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<p>The objective of this study was to assess coronal discoloration due to four commonly used endodontic sealers with gutta-percha, using spectrophotometric analysis. Extracted human teeth were obturated with the experimental sealers and GP. The sealers that were tested included AH Plus, EndoRez, and Kerr Pulp Canal Sealer. The teeth were maintained in a moist environment at 37 C. Immediate pretreatment readings of the crowns of the extracted teeth with a spectrometer were used as baseline data. Subsequent readings were taken every two weeks for two months. Results were analysed using Wilcoxson Signed Rank sum test and Kruskal Wallis test.</p>

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2004. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2006. / Härtill 4 uppsatser.

Orientadores: Débora Alves Nunes Leite Lima, Luis Alexandre Maffei Sartini Paulillo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-22T12:36:12Z (GMT). No. of bitstreams: 1 Publio_JulianadoCarmo_M.pdf: 1849984 bytes, checksum: 80c6278fc7a03f56e6011fd3f302e6ea (MD5) Previous issue date: 2013 / Resumo: O objetivo deste estudo foi avaliar a influência da espessura do esmalte e a aplicação prévia de dessensibilizante na eficácia do tratamento clareador. O trabalho foi dividido em 2 estudos. No primeiro estudo foi testada a influência da espessura do esmalte (0,5mm de espessura, 1,0mm de espessura planificada, 1,0mm de espessura não planificada e sem esmalte- controle) na eficácia do clareamento em profundidade, variando-se o tipo de agente clareador, peróxido de carbamida (PC) 10% e peróxido de hidrogênio (PH) 35%. No segundo estudo foi avaliada a influência da aplicação prévia de agente dessensibilizante, fluoreto de sódio 2% e nitrato de potássio 5% associado ao fluoreto de sódio 2% e, sem agente dessensibilizante (controle) na eficácia do clareamento dental com PH35%. Nos dois estudos foram usados fragmentos dentais bovinos, pigmentados por chá preto, e distribuídos por esquema inteiramente casual no primeiro estudo e aleatório por sorteio no segundo estudo (n=10) em grupos de acordo com os tratamentos acima. As amostras foram armazenadas em saliva artificial durante as 3 semanas de tratamento. As leituras de cor da dentina oposta (1,75mm de espessura) do estudo 1 e as leituras de cor do esmalte (1,0mm de espessura) e dentina oposta (1,75mm de espessura) do estudo 2 foram realizadas após o manchamento (baseline) e após cada semana de tratamento clareador, utilizando o método CIE Lab através de espectrofotômetro (Konica Minolta CM 700 d, Japan). Para o estudo 1 os valores de ?E, ?L, ?a e ?b datados foram submetidos à análise de variância ANOVA em esquema fatorial e teste de Tukey (?=0,05). Para o estudo 2, a coordenada L* datada (L=100 - lightness; L=0 - darkness) foi submetida por meio de análise de medidas repetidas PROC MIXED e teste de Tukey-Kramer e os valores de ?E datados foram submetidos à análise de variância ANOVA e teste de Tukey (?=0,05). O esmalte de 2 amostras de cada grupo do estudo 2 foi observado em microscopia eletrônica de varredura (MEV). Nos resultados destes estudos pode-se observar que o clareamento com PC10% foi mais efetivo que o PH35% em profundidade dentinária para todos os parâmetros de delta, com exceção no terceiro tempo dos deltas. A presença da camada aprismática no esmalte interferiu na eficácia do PC10% somente no primeiro tempo de clareamento em ?E1, ?L1 e ?b1, entretanto não interferiu nos tempos de clareamento testado com PH35% (estudo 1). Ainda, o uso de agente dessensibilizante realizado previamente ao clareamento dental não interferiu no mecanismo de ação do PH35% em profundidade (estudo 2) / Abstract: The aim of this study was to evaluate the influence of enamel thickness and prior application of a desensitizing agent on the effectiveness of bleaching treatment. This project was divided into two studies. Firstly, we tested the influence of enamel thickness (0.5 mm thick, 1.0 mm planned thick, 1.0 mm unplanned thick and absence of enamel - control) on the effectiveness of bleaching, in-depth, according to the type of bleaching agent, as follows: 10% carbamide peroxide and 35% hydrogen peroxide. Secondly, we evaluated the influence of prior application of a desensitizing agent (potassium nitrate associated with 2% sodium fluoride, 2% neutral fluoride, or with no desensitizing agent - control) on the effectiveness of tooth bleaching by using 35% hydrogen peroxide. In both studies we used bovine teeth fragments, stained with black tea, which were allocated into groups according to the aforementioned treatments, by an entirely causal scheme for the first study and by random drawing for the second one (n=10). The specimens were stored in artificial saliva during the 3-week-treatment. Color readings of the underlying dentin (1.75 mm thick) concerning the study 1, and color readings of enamel (1.0 mm thick) and underlying dentin (1.75 mm thick) of the study 2, were performed after staining (baseline) and after each week of bleaching treatment using the CIE Lab method by means of spectrophotometer (Konica Minolta CM 700d, Japan). For the study 1, the values of ?E, ?L, ?a and ?b recorded were subjected to factorial analysis of variance (ANOVA) and Tukey's test (? = 0.05). For the study 2, the coordinate L* recorded (L = 100 - lightness, L = 0 - darkness) was submitted to analysis of repeated measures PROC MIXED and Tukey-Kramer's test, and the ? values registered underwent analysis of variance (ANOVA) and Tukey's test (? = 0.05). The enamel of 2 specimens from each group of the study 2 was observed under scanning electron microscopy. According to the findings, it could be observed that the bleaching with 10% CP was more effective than that with 35% PH as regards dentin depth for all parameters delta, except the third time deltas. The presence of the prismless layer of enamel interfered with the effectiveness of 10% CP just in the first time of bleaching in ?E1, ?L1and ?b1, however it did not affect the times of bleaching when 35% HP was tested (study 1). In addition, the use of a desensitizing agent prior to tooth bleaching did not interfere with the mechanism of action of the 35% hydrogen peroxide concerning tooth depth (study 2) / Mestrado / Dentística / Mestra em Clínica Odontológica

Magister Scientiae Dentium - MSc(Dent) / The objective of this study was to assess coronal discoloration due to four commonly used endodontic sealers with gutta-percha, using spectrophotometric analysis. Extracted human teeth were obturated with the experimental sealers and GP. The sealers that were tested included AH Plus, EndoRez, and Kerr Pulp Canal Sealer. The teeth were maintained in a moist environment at 37 C. Immediate pretreatment readings of the crowns of the extracted teeth with a spectrometer were used as baseline data. Subsequent readings were taken every two weeks for two months. Results were analysed using Wilcoxson Signed Rank sum test and Kruskal Wallis test. / South Africa

The pigments responsible for pink or red discoloration in cooked vacuum-packaged meat products {bratwurst (pork and beef), ground pork, and pork roasts} were investigated. In bratwurst, this study attempted to characterize the red pigment that appears upon refrigerated storage, and to determine the effect of pH, cooking and storage temperature, and sodium lactate on incidence of red discoloration. Myoglobin was identified in the exudate of samples with red discoloration. Myoglobin levels of cooked products were significantly lower in samples of low initial pH (5.5) or cooked to higher than normal internal temperature (74°C). Red discoloration was associated with microbial growth. Frozen samples had no red discoloration after 4 weeks storage. Microbial plate count and incidence of red discoloration were lower in samples of lower pH (5.5 vs 5.8 or 6.2), samples cooked to higher internal temperature (74° vs 68°C), and samples containing 3% sodium lactate. Further, the effects of microbial growth in raw materials (ground pork) on cooked pork color were investigated. In two trials with sow meat held aerobically at 2°C for 3 weeks, microbial load reached spoilage levels (107 cfu/g), pH increased to 6.46, and samples cooked to 71°C had red exudate, shown by absorption spectroscopy to contain myoglobin and cytochrome c. Samples cooked to 82°C received high panel ratings for red color, due to red, flocculent precipitate in exudate, but samples containing undenatured myoglobin levels received low panel ratings. In sow meat held frozen or vacuum packaged at 2°C, pH after 3 weeks was 6.03 and 6.18, and plate counts were 104 and 107, respectively, but exudates after cooking were much less red. In five trials with fresh U. S. #1 pork legs, plate counts also reached 107 cfu/g by 3 weeks storage, and pH increased from 5.99 to 6.37, but cooked samples were not red. Higher myoglobin levels in sow meat probably accounted for the red color and the high level of undenatured myoglobin remaining after cooking of high pH, spoiled samples. Finally, pink or red discoloration was investigated in the cooked U. S. #1 pork roasts. Myoglobin was the pigment responsible for pink color in pork roasts cooked to 65°C. Roasts cooked to 82°C had gray internal color after cooking, but developed pink internal color after refrigerated storage. Reflectance spectra of pink slices from roasts, cooked to 82°C, then stored for 12 days at 2°C, were charactetistic of denatured globin hemochromes or related non-nitrosyl hemochromes.

Indiana University-Purdue University Indianapolis (IUPUI) / Whitening dentifrices use different mechanisms for stain removal and prevention. These approaches are abrasives, oxidizing agents, and chemical cleaning agents. The objectives of this in-vitro study were: 1) To compare the whitening effect of commercial whitening and non-whitening dentifrices; 2) To verify the mechanism of action of whitening dentifrices by contrasting two experimental models: chemical model (toothpaste exposure only) and chemo-mechanical (toothpaste exposure with tooth-brushing abrasion). The 256 bovine enamel specimens (10 mm x10 mm) were prepared and partially stained. They were assigned to 8 groups: 6 whitening dentifrices, 1 non-whitening reference dentifrice and deionized water (control); and they were further divided in 2 subgroups (n = 16), chemical and chemo-mechanical. Specimens were exposed to dentifrice slurries 2X/day for 1 min and brushed or not, according to each model. In between dentifrice treatments, specimens were exposed to the staining solution for 5 h. This protocol was repeated for 5 consecutive days and enamel color changes (∆E, ∆L) were measured by spectrophotometry after each day. The abrasivity of the toothpastes was determined using a standard test (ISO 11609). Significantly higher ∆E values (whitening effect) were observed for all groups (p < 0.05), except for the control, when tested in the chemo-mechanical model. In this model, the whitening ability of the toothpastes was mainly determined by their abrasive levels. For the chemical model, no significant differences were observed among groups (p > 0.05). Whitening dentifrices can be effective in preventing and removing enamel surface staining, when associated with tooth-brushing abrasion. This was modulated by the abrasive level of the tested toothpastes, with no chemical action attributed to the chemical agents. / indefinitely

Tooth discoloration is considered a challenging clinical condition for restoration procedures. Layering technique with resin composites of different translucencies can be applied to cover-up discolored substratum and produce esthetic harmonic restorations. The aim of the present study was to assess the masking ability of the layering technique with the following resin composites restoration systems - IPS Empress Direct (Ivoclar Vivadent), Charisma Diamond (Heraeus Kulzer) and Filtek Z350XT (3M-ESPE). Ninety specimens with 1.5mm thick were produced and divided in groups according to the restoration system and resin composite combination. Color measurements were carried out by reflectance spectrophotometer (SP60 - EX-Rite) through CIE L*a*b* color system against a C4 shade background (C4), and an inherent color background (IC). These two backgrounds simulate a severely discolored substratum (C4) and a tooth surface with no discoloration (IC). The total color difference (ΔE) between both color measures indicates the masking ability of the resin combination. The normal data distribution was verified with Kolmogorov-Smirnov test. The mean ΔE* values were analyzed by ANOVA and Tukey s post hoc tests (α =0.05). Three groups presented ΔE* values under clinical acceptance threshold (ΔE*≦3,3): 1.5mm Dentin; 1.0mm Dentin / 0.5mm Body and 1.0mm Dentin / 0.5mm Enamel, all groups from Z350 XT restoration system. Filtek Z350 XT system was capable to mask C4 background. The dentin shade of this system was considered more effective when compared to IPS Empress and Charisma Diamond dentin shade resins and masked the discolored background in single layer mode or combined with Z350 enamel and body shade through layering technique. / Alterações de cor em um ou mais elementos dentais são consideradas situações desafiadoras sob o ponto de vista restaurador. A técnica de estratificação de resinas compostas com diferentes propriedades ópticas pode ser aplicada para recobrir e mascarar substratos escurecidos e obter restaurações harmônicas. O presente estudo avaliou a capacidade de mascaramento dos sistemas restauradores de resina composta IPS Empress Direct (Ivoclar Vivadent), Charisma (Heraeus Kulzer) e Filtek Z350 XT (3M-ESPE), a partir da estratificação de diferentes espessuras de resinas com propriedades ópticas distintas. 90 corpos de prova de 1,5mm de espessura foram confeccionados e divididos em grupos conforme o sistema restaurador e a combinação de resinas compostas utilizada. Os espécimes foram posicionados sobre dois fundos, um de cor C4 e outro da cor inerente da resina de dentina de cada sistema. As mensurações foram realizadas com um espectrofotômetro com o sistema CIE L*a*b*. A capacidade de mascaramento foi avaliada pela diferença total da cor (ΔE) entre a cor dos espécimes posicionados sobre os fundos C4 e o fundo de resina composta de dentina de cada sistema. A normalidade dos dados foi verificada com o teste Kolgomorov- Smirnov e os valores médios de ΔE* analisados por ANOVA e post hoc Tukey (α =0.05). Dentre todas as composições testadas, 3 grupos apresentaram valores dentro do limiar clinicamente aceitável (ΔE*≦3,3): 1,5mm Dentina; 1,0mm Dentina + 0,5mm Corpo e 1,0mm Dentina + 0,5mm Esmalte, todos os grupos pertencentes ao sistema Filtek Z350 XT. O sistema Filtek Z350 XT foi capaz de mascarar o fundo da cor C4. A resina de dentina do sistema Z350 foi considerada mais efetiva em relação as resinas de dentina dos outros sistemas e foi capaz de mascarar o fundo escurecido quando aplicada em único incremento ou combinada com resinas de esmalte e corpo pela técnica de estratificação.

Indiana University-Purdue University Indianapolis (IUPUI) / Introduction: Some intracanal medicaments used in regenerative endodontics may compromise the bond strength of root cements and lead to tooth discoloration. Objectives: To evaluate the effects of 1) low concentrations of TAP and DAP (1 mg/mL) on push-out bond strength of various root cements, and 2) low concentrations of TAP and DAP (1 mg/mL and 10 mg/mL) on crown discoloration. Materials and Methods: Single rooted human teeth (n = 144) were horizontally decoronated and instrumented according to standardized protocol. The samples were randomized into six experimental groups (Ca(OH)2, 1000 mg/mL TAP and DAP, 1 mg/mL TAP and DAP, and no medicament control group. After four weeks, the medicaments were removed and each group was divided into three subgroups to receive MTA cement, Biodentine cement, or Endosequence Bioceramic putty cement for two weeks. Then, two root cylinders were obtained from each root and push-out bond strength testing was performed. For the crown discoloration experiment, 160 crowns were obtained from intact human molars and randomized into experimental groups as described earlier with the addition of two groups (10 mg/mL TAP and DAP). The pulp chambers in half of the samples from each group were coated with an adhesive bonding agent before receiving the assigned intracanal medicament. Color changes (ΔE) were detected by spectrophotometer at 1 day, 1 week, and 4 weeks after application, as well as after thermocycling. Results: In the push-out bond strength experiment, 1 mg/mL DAP generally demonstrated significantly higher bond strength of root cements compared with the other treatment groups. For the crown discoloration experiment, when an adhesive bonding agent was used prior to (10 mg/mL or 1000 mg/mL) TAP, the crowns had significantly less discoloration than those without adhesive. DAP 10 mg/mL had the least significant color change at all time points regardless of whether adhesive was used. Conclusion: 1) 1 mg/mL DAP and Ca(OH)2 did not have significant negative effect on the bond strength of calcium-silicate-based cement to radicular dentin. 2) 1 mg/mL and 10 mg/mL of DAP and Ca(OH)2 had significantly less effect on the color change of the human tooth crown than all intracanal medicaments used in this study. / 2020-08-13