Although several enzymes presumed to be part of the delignification/kraft pulp biobleaching system of the white-rot basidiomycete Trametes versicolor have been studied, characterized, and even exploited as pulp treatments, the complete system remains poorly understood. Little is known about which enzymes are essential for delignification, how they are regulated, or whether there remain unknown enzymes essential to wood decay in this system. Auxotrophic mutants of T. versicolor 52J were developed and characterized. Plasmid pUC18 was complemented with the T. versicolor 52J genome to create a gene library. Transformation with this plasmid-gene library converted argB and ade2 auxotrophs of T. versicolor 52J to prototrophy. Attempts to rescue the plasmids responsible were unsuccessful. Several different pre-existing plasmid constructs were examined for their potential as selectable markers on the fungus. One of these, pGPhT, worked well at conferring phleomycin resistance. Given that there are now available partial or complete sequences for four T. versicolor laccases, the single cellobiose dehydrogenase, and a lignin peroxidase isozyme, these genetic tools should be very useful in dissecting the mechanisms of white-rot delignification.

Objective: To evaluate the effect of an in-office plus at-home bleaching protocol on shear bond strength of orthodontic buttons when using a fluoride-releasing sealant. Methods and Materials: One hundred and sixty extracted human molars were randomly divided into bleached (N=80) and unbleached groups (N=80). The bleached group was treated with 45% carbamide peroxide for half an hour, followed with five applications of 20% carbamide peroxide at 24 hour intervals. After two weeks, lingual buttons were bonded on the teeth in both groups using either Transbond XT primer or Pro Seal sealant. The teeth were then stored in artificial saliva and subjected to shear testings at 24 hours and 3 months using a Zwick Universal Test Machine. Results: The ANOVA analysis of the 24-hour results indicated a significant difference between the four subgroups (p<.0011). Further simple t-tests indicated that the differences were significant only between bleached and unbleached subgroups (p<.0011). The 3-month results showed the mean shear bond strengths of the unbleached group using Pro Seal sealant was statistically significantly lower than the others although still greater than clinically minimal suggested bond strengths. Interestingly, 15% of the bleached teeth exhibited enamel fracture at the 3-month testing. Conclusion: At 24 hours, both Pro Seal sealant and Transbond XT primer appear to be a reliable choice on both bleached and unbleached teeth. However, at the 3-month period, Pro Seal sealant yielded significantly lower shear bond strength on unbleached teeth, nevertheless well within the range of values considered to be "clinically acceptable".

University of Technology, Sydney. Faculty of Science. / Global climate change is leading to the rise of ocean temperatures and is triggering mass coral bleaching events on reefs around the world. This involves the expulsion of the symbiotic dinoflagellate algae, known as zooxanthellae, from the coral host. Coral bleaching is believed to occur as a result of damage to the photosynthetic apparatus of these symbionts, although the specific site of initial impact is yet to be conclusively resolved. This thesis examined a number of sites within the light reactions of photosynthesis and evaluated the efficiency of photoprotective heat dissipating pathways. Upon expulsion, the capacity for long-term survivorship of expelled zooxanthellae in the water column was also assessed. A reduction in photosystem II (PSII) photochemical efficiency during exposure to elevated temperature and high light (bleaching conditions) was found to be highly dependent upon the increase in abundance of QB non-reducing PSII centres (inactive PSII centres), indicating damage to the site of the secondary electron acceptor, QB, resulting in a limited capacity for its reduction. Therefore, this reduced the rate of the reoxidation of the primary electron acceptor, QA-. Fast induction curve (FIC) analysis of the rise from minimum fluorescence to maximum fluorescence revealed a lower amplitude in the J step along this curve, which was consistent with a reduction in the rate of QA reoxidation. This photoinhibition of PSII was found to occur once the effectiveness of excess energy dissipation through energy-dependent quenching and state-transition quenching was exceeded, suggesting that these mechanisms were incapable of preventing photodamage. Antenna size heterogeneity showed little change under bleaching conditions with a significant increase in PSIIbeta only apparent in one species of coral. The thermostability of the oxygen evolving complex (OEC) and thylakoid membrane were found to increase during exposure to bleaching conditions and exceeded bleaching thresholds of corals. This rapid rise in temperature-dependent thermostability also occurred over seasons, where variation in ocean temperatures was matched by gradual shifts in OEC and thylakoid membrane thermotolerance. Variation in thermostability between species was not found to be linked to zooxanthellae genotype, and instead was related to the bleaching susceptibility of the host. Despite this capacity for resilience to bleaching conditions, the PSII reaction centres did not exhibit such a mechanism for rapid acclimatisation. Corals can only be as tolerant to bleaching conditions as their most sensitive component allows. The formation of nonfunctional PSII centres is therefore suggested to be involved in the initial photochemical damage to zooxanthellae which leads to a bleaching response. Zooxanthellae were found to be expelled irrespective of OEC function and thylakoid membrane integrity, as these sites of the photosynthetic apparatus were still intact when cells were collected from the water column. Although zooxanthellae were photosynthetically competent and morphologically intact upon expulsion, their longevity in the water column was dependent on the time of expulsion following the onset of bleaching and the ambient water temperatures. The survivorship of these zooxanthellae was restricted to a maximum of 5 days in the water column which suggests that unless expelled zooxanthellae inhabit other environs of coral reefs which may be more favourable for survival, their capacity for persistence in the environment is extremely limited. Chlorophyll a fluorescence measurements are a common tool for investigating photosynthetic impacts to in hospite zooxanthellae of corals. Pathways causing dark-reduction of the plastoquinone pool are shown to be active in corals and affect measurements which require dark-adaptation. Pre-exposure to far-red light was found to be an effective procedure to oxidise the inter-system electron transport chain and ensure determination of the true maximum quantum yield of PSII and accurate FICs. It is concluded that the trigger for coral bleaching lies in the photosynthetic apparatus of zooxanthellae and evidence is presented in support of this impact site not being the OEC or thylakoid membrane.

No description available.

Submitted by Suelen Reis (suziy.ellen@gmail.com) on 2013-04-23T15:36:04Z No. of bitstreams: 1 Dissertação Claudia Cunha.pdf: 593651 bytes, checksum: 6c5d95ef14354b9c51134dc0be1a0079 (MD5) / Approved for entry into archive by Rodrigo Meirelles(rodrigomei@ufba.br) on 2013-05-16T17:59:41Z (GMT) No. of bitstreams: 1 Dissertação Claudia Cunha.pdf: 593651 bytes, checksum: 6c5d95ef14354b9c51134dc0be1a0079 (MD5) / Made available in DSpace on 2013-05-16T17:59:41Z (GMT). No. of bitstreams: 1 Dissertação Claudia Cunha.pdf: 593651 bytes, checksum: 6c5d95ef14354b9c51134dc0be1a0079 (MD5) Previous issue date: 2004 / O presente estudo avaliou o efeito do peróxido de hidrogênio a 35% na resistência de união de diferentes sistemas adesivos (à base de álcool, acetona e primer auto-condicionante) ao esmalte dental, em diferentes períodos de tempo (24 h, 7 e 14 dias). Cinquenta terceiros molares humanos recém extraídos, divididos aleatoriamente em 12 grupos, sendo 3 controles e 9 experimentais, tiveram suas coroas seccionadas no sentido M-D e V-L, obtendo-se 4 fragmentos por dente, que foram abrasionados em suas superfícies lisas para a obtenção de uma área plana em esmalte. Os espécimes controle (G1, G2 e G3) foram armazenados em água destilada, durante todo o experimento, enquanto os espécimes dos grupos experimentais foram clareados com peróxido de hidrogênio a 35% (Whiteness HP - FGM), durante 1 sessão de 3 aplicações, e armazenados em água destilada por 24 h (G4, G7 e G10), 7 dias (G5, G8 e G11) e 14 dias (G6, G9 e G12). Posteriormente, cones de resina composta Z-250 (3M/ESPE) foram fixados, utilizando para os grupos G1, G4, G5 e G6 o sistema adesivo Single-Bond (3M/ESPE); para os grupos G2, G7, G8 e G9 o Prime & Bond N.T (Dentsply); e, para os grupos G3, G10, G11 e G12 o Clearfil SE Bond (Kuraray). Em seguida, foram submetidos ao teste de resistência de união à tração, em máquina de ensaio universal, a uma velocidade de 5 mm/min. Os resultados submetidos à análise de Variância ? ANOVA (p>0,05), demonstraram, que o peróxido de hidrogênio a 35% não alterou os valores de resistência de união, quando comparado aos grupos controle, independentemente do sistema adesivo utilizado e dos diferentes tempos testados. O padrão predominante de falhas ocorridas nos grupos clareados foi do tipo coesiva em resina composta, enquanto que nos grupos controle predominou a fratura mista (adesiva/coesiva em resina composta). / Salvador

Made available in DSpace on 2016-02-05T18:30:07Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-09-29. Added 1 bitstream(s) on 2016-02-05T18:34:15Z : No. of bitstreams: 1 000857688.pdf: 2857494 bytes, checksum: 1d6e5c2ee5ca46f4f586ec6e08563895 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Estudos demonstram danos causados à polpa dentária, e sua capacidade de reparo tecidual, após procedimento de clareação dentária. Este estudo investigou o processo de necrose, o nível de proliferação celular (imunomarcação com PCNA) e apoptose (Caspase-3-clivada), e a resposta imune inflamatória (IL-17, IL-6 e CD5) no tecido pulpar após este procedimento. Foram utilizados dois protocolos de clareação dentária com peróxido de hidrogênio (H2O2) nos molares superiores de 40 ratos Wistar, formando os grupos Controle (gel placebo), BLUE (H2O2 a 20% 1x50min) e MAXX (H2O2 a 35%, 3x15min). Após 2 e 30 dias, os ratos foram eutanasiados e as maxilas processadas para avaliação histológica (H.E.) e imunoistoquímica. Foram realizados os testes estatísticos referentes a cada caso, considerando p<0,05. Aos dois dias, foi observada necrose no terço oclusal do grupo MAXX, e infiltrado inflamatório moderado no BLUE (p<0,05). Aos 30 dias, não houve infiltrado inflamatório nos grupos, e grande área da câmara pulpar foi ocupada por dentina terciária. A marcação para PCNA aos 2 dias, demonstrou maior nível de proliferação celular no terço médio do grupo BLUE (p<0,05) e no terço cervical do MAXX (p<0,05), com redução significativa aos 30 dias no terço cervical (p<0,05). Caspase-3-clivada foi presente em todos os grupos, apresentando maior nível de apoptose nos grupos clareados quando comparados com o controle, nos dois períodos de análise (p<0,05); quando comparados os grupos aos 2 e 30 dias, foi observada redução significativa do nível de apoptose apenas no grupo BLUE (p<0,05). Células CD5 positivas foram presentes em todos os grupos, em ambos períodos de análise; aos dois dias, o grupo BLUE apresentou maior imunomarcação para CD5 no terço oclusal quando comparado aos demais grupos (p<0,05); nos demais terços... / Studies have shown damage to tooth pulp, and your capacity of tissue repair, after dental bleaching. This study investigated the necrosis process, the level of cell proliferation (immunolabeling with PCNA) and apoptosis (Caspase-3, cleaved), and inflammatory response (IL-17, IL-6 and CD5) generated in the pulp tissue after this procedure. Wistar rats were divided into Control (placebo gel), BLUE (20% H2O2,1x50min), and MAXX (35% H2O2, 3x15min) groups. At 2 and 30 days, the rats were killed (n=10).The jaws were removed and processed for histology analysis (H&E) and immunohistochemistry. Statistical tests were performed for each case, considering p<0.05. At two days, necrosis was observed on the occlusal third MAXX group and moderate inflammatory infiltrate in BLUE (p<0.05). At 30 days, there was no inflammatory infiltrate in groups, and large area of the pulp chamber was occupied by tertiary dentin. The immunolabeling for PCNA, at two days, was more expressive in the middle third of the BLUE group (p<0.05) and the cervical third of the MAXX (p<0.05), with significant reduction to 30 days in the cervical third (p<0.05). Caspase-3-cleaved was present in all groups, showing a higher level of apoptosis in the bleached groups compared with the control in both analysis periods (p<0.05); comparing the groups at 2 and 30 days, significant reduction in the level of apoptosis was observed only in BLUE group (p<0.05). CD5 positive cells were found in all groups in both analysis periods; at two days, the BLUE group had higher immunolabeling for CD5 in the occlusal third when compared to the other groups (p<0.05); in other thirds, both groups bleached showed most immunolabeling compared with the control group (p<0.05); there was no significant difference in the comparison of each group at 2 and 30 days (p>0.05). The MAXX group presented... / FAPESP: 11/13709-2

Made available in DSpace on 2014-06-11T19:31:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-07-14Bitstream added on 2014-06-13T20:22:08Z : No. of bitstreams: 1 cunha_la_dr_sjc.pdf: 684863 bytes, checksum: 8e211a6d2f18322f88b6df2f1dbde3dc (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este estudo in vitro avaliou o efeito da abrasão do esmalte humano na rugosidade superficial e na alteração de cor de dentes previamente submetidos à erosão. Quarenta e oito pré-molares humanos hígidos foram divididos em face vestibular e lingual, totalizando 96 fragmentos. Os espécimes foram divididos em quatro grupos (n=24): C - controle; O - clareamento com peróxido de hidrogênio a 38% (Opalescence Xtra Boost); OR - clareamento e imersão em refrigerante a base de cola (Coca-cola); R - imersão em refrigerante. Cada grupo foi dividido em dois subgrupos, para escovação com dentifrício de abrasividade regular (DR) e dentifrício branqueador (DB), em máquina simuladora de escovação. Antes e após o tratamento preconizado para cada grupo, a rugosidade foi mensurada em um rugosímetro (SJ-400, Mitutoyo) e a aferição da cor por meio de um espectofotômetro (Easyshade, Vita). Os dados foram submetidos à ANOVA e testes de Dunnett e Tukey. O grupo OR apresentou o maior aumento de rugosidade (0,092), que foi estatisticamente semelhante ao grupo O (0,046) e diferente da diminuição causada por R (-0,007). Quanto à alteração de cor, OR apresentou valores intermediários (7,95), sendo estatisticamente semelhante tanto ao grupo O (9,96) quanto ao R (6,37), que diferiram entre eles. Concluiu-se que a exposição do esmalte tanto ao gel clareador como à coca-cola não aumentou a rugosidade e que a exposição à coca-cola durante o tratamento clareador não ocasionou descoloração dental. Os dentifrícios regular e branqueador apresentaram desempenho de rugosidade e de alteração de cor estatisticamente semelhantes em todos os grupos avaliados. / This in vitro study aimed to evaluate the effect of human enamel abrasion on the surface roughness and color change of teeth previously submitted to erosion. Forty eight intact human pre-molars were divided in buccal and lingual faces, adding up to 96 fragments. The specimens were divided into four groups (n=24): C – control; O – bleaching with 38% hydrogen peroxide (Opalescence Xtra Boost); OB – bleaching and immersion in cola beverage; B – immersion in cola beverage. Each group was further divided into two subgroups, for brushing with regular abrasiveness dentifrice (RD) and whitening dentifrice (WT), in a toothbrushing machine. Before and after the treatment proposed for each group, roughness was measured in a profilometer (SJ-400, Mitutoyo) and colour evaluation was performed with a spectrophotometer (Easyshade, Vita). Data was submitted to ANOVA and Dunnett and Tukey tests. Group OB presented the highest roughness increase (0.092), which was statistically similar to group O (0.046) and different from the decrease caused by B (-0.007). Regarding colour change, OB presented intermediary values (7.95), which were statistically similar to group O (9.96) and B (6.37), which were different between them. It was concluded that exposure of enamel to bleaching gel or cola beverage did not increase roughness and exposure to cola soft drink during bleaching treatment did not cause dental discolouration. Regular and whitening dentifrices presented similar performance regarding surface roughness and colour change in all evaluated groups.

Orientador: Luciano Tavares Angelo Cintra / Coorientador: André Luiz Fraga Briso / Banca: Marco Antonio Hungaro Duarte / Banca: Eloi Dezan Junior / Resumo: Estudos demonstram danos causados à polpa dentária, e sua capacidade de reparo tecidual, após procedimento de clareação dentária. Este estudo investigou o processo de necrose, o nível de proliferação celular (imunomarcação com PCNA) e apoptose (Caspase-3-clivada), e a resposta imune inflamatória (IL-17, IL-6 e CD5) no tecido pulpar após este procedimento. Foram utilizados dois protocolos de clareação dentária com peróxido de hidrogênio (H2O2) nos molares superiores de 40 ratos Wistar, formando os grupos Controle (gel placebo), BLUE (H2O2 a 20% 1x50min) e MAXX (H2O2 a 35%, 3x15min). Após 2 e 30 dias, os ratos foram eutanasiados e as maxilas processadas para avaliação histológica (H.E.) e imunoistoquímica. Foram realizados os testes estatísticos referentes a cada caso, considerando p<0,05. Aos dois dias, foi observada necrose no terço oclusal do grupo MAXX, e infiltrado inflamatório moderado no BLUE (p<0,05). Aos 30 dias, não houve infiltrado inflamatório nos grupos, e grande área da câmara pulpar foi ocupada por dentina terciária. A marcação para PCNA aos 2 dias, demonstrou maior nível de proliferação celular no terço médio do grupo BLUE (p<0,05) e no terço cervical do MAXX (p<0,05), com redução significativa aos 30 dias no terço cervical (p<0,05). Caspase-3-clivada foi presente em todos os grupos, apresentando maior nível de apoptose nos grupos clareados quando comparados com o controle, nos dois períodos de análise (p<0,05); quando comparados os grupos aos 2 e 30 dias, foi observada redução significativa do nível de apoptose apenas no grupo BLUE (p<0,05). Células CD5 positivas foram presentes em todos os grupos, em ambos períodos de análise; aos dois dias, o grupo BLUE apresentou maior imunomarcação para CD5 no terço oclusal quando comparado aos demais grupos (p<0,05); nos demais terços... / Abstract: Studies have shown damage to tooth pulp, and your capacity of tissue repair, after dental bleaching. This study investigated the necrosis process, the level of cell proliferation (immunolabeling with PCNA) and apoptosis (Caspase-3, cleaved), and inflammatory response (IL-17, IL-6 and CD5) generated in the pulp tissue after this procedure. Wistar rats were divided into Control (placebo gel), BLUE (20% H2O2,1x50min), and MAXX (35% H2O2, 3x15min) groups. At 2 and 30 days, the rats were killed (n=10).The jaws were removed and processed for histology analysis (H&E) and immunohistochemistry. Statistical tests were performed for each case, considering p<0.05. At two days, necrosis was observed on the occlusal third MAXX group and moderate inflammatory infiltrate in BLUE (p<0.05). At 30 days, there was no inflammatory infiltrate in groups, and large area of the pulp chamber was occupied by tertiary dentin. The immunolabeling for PCNA, at two days, was more expressive in the middle third of the BLUE group (p<0.05) and the cervical third of the MAXX (p<0.05), with significant reduction to 30 days in the cervical third (p<0.05). Caspase-3-cleaved was present in all groups, showing a higher level of apoptosis in the bleached groups compared with the control in both analysis periods (p<0.05); comparing the groups at 2 and 30 days, significant reduction in the level of apoptosis was observed only in BLUE group (p<0.05). CD5 positive cells were found in all groups in both analysis periods; at two days, the BLUE group had higher immunolabeling for CD5 in the occlusal third when compared to the other groups (p<0.05); in other thirds, both groups bleached showed most immunolabeling compared with the control group (p<0.05); there was no significant difference in the comparison of each group at 2 and 30 days (p>0.05). The MAXX group presented... / Mestre

Orientador: André Luiz Fraga Briso / Banca: Paulo Henrique dos Santos / Banca: Mirela Sanae Shinohara / Resumo: Este estudo analisou a influência do ascorbato de sódio 10% (AS) na formação de tags e camada híbrida em dentina após clareamento dental. Materiais e métodos: Foram testados 6 grupos. GI- Controle: somente restaurações de Resina Composta (RC); GII- Ascorbato de Sódio (AS) + RC; GIII- clareamento com peróxido de carbamida 10% (PC) + RC; GIV- PC + AS + RC; GV- clareamento com peróxido de hidrogênio 35% (PH) + RC; GVI- PH + AS + RC. Após os tratamentos, os dentes foram seccionados e descalcificados. Os cortes foram montados em lâminas de vidro e corados pelo método Brown & Brenn. A análise em microscopia óptica comum (Axiophot) em 400X, evidenciou os tags e camada híbrida formados. Resultados: Os dados foram tabulados, sendo obtidas as respectivas médias para comprimento dos tags e a espessura da camada híbrida: GI- 10 e 3.1μm, GII- 9.2 e 2.4 μm, GIII- 5.4 e 1.5 μm, GIV- 6.8 e 2.1 μm, GV- 5.7 e 1.6 μm, GVI- 7.1 e 2.1 μm. Conclusão: O clareamento dental com PC ou PH prejudica a formação de tags resinosos e camada híbrida. O uso do AS aumentou o comprimento destas estruturas / Abstract: This study analyzed the influence of 10% sodium ascorbate (SA) on tag and hybrid layer formation in dentin after bleaching. Materials and Methods: Six groups were tested: GI- Control: restoration; GII- Sodium Ascorbate (SA) + restoration; GIII- Bleaching with carbamide peroxide (CP) + restoration; GIV- bleaching with CP + SA+ restoration; GV- bleaching with 35% hydrogen peroxide (HP) + restoration; and GVI- HP + SA + restoration. After treatments, the teeth were sectioned and decalcified. The length of resin tags and thickness of the hybrid layer were analyzed using optical microscopy (Axiophot). Results: The following results were obtained for the groups: GI- 10 and 3.1 μm, GII- 9.2 and 2.4 μm, GIII- 5.4 and 1.5 μm, GIV- 6.8 and 2.1 μm, GV-5.7 and 1.6 μm, GVI-7.1 and 2.1 μm (length of resin tags and thickness of the hybrid layer, respectively). Conclusion: Dental bleaching with CP or HP impairs the formation of resin tags and hybrid layer. The use of SA increases these measures / Mestre

Orientador: Caneppele, Taciana Marco Ferraz / Banca: Eduardo Bresciani / Banca: Carlos Martins Agra / Resumo: Objetivos: o objetivo deste estudo foi comparar a efetividade de enxaguatórios clareadores sobre dentes, clareados previamente ou não, expostos a corantes alimentícios. Material e Método: Cento e vinte espécimes de esmalte e dentina de 3 mm de diâmetro foram obtidos a partir de incisivos bovinos. Os espécimes foram manchados por 14 dias em caldo de manchamento. Após o manchamento, a leitura inicial da cor foi realizada, por meio do espectrofotômetro CM-2600d (Konica Minolta, Osaka, Japão). Sessenta espécimes (Subgrupos PC) foram submetidos ao clareamento com Peróxido de Carbamida a 10% por 14 dias. Após, foram subdividos em 4 subgrupos, com ciclos de manchamento (5 min) e enxaguatório (2 min) por 12 semanas, sendo PC-LI: Listerine Whitening Pré- escovação; PC-PL: Plax Whitening; PC-BP: Bromelina + Papaína; PC-AG: água deionizada. Os subgrupos LI, PL, BP e AG foram submetidos aos mesmos ciclos citados, porém não foram submetidos ao clareamento prévio. A leitura de cor dos espécimes foi feita após 4, 8 e 12 semanas de tratamento com os enxaguatórios. Os dados foram coletados e submetidos à Análise de variância (ANOVA) de medidas repetidas. A comparação entre os subgrupos para a avaliação das diferenças estatísticas foi realizada pelo Teste de Tukey. Todos os testes empregados admitiram 5% como nível de significância estatística. Os resultados mostraram que os valores de ΔL*, Δa*, Δb* e ΔE* confirmaram o clareamento para os subgrupos PC-LI, PC-PL, PC-BP e PC-AG, após o tratamento com peróxido de carbamida, e para os subgrupos PC-LI, PC-PL, LI e PL, após os ciclos manchamento-enxaguatório. Os subgrupos PC-BP e BP assemelharam-se aos subgrupos controle PC-AG e AG. Conclui-se, desse modo, que o enxaguatório bucal Listerine Whitening apresentou maior efeito clareador, seguido do enxaguatório Plax Whitening. Porém, nenhum desses enxaguatórios foi capaz de produzir clareamento semelhante ao evidenciado pelo.. / Abstract: Objectives: The aim of this study was to compare the effectiveness of whitening mouthrinses on teeth previously whitened or not, exposed to food dyes. Material and Methods: One hundred and twenty specimens of enamel and dentin of 3 mm in diameter were obtained from bovine incisors. The specimens were stained for 14 days in broth staining. After staining, the initial color reading was performed by a spectrophotometer CM-2600d (Konica Minolta, Osaka, Japan). Sixty specimens (Subgroups CP) were submitted to whitening (Carbamide Peroxide 10%) for 14 days. Then they were subdivided into 3 subgroups, and were submitted to cycles of staining (5 min) and mouthrinse (2 min) for 12 weeks, with CP-LI: Listerine Whitening Pré- Escovação; CP-PL: Plax Whitening; CP-BP: Bromelain + Papain; CP-DW: deionized water. LI, LP, BP and DW subgroups were submitted to the same cited cycles, but without bleaching before. The color measurements were performed after 4, 8 and 12 weeks of treatment with mouthrinses. Data were collected and subjected to analysis of variance (ANOVA) for repeated measures. The comparison between the subgroups for the evaluation of statistical differences was performed by Tukey test. All tests admitted statistical significance level of 5%. The results showed that the values ΔL*, Δa*, Δb* and ΔE* confirmed bleaching to PC-LI, PC-PL, PC-BP and PC-DW subgroups, after treatment with carbamide peroxide and to CP-LI, CP-PL, LI and PL subgroups, after the staining-mouthrinse cycles. CP-BP and BP subgroups were similar to CP-DW and DW. We conclude, therefore, that the mouthrinse Listerine Whitening presented the highest bleaching effect, followed by mouthrinse Plax Whitening. Both of them were able to maintain the bleaching effect of CP after 12 weeks of dye-rinse cycles. However, none of these rinses was able to produce whitening similar to that evidenced by the Carbamide Peroxide. The mouthrinse containing... / Mestre