Color Mismatch Research Articles

Baseline incision characteristics and early scar maturation indices following cardiac device implantation.

AimsDermatologic evaluation for cardiac implantable electronic devices (CIEDs) has not been established. We sought to ascertain baseline wound scar features using quantifiable surgical tools and scar scales on post‐CIED patients.MethodsA single‐center, prospective observational case‐control study was performed where 92 study subjects (40 healthy volunteers and 52 post‐CIED patients) completed the study. Durometer was used to quantify skin pliability before CIED placement, postprocedure, and 2 weeks postprocedure. Higher durometer readings signified reduced skin pliability. Durometer readings were compared to the patients’ contralateral pectoral skin and to a healthy volunteer's cohort skin within the prepectoral region. Patient wounds were observed and graded using the Patient Observer Scar Assessment Scale (POSAS) and Manchester Scar Scale (MSS).ResultsBaseline pectoral skin pliability readings were similar in healthy volunteers and CIED patient population. In comparison to preprocedural measurements, surgical site skin pliability decreased in postprocedural and 2 weeks follow‐up time points (P‐value .004 and <.001, respectively). The increases in durometer readings were higher in the older population (age >75 over time, P = .008). POSAS evaluations showed on average a thin painless hypopigmented scar with moderate stiffness. MSS scar evaluation showed a palpable scar with slight contour differences and color mismatch and appeared to be slightly better in the African American population. There was no difference in scar characteristics with preprocedural use of antiplatelet or anticoagulation or staple closure or gender.ConclusionsSerial measurements could be of value for development of new strategies for cosmesis and improved wound healing.

Effect of whitening toothpastes containing activated charcoal, abrasive particles, or hydrogen peroxide on the color of aged microhybrid composite

This study aimed to assess the effect of different whitening toothpastes containing activated charcoal, abrasive particles or hydrogen peroxide on the color of aged microhybrid composite. In this in vitro, experimental study, 45 composite discs (2 mm × 7 mm) were fabricated of a microhybrid composite. They underwent accelerated artificial aging for 300 h, corresponding to 1 year of clinical service. The composites were then randomly divided into five groups (n = 9). One group served as the control and underwent tooth brushing with distilled water. The remaining four groups underwent tooth brushing with Colgate Total whitening (Gt), Colgate Optic White (Go), Perfect White Black (Gp) and Bencer (Gb) toothpastes in a brushing machine The International Commission on Illumination values (Lm, am, bm) were determined using a spectrophotometer. Color change (ΔE) calculated based on this formula: ΔEm= ([ΔLm] 2 + [Δam] 2 + [Δbm] 2)½. The differences were defined by ΔE1 (after aging-baseline),ΔE2 (after brushing-after aging) and ΔE3 (after brushing-base line). ΔE1 were evaluated to ensure that color mismatch had occurred (ΔE1 > 5.5). Difference in (L, a, b) parameters after aging and after tooth brushing in each group, color parameter changes (ΔL2, Δa2, Δb2, ΔL3, Δa3, Δb3) and ΔE2 and ΔE3 were analyzed and compared using Wilcoxon test and independent sample median test at P = 0.05 level of significance. The color parameter changes, ΔE3 and Δ E2 were not significantly different among the five groups (P > 0.05). In Gp and Gb charcoal a*, b*, and L* after tooth brushing (P < 0.05). In Colgate Optic group, the a* parameter significantly decreased while the L* parameter significantly increased (P < 0.05). The results showed that there is no significant difference in the color change of Spectrum composite following tooth brushing with different whitening toothpastes for two weeks. It should be noted that Δ E3 reached to <3.3 only in charcoal whitening toothpastes.

Experimental assessment of pigment dispersion in compounding of plastics: Rheological characterization at the crossover points

Imparting colors to plastics is play a key role in the production of attractive products for a variety of consumer demands. It requires a good understanding of the processing conditions and formulation of compositions, including pigments and their dispersion. Key findings from these studies are studying the rheological characteristics of the compound of polycarbonate resins with different melt flow indexes and temperatures. The temperature was varied at three stages to study its effect on rheological characteristics and dispersions.The rheological behavior of grade was investigated using oscillatory rheometry at a variant temperatures, thereby improving the dispersion of pigments. Furthermore, it is determined that the crossover point (G″/G′) is considered as a good indication for higher pigment dispersion and lower color difference. However, the study will enable us to understand the dependence of the crossover points (G″/G′), which occurs at 255 °C at (72.6 Hz, 1.82 X105Pa). It is determined that the moving of the crossover point to a higher frequency as the temperature increases to 255 °C, is proportional to the temperature and higher shear rate. Lower viscosity improves pigment wetting, lowers color difference and ultimately results in higher dispersion occurs at or greater than the crossover point at 255 °C.Furthermore, many conclusions found here can be used to optimize compounding materials, studied effects of rheology, looked at the effects of processing parameters on dispersion, pigment size distribution (PSD), and the morphology of pigments in polycarbonate compounds. In general, the total color difference decreased when processing parameters were increased. De-agglomeration occurred in zones of high shear and was found to significantly increase the number of particles and generate an efficient dispersion process, and hence reduce color mismatch so that wastage is minimized.

Scar Appearance and Patient Satisfaction after the Tear Trough Incision for External Dacryocystorhinostomy

Background: Postoperative scar is the major disadvantage of external dacryocystorhinostomy (DCR). Modified incision should be performed to reduce postoperative scarring. Objective: To evaluate scar appearance and patient satisfaction after the tear trough incision for external DCR. Materials and Methods: The present study was a descriptive study with information collected by telephone survey and retrospective chart review. Patients that underwent external DCR over a period of eight years were enrolled and completed the validated Patient Scar Assessment Questionnaire (PSAQ). Scar appearance, consciousness, symptom, and satisfaction were determined. Patient demographics, surgical information, and postoperative scar evaluation using the Scar Cosmesis Assessment and Rating (SCAR) scale were obtained from the medical records. Results: Fifty-eight patients responded to the telephone interview with 71 DCR surgeries performed. The most common scar characteristic and symptom reported by patients was color mismatch in 11.3% of scars and itching in 15.5%. Scar evaluated by patients was invisible in 57.7% of scars, minimally visible in 40.8%, and moderately visible in 1.4%. Among all patients with noticeable scars, 92% of these made no attempt to conceal the scars. The average patient scar grade was 0.44 (scale 0 to 3). The majority (93.1%) of patients were very satisfied with the scar outcome. Of the 64 scars evaluated by physician using the SCAR scale, common scar characteristics were scar spread (40.6%), hypopigmentation (15.6%), and hypertrophic scar (12.5%). The scar evaluated by physician was invisible in 59.4% of scars, minimally visible in 34.4%, and moderately visible in 6.3%, with an average scar grade of 0.47 (scale 0 to 3). Conclusion: The tear trough incision for external DCR results in minimal postoperative scarring, providing a very high satisfaction rate in most patients. Keywords: External dacryocystorhinostomy, DCR, Scar, Tear trough incision, Patient satisfaction

Effect of Hairiness on Fabric Colour Characteristics

Designing the colour appearance of textiles requires taking into account their surface properties, hairiness among others. The villi protruding on the surface not only affect the quality of textile dyeing, but also largely determine its optical properties and the colour phenomenon. The analysis of studies of optical properties shows that the influence of hairiness on the phenomenon of colour is not well understood and that the amount of hairiness at which colour changes become significant for human perception remains indefinable. In this work, we studied the change in colour characteristics depending on the change in the hairiness of woollen fabrics, comparing “yarn – raw fabric”, “yarn – raised fabric”, “raw fabric – raised fabric”. Hairiness was estimated by the hairiness index, which was obtained from the analysis of sample microphotographs of yarn and fabric using software. The value of colour characteristics (lightness, chroma and colour difference) was measured in the CIELAB colour space (1976) using a spectrophotometer. The obtained experimental results showed that the changes in lightness and saturation of textile materials from the index of its hairiness are directly proportional. However, the value of changes is different for raw and napped fabrics, undyed and dyed samples, the initial colour hue and raw material composition also making certain adjustments. This study analysed the colour difference and established the level of variation in hairiness at which the colour mismatch between woollen fabrics becomes visually noticeable. The results of the study can be used to predict the colour and design the optical properties of fabrics for weaving and finishing.

Observer metamerism to display white point between LCD and OLED displays

Displays with different primary sets were found to introduce perceived color mismatch between pairs that are computationally metameric and to affect the degree of observer metamerism. OLED display is becoming more and more popular than LCD display in different imaging systems. In this study, human observers used an LCD and eight OLED displays to match the color appearance of a D 70 white stimulus produced by a spectrally tunable LED device. It was found the chromaticities of the LCD display were significantly different from those of the OLED displays to achieve a match. When the colors were adjusted to have matched appearance, the chromaticities of the OLED displays were always shifted towards closer to the blackbody locus using the CIE 1931 Color Matching Functions (CMFs). The results also suggested that the CIE 2006 2° Color Matching Functions had the best performance.

Does background color influence visual thresholds?

ObjectiveTo evaluate the influence of neutral color backgrounds on visual thresholds using three color difference metrics: CIELAB, CIEDE2000(1:1:1) and CIEDE2000(2:1:1). MethodsSixty observers (dentists and laypersons; n = 30) from three countries participated in the study. A psychophysical experiment based on visual assessments of simulated images of teeth on a calibrated display was performed. Images of simulated upper central incisors (SUCI) were consecutively displayed in pairs (60) on 3 neutral color backgrounds (black, grey and white). Three color difference metrics (CIELAB, CIEDE2000(1:1:1), and CIEDE2000(2:1:1)) were used to calculate the visual thresholds (PT- perceptibility threshold; and AT- acceptability threshold) with 95 % confidence intervals (CI) and a Takagi-Sugeno-Kang (TSK) Fuzzy Approximation model was used as fitting procedure. Data was statistically analyzed using paired t-test (p = 0.05). ResultsThe50:50 % PT values were significantly lower over white background than over black background. The 50:50 % AT values were significantly greater over white background than over grey and black backgrounds. In most cases, the thresholds (PT and AT) values were significantly different for each color different metric over each background color (p ≤ 0.05). No difference was found between observers for PT and AT values. ConclusionsThe perceptibility and acceptability thresholds in dentistry are affected by the color difference metrics and by the background color. SignificanceDental color mismatches are more difficult to be accepted over a white background.

RETROSPECTIVE ANALYSIS OF THE STATE OF DIRECT DENTAL RESTORATIONS AFTER ENDODONTIC TREATMENT

Endodontic treatment is accompanied by the loss of a significant amount of tooth crowns, which leads to a significant decrease in their strength characteristics. The restoration of endodontically treated teeth, as a rule, is carried out by the direct method, however, a unified approach regarding direct or indirect restoration has not yet been determined. The aim – retrospective analysis of the clinical condition of direct restorations of endodontically treated teeth. Materials and methods. 284 patients aged 25 to 60 years were examined; they studied the state of 888 previously performed direct restorations of the anterior and posterior teeth after endodontic treatment in a period of 2 to 10 years. Restorations were evaluated according to the adapted clinical criteria “integrity of the restoration”, “marginal fit of the material”, “marginal staining”, “anatomical shape”, “colour correspondence for the restoration”, “roughness of the surface of the material”, as well as the criterion “condition of the contact point” for located on the contact surfaces of the teeth of the restorations. Results. Of the 888 examined direct restorations, 760 restorations (85.6±1.18 %) were located in the posterior teeth, with 562 restorations in the molars (63.3±1.62 % of the total) and 198 in the premolars (22 , 3±1.40 %), and 128 restorations (14.4±1.18 %) were detected in the anterior teeth, while in the incisors - 80 restorations (9.0±0.96 %), in the fangs – 48 (3.5±0.76 %). 720 restorations (81.1±1.31 %) were made from photocomposite materials, 97 restorations (10.9±1.05 %) from chemical curing composites, 71 (8.0±0.91 %) from glass-ionomer cements . The most common violations were colour mismatch – in 511 restorations (57.5±1.66 %), marginal staining - in 470 restorations (52.9±1.68 %), surface roughness - in 357 restorations (40.2±1.0, 65 %). More often than others, in the reconstructions of their photocomposites and glass ionomers there was a colour mismatch, and surface roughness for chemical composites. Conclusions. For direct tooth restoration after endodontic treatment in 81.1±1.31 % of cases, photocomposite materials are used, less often chemical curing composites and glass ionomers. Of the violations of such restorations, the most frequent are colour mismatch, surface roughness and edge staining.

Effect of fluorescent and nonfluorescent glaze pastes on lithium disilicate pressed ceramic color at different thicknesses

Statement of problemMaterials possessing fluorescent properties are assumed to emit sufficient visible light to change tooth color under daylight illumination. Fluorescent and nonfluorescent glaze pastes are available to finish the surface of a pressed lithium disilicate restoration. However, the effect of a fluorescent-glaze layer on the final color of the restoration remains unclear. PurposeThe purpose of this in vitro study was to measure the color dimensions of lithium disilicate glass-ceramic with different thicknesses and different surface treatments under daylight (D65) illumination conditions. Material and methodsA total of 120 pressed lithium disilicate glass-ceramic disks were fabricated with 4 different thicknesses: 0.7, 1.2, 1.7, and 2.2 mm. In each thickness, 3 different subgroups were created based on the surface treatment performed (n=10): polished (NG), clear glaze (CG), and fluorescent glaze (FG). For the NG group, disks were polished with 180-, 320-, 600-, 800-, and 1400-grit SiC papers and a polishing machine. For the glazed groups, the CG and FG groups, the specimens were polished with 180-grit SiC papers and the same polishing machine. After the polishing sequence, the final thickness was verified in all groups by using digital calipers (0.5, 1.0, 1.5, and 2.0 mm). Additionally, 20 μL of clear glaze or fluorescent glaze was applied on the CG and FL groups by using an electronic positive displacement repeating pipette. The glaze layer was crystallized in a furnace according to the manufacturer recommendations. Color measurements in the CIELab coordinates were made with a spectrometer coupled to an integrating sphere and a standardized photography gray card as a background. Color difference (ΔE) values were calculated by using the CIE76 and CIEDE2000 formulas. The Shapiro-Wilk test revealed that the data were normally distributed. Two-way ANOVA and the Bonferroni test for multiple comparisons were used to analyze the data (α=.05). ResultsStatistically significant differences were found among the groups for the L∗, a∗, and b∗ values for the different ceramic thicknesses and surface finishing treatments evaluated (P<.001), except for the b∗ value between the FG and CG groups (P=.988). The L∗ value on the polished group was significantly higher than that on the glazed specimens, followed by the fluorescent-glazed and then by the clear-glazed specimens (P<.001). The ΔE values using the CIE76 formula varied from 0.87 to 2.76 among specimen groups and from 0.32 to 2.34 using the CIEDE2000 among the tested groups. ConclusionsCeramic thickness and surface finishing treatment affected all color dimensions (L∗, a∗, and b∗ values) of lithium disilicate ceramic under daylight conditions. These differences resulted in a perceptible but acceptable color mismatch. The value (L∗ color dimension) of the lithium disilicate ceramic was higher on fluorescent-glazed than on not–fluorescent-glazed specimens.

Observer metamerism to display white point using different primary sets.

Displays with different primary sets were found to introduce perceived color mismatch between stimuli that are computationally metameric and to affect the variations of the perceived color difference of metameric stimuli among observers (i.e., observer metamerism). In this study, computational analyses and psychophysical experiments were carried out to investigate the possibilities of increasing the color gamut area of a commercially available liquid crystal display (LCD) system using 16 three-primary sets, so that the perceived color difference of the white point between the system and the reference display and observer metamerism can be minimized. It was found the primary set with the peak wavelengths of 450, 525, and 665 nm was able to increase the sRGB color gamut by 72.1% in the CIE 1931 chromaticity diagram, which was found to have a strong correlation to the color volume of wide color gamut displays, while introducing the minimal color mismatch to the white point of the reference display and observer metamerism. The small white point color mismatch could be due to the similar wavelengths of the blue and green primaries in comparison to the reference display. In addition, the experiment results suggested that the CIE 2006 2° Color Matching Functions (CMFs) had better performance in characterizing the color match of the white point than the CIE 1931 2°, 1964 10°, and 2006 10° CMFs, which could be due to the fact that the stimulus used in the experiment only had a field of view (FOV) around 3.8°.

Snow-mediated plasticity does not prevent camouflage mismatch

Global reduction in snow cover duration is one of the most consistent and widespread climate change outcomes. Declining snow duration has severe negative consequences for diverse taxa including seasonally color molting species, which rely on snow for camouflage. However, phenotypic plasticity may facilitate adaptation to reduced snow duration. Plastic responses could occur in the color molt phenology or through behavior that minimizes coat color mismatch or its consequences. We quantified molt phenology of 200 wild snowshoe hares (Lepus americanus), and measured microhabitat choice and local snow cover. Similar to other studies, we found that hares did not show behavioral plasticity to minimize coat color mismatch via background matching; instead they preferred colder, snow free areas regardless of their coat color. Furthermore, hares did not behaviorally mitigate the negative consequences of mismatch by choosing resting sites with denser vegetation cover when mismatched. Importantly, we demonstrated plasticity in the initiation and the rate of the molt and established the direct effect of snow on molt phenology; greater snow cover was associated with whiter hares and this association was not due to whiter hares preferring snowier areas. However, despite the observed snow-mediated plasticity in molt phenology, camouflage mismatch with white hares on brown snowless ground persisted and was more frequent during early snowmelt. Thus, we find no evidence that phenotypic plasticity in snowshoe hares is sufficient to facilitate adaptive rescue to camouflage mismatch under climate change.

Clinical Results of Ear Elevations in Patients with Microtia Using Skin Grafts from Three Donor Sites: A Retrospective Study.

Skin grafts, frequently used for ear elevation in ear reconstructions, may suffer from color mismatches, scar hypertrophy, secondary contraction, and auricular sulcus depth differences. To determine the most suitable donor area, we compared the contralateral postauricular area, groin, and scalp as potential donor sites. Since 2008, we have used three donor sites for obtaining skin grafts used in ear reconstructions. Full-thickness groin skin, split-thickness grafts from the scalp, and contralateral postauricular and groin composite full-thickness skin grafts were used in 202, 231, and 195 patients, respectively. Photographic assessments were used to assess color matching, sulcus depth, cranioauricular angle symmetry, and flatness of the skin grafts; surgical complications were also documented. Among the three donor sites, there were no significant differences in the color matching scores (p = 0.456). The scalp donor scores had significantly lower mean scores for sulcus depth and symmetry and for graft flatness scores than the other donor sites. The assessment scores between the groin and postauricular donor groups were similar. Each donor site was associated with some surgical complications. However, postauricular skin, when combined with groin skin, demonstrated the best cosmetic results and the fewest complications. All three donor sites are viable options for skin graft donor sites in ear elevation surgeries. Although the advantages and disadvantages of each site should be explained to the patient, the ultimate donor site selection may be determined according to patient and surgeon preferences. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Comparison of visual analog shade matching, a digital visual method with a cross-polarized light filter, and a spectrophotometer for dental color matching

Statement of problemDuring the selection of tooth color, subjective communication with the laboratory and an incorrect color registration technique can lead to a poor color match of a restoration to adjacent teeth and oral structures. PurposeThe purpose of this cross-sectional study was to compare color registration and color matching in a young Chilean population with 3 different methods: visual with a shade guide, digital visual with a cross-polarized filter, and instrumental with a spectrophotometer. Material and methodsA total of 60 young volunteers were selected for tooth color registration of the maxillary right central incisor by using 3 different methods. Tooth color registration was performed using the CIELab and ΔE coordinate system. ResultsSignificant differences were detected between the coordinates recorded by the visual analog method in comparison with the other 2 methods. In contrast, no significant differences were found between the L∗ and b∗ coordinates of the spectrophotometer and the digital visual method with use of a cross-polarization filter. The ΔE obtained between the visual shade and spectrophotometer was 7.35, and the ΔE between the digital visual method with the use of a cross-polarization filter and the spectrophotometer was 6.12. ConclusionsNo statistically significant differences were observed in the digital image with the cross-polarization filter and the spectrophotometer in the L∗ and b∗ coordinate of the CIELab system. In contrast, the visual analog method led to large differences with the other methods under study. The ΔE of the digital visual method with the use of cross-polarization filters and the spectrophotometer was 6.2, considered as an acceptable color mismatch (<ΔE 6.8).

A randomized controlled study comparing guided bone regeneration with connective tissue graft to re-establish buccal convexity: One-year aesthetic and patient-reported outcomes.

To compare guided bone regeneration (GBR) with connective tissue graft (CTG) in terms of aesthetic and patient-reported outcomes (PROMs). Patients with a single tooth gap in the anterior maxilla and horizontal alveolar defect were enrolled in a single-blind RCT. All sites had a buccopalatal bone dimension of at least 6mm, received a single implant and were randomly allocated to the control (GBR) or test group (CTG) to re-establish buccal soft tissue convexity. Primary outcomes were Pink Esthetic Score (PES) and Mucosal Scarring Index (MSI) assessed after 1year. Secondary outcomes included PROMs registered during the early stages of healing and after 1year. Twenty-one patients were included per group (control: 11 females, mean age 51; test: nine females, mean age 48). Although there was no significant difference in the PES between the groups (control: 10.11; test: 10.48; p=.577), the MSI was significantly lower in the test (1.10) than in the control group (2.53) (p=.017). Based on descriptive statistics, the latter demonstrated wider scars, more colour mismatch and slightly more suture marks. However, these were not considered disturbing by the patients given similar VAS on soft tissue aesthetics (control: 84; test: 87). Oedema and haematoma were rated twice as high in the control group on at least two postoperative time points, and patients took more painkillers (7.10 vs. 4.86). OHIP-14 decreased in both groups between baseline and 1-year follow-up, indicative of less discomfort in daily life. Differences in MSI and PROMs between the groups may be explained by the need of a vertical releasing incision in order to achieve sufficient access for GBR, periosteal incisions and the use of biomaterials that may induce inflammation. GBR and CTG resulted in favourable aesthetic outcomes as assessed by professionals and patients. However, given additional vertical and periosteal incisions, GBR resulted in more scarring, postoperative discomfort and a higher need for painkillers.

Dermopigmentation of the nipple-areola complex in a dedicated breast cancer centre, following the Treviso Hospital (Italy) LILT model.

Dermopigmentation, also known as medical tattooing, is a complementary technique in the reconstruction of the nipple-areola and an adjuvant procedure to improve colour mismatch. In 2009, tattooing of the nipple-areola complex (NAC) was introduced by Treviso Hospital through a project conducted in cooperation with the local section of the Italian Anti-Cancer League (LILT). From 2010 to 2016, 169 patients treated for breast cancer underwent dermopigmentation treatments. Patients were selected by the hospital plastic and breast surgeons. Dermopigmentation was performed at the LILT (Lega Italiana per la Lotta contro i Tumori, Italian Cancer League) facility following a specific procedure to ensure safety. A sterile disposable surgical set was used. Of 169 patients treated in 309 treatment sessions, no serious complications were reported after tattooing, with only three cases seen of minor complications. Patients expressed a high level of satisfaction (90%) with the aesthetic results. The study found that dermopigmentation of the NAC is a safe approach, providing benefits both to the patients and the hospital itself. Medical tattooing of the NAC is a simple and safe nonsurgical technique that reduces missed workdays and increases the time available for other commitments. This ultimately translates into savings for society and the healthcare system.

Evaluation of Color and Width of Attached Gingiva Gain in Two Surgical Techniques: Free Gingival Graft and Connective Tissue Graft Covered By Thin Mucosal Flap, a Clinical Trial.

Statement of the Problem:The periodontal health and marginal stability of gingiva can be negatively affected by a number of dental conditions in association with deficiency of attached gingiva. Purpose:This study aimed to compare the color and width of tissue grafted by two surgical techniques of keratinized gingival augmentation, namely free gingival graft(FGG) and connective tissue graft (CTG) covered by thin mucosal flap . Materials and Method: This clinical trial was performed on 15 adult individuals. The patients showed less than 2mm keratinized gingiva on two different recipient sides. One side was to be treated with CTG as the test group and the other side to be treated with FGG as the control group. The amount of keratinized gingiva before the surgery, size of grafted tissue during the surgery and 6 month after the surgery was documented. Six months after healing, the test and control sides were compared in terms of the width of generated gingiva on both sides, and the color match of the grafted areas with the surrounding gingiva or mucosa. The color of the grafted areas was determined and compared by using both professional evaluation and digital evaluation. Results: In digital evaluation, ∆E (which shows color mismatch) was higher in FGG. In professional evaluation, visual analogue scale (VAS) was used by two blinded periodontists. The mean VAS in FGG was less than CTG. The mean increase of gingival width was higher in CTG. The increased width in CTG technique was more than that in FGG technique. This difference was statistically, but not clinically, significant. Conclusion:Higher ∆E in control side and higher mean VAS CTG both showed better color adaptation of CTG side. FGG can be used in case of increasing keratinized gingiva, vestibular depth, and in patients with low smile line without esthetic concerns. However, using connective tissue in the underlying thin mucosal layer is preferred for gingival augmentation if there are adequate vestibule depth and esthetic concerns, like in maxillary canine.

Applicability of colour transfer techniques in Twelve fringe photoelasticity (TFP)

Colour adaptation techniques are useful in extending the method of Twelve fringe photoelasticity (TFP) to solve problems in industries as one can minimise the generation of specific calibration tables for each experiment. Image artefacts affect the functioning of existing colour adaptation techniques affecting the fringe order demodulation. Colour transfer is a popular technique in the field of image processing to tackle colour mismatch between images. In this paper, the applicability of two colour transfer strategies in the context of TFP is explored, of which one is selected for implementation. A comparative study on the performance of the novel colour transfer method with the existing colour adaptation techniques is carried out.

Outcome of Repeated Use of Donor Site for Noncultured Epidermal Cellular Grafting in Stable Vitiligo: A Retrospective Study.

Background Noncultured epidermal suspension (NCES) is a surgical technique which employs cellular grafting onto depigmented lesions. However, scarring and dyschromia at the donor site often occurs. Objective To assess the outcome of reusing the same donor site in subsequent sessions of NCES procedures. Methods Electronic records of vitiligo patients who had undergone two sessions of NCES procedures were retrospectively reviewed. Information on the first and second NCES was retrieved for analyses. Results A total of 30 patients (female 19 and male 11) were included. The majority of patients had nonsegmental vitiligo (66.7%). The median donor-to-recipient ratios were 1 : 3 (1 : 1–1 : 20) for the first session and 1 : 3 (1 : 1–1 : 13.5) for the second session (p=0.661). The mean melanocyte count was 220.7 ± 65.5 cells/mm2 vs. 242.4 ± 55.3 cells/mm2 on the first and second sessions, respectively (p=0.440). The mean repigmentation rate was 84.2% (±21.1%) and 82.3 (±22.1%) for the first and second NCESs, respectively (p=0.645). The frequency of color mismatch and pigment loss were similar between both sessions (p=0.706 and p=1.000). Conclusions Repeated use of donor sites in subsequent NCES sessions gave comparable repigmentation.

КЛИНИЧЕСКАЯ ОЦЕНКА ФИКСИРОВАННЫХ ЗУБНЫХ ПРОТЕЗОВ НА КОБАЛЬТ-ХРОМОВОЙ ОСНОВЕ

Subject. Ceramic-metal prostheses are distinguished by high wear resistance, resistance to deformation, and tight fit to the gums. However, there are relatively large differences in determining the success / survival of cobalt chromium based restorations. The article presents the results of a study of cobalt-chromium fixed dentures.&#x0D; Objectives — evaluate the effectiveness of cobalt-chromium fixed dentures made using the direct metal laser sintering (DMLS) technique. &#x0D; Material and methods. 32 patients (mean age 41.8 ± 2.46 years) were found to have 54 fixed cobalt-chromium fixed bridges made using direct laser sintering of metals. Dentures were evaluated between 6, 12, 24, 36 months according to G. Ryge criteria. The survival rate of restorations is calculated according to Kaplan-Meyer. &#x0D; Results. Assessment of fixed prostheses revealed the absence of criteria C and D in all 3 categories. A comparative analysis of prostheses showed no change in the period 6, 12, 24 months. After 36 months, chips that did not violate the function of the prosthesis were revealed in 5.5 % of cases, visible signs of a cleft in the category of “marginal adaptation” in 1.8 % of cases, edge discoloration of the surface in 3.7 % of cases. Radiographically, 1 patient showed signs of incipient proximal caries and periapical changes, respectively. During the study period of 6-24 months. survival rate was 1.0. The survival of the restoration over a 3-year period was 88.9 %. &#x0D; Conclusion. The frequency of cleavage was 5.5 %, which is comparable to the usual performance of ceramic-metal restorations. The visible signs of a cleft in the regional adaptation was 1.8 %, and the regional color mismatch was 3.7 %. 1.8 % of restoration was detected. Signs of incipient proximal caries were 1.8 %, periapical changes — 1.8 %. Survival was 88.9 %.

Color dimensions of additive manufactured interim restorative dental material

Statement of problemInterim dental restorations can be fabricated by using additive manufacturing (AM) technologies. Although dental restoration contours can be easily and accurately fabricated by using computer-aided design (CAD) procedures, protocols for creating predictable color dimensions of AM interim restorations are lacking. PurposeThe purpose of this in vitro study was to measure and compare color dimensions of different AM and conventional interim restorative materials. Material and methodsDisks (N=420) were fabricated by using either conventionally (CNV group) or additively manufactured (AM group) materials. The CNV group was further divided into the subgroups CNV-1 (Protemp 4; 3M ESPE) and CNV-2 (Anaxdent new outline dentin; Anaxdent). AM subgroups included AM-1 (FreePrint temp; Detax), AM-2 (E-Dent 400; Envisiontec), AM-3 (NextDent C&B; NextDent), AM-4 (NextDent C&B MFH; NextDent), and AM-5 (Med620 VEROGlaze; Stratasys). Color measurements in the CIELab coordinates were made by using a spectrophotometer (VITA EasyShade Advance 4.0; VITA) with a standardized photography gray card as a background under room light conditions (1003 lux). Color difference (ΔE*) values were calculated by using the CIE76 and CIEDE2000 formulas. The data were analyzed by using the Kruskal-Wallis test with nonparametric pairwise comparisons. ResultsOwing to a software error, the spectrophotometer was unable to measure the color of any specimens in the AM-5 subgroup, which was consequently excluded from further analysis. Significant differences (P=.001) between 2 manufacturing groups were found based on the L* variable. All subgroups were significantly different from each other for all 3 variables (P<.001). Pairwise comparisons revealed that all groups were significantly different from each other, except for the AM-1 and AM-2 subgroups, compared with the CNV-1 subgroup for the L* color dimension. The ΔE* values calculated by using the CIE76 formula varied from 6.63 to 23.1 and by using the CIEDE2000 formula from 3.43 to 10.21, suggesting a perceptible and unacceptable color mismatch between the CNV and AM groups. ConclusionsNone of the additively manufactured interim materials tested matched the conventional interim materials in all 3 CIELab color dimensions.