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

Influence of depth and translucency on the color matching of single-shade resin composites: An in vitro study

To evaluate whether the depth and translucency of the restoration influence the color matching of single-color resin composites, cylindrical cavities (2-and-4 mm depths) were prepared in acrylic teeth 62 shade (n=10). Restorations were performed with single-shade resin composites (OC: Omnichroma, Tokuyama; VU: Vittra APS Unique, FGM) and a control multi-shade (EO: Estelite Omega, Tokuyama). The color matching was measured in instrumental analysis (CIEDE2000 color difference formula (ΔE00)) and visual analysis (0 to 4 scale). The translucency of discs (2-and-4mm thickness) was obtained by color difference (ΔE00) between black and white background. Two-way ANOVA followed by the post-hoc Tukey's test was used to evaluate instrumental analysis, and Kruskal-Wallis followed by the post-hoc Tukey's test to evaluate color matching with a significance level of 5%. Restoration depths affected the ΔE00 values of OC and VU (p<0.05) (higher ΔE00 values for 4-mm depth and higher for OC and VU (p< 0.05)). The restoration depths did not influence the color matching in the visual analysis. VU and OC showed higher translucency scores than EO. At 2 mm, OC showed higher translucency values and there was no difference between OC and VU at 4 mm (p <0.05). The color matching of OC and VU was influenced by depth (instrumental analysis). While the OC had a similar color matching to EO at both depths, VU had the best color matching in both depths in the visual analysis. Single-shade materials had greater translucency than EO at different depths, and the translucency decreased with increasing depth.

Effect of opalescence in resin-based dental composites on the active color matching ability

OBJECTIVE

This study aims to evaluate the influence of opalescence in the color matching ability of dental composites.

METHODS

Single-disc samples were prepared using 10 commercially available composites (6 conventional, 3 simplified-shade, and 1 single-shade). Dual-color samples were created using Omnichroma, Ceram.X Sphere TEC (A3 shade), and DenFil (B2/C2 shade), with various cavity diameters in the center, which were then filled with the aforementioned 10 composites. Additionally, single-color samples were prepared using the 4 base composites mentioned above. The ΔESingle-Dual were calculated as differences between single and dual samples. The color coordinates (CIE L*a*b*) of the samples were measured using a spectrophotometer. The results of translucency parameters (TP) and opalescence parameters (OP) of the 10 composites were compared with ΔE measurement samples.

RESULTS

TP and OP generally had a linear correlation, and ΔESingle-Dual mostly increased with cavity diameter. Regarding the correlation between ΔESingle-Dual and TP, little correlation was observed in the conventional composite bases, but higher correlations were observed in the simplified- or single-shade composite bases. Regarding the correlation between ΔESingle-Dual and OP, inverse correlations were observed in the conventional composite bases and simplified composite bases, but the single-shade composite base showed the linear correlations with OP.

CONCLUSIONS

These findings highlight a potentially greater role for opalescence in the color matching ability of dental composites than previously acknowledged.

Visual evaluation of the color adjustment of single-shade and group shade resin composites in restorations with different cavity configurations

OBJECTIVE

To evaluate the influence of the tooth shade, type of resin composite and cavity configuration on the color adjustment of single-shade and group shade resin composites.

METHODS

Class I and V cavities were prepared in artificial acrylic mandibular right molars with different shades - A1, A2, A3, A3.5 and A4. Three single-shade (OMN, UNI, CHA) and two group shade (FIL, HAR) resin composites were evaluated. Seventy-five observers, including dentists, dental students and laypersons (n = 25), participated in the study. A psychophysical experiment based on visual assessments of the color matching between each tooth and each restoration was ranked from 0 (excellent match) to 4 (huge mismatch), and mean frequencies (%) were calculated. Visual color differences among composite materials and tooth shades were statistically tested (P < 0.05).

RESULTS

The results showed highest percentages of unacceptable color mismatches for class V compared to class I restorations, especially for more chromatic tooth shades (A3.5 and A4). The percentage of ratings of acceptability was higher for laypersons group. For class V, OMN presented significant difference only from UNI in tooth shades A1, A2, A3 and A4. However, for class I, OMN presented significant differences with CHA for A1, A2 and A4, and with HAR and FIL for A1.

CONCLUSIONS

Class I resin composite restorations exhibit superior color matching than Class V, with lighter and low chroma tooth shades demonstrating better color adjustment. The color matching of both cavity configurations is comparable for single and group shade resin composites.

CLINICAL SIGNIFICANCE

Cavity configuration and tooth shade may impact color matching of single and group shade resin composites. This study demonstrates superior color matching in class I configurations over class V for both single and group shade resin composites. Additionally, restorations placed in teeth with lighter shades exhibit more favorable color adjustment.

Assessing color mismatch in single-shade composite resins for enamel replacement

STATEMENT OF PROBLEM

Shade selection is a challenge in restorative dentistry. While single-shade composite resins may simplify this process, whether the color mismatch between this composite resin and the substrate is within acceptable levels to ensure successful outcomes is unclear.

PURPOSE

The purpose of this in vitro study was to assess the influence of background and surrounding shade, thickness, and proximity to the surrounding on color mismatch when shaded and single-shade composite resins are used in the center of an enamel layer.

MATERIAL AND METHODS

Two-layer specimens mimicking dentin (the background) and enamel (the surrounding and center) were prepared. Two shades were used for the background and the surrounding layer (OA1/A1 and OA3/A3). At the Ø3-mm center, 2 single-shade composite resins were placed, Omnichroma (OM) and Admira Fusion x-tra (FU), and also shaded composite resins A1, WE, A3, and C2. For the OA1/A1 background and surrounding, shades A1 and WE served as positive controls, while the A3 and C2 were negative controls. For OA3/A3, these controls were reversed. Two enamel layer thicknesses were evaluated (0.5- and 1.0-mm). Reflectance measurements were made at 0.0, 1.0, 2.0, and 2.5 mm from the center. Color differences were calculated between those at 2.5 mm and at other distances (ΔE0, ΔE1, and ΔE2). Data analysis employed a 4-way repeated measure ANOVA with Bonferroni corrections for the pair-wise comparisons (α=.05).

RESULTS

Background and surrounding shade, central shade, distance, and thickness affected color mismatch (P<.05). For the OA1/A1 specimens, single-shade color mismatch values were found between both the positive and negative controls (P<.05). For the OA3/A3 specimens, the color mismatch did not differ significantly from that of negative controls (P>.05). No difference was found between ΔE0 and ΔE1, but each was distinct from ΔE2. Thickness did not affect the color mismatch of the single-shade composite resins (P<.05).

CONCLUSIONS

Single-shade composite resins for enamel replacement showed higher color mismatches compared with positive controls.

Assessing shade matching capability of Omnichroma, a single shade composite in posterior restorations: an in vitro study

Recent composites are being developed to simplify shade matching in composite restorations. Only a limited amount of research has been conducted to determine the optical performance of this newly introduced composite in this area. This study investigated the Omnichroma (OMN) color matching (a single shade composite within type-I restorations) via simulated clinical cavities. A total of 72 frames were created by occupying the mold with Estelite Σ Quick (ES) of A1, A2, and A3 shades (n = 24). Each shade of composite frame was divided into three subgroups (n = 8) according to cavity dimension (width = 2, 3, and 4 mm/depth = 2 mm). Cavities were filled with Omnichroma. Color parameters were calculated based on CIEDE2000 (ΔE00) using a non-contact spectrophotometer. Finally, the data were analyzed using a two-way ANOVA (the Tukey HSD test) (P = 0.05). The surrounding frame color significantly affected the color-matching capacity of OMN (P < 0.0001). Groups A1 and A3 showed the lowest and highest amounts of ΔE00, respectively. The cavity width also influenced the color-matching ability of OMN (P < 0.0001) significantly. According to the results, 4 mm cavity width showed the lowest amount of ΔE00, and 2 mm showed the highest amount. Monochromatic composites (OMN) did not match colors well in Class I cavities in posterior teeth. In cases of teeth with less chromatic surroundings, OMN matched shades better. OMN could better match shades in posterior teeth with wider cavities.

The effect of detox solution on color stability, roughness, and microhardness of monochromatic universal composite resins

BACKGROUND

Currently, the advantages of monochromatic universal composite resin restorative materials have increased their use in dentistry. Accordingly, the optical, surface and mechanical properties of these materials have become more important. This study aimed to evaluate the effect of detox solution on discoloration, surface roughness (SR), and microhardness of different monochromatic universal composite resins (Omnichroma [O], Zenchroma [Z], Vittra [V], and Charisma Diamond One [CDO]). Another aim of this study was to evaluate the monomer conversion degree (DC) of the materials.

METHODS

A total of 80 specimens were prepared to evaluate the materials (n = 10). After the initial measurements, the specimens were immersed in a red detox solution for 21 days. Statistical data analysis was performed using one-way ANOVA and Tukey's multiple comparisons.

RESULTS

The ∆E values of Z were highest on the 21st day. There was an increase in the SR values of the materials immersed in the detox solution. On the 21st day, top surface microhardness of O was lower than the other materials. There was no statistically significant difference at DC values among material groups.

CONCLUSIONS

The use of detox solutions for a commercially recommended period of 21 days is suggested. However, this usage period can cause discoloration in restorative materials. Furthermore, especially in the initial one-week period, detox solution may have a negative impact on the microhardness of the materials. In light of all these data, we recommend the cautious use of detox solutions to prevent adverse effects on restorative materials.

Instrumental and Visual Evaluation of the Chameleon Effect of Single-shaded Composite Resins

OBJECTIVE

To evaluate the shade-matching ability of single-shade resin-based composite restorations in different thicknesses using both instrumental and visual techniques.

METHODS AND MATERIALS

Cavities with 4 mm diameter and 2 mm (n=96) or 3 mm (n=96) depth were prepared in acrylic incisor teeth of shades A2, A3, B3, and C2 and restored with three single-shade resin composites, Omnichroma (Tokuyama Dental America, Encinitas, CA, USA [OM]), Vittra APS Unique (FGM Dental Group, Joinville, SC, Brazil [VU]), Zenchroma (President Dental, Allershausen, Germany [ZC]), and a microhybrid resin composite (Filtek 3M Z250 3M ESPE, St Paul, MN, USA [FZ]) of A2, A3, B3, and C2 shades. Readings were obtained using VITA Easyshade V spectrophotometer for the teeth and restorations. The CIEDE2000 (ΔE00) color difference formula was used, and the values were assessed using three-way analysis of variance (ANOVA). Forty-eight evaluators graded the shade match of 32 different specimens visually as (A) best shade match, (B) intermediate shade match, and (C) poor shade match.

RESULTS

FZ material achieved satisfactory matches for both thicknesses, across all shades, and OM material demonstrated statistically significant lower shade matches than the ZC and the FZ materials (p<0.05). VU exhibited poor shade match with the highest ΔE00 value on C2 shade. According to the visual examination, the best shade matches were observed for FZ on A3-shade and ZC on C2-shade teeth.

CONCLUSIONS

Shade matching for 2 mm and 3 mm-thick composite resin restorations is material- and tooth-shade dependent.

The Influence of Modeling Liquid on Microhardness of Single-Shade Composite Resins: An In-Vitro Study

Aim

To assess the effect of modeling liquid on the microhardness of single-shade universal composites.

Materials and Methods

A total of 60 disk-shaped samples were prepared in six groups [Omnichroma (OM), Essentia Universal (EU), Vittra APS Unique (VA), OM + Signum, EU + Signum, and VA + Signum] for surface microhardness measurements. Samples were stored in a coffee solution for 7 days and after that bleached with an Office bleaching agent (Total Blanc Office). Surface microhardness was measured for baseline, after staining, and after bleaching. A two-way analysis of variance test was used for statistical analysis (P < 0.05).

Results

In terms of microhardness, there is a statistically significant difference (P < 0.05) between the two categories with and without modeling liquid. The alterations in microhardness measurements at baseline, after staining, and after bleaching are statistically significant (P < 0.05). The Essentia groups showed the lowest microhardness findings at all measurement times. Microhardness values decreased significantly more when EU was applied along with modeling liquid than when it was not applied at different intervals.

Conclusions

Modeling liquid affects the microhardness of single-shade composites. Microhardness is reduced when modeling liquid is used for all three single-shade universal composite resins at three different times.

Effects of background color and restoration depth on color adjustment potential of a new single-shade resin composite versus multi-shade resin composites

The objectives of this study was to evaluate the effects of background color and restoration depth on color adjustment potential of a new single-shade resin composite versus multi-shade resin composites. Two multi-shade resin composites (Spectrum TPH3 and Clearfil AP-X) marked A2 shade and a new single-shade resin composite (Charisma Diamond One) were tested. Four base shades (A1, A2, A3, and A3.5) of the same resin composite (Filtek Z250) were selected as different background colors. Dual specimens with 1-, 2-, and 3-mm restoration depth and single specimens of all materials were fabricated. CIE color coordinates were measured using a spectrophotometer, then color differences (∆E00) and translucency parameter (TP00) were calculated using the CIEDE2000 formula. Independent observers performed visual scoring. CAP-I and CAP-V values were calculated according to ΔE00 and visual scoring. The results revealed that CAP-I and CAP-V were significantly affected by resin composite type, background color, and restoration depth. CAP-I and CAP-V decreased as restoration depth increased at the same background color for all materials. Charisma Diamond One had the highest CAP-I and CAP-V values at all background colors and restoration depths, with the highest TP00 value. These findings demonstrated that color adjustment potential was dependent on resin composite type, background color, and restoration depth, so shade selection is indispensable for multi-shade resin composites. Charisma Diamond One exhibited the highest color adjustment potential and the most pronounced color shifting, contributing to simplifying the process of shade selection and improving the efficiency of clinical work.

The role of interface distance and underlying substrate on the color adjustment potential of single-shade composites

OBJECTIVE

This study assessed how the distance from the composite interface and the underlying chromatic substrate affect the color adjustment potential (CAP) of two single-shade composites.

MATERIALS AND METHODS

Cylinder-shaped specimens were created using Vittra APS Unique (VU), Charisma Diamond One (DO), and a shaded (A3) composite. Some single-shade specimens were surrounded by the A3 composite, forming dual specimens. Color measurements of simple specimens were taken against a gray background using a spectrophotometer. All specimens were positioned at a 45° angle in a viewing booth under illuminant D65, and images were captured with a DSLR camera against gray or A3 backgrounds. Image colors were measured using image processing software and converted to CIELAB coordinates. Color differences (ΔE00 ) between the single-shade composites and the A3 composite were calculated. CAP was determined by comparing data from simple and dual specimens.

RESULTS

No clinically significant differences were observed between color measurements obtained from images and the spectrophotometer. CAP was higher for DO compared to VU and increased as the distance from the composite interface decreased and when specimens were positioned against an A3 background.

CONCLUSION

The color adjustment potential increased with decreased distance from the composite interface and against a chromatic background.

CLINICAL SIGNIFICANCE

Achieving satisfactory color match in restorations using single-shade composites is crucial, and selecting an appropriate underlying substrate is essential. The color adjustment gradually decreases from the restoration margins towards its center.

Surface Analysis of a Universal Resin Composite and Effect of Preheating on its Physicochemical Properties

This study was aimed at analyzing the surface properties of a universal resin composite and evaluating the effect of preheating on its physicochemical properties. Two commercial resin composites were used under two conditions: Filtek Universal Restorative (UR); UR preheated (URH); Filtek Supreme (FS) and FS preheated (FSH). The film thickness (FT) test (n = 10) was done using two glass slabs under compression. Flexural strength (FLS) and modulus (FLM) were evaluated using a three-point flexion test (n = 10). Polymerization shrinkage stress (PSS) was evaluated in a universal testing machine (n = 5). Gap width (GW) between composite and mold was measured in internally polished metallic molds (n = 10). The degree of conversion (DC) was evaluated by Fourier Transform Infrared spectroscopy (n = 3). The morphology of the filler particles was checked by scanning electron microscope (SEM) and EDX analysis. Surface gloss (SG) and surface roughness (SR) were evaluated before and after mechanical brushing (n = 10). The outcomes were submitted to 2-way ANOVA and Tukey's test (α = 0.05). Lower mean values of FT were observed for the preheated groups when compared to the non-preheated groups. URH and FSH showed higher mean values of FLS and FLM when compared with UR and FS. No differences were observed between groups in the PSS test. The GW was higher for the UR and FS groups when compared with URH and FSH. The DC was higher for preheated resin composites when compared to the non-preheated groups. The SR of the UR composite was higher than the FS after mechanical brushing, while the SG was higher for the FS groups. In conclusion, the universal resin composite tested generally presented similar physicochemical properties compared with the nanofilled resin composite and either similar or slightly inferior surface properties. The preheating improved or maintained all properties evaluated.

Evaluation of Single-Shade Composite Resin Color Matching on Extracted Human Teeth

Introduction

Universal single-shade composite resins are characterized by a property that enables the creation of restorations that mimic tooth structure to the extent possible with fewer shades of color.

Objectives

This study aimed to instrumentally and visually evaluate the color correspondence of two single-shade composite resins in extracted human teeth multishade composite resins.

Methods

Upper central incisors and upper and/or lower molars with intact buccal surfaces were selected. The study consisted of a control group (n = 20): Z250 XT (3M ESPE) (G1) multishade composite resin in colors A1 to A4, and a test group (n = 20) divided further into two equal groups, consisting of single-shade composite resin Omnichroma (Tokuyama Dental) (G2) and single-shade composite resin Vittra APS Unique from (FGM) (G3). Instrumental evaluation was performed using a spectrophotometer, and visual evaluation was performed by three observers. Descriptive measurements related to the differences in color obtained through instrumental means were analyzed using mean and standard deviation, wherein the means were compared using ANOVA, applying the Bonferroni post hoc test.

Results

A statistically significant difference was observed among the groups (G1, G2, and G3) (ANOVA: p < 0.001). For the visual assessment, regardless of the assessment group, 77.49% of the teeth were within the acceptable color-match classification, with the single-shade resins showing better correspondence than the multishade resins.

Conclusion

Single-shade composite resins showed different color-matching results when compared to multishade resins, both in spectrophotometry and visual evaluations. Clinical Significance. Single-shade composite resins simplify the shade-selection process and are promising materials for use in dental practice.

Instrumental and visual evaluation of the color adjustment potential of different single-shade resin composites to human teeth of various shades

OBJECTIVE

The study aims to evaluate the color adjustment potential (CAP-I, CAP-V) of different single-shade resin composites.

MATERIALS AND METHODS

The shades of 40 human incisors were determined using a spectrophotometer, with the teeth divided into four groups of the same shade (n = 10). The following single-shade resin composites were tested: Omnichroma, Charisma Diamond One, Vittra Unique, and Essentia Universal. The specimens were prepared as "dual" and "single." Standardized cavity preparations (diameter, 7 mm; depth, 2 mm) were prepared in human incisor teeth and then restored for dual specimens. Composite duplicates of human incisors were prepared with resin composites for single specimens (n = 10). The color match of these specimens to that of unrestored human incisors was compared, and the color difference (ΔE*) was calculated. Independent observers conducted a visual evaluation of the specimens and scored them. CAP-I and CAP-V values were determined. A one-way analysis of variance test was used for statistical analysis (p < 0.05).

RESULTS

There was no statistically significant difference between the CAP-V and CAP-I values of the tested single-shade resin composites (p > 0.05). All the materials tested had acceptable color-matching potential.

CONCLUSIONS

In terms of color matching, there were no significant differences between the different tooth shades of all the tested resin composites.

CLINICAL RELEVANCE

Single-shade resin composites have acceptable CAP. The use of single-shade resin composites can reduce in-chair clinical times by minimizing the time spent on shade selection.

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.

The Effects of Selected Mouthwashes on the Surface Microhardness of a Single-shade Universal Resin Composite: In Vitro Study

Aim:

To investigate the effects of selected alcohol-free mouthwashes with different formulations (zinc-hydroxyapatite, hydrogen peroxide, and sodium fluoride) on the surface microhardness of a single-shade universal resin composite.

Materials and Methods:

Forty disc-shaped specimens (8 × 2 mm) from the universal resin composite (Omnichroma®), and a nano-hybrid composite (Tetric® N-Ceram) were prepared. After polymerization, baseline surface microhardness values were recorded using Vickers microhardness tester. The samples from each material were randomly assigned to 4 groups ( n = 10) and immersed in 20 ml of the mouthwashes: Biorepair®, Listerine®, Colgate® Optic White, and distilled water (control). The samples were kept in the immersion solutions for 24 hours, and post-immersion microhardness values were recorded. Data were analyzed with one-way ANOVA and paired sample t-tests at p < .05.

Results:

Significant reduction in microhardness was observed in all resin composite groups after immersion in the mouthwashes compared to baseline values ( p < .0001). The highest microhardness reduction in Omnichroma® group was observed after immersion in Colgate® Optic White; and Tetric® N-Ceram group after immersion in Listerine® mouthwash. For both materials, the least reduction in microhardness was observed after immersion in Biorepair®. Microhardness values for Omnichroma were significantly higher than Tetric® N-Ceram ( p < .0001). However, Omnichroma exhibited a significantly greater reduction in microhardness after immersion in the tested mouthwashes.

Conclusion:

In vitro simulated use of the investigated mouthwashes negatively affected the surface microhardness of both tested resin composites. The observed effects were both mouthwash and material dependent.