Mean ΔE Research Articles

Effects of glutathione and potassium iodide on silver diamine fluoride application on remineralisation and colour change in dentine caries of primary teeth: an in vitro study.

The aim of this study is to compare the effect of GSH (reduced glutathione) and KI (potassium iodide) on SDF (silver diamine fluoride) discolouration and dentine remineralisation. Sixteen primary molars were utilised, yielding 4 dentine specimens each. Three specimens per tooth were allocated: one as a control and the others to experimental groups. Initial microhardness measurements were taken from one remaining dentine specimen per tooth. Subsequently, all groups underwent exposure to a demineralisation solution. Colorimetry assessed specimen colour, and post-second microhardness measurements on demineralised specimens, treatments were administered as follows: group 1 (control, n = 16): 38% SDF, group 2 (n = 16): 38% SDF followed by KI, group 3 (n = 16): 38% SDF with 5% GSH added by weight. Following pH cycling across all groups, colorimetry reassessed 48 dentine specimens. Final microhardness measurements ensued, followed by statistical analysis. Normality was checked via Shapiro-Wilk, and homogeneity via Levene's test. Independent samples t test compared normally distributed groups; Mann-Whitney U compared non-normally distributed groups. ANOVA compared means of normally distributed groups, and Kruskal-Wallis for non-normally distributed ones. Repeated measures ANOVA compared dependent groups with normal distribution, and Friedman test for non-normal. Post hoc Bonferroni analyses identified significant differences. IBM SPSS 25 was used to conduct analyses. The mean ΔE* values for SDF and SDF + GSH groups were significantly higher than those of the SDF + KI group (p < 0.05). Significant differences in L* values during final colour measurement were noted between the SDF + KI group and both SDF and SDF + GSH groups (p < 0.05). Although mean remineralisation microhardness measurements were higher than mean demineralisation microhardness measurements in all groups, statistical significance was observed only in the SDF and SDF + KI groups (p < 0.05). The study found that the addition of 5% GSH by weight to SDF does not significantly affect discolouration. Moreover, the addition of 5% GSH to the SDF solution may have a minor impact on the remineralisation potential of SDF. The application of KI after SDF reduces discolouration and does not affect the expected remineralisation process.

Pengaruh Ekstrak Kayu Manis Cinnamomum Burmannii dan Larutan Alkalin Peroksida sebagai Pembersih Basis Gigi Tiruan Nilon Termoplastik terhadap Stabilitas Warna

The background of this study is to evaluate the effect of soaking the base of thermoplastic nylon dentures in cinnamon extract Cinnamomum burmannii and alkaline peroxide solution on color stability, considering the importance of maintaining denture hygiene with safe and effective cleaning agents. This study aimed to evaluate the colour stability of thermoplastic nylon denture bases after immersion in Cinnamomum burmannii 20% cinnamon extract, alkaline peroxide solution, and distilled water for 4 and 8 days. This research is a laboratory experimental research. This study was conducted with Post-Test Only Control Group Design, which is research with treatment on one or more groups whose final results are compared with the control group, that the colour stability of thermoplastic nylon denture bases after immersion in Cinnamomum burmannii 20% cinnamon extract and alkaline peroxide solution had similar mean ΔE unit values, namely 2.45 ΔE ± 0.27 and 2.24 ΔE ± 0.28 for 4 days, and 2.87 ΔE ± 0.19 and 2.58 ΔE ± 0.30 for 8 days. While immersion in distilled water showed lower mean values of ΔE units, namely 1.17 ΔE ± 0.10 and 1.35 ΔE ± 0.29. Statistical test results showed that there was a significant effect on colour stability (p = 0.0001), but there was no significant difference between cinnamon extract and alkaline peroxide solution, either for 4 days (p = 0.192) or 8 days (p = 0.113).

Effect of Enamel Surface Coating on Staining Capability Due to Iron-Containing Supplements on Primary Teeth: An in Vitro Study

ABSTRACT Background: The staining of primary teeth due to iron-containing supplements is a common concern among parents and healthcare providers. Materials and Methods: Forty extracted primary teeth were divided into two groups of 20 each. Group A served as the control and received no enamel coating, while Group B was treated with a commercially available enamel surface coating. Both groups were then exposed to iron-containing supplements for 7 days. The teeth were assessed for color changes using a spectrophotometer before and after exposure. The degree of staining was quantified using the CIELAB color space values, specifically the ΔE* value, which indicates the change in color. Results: The mean ΔE* value in Group A (control) was 12.5 ± 1.8, indicating significant staining. In contrast, Group B (coated) showed a mean ΔE* value of 4.2 ± 1.1, reflecting minimal staining. The difference between the two groups was statistically significant (P &lt; 0.001), demonstrating the effectiveness of the enamel surface coating in reducing staining caused by iron supplements. Conclusion: Enamel surface coatings significantly reduce the staining effect of iron-containing supplements on primary teeth.

Effect of Coffee Thermocycling on Color Stability and Translucency of CAD-CAM Polychromatic High Translucent Zirconia Compared With Lithium Disilicate Glass Ceramic.

To evaluate the effect of coffee thermocycling on color stability and translucency of CAD-CAM polychromatic high translucent zirconia compared with lithium disilicate glass ceramic. Sixteen rectangular plates (14 × 16 × 1.0 mm) of two ceramic materials (IPS E.max CAD (IEC), IPS E.max ZirCAD Prime [IZP]) were prepared. Each specimen was measured for color coordinates using a spectrophotometer following 30,000 cycles of coffee thermocycling. CIELAB formula was used to determine color and translucency differences (ΔE and ΔTP). The means of ΔE and ΔTP were compared using independent samples t-test and were evaluated using their respective 50%:50% perceptibility and acceptability thresholds (PT and AT). One-way analysis of variance was performed to evaluate the translucency parameter (TP) and surface roughness (Ra) of each material. Mean ΔE values of IEC (4.69) and IZP (4.64) were higher than the AT (ΔE ≤ 2.7) with no significant difference found between the two groups (p = 0.202). Considering the TP, only IEC showed a statistically significant increase in TP value (p < 0.001). However, the mean ΔTP of IEC (3.25) remained within the range of acceptability (1.3 < ΔTP ≤ 4.4). Within the limitations of this current study, the color stability of all materials was clinically affected by coffee thermocycling. In terms of translucency, only lithium disilicate glass ceramic was influenced by coffee thermocycling. High translucent zirconia had superior translucency stability compared to lithium disilicate glass ceramic.

Effect of phytopigments on discoloration of nanohybrid composite: An in vitro study

Objective: The purpose of this study is to comparatively evaluate the effect of discoloration of nanohybrid composite by four different phytopigments. Materials and Methods: Fifty disk-shaped samples of nanohybrid (3M Filtek Z350) resin composites were prepared using an acrylic template of dimension 5 mm × 3 mm. They were randomly divided into five groups and immersed in solutions of tomato powder, beetroot powder, java plum powder, and turmeric powder. Distilled water was used as the control group. The samples were placed in respective solutions for 3 h daily and stored in artificial saliva for the rest of the day for 28 days. Color values (L*, a*, b*) were measured by colorimeter using the CIE L*a*b* system at the end of the 7th and 28th days of immersion. Color differences ΔE*ab were statistically analyzed. Results: All the samples showed a change in color of nanohybrid composite resin to varying degrees. The mean ΔE*ab value obtained with beetroot solution was the highest among all the groups at the end of the 7th and 28th days, depicting that beetroot solution showed maximum mean color variation, followed by java plum solution, turmeric solution, and tomato solution. Conclusion: All the phytopigments used in this study have the potential to discolor the nanohybrid composite resin, with beetroot causing the most severe discoloration.

Resin infiltration for white spot lesions: An in vitro experimental trial.

To evaluate the aesthetic outcome by varying the duration allowed for infiltrant penetration when treating white spot lesions with resin infiltration. An in vitro, experimental randomised study. Artificially created white spot lesions (WSLs) were induced on 100 extracted anterior teeth (T1). Teeth were divided into enamel and dentine groups depending on the extent of the lesion and then randomly assigned into different treatment protocol groups: penetration times of 3, 6 and 9 min. Resin infiltration treatment was applied according to the treatment protocol assigned (T2). Samples were thermocycled for 10,000 cycles (1 clinical year) (T3). The samples from the 3-min enamel and dentine groups were then randomly assigned into either a repeat treatment or no additional treatment group (T4). Samples were then thermocycled for an additional 10,000 cycles (T5). Spectrophotometric analysis was measured colour change (ΔE) for all groups. Mean ΔE values equal to or greater than the critical value (3.7) indicate a detectable clinical difference in colour of the treated WSL when compared to before WSL formation. Mean ΔE values, for the enamel groups, were slightly above or significantly below the critical value, and for the dentine groups, were significantly above the critical value. Mean ΔE values within the enamel and dentine groups both demonstrated a downward trend with increasing time allowed for resin infiltrant penetration (P < 0.05). No significant mean ΔE difference (P = 0.53) was found between groups that received a single or repeat treatment. After the first thermocycling event, no significant difference in colour change was observed in all groups except for the deep dentine lesion treated for 3 min. There was a significant difference in colour change for all groups except the enamel group that received a single treatment following thermocycling after a single or repeat treatment. Increasing the resin infiltrant penetration time to at least 9 min is advised as the most optimised treatment protocol. Resin infiltration treatment should be done only once to treat a particular white spot lesion as subsequent treatment for the same lesion results in marginal colour improvement. The colour improvement of WSLs resulting from the resin infiltration treatment can be expected to last for at least 1 year. Resin infiltration treatment of shallow lesions with a single and optimised infiltration technique can be expected to last an additional year.

In Vitro Comparison of Optical Properties Between Single-Shade and Conventional Composite Resin Restorations.

The recently developed single-shade composite resin (using the concept of structural coloring) is a promising option to eliminate the process and subjectivity of shade selection. However, current evidence of its performance is still insufficient. This study aimed to evaluate the color matching, color stability, and refractive index (RI) of single-shade restorations compared with conventional composite resin. This in vitro study was conducted on 48 extracted maxillary premolars. The teeth were sorted into three tooth shade groups (B2, A3, and A3.5). Each group included two subgroups based on the materials used: Omnichroma (OM;Tokuyama Dental, Tokyo, Japan) and Filtek Z350 (FT; 3M ESPE, St. Paul, MN, USA). Buccal and lingual Class V round cavities were prepared and restored according to the randomly assigned subgroups, with the test single-shade material (OM) on one surface and the matching conventional control material (FT) of the proper shade on the other surface of each tooth. Color matching was evaluated by visual assessment and a spectrophotometer. All specimens were distributed into four staining groups and immersed in various staining beverages (black coffee, Arabic coffee, Coca-Cola, and distilled water) for four weeks. Color changes were assessed using a spectrophotometer. Four groups of disc-shaped specimens (single-shade, B2, A3, and A3.5) were fabricated to evaluate the RI using a refractometer. Statistical analyses were performed to compare the materials. The mean value of the color difference (ΔE) of single-shade restorations was significantly higher than that of paired conventional restorations in all shade groups. The highest mean ΔE was in subgroup A3.5-OM (8.84 ± 2.39) and showed significantly less color matching than other OM subgroups (p=0.009). The visual assessment showed comparable and acceptable color matching in all subgroups except A3.5-OM (p=0.006). There was a significant color change after the staining test within and across staining groups, but the color change was comparable between the OM and FT subgroups. The RI of single-shade material was significantly higher than conventional material (p<0.05). The color matching of single-shade restorations was affected by tooth shade. Its color stability was influenced by various staining substances but was similar to conventional restorations.

Color stability and marginal adaptation of ceramic veneers cemented using different composite resins.

The purpose of this study was to compare the color stability and marginal adaption of lithium disilicate veneers before and after thermocycling using various resin composite materials employed as cement. Laminate veneer preparation was done on an acrylic tooth according to standardized procedures. The veneer preparations were duplicated into twenty-one dies. The veneers were fabricated from lithium disilicate using the CEREC in Lab system. According to the cement type, the twenty-one die specimens were randomly divided into three equal groups: group I, with light cured adhesive resin cement (N.=7), group II, with flowable light cured composite, and group III, with preheated nano filled composite. The cemented specimens underwent 5000 thermocycling cycles. Color was assessed using a reflective spectrophotometer. The vertical marginal gap, following cementation and thermocycling, was measured using a digital microscope. One-way ANOVA followed by Tukey's post-hoc test was used to statistically assess the data. After thermocycling, there was no statistically significant difference in ΔE among cement type groups for color stability (P=0.369). However, the preheated composite showed the lowest ΔE mean values. Within adhesive resin cement and flowable composite groups, marginal gap means values recorded after thermocycling were significantly higher than those after cementation (P=0.013 and P<0.001, respectively). Although preheated composite cement showed the highest marginal discrepancy, it would be the best choice regarding color stability.

Effect of strontium fluorophosphate bioactive glass on color, microhardness and surface roughness of bleached enamel.

Undesirable effects of tooth bleaching can alter the biomechanical properties of enamel. To determine the influence of strontium fluorophosphate bioactive glass (Sr-FPG) on color, microhardness and surface roughness of enamel bleached with 35% hydrogen peroxide. The labial enamel of 36 extracted intact human anterior teeth were divided into 3 groups (n= 12), group 1 (HP): bleaching with 35% hydrogen peroxide only, group 2 (Sr-HP): bleaching with Sr-FPG incorporated 35% hydrogen peroxide and group 3 (HP-SrFPG): bleaching with 35% hydrogen peroxide followed by remineralization with Sr-FPG. Four consecutive eight-minute applications of the bleaching gel were done twice in all the groups. Color change (ΔE), microhardness and surface roughness were evaluated at baseline, post-bleaching and post-remineralization using spectrophotometer, Vickers hardness tester and profilometric analysis respectively. The mean ΔE among the groups was statistically similar (p> 0.05). Bleaching with HP significantly reduced microhardness (p< 0.05), whereas bleaching with Sr-HP and HP-SrFPG did not (p> 0.05). Post-bleaching microhardness in Sr-HP was significantly higher than HP-SrFPG (p< 0.05). An increased surface roughness was seen in Sr-HP bleached samples (p< 0.05). The addition of Sr-FPG to hydrogen peroxide significantly improved enamel microhardness than its use post-bleaching. An increase in surface roughness was seen post-bleaching with HP and Sr-HP.

Evaluating the Color Matching Ability of a Smart Chromatic Technology-Based Composite Resin for Premolar Teeth Restoration.

Objectives: This study aims to evaluate the color-matching ability of OMNICHROMA composite, a single-shade composite, using the CIE L ∗ a ∗ b ∗ system and determining ΔE values. Materials and Methods: In this in vitro study, 30 intact premolar teeth were collected, cleaned, and disinfected with 0.5% thymol solution. The teeth were stored in distilled water at 37°C. A putty index calibrated the color assessment sites on buccal and lingual surfaces. Two cavities were prepared, one with 1.25 mm depth (enamel) and another with 2.25 mm depth (dentin), and restored using OMNICHROMA composite resin. The putty index measured the color of the cured composite, and ΔE between the composite and original tooth color was calculated. Statistical analysis: Data analysis included t-tests, correlation coefficients, and Fisher's exact test (α = 0.05). Results: The mean ΔE was 2.39 in enamel cavities and 2.32 in dentin cavities, both within the clinically acceptable range (<3.3). In enamel cavities, the composite color was darker than the tooth, shifting toward green and blue shades. In dentin cavities, the composite color was lighter than the tooth, with shifts toward green and yellow shades. Color matching was slightly better in dentin cavities, but the difference was not statistically significant (p=0.719). Conclusion: OMNICHROMA composite resin's color matching falls within the clinically acceptable range, unaffected by cavity depth.

Assessment of the color stability of two silicone elastomers for maxillofacial prostheses upon exposure to cold beverages.

This study investigated the color stability of different commercially available silicone materials for facial prostheses upon exposure to everyday beverages. It was hypothesized that the beverages would not alter the color of the silicone under conditions simulating daily exposure. Sixty specimens were fabricated using two materials - VST-50 and Silfy - and exposed to commercially available cold mineral water, tea, or coffee. Specimen color was evaluated on days 1 and 15. The color was measured with a spectrophotometer based on CIELab system and color differences were calculated as ΔE. Statistical analysis was performed using the Kruskal-Wallis test and Mann-Whitney U test. The mean ΔE values after 15 days of exposure to mineral water, cold green tea, and coffee were 1.016, 3.480, and 3.636 for VST-50 and 0.440, 0.798, and 1.425 for Silfy, respectively. Both materials showed significant differences in color, and VST-50 showed a greater color change than Silfy, especially for coffee. Pigmented silicone elastomers have low color stability, leading to an overall color change in silicone prostheses when exposed to pigmented beverages. Color changes in such prostheses can be mitigated by selecting materials with better color stability to extend their longevity.

Comparison of different digital shade selection methodologies in terms of accuracy.

This study aims to evaluate the accuracy of different shade selection techniques and determine the matching success of crown restorations fabricated using digital shade selection techniques. Teeth numbers 11 and 21 were prepared on a typodont model. For the #11 tooth, six different crowns were fabricated with randomly selected colors and set as the target crowns. The following four test groups were established: Group C, where the visual shade selection was performed using the Vita 3D Master Shade Guide and the group served as the control; Group Ph, where the shade selection was performed under the guidance of dental photography; Group S, where the shade selection was performed by measuring the target tooth color using a spectrophotometer; and Group I, where the shade selection was performed by scanning the test specimens and target crowns using an intraoral scanner. Based on the test groups, 24 crowns were fabricated using different shade selection techniques. The ΔE values were calculated according to the CIEDE2000 (2:1:1) formula. The collected data were analyzed by means of a one-way analysis of variance. For the four test groups (Groups C, Ph, S, and I), the following mean ΔE values were obtained: 2.74, 3.62, 2.13, and 3.5, respectively. No significant differences were found among the test groups. Although there was no statistically significant difference among the shade selection techniques, Group S had relatively lower ΔE values. Moreover, according to the test results, the spectrophotometer shade selection technique may provide more successful clinical results.

Comparison of Enamel Discoloration using Flash-Free and Conventional Adhesive Brackets with Different Finishing Protocols.

The aim of this study was to compare the effects of flash-free and conventional adhesive brackets and different finishing techniques on enamel discoloration. Forty human premolar teeth were utilized and randomly divided into four groups based on the type of brackets and finishing technique: (1) Gemini® brackets were used for orthodontic bonding. After debanding, adhesive remnants were cleaned using a 12-blade tungsten carbide bur. (2) Gemini® suspenders were used for orthodontic bonding. After debanding the brackets, adhesive remnants were cleaned using12-blade APC™ Flash-Free brackets were used for orthodontic bonding. After debanding, adhesive remnants were cleaned a 12-blade tungsten carbide bur and polished with Sof-Lex disks. (4) APC™ Flash-Free brackets were used for orthodontic bonding. After debanding, the adhesive remnants were cleaned using a 12-blade tungsten carbide bur. A Vita Easyshade spectrophotometer was used to measure the color change values of the 40 teeth. The color change of the enamel surface in the Flash Free bracket group was significantly less than that in the conventional groups (p=0.003 p˂0.05). The mean ΔE values obtained from the Sof-Lex groups were lower than those obtained from the groups without Sof-Lex, but these results were not statistically significant (p=0.280 p>0.05). It is recommended to use Flash-Free brackets and polish with Sof-Lex disk following the clean-up procedures to minimize the possibility of discoloration of the teeth during orthodontic treatment.

Silver Diamine Fluoride Staining With Potassium Iodide: A Prospective Cohort Study

Staining after silver diamine fluoride (SDF) treatment limits treatment acceptability but is also used as a clinical indicator of lesion stability. Potassium iodide (KI) has been postulated to modify SDF staining. Understanding the natural history and resultant shade of SDF/KI-treated lesions will inform clinical decision-making. This study describes the change in colour of carious lesions in primary teeth treated with SDF and KI. One hundred carious lesions in primary teeth were treated with SDF+KI (Riva Star, SDI) and followed up over 6 months. Lesion shade was determined using standardised intraoral photography and broadly categorised into 4 shades: yellow, light brown, dark brown, and black. Lesions were digitally isolated, and colour was evaluated using CIELAB (L*: lightness, a*/b*: hue) and perceptible colour change (ΔE). One hundred valid observations were analysed on 129 lesions included in the study. Lesions were excluded if subsequently restored (n=15), teeth exfoliated (n=2), exhibited pulpal exposure (n=1), or failed to attend at follow-up visits (n=11). At baseline, the shade of carious lesions was yellow (n=22), light brown (n=19), dark brown (n=29), or black (n=30). The changes in shade between baseline and 6 months were clinically perceptible to the human eye, with the mean ΔE being 12.2 (SD=6.9). Neither tooth type, lesion severity, nor baseline shade was statistically associated with the degree of perceptible change at 6 months. Carious lesions exhibited clinically significant changes in colour after application of SDF+KI, primarily attributed to differences in L* of lesions over the 6 months.

Effect of Laser and Conventional Office Bleaching and Polishing on the Color Change of Stained Nanohybrid and Microhybrid Composite Resin.

The present study investigated the effects of laser and conventional in-office bleaching, and polishing on the color of stained composite resin. A microhybrid composite (Clearfil AP-X) and a nanohybrid composite (Grandio) were selected. Twenty-four discs (2 × 10 mm) for each composite were prepared. The samples were immersed in coffee solution (25 g of coffee in 250 mL water) for seven days. Then the samples were divided into three groups (n = 8) and the stains were removed using bleaching (with Opalescence Xtra Boost), diode laser irradiation with Heydent material and a Sof-Lex polishing kit. The L ∗a ∗b ∗ color parameters were determined using a spectrophotometer before and after immersion and after stain removal procedures, and the overall color changes (ΔE) were calculated. The data were analyzed with two-way analysis of variance. In the Clearfil composite resin group, the mean ΔE compared to the baseline using in-office bleaching, laser irradiation, and Sof-Lex polishing kit were 3.31, 3.35, and 4.93, respectively. These values with the Grandio composite resin were 3.31, 6.35, and 4.57, respectively. The highest capacity to remove stains was related to the conventional in-office bleaching method. Grandio composite resin underwent more color changes than Clearfil composite resin significantly (P-value < 0.05). Both composite resins exhibited color changes after immersion in the discoloring solution. However, after staining-removing procedures, the ΔE values decreased. Decreases in the ΔE values were not sufficient to restore the color to that before immersion in the discoloring solution with any stain-removing methods.

Color match of ultra-translucency multilayer zirconia restorations with different designs and backgrounds.

The purpose of this in vitro study was to assess the color match of ultra-translucency multilayer zirconia restorations with different designs and backgrounds. Thirty ultra-translucency multilayer zirconia crown specimens were made in VITA classical shade B2 for a prepared maxillary central incisor. The specimens were divided into three groups based on the restoration design: veneered zirconia with a trestle design (VZT), veneered zirconia with a dentin core design (VZD), and full-contour zirconia (FCZ). In the groups VZT and VZD, the zirconia specimens were layered with a feldspathic veneering ceramic. The specimens were seated on five different backgrounds: shade B2 composite resin, shade B2 zirconia, copper-colored metal alloy, silver-colored metal alloy, and the prepared central incisor. CIELab values of the labial middle sections of the crown specimens were measured with a spectrophotometer. Color differences between the specimens and a shade B2 VITA classical tab (as a control) were calculated from the ΔE* ab formula and compared with an acceptability threshold (ΔE* ab=3.7) to be clinically explicated. Mean ΔE* ab values ranged between 1.17 and 8.48. The restoration design, the background type, and their interaction affected the ΔE* ab (p<0.001). The mean ΔE* ab values for VZT with all backgrounds and for VZD with the silver-colored metal background were greater than the threshold (p<0.001), whereas the mean ΔE* ab values for VZD with the other backgrounds and FCZ with all backgrounds were less than the threshold (p=1). Restoration design and background type affected the color match of ultra-translucency multilayer zirconia restorations. VZT restorations on all backgrounds and VZD restorations on a silver-colored metal background showed color mismatches. However, VZD restorations on the other backgrounds and FCZ restorations on all backgrounds demonstrated color matches.

Coffee Staining and Simulated Brushing Induced Color Changes and Surface Roughness of 3D-Printed Orthodontic Retainer Material.

This in vitro study evaluated the influence of combined coffee staining and simulated brushing-induced color changes and surface roughness on 3D-printed orthodontic retainers. Specimens measuring 10 × 10 × 0.75 mm3 were obtained either by conventional vacuum forming or 3D printing at four print angulations (0°, 15°, 30°, and 45°) (n = 10). The prepared specimens were immersed in a coffee beverage and then mechanically brushed using a simulating device. The specimen's color difference (ΔE) and surface roughness (Ra) were quantified using a spectrophotometer and a non-contact profilometer, respectively. The highest and lowest mean ΔE values were recorded for the 3D-printed-45° (4.68 ± 2.07) and conventional (2.18 ± 0.87) groups, respectively. The overall mean comparison of ΔE between the conventional and 3D-printed groups was statistically significant (p < 0.01). After simulated brushing, all groups showed a statistically significant increase in the Ra values (p < 0.01). The highest Ra was in the 3D-printed-45° (1.009 ± 0.13 µm) and conventional (0.743 ± 0.12 µm) groups, respectively. The overall ΔE of 3D-printed orthodontic retainers was not comparable to conventional VFRs. Among the different angulations used to print the retainers, 15° angulations were the most efficient in terms of color changes and surface roughness and were comparable to conventional VFRs.

Usefulness of texture and color enhancement imaging (TXI) in early gastric cancer found after Helicobacter pylori eradication

Early-stage gastric cancer (EGC) found after Helicobacter pylori (Hp) eradication is often difficult to diagnose using conventional white light (WL) endoscopy. We aimed to evaluate whether Texture and Color Enhancement Imaging (TXI), a new image-enhanced endoscopy enhances the EGC lesions after Hp eradication. We also compared diagnostic accuracy and lesion detection time between WL and TXI in trainee endoscopists. 58 EGC lesions after successful Hp eradication were enrolled. Using endoscopic images in WLI, TXI mode 1 (TXI1), and TXI mode 2 (TXI2), visibility of EGC was assessed by six expert endoscopists using a subjective score. Mean color differences (ΔE) of four matched adjacent and intra-tumoral points were examined. Using randomly allocated images, diagnostic accuracy and lesion detection time were evaluated in three trainee endoscopists. Visibility score was unchanged (Score 0) in 20.7% (12/58) and 45.6% (26/57), slightly improved (Score 1) in 60.3% (35/58) and 52.6% (30/57), obviously improved (Score 2) in 45.6% (26/58) and 1.8% (1/57), in TXI1 and TXI2 compared to WL, respectively. Mean ΔE ± SEM in TXI1 (22.90 ± 0.96), and TXI2 (15.32 ± 0.71) were higher than that in WL (1.88 ± 0.26, both P < 0.0001). TXI1 presented higher diagnostic accuracy compared to WL, in two of three trainees (94.8% vs. 74.1%, 100% vs. 89.7%, P = 0.003; < 0.005, respectively). Lesion detection time was shorter in TXI1 in two of three trainees (P = 0.006, 0.004, respectively) compared to WL. TXI improves visibility of EGC after Hp eradication that may contribute to correct diagnosis.

Color Stability of Nanoparticles-Modified Dental Resin-Based Composites

To evaluate the effect of beverages (coffee, tea, Cola-Cola, and mineral water) on the color stability of resin-based composite (RBC) materials modified with different nanoparticles (NPs). The specimens (70/beverage) were fabricated from light-cured RBCs and divided according to NPs into four groups: one control, unmodified (N0); and three experimental—ZrO2 (Zr), TiO2 (Ti), and SiO2 (Si) groups. Each experimental group was further subdivided into two subgroups according to NP concentrations: 3 wt.% and 7 wt.% (n = 10). A spectrophotometer was used to assess the color change (∆E) before and after six months of immersion. Data were analyzed and compared using one-way-ANOVA followed by Bonferroni’s post-hoc test (α = 0.05) and subsequently ∆E value conversion to National Bureau of Standards (NBS) units. The modified light-cured RBCs with ZrO2, TiO2, and SiO2 demonstrated smaller color changes after immersion in the beverages than the unmodified group (p &lt; 0.001). Zr groups showed the lowest ΔE, followed by Ti and Si groups; a 3% concentration resulted in a lower mean ΔE than the 7% concentration. NBS findings showed that coffee and tea produced marked unacceptable color changes (NBS units were &gt;3), and Coca-Cola resulted in noticeable color changes (NBS units between 1.5 and 3), while water produced slight color changes (NBS ≤ 1). Modification of RBCs with both concentrations of ZrO2, as well as 3% of TiO2 and SiO2, may improve its color stability. Based on NBS results, RBCs immersed in mineral water and Coca-Cola showed clinically acceptable color changes, while those immersed in coffee and tea were clinically unacceptable.

Evaluation of the Color Adjustment Potential of Single-Shade Composite Resin in Primary Teeth

Restoring composite resins with the optimal shades for all primary teeth is a great challenge for pediatric dentists. A newly developed single-shade composite resin can exhibit a color similar to that of the surrounding tooth structure based on the structural color phenomenon. This study aims to evaluate the color adjustment potential (CAP) of a single-shade composite resin compared to conventional multi-shade composite resins in primary teeth. A single-shade composite resin and two conventional multi-shade composite resins were included in this study. Two types of specimens, a single specimen and a dual specimen, were evaluated. For single specimens, duplications of the primary second molar denture teeth were made using experimental composite resins. For dual specimens, cavities were prepared on the buccal surfaces of extracted primary second molars and restored with experimental composite resins. The L*, a*, and b* values were measured using a colorimeter for the extracted teeth and specimens. The mean ΔE&lt;sub&gt;ab&lt;/sub&gt;&lt;sup&gt;*&lt;/sup&gt; values for single and dual specimens and CAP were calculated. Bonferroni post-hoc analysis was performed to confirm the statistical significance between the ΔE&lt;sub&gt;ab&lt;/sub&gt;&lt;sup&gt;*&lt;/sup&gt; and CAP values of the experimental resins. Among the single specimens, the single-shade composite resin showed significantly higher ΔE&lt;sub&gt;Single&lt;/sub&gt; compared to other composite resins (&lt;i&gt;p&lt;/i&gt; &lt; 0.0167). There was no significant difference between ΔE&lt;sub&gt;Dual&lt;/sub&gt; for all experimental resins. The single-shade composite resin showed highest CAP compared to other multi-shade composite resins. A single-shade composite resin exhibited the most prominent color adaptability compared to other conventional multi-shade composite resins for primary second molars. A single-shade composite resin can simplify shade matching and provide esthetic outcomes for the restoration of primary second molars.