Masking ability of bleach-shade resin composites using the multilayering technique.

OBJECTIVE: Evaluate the masking ability of bleach-shade resin composites applied by multilayering techniques over colored substrates. MATERIALS AND METHODS: Disc-shaped specimens were fabricated from bleach-shade resin composites using different multilayering techniques. Substrates were produced in opaque ceramic discs simulating colored substrates (A2, A3, A3.5, C2, C3, C4) and a bleached tooth (0M1). Color coordinates were obtained using a reflectance spectrophotometer. Color difference was calculated by CIEDE2000 using coordinates of 0 M1 ceramic as standard reference. Data were analyzed by one-way ANOVA and Tukey's post-hoc test (p ≤ 0.05). Masking ability interpretation was based on perceptibility and acceptability thresholds. RESULTS: All combinations presented ΔE00 above the acceptable threshold (ΔE00 >1.8), ranging from 2.49 to 7.42, regardless of the restorative system, multilayering strategy or substrate color. Multilayering combinations placed over A2, A3 and A3.5 were moderately (1.8<ΔE00 ≤3.6) and clearly unacceptable (3.6<ΔE00 ≤5.4), combinations associated with C2, C3 and C4 were clearly unacceptable and, extremely unacceptable (ΔE00 >5.4). Lower ΔE00 was observed for combinations with 0.5 mm extra white enamel layer (2.49), or 1.0 mm white dentin layer (2.69), over A2 and A3.5 substrates. Lightness difference showed the greatest contribution to ΔE00 . CONCLUSIONS: Bleach-shade resin composite systems applied by the multilayering technique were not able to ensure effective masking ability. CLINICAL SIGNIFICANCE: Bleach-shade resin composites applied with different combinations of the multilayering technique were not effective in masking colored substrates. Alternative strategies, techniques and dental materials should be explored to obtain acceptable masking.

Masking Ability of the Combined Application of Opaquers and Resin Composite on Discolored Backgrounds.

The aim of this study was to evaluate the masking ability of a combined application of opaquers and resin composite over discolored backgrounds: A3, A3.5, C2, C3, and C4. The groups were divided according to the opaquer brand, the number of opaquer coats (one or two), and the thickness of the resin composite layer (0.5 or 1.0 mm). The color measurements were made by a reflectance spectrophotometer (SP60, EX-Rite). The color difference between the opaquer + resin composite + background and a reference background was calculated using the CIEDE2000 formula. ANOVA and Tukey's post hoc test (α=0.05) were used to analyze the ΔE00 mean values. A bivariate analysis was used to determine the association between dependent and independent variables. The masking ability was rated by the ΔE00 visual thresholds of acceptability and perceptibility (Excellent Match: ΔE00 ≤ 0.8; Acceptable Match: 0.8 < ΔE00 ≤1.8; Moderately Unacceptable Mismatch: 1.8 < ΔE00 ≤ 3.6; Clearly Unacceptable Mismatch: 3.6 < ΔE00 ≤ 5.4; Extremely Unacceptable Mismatch: ΔE00 > 5.4). The mean ΔE00 values ranged from 0.5 to 5.52. Masking ability was affected by the opaquer brand, thickness of the resin composite layer, and background shades. Most of the combinations that achieved either excellent or acceptable masking ability were obtained with combinations composed of one or two coats of opaquer and a 1.0-mm-thick resin composite layer for all backgrounds except C4. Acceptable results were also obtained for combinations with 0.5-mm-thick resin composite over C2, A3, and A3.5 backgrounds.

Oral health status of schoolchildren living in rural and urban areas in southern Brazil.

This study assessed the effect of area of residence (rural vs. urban) on dental caries experience among southern Brazilian schoolchildren. This cross-sectional survey was conducted in Rosário do Sul, southern Brazil, and included 373 9-14-year-old schoolchildren attending public municipal schools (122 living in the rural area, and 251, in the urban area). Data collection included a questionnaire and a clinical examination. Clinical examination of the permanent dentition involved visible plaque index, gingival bleeding index and dental caries experience (non-cavitated and cavitated, inactive and active lesions). Samples of water were collected to check the fluoride concentration. Caries prevalence and extent using different criteria were compared between rural and urban schoolchildren using the chi-square test and the Mann-Whitney test, respectively. The association between explanatory variables and the extent of caries activity (number of active caries lesions) was assessed using Poisson regression. When caries was recorded at the cavity level (WHO criterion), no difference was observed between rural and urban populations (p ≥ 0.05). Conversely, higher caries prevalence and extent were found among urban schoolchildren when active non-cavitated lesions were also computed (p < 0.05). In the adjusted Poisson regression model, urban schoolchildren were 57% more likely to present more active lesions than rural students (RR = 1.57; 95%CI = 1.29-1.92). Rural communities did not have sufficient fluoride in the water supply, whereas ideal concentrations were detected in the urban areas. In conclusion, this cross-sectional study found that urban schoolchildren showed greater caries experience than rural students, and that this increment was related to active non-cavitated lesions.

Effect of different placement techniques on color stability and surface roughness of resin composites / Efeito das técnicas de inserção e alisamento na estabilidade de cor e rugosidade superficial de resinas compostas

Abstract Introduction Longevity and clinical success of dental restorations can be influenced by many factors during the restorative procedures. Objective This study aimed to evaluate the influence of different placement techniques on color stability and surface roughness of two resin composites. Material and method The groups of specimens (n=10) were divided according to resin composite (FiltekTM Z250 XT and FiltekTM Z350 XT) and placement technique: Mylar strip, spatula, dry brush, modeling liquid, and surface sealant. Color stability and surface roughness were accessed using a spectrophotometer (CIELab color space) and a rugosimeter (standard cutoff of 0.8 mm), respectively, after water storage. Subsequently, the specimens were immersed in coffee for 48 h and final color was measured. The data were analyzed using ANOVA and the Tukey's post hoc test (α=5%) and the correlation between surface roughness (Ra) and color change (∆Eab) was assessed using the Pearson's correlation coefficient. Result The different placement techniques influenced Ra and ∆Eab on both resin composites. The groups treated with surface sealant showed greater difference in ∆Eab for both resin composites. The FiltekTM Z250 XT resin showed greater color stability compared with the FiltekTM Z350 XT resin regardless of the placement technique used. Ra of each placement technique was similar among the resin composites except for the FiltekTM Z350 XT modeling liquid group, which presented lower Ra values compared with those of FiltekTM Z250 XT. A correlation between Ra and staining was identified (p=0.268). Conclusion Color stability and Ra are influenced by different placement techniques.

Resumo Introdução A longevidade e o sucesso clínico das restaurações dentárias podem ser influenciados por muitos fatores durante os procedimentos restauradores. Objetivo Avaliar a influência da técnica de alisamento na estabilidade de cor e rugosidade superficial de duas resinas compostas. Material e método Os grupos de amostras (n=10) foram divididos conforme a resina composta (FiltekTM Z250 XT e FiltekTM Z350 XT) e as técnicas empregadas: tira de poliéster, espátula, pincel seco, selante de superfície. A cor e a rugosidade da superfície foram avaliadas por espectrofotômetro (espaço de cor CIELab) e rugosímetro (corte padrão de 0,8 mm), respectivamente, após o armazenamento em água. Posteriormente, as amostras foram imersas em café por 48h e a cor final foi aferida. Os dados foram analisados usando teste ANOVA e Tukey post hoc (α = 5%) e a correlação entre rugosidade da superfície (Ra) e variação de cor (∆Eab) através do coeficiente de correlação de Pearson. Resultado As técnicas de alisamento influenciaram a Ra e a ∆Eab em ambas as resinas compostas. Os grupos tratados com selante de superfície apresentaram maior diferença na ∆Eab. A resina FiltekTM Z250 XT apresentou maior estabilidade de cor comparada à FiltekTM Z350 XT, independentemente da técnica utilizada. A Ra das técnicas de alisamento foi semelhante entre os compósitos, exceto para o grupo do líquido modelador da FiltekTM Z350 XT, que apresentou os menores valores. Uma correlação entre Ra e manchamento (p = 0,268) foi identificada. Conclusão A estabilidade da cor e a Ra são influenciadas pelas técnicas de alisamento utilizadas.

Oral health status of schoolchildren living in rural and urban areas in southern Brazil

Abstract This study assessed the effect of area of residence (rural vs. urban) on dental caries experience among southern Brazilian schoolchildren. This cross-sectional survey was conducted in Rosário do Sul, southern Brazil, and included 373 9-14-year-old schoolchildren attending public municipal schools (122 living in the rural area, and 251, in the urban area). Data collection included a questionnaire and a clinical examination. Clinical examination of the permanent dentition involved visible plaque index, gingival bleeding index and dental caries experience (non-cavitated and cavitated, inactive and active lesions). Samples of water were collected to check the fluoride concentration. Caries prevalence and extent using different criteria were compared between rural and urban schoolchildren using the chi-square test and the Mann-Whitney test, respectively. The association between explanatory variables and the extent of caries activity (number of active caries lesions) was assessed using Poisson regression. When caries was recorded at the cavity level (WHO criterion), no difference was observed between rural and urban populations (p ≥ 0.05). Conversely, higher caries prevalence and extent were found among urban schoolchildren when active non-cavitated lesions were also computed (p < 0.05). In the adjusted Poisson regression model, urban schoolchildren were 57% more likely to present more active lesions than rural students (RR = 1.57; 95%CI = 1.29-1.92). Rural communities did not have sufficient fluoride in the water supply, whereas ideal concentrations were detected in the urban areas. In conclusion, this cross-sectional study found that urban schoolchildren showed greater caries experience than rural students, and that this increment was related to active non-cavitated lesions.