Color variations in PMMA acrylic resins after thermocycling and mouthwash simulation / Variações de cor em resinas acrílicas de PMMA após termociclagem e simulação de enxaguatório bucal

Estabilidade de cor é um requisito estético fundamental das resinas acrílicas provisórias, em especial quando esses materiais são submetidos a longos períodos na cavidade oral. Embora resinas acrílicas temporárias novas e aprimoradas estejam disponíveis, os efeitos da variação térmica e de soluções antissépticas na estabilidade de cor de resinas acrílicas provisórias ainda não foram completamente elucidados. Portanto, este estudo avaliou a coloração de resinas autopolimerizáveis polimetilmetacrilato (PMMA) e bis-acrilo submetidas à termociclagem e imersão em clorexidina. Amostras padronizadas (n=10) foram preparadas de duas resinas acrílicas temporárias a base de PMMA (Alike® e Duralay®). Foram realizadas três avaliações de cor (T1 ­ 24h após o preparo da amostra, T2 ­ após termociclagem e T3 ­ após termociclagem e imersão em clorexidina) por meio de espectrofotômetro eletrônico de seleção de sombra (Vita Easy Shade). Os dados obtidos foram analisados por ANOVA e teste t (α=0,05). As resinas de PMMA Alike e Duralay apresentaram alteração de cor após a termociclagem e também após a imersão em clorexidina.

Color stability is a fundamental aesthetic requirement for temporary acrylic resins, especially when these materials are subjected to long periods in the oral cavity. Although new and improved temporary acrylic resins are available, the effects of thermal variation and antiseptic solutions on the color stability of temporary acrylic resins have not yet been fully elucidated. Therefore, this study evaluated the color of self-polymerizing resins polymethyl methacrylate (PMMA) and bis-acryl subjected to thermocycling and immersion in chlorhexidine. Standardized samples (n=10) were prepared from two PMMA-based temporary acrylic resins (Alike® and Duralay®). Three color evaluations were carried out (T1 ­ 24h after sample preparation, T2 ­ after thermocycling and T3 ­ after thermocycling and immersion in chlorhexidine) using an electronic shade selection spectrophotometer (Vita Easy Shade). The data obtained were analyzed by ANOVA and t test (α=0.05). PMMA Alike and Duralay resins showed color changes after thermocycling and also after immersion in chlorhexidine.

The role of color Doppler and multidetector CT angiography in evaluation of peripheral arterial diseases of lower limb

Background: Characterized by atheromatous narrowing and hardening of arteries supplying blood to the legs and feet. Diabetes, along with other risk factors such as hypertension and smoking, exacerbates the prevalence and severity of PAD, leading to decreased blood flow and subsequent tissue injury. The prevalence of PAD in diabetics rises with age, underscoring the importance of early detection and management strategies. Methods: This study aims to evaluate the efficacy of color Doppler and MDCT Angiography in assessing lower limb peripheral arterial diseases. Conducted over twenty-four months, the cross-sectional study involved clinically suspected symptomatic cases aged 30 years and above, presenting at a tertiary care center. Patients underwent thorough clinical examination and demographic assessment before undergoing Color Doppler flowmetric studies and MDCT angiography. Results: Results revealed that color Doppler, with its ability to measure wall thickness and vascular flow, demonstrated promising diagnostic efficacy compared to MDCT angiography. Additionally, follow-up records of patients undergoing medical or surgical interventions provided valuable insights into the practical utility of these imaging modalities in guiding clinical management decisions. Conclusions: Overall, this study underscores the importance of non-invasive imaging techniques in diagnosing and evaluating the progression of peripheral arterial diseases. It suggests that Color Doppler Ultrasound, with its accessibility, low cost, and radiation-free nature, could serve as a suitable alternative to MDCT Angiography for assessing arterial characteristics in patients with PAD.

The visual and instrumental analyses of different single-shade resin composites / Análisis visual e instrumental de diferentes resinas compuestas omnicromáticas

Abstract The purpose of this study was to evaluate the color adaptation of single-shade resin composites applied to different tooth shades. A total of 108 class III preparations (n=6) were performed on the acrylic denture maxillary incisors (2mm depth and 2mm height). 5 single-shade resin composites (Vittra APS Unique, Omnichroma, ZenChroma, Clearfil Majesty ES-2 Universal, Charisma Topaz One) and 1 multishade resin composite (Estelite Asteria) were placed in the cavities and polished. I performed visual and instrumental color analyses. The CIEDE2000 formula was used to assess the shade differences (ΔE) between teeth and restorations. The obtained ΔE values were recorded and statistically analyzed. For the instrumental analysis, ZenChroma in A1 shade groups showed statistically significant higher differences (p<0.05). Among all tested materials, A3 shade groups showed lower ΔE values (p<0.05). For the visual analysis, there were no significant differences between materials and scores in A1 and A3 shade groups (p>0.05). There were statistically significant differences between the materials and the scores in A2 shade groups (p<0.05). As a result of this study, it was concluded that, making esthetic restorations with single-shade resin composites promises proper color adaptation, but their properties still need improvement. Single-shade resin composites can reduce chair-time and technical sensitivity with good color matching.

Resumen El objetivo de este estudio fue evaluar la adaptación del color de resinas compuestas omnicromáticas. Se realizaron un total de 108 preparaciones de clase III (n=6) en los incisivos superiores de prótesis acrílicas (2mm de profundidad y 2mm de altura). Se colocaron cinco resinas compuestas omnicromáticas (Vittra APS Unique, Omnichroma, ZenChroma, Clearfil Majesty ES-2 Universal, Charisma Topaz One), además de una resina multitono (Estelite Asteria) en las cavidades y se pulieron. Se realizó el análisis de color visual e instrumental. Se utilizó la fórmula CIEDE2000 para evaluar las diferencias de tono (ΔE) entre dientes y restauraciones. Los valores de ΔE obtenidos se registraron y analizaron estadísticamente. Para el análisis instrumental, ZenChroma en los grupos de color A1 mostró diferencias mayores estadísticamente significativas (p<0,05). Entre todos los materiales probados, los grupos de tonos A3 mostraron valores de ΔE más bajos (p<0.05). Para el análisis visual, no hubo diferencias significativas entre materiales y puntuaciones en los grupos de color A1 y A3 (p>0,05). Hubo diferencias estadísticamente significativas entre los materiales y las puntuaciones en los grupos de color A2 (p<0,05). Como resultado de este estudio, se concluyó que la realización de restauraciones estéticas con resinas compuestas omnicromáticas promueve una adecuada adaptación del color, pero aún necesitan mejorar sus propiedades. Las resinas compuetas omnicromáticas pueden reducir el tiempo de atención clínica y la sensibilidad técnica con una adecuada combinación de colores.

Nuevos registros de aves con alteraciones de color de Ecuador / New records of birds with color alterations from Ecuador

Resumen Reportamos seis nuevos casos de aves silvestres con aberración cromática provenientes de cuatro provincias de Ecuador. Los registros fotográficos provienen de observaciones oportunistas. El presente es el primer registro de plumaje aberrante para Anas bahamensis, Florisuga mellivora, Opisthocomus hoazín, Dendrocincla fuliginosa y Asemospiza obscura; mientras que se suman casos de individuos aberrantes en Turdus fuscater. El caso de F. mellivora es el más relevante por su rareza y evidencia patrones de coloración en la especie. Resaltamos la importancia de documentar y publicar el encuentro de estos eventos.

Abstract We report six new cases of wild birds with chromatic aberration from four provinces of Ecuador. The photographic records come from opportunistic observations. This is the first record of aberrant plumage for Anas bahamensis, Florisuga mellivora, Opisthocomus hoazín, Dendrocincla fuliginosa y Asemospiza obscura; while cases of aberrant individuals are added in Turdus fuscater. The case of F. mellivora is the most relevant due to its rarity and evidence of coloration patterns in the species. We highlight the importance of documenting and publishing the encounter of these events.

Influencia del termociclado sobre la estabilidad del color de dos resinas compuestas / Influence of thermocycling on the color stability of two composite resins

Objetivo: Cuando las resinas compuestas son expuestas a procesos de envejecimiento naturales en boca, como es el ciclaje térmico, pueden sufrir un deterioro en sus propiedades ópticas. El objetivo de este estudio fue evaluar la influencia del envejecimiento térmico sobre la estabilidad del color de dos resinas compuestas. Materiales y métodos: Se confeccionaron 120 pas- tillas de resinas compuestas, divididas en dos grupos: uno de resina Spectra Smart (n=60) y otro de resina Filtex Z350 XT (n=60). Estas muestras fueron sometidas a distintos regíme- nes de ciclaje térmico de 0, 10.000, 20.000 y 30.000 ciclos con temperaturas de entre 5 ºC +/- 2 ºC y 55 ºC +/- 2 °C. Los parámetros de color CIE L*a*b* de cada muestra se mi- dieron con un espectrofotómetro antes y después del proceso de envejecimiento. Las diferencias de color se calcularon me- diante la fórmula CIELAB (ΔE). Los datos fueron analizados estadísticamente usando la prueba no paramétrica de Kruskal Wallis y de U-Mann Whitney. Resultados: Los distintos regímenes de termociclado produjeron cambios de color estadísticamente significativos en ambos materiales. El material que tuvo menor estabilidad cromática fue Spectra Smart aunque sin diferencias estadísti- camente significativas. Conclusión: El envejecimiento térmico simulado a tres años afecta la estabilidad de color de las muestras, tanto de las resinas Spectra Smart, como de Filtex Z350 XT, sin alcanzar los valores que clínicamente determinarían la necesidad del reemplazo de las restauraciones (AU)

Aim: When composite resins are exposed to natural ag- ing processes in the mouth, such as the thermal cycling, they may suffer a deterioration in their optical properties. The aim of this study was to evaluate the influence of thermal aging on the color stability of two composite resins. Materials and methods: 120 composite resins tablets were made, divided into two groups: one of Spectra Smart res- in (n=60) and another of Filtex Z350 XT resin (n=60). These were subjected to different thermal cycle regimes of 0, 10,000, 20,000 and 30,000 cycles with temperature between 5 °C +/- 2 °C and 60 °C +/- 2 °C. The CIE L*a*b* color parameters of each sample were measured with a spectrophotometer before and after the aging process. Color differences were calculat- ed using the CIELAB formula (ΔE). The data were statisti- cally analyzed using the non-parametric Kruskal Wallis and U-Mann Whitney tests. Results: The different thermocycling regimes produce statistically significant color changes in both materials. The material that had the least chromatic stability was Spectra Smart, although without statistically significant differences. Conclusion: Simulated 3 year thermal aging affects the color stability of the samples, both Spectra Smart resins and Filtex Z350 XT, without reaching the values that would clini- cally determine the need to replace the restorations (AU)

Research progresses of superb microvascular imaging in musculoskeletal diseases / 中国医学影像技术

Superb microvascular imaging(SMI)is a new kind of Doppler technology,being sensitive for displaying low-velocity microvascular blood flow in muscles,tendons,synovium,nerves and reflecting microcirculation changes,able to provide imaging evidences for diagnosing musculoskeletal system diseases,monitoring processes and evaluating therapeutic effect.The research progresses of SMI applicated in musculoskeletal diseases were reviewed in this article.

Research Progress of Contrast-Enhanced Ultrasound in the Diagnosis of Lower Extremity Lymphedema / 中国医学影像学杂志

Lymphoedema of lower extremities,chronic and progressive,will severely deteriorate the quality of life of patients as it progresses.Thus,early diagnosis and treatment to delay the progress of the disease is conducive to improving the prognosis of patients.At present,common techniques for the diagnosis of lower limb lymphedema,whose advantages and disadvantages vary,cannot be applied to individual case comprehensively.CEUS has the advantages of non-invasion,convenience,real-time,and good repeatability for this disease.CEUS can enhance the image of lymph in lymphatics,and has a high sensitivity to superficial lymphatics,gradually applied in lymphedema of lower limbs.This article reviews the application of CEUS in lower limb lymphedema.

Study on the combined detection of mammography,ultrasound Doppler and serum tumor markers in the diagnosis of early breast cancer / 中国医学装备

Objective:To explore the values of single and combined detection of mammography,ultrasound Doppler and serum markers of tumor included serum prostate specific antigen(PSA),serum carbohydrate antigen 15-3(CA153),mucin 1(MUC1)and human growth differentiation factor 3(GDF3)in diagnosing early breast cancer.Methods:A total of 96 patients with breast cancer,who admitted to Tangshan People's Hospital from January 2018 to December 2021 and were confirmed by pathological examination,were selected as breast cancer group.At the same time,70 patients with benign breast diseases who received diagnosis and treatment in our hospital were selected as benign lesions group.In addition,50 normal people who were confirmed as health by physical examination in our hospital were selected as research subjects of healthy control group.The postoperative pathological examination was used as the gold standard to compare the diagnostic values of single mammography,ultrasonic Doppler examination,serum PSA,CA153,MUC1,GDF3 and the combined examination of them for breast cancer.Results:In the breast cancer group,78 cases of the 96 patients with breast cancer were diagnosed as malignant tumor by ultrasound on breast,with a positive detection rate of 81.3%,and 80 cases of them were diagnosed as malignant tumor by mammography X-ray examination,with a positive detection rate of 83.1%.The levels of serum PSA,CA153,MUC1 and GDF3 of breast cancer group were respectively higher than those of the benign lesion group and healthy control group,and the differences were statistically significant(t=8.783,10.361,11.258,18.965,9.564,12.658,12.688,20.163,P<0.05).Using breast cancer as the dependent variable,and using serum PSA,CA153,MUC1 and GDF3 as independent variable to perform Logistic regression analysis.The results of Logistic regression analysis indicated that serum PSA,CA153,MUC1 and GDF3 were important risk factors of breast cancer(OR value =1.165,1.168,1.472,1.248,P<0.05).The results of receiver operating characteristic(ROC)curve(95%CI),sensitivity and specificity of single application of each indicator of ultrasound on breast,mammography,serum PSA,CA153,MUC1 and GDF3 were respectively[0.723(0.595-0.851),82.56%and 67.32%],[0.761(0.636-0.886),85.79%and 65.36%],[0.833(0.726-0.941),81.48%and 85.73%],[0.837(0.738-0.926),61.25%and 70.17%],[0.768(0.648-0.889),71.49%and 80.87%],[0.613(0.469-0.758),52.94%and 50.57%].However,the AUC(95%CI),sensitivity and specificity of the combined application of 6 items were respectively 0.958(0.905-0.999),96.37%and 84.83%,which had higher diagnostic efficiency.Conclusion:The combined detection performance of mammography,ultrasound Doppler and serum PSA,CA153,MUC1 and GDF3 is higher than that of single each detection,which is helpful to conduct early identification and diagnosis for breast cancer.

Comparative study of UE and CDFI in distinguishing triple-negative breast cancer and fibroadenoma / 中国医学装备

Objective:To investigate the values of ultrasound elasticity(UE)imaging and color Doppler flow energy(CDFI)in differential diagnosis for triple negative breast cancer(TNBC)and fibroadenoma.Methods:A total of 50 TNBC patients who admitted to People's Hospital of Wanning from January 2021 to January 2022 and were confirmed by surgical pathology were selected,and they were divided into TNBC group.On the other hand,a total of 50 patients with fibroadenoma who were confirmed by surgical pathology during the same period were selected and they were divided into fibroadenoma group.All patients did not undergo any clinical intervention before ultrasound examination.UE and CDFI were used respectively to evaluate the degrees of softness and hardness of the tissues,the color blood flow and elasticity scores of lesions.The pathological result was used as the gold standard to analyze respectively the diagnostic efficacies of UE and CDFI for TNBC and fibroadenoma.Results:According to the characteristics of ultrasound imaging,the TNBC group mostly showed burr sign on lesion edge,the attenuation and hyperechoic halo of posterior echo,and existing axillary lymph node metastasis.The fibroadenoma group mostly showed clear boundaries of lesion area,regular lesion morphology,non-microcalcification.The diagnostic sensitivity,specificity and accuracy of UE detection were respectively 90.91%,82.14%and 86.00%,while these indicators of CDFI were respectively 73.08%,75.00%and 74.00%.In addition,the sensitivity,specificity and accuracy of the combined detection of them were respectively 94.23%,95.83%and 96.00%.The detection efficiency of the combined detection was higher than that of each single detection.Conclusion:UE has higher sensitivity in the differential diagnosis of TNBC and fibroadenoma,but it's specificity is not high.The combined detection of UE and CDFI can improve the specificity and accuracy of differential diagnosis.

The application effect of multi-color non-woven packaging in the management of surgical instrument / 中国医学装备

Objective:To analyze the impact of multi-color non-woven packaging in surgical instrument management on surgical turnover efficiency,surgical instrument preparation,and satisfaction of surgical medical staff and patients.Methods:31,589 surgical instruments from Beijing Friendship Hospital Capital Medical University from March 2016 to December 2021 were Selected.According to different management methods,71,007 surgical patients and corresponding 16,224 surgical instruments from March 2016 to January 2019 were included in the control group,which adopted traditional gauze-cotton bag packaging surgical instrument management method;62,548 surgical patients and the corresponding 15,365 surgical instruments from February 2019 to December 2021 were included in the observation group,which adopted multi-color non-woven packaging surgical instrument management method.The surgical turnover efficiency,surgical instrument preparation and satisfaction of surgical staff and patients were compared between the two groups.Results:The room entry time,room entry to skin incision time,the following surgery room entry to skin incision time,and surgical delay rate of surgeries of patients in the observation group were lower than those in the control group,the difference was statistically significant(t=52.681,37.167,72.524,x2=9.605,P<0.05).Compared with the control group,the number of outgoing deliveries,assembly errors and loss of instruments decreased significantly,the number of intact devices was increased significantly,the difference was statistically significant(x2=107.345,11.782,8.727,66.223,P<0.05.The satisfaction of patients and medical staff in the observation group was significantly higher than that in the control group,the difference was statistically significant(t=100.723,6.756,P<0.05).Conclusion:The application of multi-color non-woven packaging in the management of surgical instruments can help to improve surgical turnover rates,improve the efficiency of the central sterile supply department by reducing the number of outgoing deliveries,assembly errors and instrument losses,and improve the satisfaction of surgical medical staff and patients with multi-color non-woven packaging of surgical instruments.

Study on Objective Recognition and Color Classification of Sublingual Veins / 中国中医药信息杂志

Objective To explore the method of objective identification of color information in sublingual veins diagnosis of TCM.Methods Combined with computer vision,compact fully convolution networks(CFCNs)and 19 deep learning classification models were used for study,and a double pulse rectangle algorithm was designed as a means of segmentation and recognition of sublingual veins and color information extraction.Results The accuracy of segmentation of tongue bottom obtained by the method of removing reflection + data expanding + data post-processing was 0.955 9,F1 value was 0.947 3,and mIoU value was 0.900 0.The accuracy of segmentation of sublingual veins obtained by the method of removing reflection + tongue input + data expanding + corrosion expansion was 0.778 4,F1 value was 0.738 3 and mIoU value was 0.585 1,which were obviously superior to the current classic or improved U-net model.On the color classification of sublingual veins,the best classification model was DenseNet161-bc-early_stopping with an accuracy rate of 0.803 7.Conclusion The deep learning method has a certain effect on identifying the color information of sublingual veins in TCM,which provides a new method for the research of quantitative color detection technology of sublingual veins diagnosis in TCM.

Study on the effect of addition or subtraction of Astragalus membranaceus and Draba nemorosa on CHF and changes of cardiac color ultrasound parameters / 中国现代医生

@#Objective To analyze the efficacy of Astragalus membranaceus and Draba nemorosa in the treatment of chronic heart failure(CHF),the change of cardiac color ultrasound parameters and its predictive value for adverse end events.Methods A total of 92 patients with Qi-deficiency and blood-stasis combined with Shuiyin CHF treated in Wenzhou Hospital of Traditional Chinese Medicine from September 2019 to September 2021 were randomly selected and divided into two groups by random number table method,with 46 cases in each group.Patients in control group were received conventional Western medicine treatment,and patients in observation group were received the addition and subtraction treatment of Yiqi Huoxue Lishui prescription based on Astragalus membranaceus and Draba nemorosa.The clinical efficacy,TCM syndrome score,heart color ultrasound parameters and the incidence of adverse endpoint events within 6 months were compared between the two groups.Cardiac color doppler ultrasound parameters were compared between the occurrence group and the non-occurrence group,and receiver operating characteristic curve was drawn to analyze the predictive value of cardiac color Doppler ultrasound parameters for adverse end events.Results The total clinical effective rate of the observation group(95.65%)was higher than that of the control group(71.74%)(P<0.05).After treatment,palpitation,weakness,shortness of breath,lethargy and lip purple score in observation group were lower than those in control group(P<0.05).The left ventricular end-diastolic diameter(LVEDD)and left arial diameters(LAD)of the observation group were lower than those of the control group after treatment(P<0.05).After treatment,the left ventricular ejection fraction(LVEF)of the observation group was higher than that of the control group(P<0.05);The incidence of adverse endpoint events within 6 months in the observation group(2.17%)was lower than that in the control group(19.57%)(P<0.05).The LVEDD and LAD in the adverse end point event group were higher than those in the without adverse end point event group(P<0.05),and the LVEF was lower than that in the without adverse end point event group(P<0.05).The area under the curve(AUC)of LVEDD,LAD and LVEF combined to predict the occurrence of adverse endpoint events was 0.812,and the 95%CI confidence interval was 0.734-0.968;The sensitivity of combined detection(93.42%)was higher than that of single detection(71.52%,75.11%,79.62%)(P<0.05).The specificity of combined detection(82.27%)compared with that of single detection(70.19%,73.07%,77.28%)(P>0.05).Conclusion Supplementing qi and promoting blood circulation and rehydrating water based on Astragalus membranaceus and Draba nemorosa can effectively improve the cardiac function of CHF patients,alleviate symptoms such as palpitations and fatigue,and reduce the incidence of adverse endpoint events.In addition,the combined detection of cardiac ultrasound parameters can improve the prediction efficiency of adverse endpoint events,which has certain clinical value.

Analysis of color stability and degree of conversion of different types of resin composites

Abstract Resin composites containing surface pre-reacted glass (S-PRG) have been introduced to reduce demineralization and improve remineralization of the tooth structure. However, water diffusion within the material is necessary for its action, which can impair its overall physicomechanical properties over time, including color stability. This study aimed to evaluate the color stability and related degree of conversion (DC) of four resin composites. Discs (6 x 4 mm, n = 5/group) of microhybrid (MH), nanofilled (NF), nanohybrid (NH), and S-PRG-based nanohybrid (S-PRG-NH) composites with two opacities (A2/A2E and A2O/A2D) were prepared. Color (CIELab and CIEDE2000) was evaluated with a spectrophotometer after aging in grape juice (2 x 10 min/10mL/7days). The DC was analyzed by using Fourier transform infrared spectroscopy before and after light-curing. Data were statistically analyzed by using two-way analysis of variance and post-hoc least significant difference tests (p<0.05). In the color stability analysis, the interaction between filler type and opacity was significant (CIELab, p = 0.0015; CIEDE2000, p = 0.0026). NH presented the highest color stability, which did not differ from that of MH. The greatest color alteration was observed for S-PRG-NH. S-PRG fillers also influenced DC (p < 0.05). The nanohybrid resin composite presented favorable overall performance, which is likely related to its more stable organic content. Notwithstanding the benefits of using S-PRG-based nanohybrid resins, mostly in aesthetic procedures, professionals should consider the susceptibility of such resins to color alteration, probably due to the water-based bioactive mechanism of action.

Effect of Toothpaste Fluoride Concentration on Color Stability of Resin Composites: An In Vitro Study

ABSTRACT Objective: To investigate the effects of two different dentifrice fluoride concentrations on the color stability of the composite. Material and Methods: Twenty-seven specimens (2×4×5 mm) each of microfilled (Gradia, GC, Japan) and nanohybrid (Grandio, VOCO, Germany) composites were prepared. The specimens were randomly divided into six groups (control, Fluoflor caries protection toothpaste with 1450ppm Fluoride (EXW, France), and Fluoflor kids toothpaste with 500ppm Fluoride (EXW, France) (n = 9). The specimens were immersed in a mixture of artificial saliva and toothpaste in a ratio of 1:3 and applied for 60 seconds every 12 hours for 42 days. The control samples were incubated in artificial saliva at 37°C. Primary and secondary color measurements were performed using color parameters (L∗a∗b) with a spectrophotoshade (MHT Optic Research AG, Niederhasli, Switzerland). Data were analyzed using a two-way analysis of variance at a significance level of 0.05. Results: According to the two-way ANOVA analysis, there was no significant difference in color change between the composites and no difference in the level of discoloration between different fluoride concentrations(p>0.05). Also, None of the dentifrices caused clinically significant color changes(∆E˂3.3). Conclusion: No clinically unacceptable color changes were observed in the microfilled and nanofilled composites with different concentrations of fluoride toothpaste.

Color variation of composite resins in relation to the Vita Classical shade guide: colorimetric analysis

Aim: The aim of this study was to verify the color variation between different composite resins and the Vita Classical Shade Guide. Methods: Two-millimeter thickness samples were made (n = 6) from eight commercial brands of composite resin (shade A2): Charisma (Kulzer), Forma (Ultradent), Harmonize (Kerr), Luna (SDI), Opallis (FGM), Oppus Bulk Fill (FGM), Vittra (FGM) and Filtek Z250 XT (3M ESPE). Specimens were stored in distilled water for 7 days and then polished. Color measurements of samples and A2 shade of the Vita Classical Shade Guide were performed using the Vita Easy Shade Advance 4.0 spectrophotometer on a black background. Color variations were calculated using the CIEDE2000 formula, considering values ≥0.81 being noticeable by the human eye and ≥1.77 being clinically unacceptable. Results were statistically analyzed with a 5% significance level. Results: Color variation (ΔE) of composite (E1 ) compared to the Vita Classical Shade Guide (E0 ) was greater than clinically acceptable for all the materials evaluated in this study. Forma (ΔE=2.08 ± sd=0.47) and Filtek Z250 XT (2.50 ± 0.20) had the smallest amount of color variation values found in the results. Harmonize (3.32 ± 0.63) presented values similar to Filtek Z250 XT, but it was worse than Forma. Vittra (3.51 ± 0.28), Charisma (3.80 ± 0.20), Opallis (4.24 ± 0.30) and Luna (5.67 ± 0.20) did not differ among each other and presented higher color variation than Forma, Filtek Z350XT and Harmonize. Oppus Bulk Fill (13.94 ± 1.12) was the composite with the greatest color variation. Conclusions: The findings in this study show that attention should be taken when using the Vita Color Shade Guide for composite shade selection

Color matching and color recovery in large composite restorations using single-shade or universal composites

Abstract This study assessed the color-matching ability and color recovery of unprepared teeth when using single-shade composites and a universal composite in large restorations. Buccal and palatine surface colors of molars were measured with a spectrophotometer (CIELAB) before preparing round cavities (6 mm in diameter, 2 mm in depth). The cavities were randomly filled with a single-shade composite (Omnichroma, Diamond One, or Vittra APS Unique) or a universal composite (Filtek Universal). Color measurements of the restored cavities were taken, and overall color differences (ΔEab and ΔE00) and differences in the whitening index for dentistry (ΔWID) from baseline were calculated. Additionally, visual assessments of a color match to the surrounding enamel were performed by forty evaluators (laypersons and undergraduate students of dentistry) in a viewing booth under illuminant D65, with rating scores from 0 (no color mismatch) to 4 (not acceptable). Data were analyzed using RM or one-way ANOVA (α = 0.05). Results showed that the restorations generally exhibited whiter colors (WID ranged from 27.9 to 41.3) than the unprepared teeth (WID ranged from 15.9 to 19.3). The composite Filtek Universal demonstrated the lowest color discrepancy (ΔWID = 8.6; ΔE00 = 10.8; and ΔE00 = 6.2), and no significant differences were observed among the evaluated single-shade composites. Furthermore, all composites showed similar and adequate color matches to the surrounding enamel. However, it is important to note that despite their ability to match the surrounding enamel reasonably, none of the composites evaluated in large restorations fully recovered the color observed in unprepared teeth.

Resumo Este estudo avaliou a habilidade de combinação de cores e recuperação de cor de dentes não preparados ao utilizar resinas compostas de única tonalidade e uma resina composta universal em grandes restaurações. As cores das superfícies bucais e palatinas de molares foram medidas com um espectrofotômetro (CIELAB) antes de preparar cavidades esféricas (6 mm de diâmetro, 2 mm de profundidade). As cavidades foram preenchidas aleatoriamente com uma resina composta de única tonalidade (Omnichroma, Diamond One ou Vittra APS Unique) ou com uma resina composta universal (Filtek Universal). Foram realizadas medições das cores das cavidades restauradas e calculadas as diferenças de cor globais (ΔEab and ΔE00)) e as diferenças no índice de clareamento para odontologia (ΔWID) em relação à cor inicial. Além disso, foram realizadas avaliações visuais da correspondência de cor com o esmalte circundante por quarenta avaliadores (leigos e estudantes de odontologia) em uma cabine de visualização sob iluminante D65, com pontuações de 0 (nenhuma discrepância de cor) a 4 (não aceitável). Os dados foram analisados usando RM ou ANOVA unidirecional (α = 0,05). Os resultados mostraram que as restaurações geralmente apresentavam cores mais brancas (WID variou de 27,9 a 41,3) do que os dentes não preparados (WID variou de 15,9 a 19,3). A resina composta Filtek Universal demonstrou a menor discrepância de cor (ΔWID = 8,6; ΔE00 = 10,8; and ΔE00 = 6,2), e não foram observadas diferenças significativas entre as resinas compostas de única tonalidade avaliadas. Além disso, todas as resinas compostas apresentaram correspondência de cor similar e adequada com o esmalte circundante. No entanto, é importante observar que, apesar de sua capacidade de corresponder razoavelmente com o esmalte circundante, nenhuma das resinas compostas avaliadas em grandes restaurações recuperou completamente a cor observada nos dentes não preparados.

Influence of repositioning guides' color and usage on precision in tooth color measurement with a clinical spectrophotometer

Abstract Repositioning guides are commonly employed in clinical studies to ensure consistent tooth color measurements. Yet, their influence on measured color remains uncertain. Objective This study evaluated the impact of repositioning guides' color and usage on tooth color measurement using a clinical spectrophotometer. Methodology In total, 18 volunteers participated in this study, in which the color of their upper left central incisor and upper left canine was measured with or without repositioning guides (control). The guides were made from pink, blue, or translucent silicone, as well as an acetate-based bleaching tray. Tooth color was measured in triplicates using a clinical spectrophotometer based on the CIELAB system. The standard deviations of these readings were used to estimate reproducibility, and color differences (ΔE00) between the measurements with guides and the control were calculated. Results Repositioning guides had a minimal effect on L* values and no effect on b* values. The use of pink silicone increased a* values, whereas blue or translucent silicone reduced them. Irrespective of the evaluated tooth, the lowest ΔE00 values were observed for the translucent silicone and bleaching tray. The usage of guides only affected data variability for the L* color coordinate. Conclusion Using repositioning guides can significantly impact the precision of tooth color measurement with a clinical spectrophotometer.

Reliability of the color measurement of resin composites using images obtained using a stereoscopic loupe

Abstract This study assessed the reliability of a color measurement method using images obtained from a charge-coupled device (CCD) camera and a stereoscopic loupe. Disc-shaped specimens were created using the composite Filtek Z350 XT (shades DA1, DA2, DA3, and DA4) (n = 3). CIELAB color coordinates of the specimens were measured using the spectrophotometer SP60 over white and black backgrounds. Images of the same specimens were taken using a CCD camera attached to a stereoscopic loupe. The color of the image was measured (red-green-blue [RGB]) using an image processing software and converted to CIELAB coordinates. For each color coordinate, data from images were adjusted using linear regressions predicting those values from SP60. The whiteness index for dentistry (WID) and translucency parameter (TP00) of the specimens as well as the color differences (ΔE00) among pairwise shades were calculated. Data were analyzed via repeated-measures analysis of variance and Tukey's post hoc test (α = 0.05). Images obtained using the loupe tended to be darker and redder than the actual color. Data adjustment resulted in similar WID, ΔE00, and TP00 values to those observed for the spectrophotometer. Differences were observed only for the WID of shade DA3 and ΔE00 for comparing DA1 and DA3 over the black background. However, these differences were not clinically relevant. The use of adjusted data from images taken using a stereoscopic loupe is considered a feasible method for color measurement.

Effect of charcoal-containing toothpastes on roughness and color stability of bulk-fill resin composites / Efeito de dentifrícios contendo carvão na cor e rugosidade de resinas compostas bulk-fill

Objective: To evaluate the effects of different commercially available charcoal-based toothpastes (CBTs) on the roughness and color of bulk-fill resin composites (RCs). Materials and Methods: Disc-shaped samples (6 × 2 mm) were made with nanofilled (NF) bulk-fill (Filtek One, 3M Oral Care) or nanohybrid (NH) bulk-fill (Aura, SDI) RCs. The analyses were performed initially (baseline) and after 10,000 brushing cycles in a tooth-brushing machine using (n=10): regular toothpaste (Colgate Total 12, Colgate-Palmolive) or three types of CBTs (Colgate Luminous White Activated Charcoal - Colgate-Palmolive; Black is White - Curaprox; 3D White Mineral Clean - Oral-B). The specimens were analyzed for roughness (Ra, µm) and quantified by coordinates of the CIEL*a*b* color space, Vita Classical scale (shade guide unit, SGU), and general color alteration (ΔEab; ΔE00). The data were evaluated using generalized linear models (Ra, L*, b*, ΔEab; ΔE00), Mann-Whitney, Kruskal-Wallis, and Dunn tests (a*; ΔSGU), with α=0.05. Results: Regardless of the toothpaste, Ra increased after brushing, but was significantly higher in NH than NF (p=0.0001). L* significantly decreased after brushing with Black is White toothpaste (p=0.0027). NF showed higher ΔE00 values after brushing with the CBTs, compared with regular toothpaste. Moreover, NH exposed to Black is White exhibited higher ΔEab and ΔE00 values than the other toothpastes (p<0.0001). Conclusion: The roughness alteration was not mediated by the type of toothpaste. However, the CBTs were able to change the optical properties of bulk-fill RCs, with more pronounced effects, as observed with Black is White (AU)

Objetivo: Avaliar os efeitos de diferentes dentifrícios contendo carvão (DCCs) na rugosidade e cor de resinas compostas (RCs) bulk-fill. Material e Métodos: Amostras cilíndricas (6 × 2 mm) foram confeccionadas com as RCs nanoparticulada (NP) bulk-fill (Filtek One, 3M Oral Care) e nano-híbrida (NH) bulk-fill (Aura, SDI). As análises foram realizadas nos tempos: inicial (baseline) e após 10000 ciclos de escovação em máquina simuladora utilizando (n = 10): dentifrício regular (Colgate total 12, Colgate-Palmolive) e DCCs (Colgate Luminous White Carvão Ativado - Colgate-Palmolive; Black is White - Curaprox; 3D White Mineral Clean - Oral-B). As amostras foram analisadas quanto à rugosidade (Ra, µm) e quantificadas nas coordenadas do sistema CIEL*a*b*, na escala Vita Classical (SGU), e em valores de alteração geral da cor (ΔEab; ΔE00). Os dados foram avaliados por modelos lineares generalizados (Ra, L*, b*, ΔEab; ΔE00), testes de Mann Whitney, Kruskal-Wallis e Dunn (a*; ΔSGU), com α=0,05. Resultados: Independentemente do dentifrício, a Ra aumentou após a escovação, mas com valores significativamente maiores para a NH do que para a NP (p = 0,0001). Os valores de L* diminuíram significativamente (p = 0,0027) após escovação com Black is White. NP mostrou maiores valores de ΔE00 após escovação com os DCCs comparada ao dentifrício regular. Adicionalmente, NH exibiu maiores valores de ΔEab e ΔE00 quando exposta ao dentifrício Black is White comparada aos outros dentifrícios (p < 0,0001). Conclusão:A alteração de rugosidade não foi mediada pela tipo de dentifrício. Entretanto, os DCCs foram capazes de alterar as propriedades ópticas das RC bulk-fill, com efeitos mais potencializados com o dentifrício Black is White (AU)

Bleaching as a complement to fluoride-enhanced remineralization or resin infiltration in masking white spot lesions

Abstract There are many suitable strategies for addressing caries, which is an ongoing worldwide problem. Although white spot lesions (WSLs) can be either remineralized naturally or treated with non- or micro-invasive strategies, their whitish and opaque appearance may persist. Objective To evaluate the effects of tooth bleaching as a complement to fluoride-enhanced remineralization or resin infiltration in masking WSLs, as well as in enamel surface roughness relative to that of the adjacent enamel. Methodology Flattened rectangular bovine enamel fragments (6×3×~2.9 mm length, width and thickness) were divided into six groups (L/N, F/N, F.BL/BL, I/N, I.BL/BL, N/N; n=15). Treatments applied to the 3×3 mm left half included: L (Lesion) - WSL simulation with 50 mM acetate buffer, 96 hours, 37ºC; F (Fluoride) - WSL treatment with 2% NaF neutral gel, 1x/week, 8 weeks; I (Infiltration) - WSL treatment with H3PO4 37%/10 s; Icon®-Dry/30 s; Icon®-Infiltrant/3 min+1 min; N (Nothing) - sound enamel/control. Treatments applied to both halves after F and I included: BL (Bleaching) - Opalescence Boost 40%, 3×/20 min each; N (Nothing) - control. The differences in color (ΔE00, ΔL, Δa, Δb) and surface roughness (ΔRa) between the left and right halves were measured. Kruskal-Wallis/post-hoc tests were applied to ΔE00, ΔL, Δa and ΔRa, and 1-way ANOVA/Tukey tests to Δb (α=0.05). Results The factor under study significantly influenced ΔE00 (p=0.0001), ΔL (p=0.0024), Δb (p=0.0015), and ΔRa (p<0.001), but not Δa (p=0.1592). Both fluoride-enhanced remineralization and resin infiltration were able to mask WSL, regardless of subsequent bleaching. However, when bleaching was performed, ΔE00 median values did not exceed the acceptability threshold for color difference. Only resin infiltration reduced ΔRa between WSL and the adjacent enamel. Conclusions Both remineralization and infiltration, particularly if complemented by bleaching, fostered satisfactory esthetic results. Only infiltration without bleaching led to really good results in surface roughness.