hybrid composite data showed less changes in color under both exposures with 0.85 ΔE mean under the conventional cigarette smoke and 0.48 under the electronic cigarette smoke with (p < 0.004). Conclusions: The conventional cigarette smoke has more effect on the color stability of the composite resins than electronic cigarettes. From a clinical point of view, the effect of smoke exposure on the tested specimens’ color, for the time duration to which the specimens were exposed, were moderate (ΔE < 2). The micro-hybrid composites showed better color stability as compared to the nano-hybrid composites.

Effects of storage time and restoration depth on instrumental color adjustment potential of universal resin composites

PURPOSE

To determine the instrumental color adjustment potential (CAP-I)of 3 universal composites at 2 time intervals and 2 depths.

METHODS

Omnichroma, Estelite Sigma Quick, and Filtek Universal Restorative were tested. Two types of specimens were prepared. For dual specimens, Class V restorations were created in anterior denture teeth and restored with resin composites. For single specimens, replications were fabricated with resin composites (n = 10). Unrestored teeth were used for comparison. Color was measured with a spectrophotometer at 24 h and 1 month, and CAP-I was calculated. Data were compared by analysis of variance followed by the Student t-test and paired sample t-test.

RESULTS

The CAP-I of tested materials ranged from 0.11 to 0.27 at 24 h and from 0.60 to 0.76 at 1 month. At 24 h, Omnichroma yielded the highest values, followed by Estelite Sigma Quick and Filtek Universal Restorative (P < 0.05). CAP-I was significantly higher at 1 month than at 24 h in all groups. In all groups, restorations with a depth of 3.0 mm yielded better results than restorations with a depth of 2.0 mm (P < 0.05).

CONCLUSION

Storage time and restoration depth were positively associated with CAP-I. Single-shade and multi-shade universal composites are good alternatives for color-matched, esthetically satisfying restorations.

The Effect of Different Dietary and Therapeutic Solutions on the Color Stability of Resin-Matrix Composites Used in Dentistry: An In Vitro Study

The purpose of this study was to evaluate the color stability of aesthetic restorative resin-matrix materials after their immersion in different dietary and therapeutic solutions. Thirty disc-shaped specimens (10 × 2 mm) were prepared from three different types of resin-matrix composites used in dentistry (BE, FS, AF). The color coordinates (L*a*b*, ΔL*, Δa*, Δa*, Δb* and ΔE*) were measured using a VITA Easyshade 3D-Master (VITA Zahnfabrik, Bad Säckingen, Germany) before and after the immersion of the specimens in coffee, red wine, Coca-Cola^®, Eludril Care^®, and distilled water solutions for 40 h. The color change (ΔE*) was calculated and analyzed by the Kolmogorov -Smirnov test and the Kruskal -Wallis multiple-comparison test. All the restorative materials showed significant color (ΔE*) changes after their exposure to red wine, followed by coffee and Coca-Cola^®; however, one nanohybrid resin-matrix composite showed a high color stability in such colored test solutions. The chemical composition and content of the organic matrix played a key role in the color stability of the resin-matrix composites. Clinicians should advise their patients about the chemical interaction between dietary substances and different resin-matrix composites.

Charcoal-based dentifrices: Effect on color stability and surface wear of resin composites

OBJECTIVE

To evaluate the effect of charcoal-based dentifrices on the color change (CC) and surface wear (SW) of resin composites.

MATERIALS AND METHODS

Five dentifrices, including three toothpastes: Colgate total-12 (C12), Black is the new White (CPX), and Natural (NAT); and two powders: Carvvo (CVV) and Whitemax (WMX), were evaluated. Composite blocks (5x5x2mm- Z350 3 M/ESPE, shade A2) were subjected to 417 and 5004 brushing cycles. The CC (n = 7, CIEDE2000; ΔE₀₀ ) was evaluated using a spectrophotometer. SW (n = 5) was assessed using profilometry. The dentifrice particles were characterized by scanning electron microscopy (SEM).

RESULTS

In 417 brushing cycles, resin composite exhibited higher color change upon being exposed to NAT, CVV and WMC than to C12 (p ≤ 0.05). In 5004 brushing cycles, resin composite showed higher color change values when exposed to all dentifrices, except C12 (p ≤ 0.05). The powders promoted higher SW on resin composite than C12 in both evaluation times (p ≤ 0.05). In 417 cycles, WMX caused higher SW on composite than C12, CPX, and NAT (p ≤ 0.05). No significant different SW was found between powders and charcoal-based toothpastes after 5004 brushing cycles (p > 0.05). SEM showed larger particles for powder than for toothpaste dentifrices.

CONCLUSION

Within the limitations of this study, both null hypotheses have been rejected. Resin composites exposed to charcoal-based dentifrices exhibited significantly (p ≤ 0.05) higher color change and surface wear than conventional toothpastes.

CLINICAL SIGNIFICANCE

Color change and surface wear shown by charcoal dentifrices may compromise the longevity of restorations.

Evaluation of Color-matching Ability of a Structural Colored Resin Composite

PURPOSE

The present study evaluated the color-matching ability of a structural colored resin composite to compare it with resin composites employing pigments.

METHODS AND MATERIALS

A structural colored resin composite (Omnichroma [OMC]), a supranano-filled resin composite (Estelite ∑ Quick [ELQ]), and a nano-filled resin composite (Filtek Supreme Ultra [FSU]) were used. Each resin composite was packed into a Teflon mold and pressed down with a clear strip under a glass slide. The specimens were light irradiated through the slide with a light-emitting diode curing unit. The thickness of the specimens (n=6) was measured with a digital caliper before being transferred to distilled water and stored at 37°C for 24 hours. The measurements of the optical characteristics of the specimens on a black-and-white background were performed using a spectrophotometer. D65 (CIE D65) was used as a light source for the spectrophotometer. Measurements were repeated three times for each specimen under each color-measurement condition, and average values for three same-shade specimens were calculated. One-way analysis of variance and Tukey post hoc tests were used (α=0.05). To determine its ability to match the color of artificial teeth, each shade of resin composite was placed in a cavity before performing color measurements. Using a spectrophotometer (CMS-35F S/C) with a flexible sensor, L*, a*, and b* values were obtained.

RESULTS

The spectral reflectance curve of OMC showed that it reflected light wavelengths from 430-700 nm regardless of the background color and thickness of the specimens. The percentage of reflectance of ELQ decreased near wavelengths of 550-580 nm. Regarding the influence of background color on CIE L*, a*, b* values, the L* level showed significantly higher values for all tested materials with white backgrounds, and OMC was most affected by the difference in background color. However, a* values of ELQ and FSU were significantly higher with a black background than with a white background, and OMC showed a significantly higher value with a white background than with a black background. The b* values were higher with a white background than with a black background and were significantly higher for all three products, and these tendencies were much greater for ELQ and FSU.

CONCLUSIONS

The ability of OMC to match the color of artificial teeth showed acceptable color compatibility, regardless of the shade of the artificial teeth and the depth of the cavity. However, ELQ and FSU showed reduced color compatibility, especially for a cavity depth of 3.0 mm. Excellent color matching ability was confirmed for the structural colored resin composite OMC, resulting in reduced color differences and therefore improving the esthetic appearance of the restoration, simplifying shade matching, and compensating for any color mismatch.

Spectrophotometric comparison of color stability of microhybrid and nanocomposites following exposure to common soft drinks among adolescents: an in vitro study

PURPOSE

To compare the color stability of a microhybrid and two nanocomposites after exposure to common soft drinks among adolescents.

METHODS

Ninety discs were prepared from a microhybrid (Filtek Z250) and two nanocomposites (Filtek Z350 and Tetric N-Ceram) (n = 30 each). Six discs from each material were then immersed in one of five drinks (iced tea, sports drink, orange juice, cola, and distilled water) for 15 days. Color measurement was performed at baseline and after 15 days using a spectrophotometer according to the CIE L*a*b* system, and the change in color values as well as total color change (ΔE) was calculated and compared. ANOVA and Tukey's HSD test were used to analyze the data (p < 0.05).

RESULTS

Significant change in color values and total color (ΔE > 3.3) was observed in the composite materials after immersion in the soft drinks compared to immersion in distilled water (ΔE < 3.3). The highest mean values were those of Filtek Z350, being significantly different from the rest of the materials. Independent of the composite material, iced tea resulted in the highest mean values, being significantly different from the rest of the drinks (p < 0.05).

CONCLUSION

All soft drinks resulted in clinically unacceptable discoloration of the composite materials with maximum discoloration being that following immersion of composite materials, particularly Filtek Z350, in iced tea. Consequently, in dental practice, adolescents should be asked about their consumption of soft drinks, particularly iced tea, and made aware of their potential to discolor composite restorations if they are to receive them.

Effects of Different Amine Activators on the Monomer Conversion, Biaxial Flexural Strength, and Color Stability of Experimental Provisional Dental Restorations

Objective  The aim was to assess the effect of different amine activators including N, N-dimethyl-p-toluidine (DMPT) or Na-N-tolyglycine glycidyl methacrylate (NTGGMA) on chemical-activated monomer conversion, biaxial flexural strength (BFS), and color stability of composites for provisional dental restorations.

Materials and Methods  Two formulations of composites containing either DMPT (D-temp) or NTGGMA (N-temp) were prepared. The degree of monomer conversion was assessed. The BFS of the materials was tested using the ball-on-ring testing jig. The color difference (∆E ₀₀ ) of the materials after immersion in water was also determined. The commercial comparisons were Unifast (UF), Protemp (PT), Luxacrown, and Luxatemp (LT).

Results  The monomer conversion of D-temp (57.4 ± 1.3%) was comparable to that of N-temp (59.0 ± 1.3%). The conversion of both D-temp and N-temp were higher than that of PT (48.1 ± 3.4%) and LT (48.0 ± 1.6%). BFS of both D-temp (164.2 ± 18.1 MPa) and N-temp (168.6 ± 8.9 MPa) were comparable but higher than that of UF (119.8 ± 13.6 MPa). ∆E ₀₀ of D-temp (2.7 ± 0.7) and N-temp (2.5 ± 0.8) were comparable but higher than that of other commercial materials (0.6–1.2).

Conclusion  The use of DMPT or NTGGMA showed negligible effect on monomer conversion, BFS, and color stability of the experimental provisional restorations. The conversion and BFS of the experimental materials were in the range of that obtained from commercial bis-acryl-based materials. However, the color stability of the experimental materials was lower than that of commercial materials.

Clinical acceptability of PEEK fixed dental prosthesis in partially edentulous patient - A one year single arm pilot study

Purpose

The study evaluated the clinical efficacy of Polyether ether ketone (PEEK) fixed dental prosthesis (FDP) over a period of one year using modified Ryges criteria and California Dental Assessment system.

Methods

The group consisted of 20 patients restored with posterior three-unit PEEK FDP. Patient recall and clinical examination of the restorations were done at interval of 0, 3, 6, 9 and 12 months. Clinical examination for evaluation of longevity of restorations was done using modified Ryges criteria and California dental assessment system on chipping of the veneered composite, discoloration at the marginal areas, and marginal adaptation, retention, periodontal health and hygiene of PEEK FDP. Radiographic assessment was done after 12 months. Statistical analysis were done using Friedman test.

Results

95% of the patients had maintained the restoration of PEEK FDP without fracture during the study period. 5% patient reported with de-cementation of fixed dental prosthesis. 10% of the PEEK FDP shows marginal discoloration. However, no significant changes were observed during the periodic time interval evaluation in marginal adaptation, oral hygiene status and periodontal health. (p < 0.5).

Conclusion

PEEK FDP had satisfactory clinical efficacy and acceptable clinical outcome during the observation period of 12 months. No significant radiological changes were observed at the end of 12 months.

The effect of artificial accelerated aging on the color stability, microhardness, and surface roughness of different dental laminate veneer materials

OBJECTIVE

This study aimed to evaluate the effect of artificial accelerated aging (AAA) on color stability, surface roughness, and microhardness of three laminate veneer (LV) materials.

MATERIALS AND METHODS

Specimens of ceramic LV (CLV-IPS E.max Press), hand-layered composite LV (hand-layered laminate veneer [HLV]-Tetric N-Ceram), and prefabricated composite LV (prefabricated laminate veneer [PLV]-Componeer Coltene) were prepared as discs (n = 10). CIE L*, a*, and b* color coordinates, the Vickers microhardness, and surface roughness were measured 24 hours after preparation and reevaluated after aging for 300 hours in an ultraviolet (UV)-AAA system (Ci35 Weather-Ometer). Color difference (CIEDE2000 [ΔE₀₀ ]) was calculated. Data were statistically analyzed with the Shapiro-Wilk test and the Kruskall-Wallis test followed by the Mann-Whitney U tests (α = .05).

RESULTS

All of the LV groups showed significant differences in ΔE₀₀ after AAA (P < .001). Comparing the color changes of the HLVs with the PLVs, no significant difference could be found (P = .705). There was a statistically significant difference in the means of changes in microhardness among the LVs materials (P < .001). The changes in surface roughness results showed a significant difference after AAA in all the LVs (P < .001).

CONCLUSIONS

Within the limitations of this in vitro study, the color stability, the microhardness, and surface roughness of tested LVs were influenced by AAA.

CLINICAL SIGNIFICANCE

The prefabricated composite LV system does not replace the individualized ceramic LV technique, but rather offers an alternative to hand-layered LVs, which is delicate and time-consuming technique.

Influence of experimental staining on the color stability of indirect computer-aided design/computer-aided manufacturing dental provisional materials

Objective:

This study presents a comparative analysis of the color stability of computer-aided design/computer-aided manufacturing (CAD/CAM)-fabricated provisional restorations with those of conventional restorations.

Materials and Methods:

Three different provisional restorative materials (Systemp C&B, 3M Protemp 4, and Telio CAD) were inspected for their color stability using four solutions (Pepsi, coffee, tea, and distilled water). All samples used were fabricated using A1 shade by following the manufacturer's instructions. Color assessment was performed using CIELAB system and a colorimeter. After baseline color measurement, color assessments were done weekly after immersion in specified solutions. Triplicate readings were taken for every sample and the mean value of the color coordinates (L*), (a*), and (b*) were recorded at baseline, week 1, week 2, week 3, and week 4. The data within different groups were compared statistically using analysis of variance (α = 0.05).

Results:

Overall, the highest color stability was found in CAD/CAM material, followed by Protemp and SystempC&B. It was also observed that the maximum color variation was observed in case of coffee, followed by tea and Pepsi.

Conclusions:

CAD/CAM provisional material (Telio CAD) showed better color stability compared to conventional materials (Protemp 3M ESPE and SystempC&B Ivoclar Vivadent). CAD/CAM provisional materials are recommended for long-term temporization procedures. This is attributed to the prepolymerization, higher monomer conversion, and minimal preparation errors in CAD/CAM materials.

Color stability of Lucirin-photo-activated resin composite after immersion in different staining solutions: a spectrophotometric study

INTRODUCTION

Exceptional optical properties characterize teeth. As such, an esthetic restorative material should enable the dental professional to imitate the optical properties of natural teeth accurately. IPS Empress Direct was introduced to the market with the claim that it can mimic optically dental tissues with superior clinical performance.

AIM

To evaluate the ability of IPS Empress Direct to mimic tooth appearance and color and resist staining.

MATERIALS AND METHODS

Three disc specimens were prepared for each shade of enamel and dentin of Lucirin-based composite, IPS Empress Direct (Ivoclar Vivadent) (A1, A2, A3, B1, and B2) (total of 60). The specimens were submitted to colorimetric evaluation in comparison after immersion in 10 different solutions (coffee, coffee with sugar, coffee with milk, red tea, red tea with sugar, red tea with milk, tomato juice, pomegranate juice, coke, and distilled water as a control group) for 4 weeks using spectrophotometric analysis.

RESULTS

After plotting the data and conducting linear regression analyses, IPS Empress showed high potential in mimicking the optical properties of natural tooth color according to the CIE color space. Three solutions showed a change in color higher than 3, coffee, coffee with sugar, and red tea. All other solution showed changes in color that are acceptable clinically.

CONCLUSION

IPS Empress Direct can satisfactory mimic teeth appearance and color while manifesting high stability of color resisting staining upon clinical aging.

Influences of Different Air-Inhibition Coatings on Monomer Release, Microhardness, and Color Stability of Two Composite Materials

The aim of this study was to evaluate the effect of light-curing protocols on two modern resin composites using different air-inhibition coating strategies. This was accomplished by assessing the amount of monomer elution, surface microhardness, and composite discoloration in different storage conditions. A total of 120 specimens were prepared using Filtek Supreme XTE (3M ESPE, Seefeld, Germany) and CeramX Universal (Dentsply DeTrey, Konstanz, Germany). Specimens were light-cured in air as per manufacturer's instructions or in the absence of oxygen. This latter condition was achieved using three different approaches: (i) transparent polyester strip; (ii) glycerin; (iii) argon gas. Specimens were assessed for release of monomers, Vickers hardness, and discoloration after storage in different solutions. The results were analyzed with ANOVA one-way test followed by Student-Newman-Keuls test. Moreover, multiple comparisons of means were performed using the Student t-test (p<0.05). The amount of monomers released from the tested specimens was very low in all conditions. The presence of oxygen induced some decrease in microhardness. The highest discoloration values, for both materials, were obtained after ageing in red wine. In case finish and polish procedures are awkward to achieve in posteriors composite restoration, light-curing in the absence of oxygen should be considered, especially when performing composite restoration in esthetic areas.