Fluorescence intensity of composite layering combined with surface sealant submitted to staining solutions.

PURPOSE: The aim of this study was to evaluate the fluorescence intensity of a composite in different layering techniques combined to a surface sealant submitted to staining solutions. METHODS AND MATERIALS: One surface sealant and one composite resin (shades A2-0, A2, and YE) were tested. Specimens were carried out using layering with different shades of composite, and dental blocks (dentin/enamel) were obtained of human molars. Fluorescence intensity measurement performed using a spectrofluorophotometer, before and after storage in cola, orange juice, red wine, and distilled water. Data were subjected to analysis of variance and Fisher's test (α = 0.05). RESULTS: Initially, only A2-O + A2 layering showed fluorescence intensity statistically similar to the natural tooth. Overall, groups sealed showed the highest fluorescence intensity compared with unsealed groups. The aging decreased the fluorescence intensity compared with initial values. Red wine showed the highest decrease on the fluorescence intensity. CONCLUSION: The fluorescence of composite restorations is dependent of the layering technique and is affected by the diet. CLINICAL SIGNIFICANCE: The staining solutions decreased the fluorescence intensity, even when the composite resins were sealed. Different shades of the same composite showed distinct fluorescence values, so there should be greater standardization of this property for tooth reconstruction success by the layering technique with large tissue loss.

Comparative study of the fluorescence intensity of dental composites and human teeth submitted to artificial aging.

The aim of this study was to evaluate quantitatively the fluorescence of resin composites and human teeth, and to determine the stability of fluorescence after aging. Ten specimens were built using a 1 mm thick increment of dentin composite overlapped by a 0.5 mm thick increment of enamel composite. Ten sound human molars were sectioned and silicon carbide-polished to obtain enamel and dentin slabs 1.5 mm in thickness. Fluorescence measurements were carried out by a fluorescence spectrophotometer before and after thermocycling (2000 cycles, 5°C and 55°C). One-way analysis of variance (ANOVA) with repeated measures and Tukey's test were performed at a significance level of 5%. Most of the tested composites showed significant differences in fluorescence both before and after aging (P < 0.05). Opallis was the only composite whose fluorescence was similar to that of human teeth at both periods of evaluation (P > 0.05), and was the only composite that showed comparable results of fluorescence to the tooth structure before and after thermocycling. With the exception of Filtek Supreme, there were significant reductions in fluorescence intensity for all the tested composites (P < 0.05).

Effect of cigarette smoke and whiskey on the color stability of dental composites.

PURPOSE: To evaluate the effect of cigarette smoke and whiskey on the color stability of resin composites. METHODS: Disk-shaped specimens (8 mm x 1 mm) were prepared with five composites in two different shades (n=10). After light-curing, the specimens were stored in dark containers with artificial saliva at 37 degrees C for 24 hours. Baseline color was measured by CIEL*a*b* using a colorimeter (Easy-Shade, VITA). Half of the specimens were subjected to a discoloration process in a cigarette smoking machine (SM) and the other half to an immersion in whiskey (WH) for 24 hours. Another color measurement was performed for discolored specimens. The samples subjected to smoking were immersed in whiskey (SM/WH) and those subjected to whiskey immersion were subjected to cigarette smoking (WH/SM) followed by another color measurement. Color changes (delta E*) were calculated and submitted to repeated measures 4-way ANOVA and Tukey tests (P<0.05). RESULTS: The most significant color change was observed after WH/SM (delta E*= 22.8-31.5) discoloration process, followed by SM (delta E*= 7.0-18.0), SM/WH (delta E*= 4.9-16.5) and WH (delta E*= 2.0 to 9.5). Translucent shades were more susceptible to discoloration than enamel shades. All the groups, with the exception of two, showed a significantly high perceptible color change (delta E*>3.3). Based on the results, the color stability of dental composites was affected by the discoloration process and was material and shade dependent.

Fluorescence intensity of resin composites and dental tissues before and after accelerated aging: a comparative study.

This study quantitatively evaluated the fluorescence intensity of resin composites with different opacities and translucencies and determined changes in fluorescence after accelerated aging, using human enamel and dentin as controls. Six microhybrid and nanofilled composites, each in three different shades, were tested. Ten sound human incisors were used to obtain enamel and dentin specimens separately. Fluorescence measurements were obtained with a fluorescence spectrophotometer before (baseline) and after accelerated aging at 150 kJ energy for 120 hours. One-way analysis of variance (ANOVA) and Games-Howell multiple comparison tests were performed at a significance level of 0.05. Student's t-test was also used for comparison before and after aging. At baseline, there was no statistically significant difference (p>0.05) between the fluorescence intensity of dentin and any of the shades of Charisma or Opallis, Esthet-X dentin shade or Vit-l-escence enamel, or the translucent shades. After accelerated aging, all shades of the 4 Seasons, enamel and the translucent shades of Esthet-X had fluorescence intensities statistically similar to that of aged dentin (p>0.05). A significant reduction in fluorescence after aging (p<0.05) was observed for all the materials, except for human enamel and translucent Filtek Supreme XT. Accelerated aging reduced fluorescence in most of the composites evaluated.

Microhardness of dentin underneath fluoride-releasing adhesive systems subjected to cariogenic challenge and fluoride therapy.

OBJECTIVES: The aim of this study was to evaluate the microhardness of dentin subjacent to the bonding interface of composite restorations using fluoride-releasing adhesive systems submitted to pH-cycling regimen associated or not to fluoride therapies. METHODS: Thirty human third molars were prepared with class V cavities with dentin cervical margins. The adhesive systems One-Up Bond F Plus (OU), Prime&Bond NT (NT), Clearfil Protect Bond (CF), Optibond Solo Plus (OP) and also the controls [-] Single Bond 2 (SB) and [+] Ketac Molar (KM) were used previously to composite resin restorations. The restorations were sectioned into four slabs and submitted to different storage media for 15 days: distilled water, pH-cycling, pH-cycling associated to NaF 0.05% and associated to NaF 1.23%. The Knoop microhardness test was performed in dentin at 50, 100, 150 and 300 microm from the adhesive interface. Data was analyzed by three-way ANOVA and Tukey HSD test (p<0.05). RESULTS: KM resulted in significantly higher microhardness when compared to all the adhesive systems at 50 microm, with the exception of OU, that was similar to KM when submitted to pH-cycling alone or associated to 1.23% NaF. Microhardness of dentin was significantly higher with all the tested materials, when pH-cycling was associated to NaF 0.05%, at 50 microm and 100 microm depths. OU resulted in similar dentin hardness at all depths and storage media. CONCLUSIONS: The incorporation of NaF 0.05% fluoride therapy to the cariogenic challenge was capable to recover the original microhardness of dentin at 50 and 100 microm with all the tested materials.

Avaliação, após clareamento, da alteração decor de dentes bovinos imersos em soluçõescom elevado potencial de pigmentação / Postbleaching color change evaluation ofbovine teeth immersed in high-pigmentationpotential solutions

Introdução: O clareamento dentário é um dos tratamentos estéticosmais procurados na Odontologia atualmente. Entretanto alteraçõessubclínicas da micromorfologia superficial dos tecidos dentáriospodem ocorrer após o clareamento, levando a uma maior facilidadede manchamento nos períodos imediatamente posteriores à suarealização. Objetivo: Avaliar, após clareamento dentário, a alteraçãode cor de dentes bovinos imersos em quatro soluções com elevadopotencial de pigmentação. Material e métodos: Clarearam-se 50 dentesbovinos com gel à base de peróxido de hidrogênio a 35%. A análise dadeterminação da cor (parâmetros do sistema CIELab) foi realizada comauxílio de um espectrofotômetro digital. Os dentes foram distribuídosem cinco grupos e imersos nas soluções (n = 10): água destilada (controle), café, chá-preto, vinho tinto e refrigerante à base de cola, por1 hora por dia durante 15 dias. Em seguida, submeteram-se novamenteos dentes a análise de cor, e as diferenças de cores (?E) entre a primeirae a segunda leitura foram calculadas. Os dados foram sujeitados aanálise de variância (Anova) e ao teste de Tukey (? = 5%). Resultados:Entre todas as substâncias, a que promoveu maior manchamento foio chá-preto (18,49), seguido pelo vinho tinto (16,41), pelo refrigeranteà base de cola (15,73) e por último pelo café (9,37). Conclusão: Todasas soluções com elevado potencial de pigmentação foram capazes demanchar os dentes bovinos, entretanto o chá-preto, juntamente com ovinho tinto e o refrigerante, causou maior escurecimento.

Introduction: Dental bleaching is one of the most commonly usedaesthetic treatments in dentistry nowadays. However, subclinical changesin the surface micromorphology of dental tissues may occur afterbleaching, leading to a greater easiness of tooth staining in the periodimmediately after its completion. Objective: To evaluate the color changeof bovine teeth immersed in four solutions with high-pigmentationpotential, after tooth whitening. Material and methods: Fifty bovineteeth were bleached using a 35% hydrogen peroxide gel. Color analysiswas performed by a digital spectrophotometer for the acquisition ofCIELab parameters. Teeth were divided into 5 groups and immersedin the following solutions (n = 10): distilled water (control), coffee,black tea, red wine and cola soft drink, for 1 h/day, during 15 days.Teeth were again submitted to color analysis and the color differences(?E) between the first and second reading were calculated. Data weresubjected to ANOVA and Tukey?s test (? = 5%). Results: Among allthe substances tested, black tea provoked the highest color difference(18.49), followed by red wine (16.41), cola soft drink (15.73), and coffee(9.37). Conclusion: All high-pigmentation potential solutions were ableto promote the staining of bovine teeth. However, black tea, red wine,and cola soft drink produced the highest color differences.