Indiana University-Purdue University Indianapolis (IUPUI)

<p>The aim of this laboratory based study is to assess the efficiency of a tooth bleaching agent by measuring the degree of color change with a spectrophotometer (Konica Minolta, CM 2600d) and not by the usual subjective visual guide methods. Objectives of the study are: To determine tooth shade with a spectrophotometer prior to staining the tooth (baseline). To determine which insult causes the most discoloration numerically. To measure the efficiency of the bleaching agent used in the study with periodic color change pectrophotometer readings.&nbsp / To assess if the baseline tooth shade can be regained by the bleaching agent.</p>

<p>The aim of this laboratory based study is to assess the efficiency of a tooth bleaching agent by measuring the degree of color change with a spectrophotometer (Konica Minolta, CM 2600d) and not by the usual subjective visual guide methods. Objectives of the study are: To determine tooth shade with a spectrophotometer prior to staining the tooth (baseline). To determine which insult causes the most discoloration numerically. To measure the efficiency of the bleaching agent used in the study with periodic color change pectrophotometer readings.&nbsp / To assess if the baseline tooth shade can be regained by the bleaching agent.</p>

Magister Scientiae Dentium - MSc(Dent) / Summary: Aim: The aim of this laboratory study is to assess the efficacy of a tooth bleaching agent by evaluating the degree of color change with the use of a spectrophotometer and not by the usual subjective, visual methods. Methodology: Twenty specimens of human teeth will be collected, polished and divided into two groups. A baseline color measurement by the CIE L* a* b* with a spectrophotometer against a white background will be taken before one group is immersed in coffee and the other in red wine for two weeks. Bleaching of the specimens will be done according to manufacturer’s instructions for two weeks. Color readings will be taken before bleaching, weekly during bleaching and 1 and 2 weeks after the bleaching treatment. Color change (ΔE) will be calculated mathematically as Δ E = [ (Δ L*)2 + (Δ a*)2 + (Δ b*)2 ]1/2. An observation of whether the baseline color reading will be regained by the bleaching process will be made. Results: Data collected will be recorded on an Excel spreadsheet. Advice from a qualified statistician will be sought to analyze the data. Results will be discussed in comparison with the existing literature on this subject. / South Africa

<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>

<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>

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

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.