Photobleaching Kinetics and Effect of Solvent in the Photophysical Properties of Indocyanine Green for Photodynamic Therapy.

Indocyanine green is an attractive molecule for photodynamic therapy due to its near infrared absorption, resulting in a higher tissue penetration. However, its quantum yields of the triplet and singlet state have been reported to be low and then, reactive oxygen species are unlikely to be formed. Aiming to understand the ICG role in photodynamic response, its photobleaching behavior in solution has been studied under distinct conditions of CW laser irradiation at 780 and 808 nm, oxygen saturations and solvents. Sensitizer bleaching and photoproduct formation were measured by absorption spectroscopy and analyzed using the PDT bleaching macroscopic model to extract physical parameters. ICG photobleaching occurs even at lower oxygen concentrations, indicating that the molecule presents more than one way of degradation. Photoproducts were produced even in solution of less than 4 % oxygen saturation for both solvents and excitation wavelengths. Also, the amplitude of absorption related to J-dimers was increased during irradiation, but only in 50 % PBS solution. The formation of photoproducts was enhanced in the presence of J-type dimers under low oxygen concentration, and the quantum yields of triplet and singlet states were one order of magnitude and two times higher, respectively, when compared to ICG in distilled H2 O.

Natural versus synthetic curcuminoids as photosensitizers: Photobleaching and antimicrobial photodynamic therapy evaluation.

Antimicrobial photodynamic therapy (aPDT) has been studied as an alternative to combat bacterial resistance to the commonly used antibiotics. aPDT requires the use of a photosensitizer and curcumin is one of the more promising, though the usage of natural curcumin can be inconsistent in certain biomedical uses due to differences in soil condition and turmeric age, besides a large quantity of the plant is necessary to obtain useful amounts of the actual molecule. As such, a synthetic analogue is preferred as it is pure, and its components are better characterized. The present work studied photophysical differences in both natural and synthetic curcumin using photobleaching experiments and searched for whether differences existed in aPDT studies against Staphylococcus aureus. The results showed a faster O2 consumption and a singlet oxygen's generation rate lower by the synthetic curcumin, in comparison with the natural derivative. However, no statistical difference was observed when inactivating S. aureus and these results were following a concentration-based pattern. Thus, the use of synthetic curcumin is indicated, as it can be obtained in controlled amounts and with less environmental impact. Although there are small changes in a photophysical context comparing natural versus synthetic curcumins, we did not observe statistical differences in the photoinactivation of S.aureus bacteria, and reproducibility in biomedical contexts is better achieved with the synthetic analogue.

Photosensitized Oxidation of Intracellular Targets: Understanding the Mechanisms to Improve the Efficiency of Photodynamic Therapy.

The development of improved photosensitizers is a key aspect in the establishment of photodynamic therapy (PDT) as a reliable treatment modality. In this chapter, we discuss how molecular design can lead to photosensitizers with higher selectivity and better efficiency, with focus on the importance of specific intracellular targeting in determining the cell death mechanism and, consequently, the PDT outcome.

Photoactivation of Erythrosine in simulated body fluids.

Photodynamic Therapy (PDT) is a powerful technique for the treatment of cancer and non-cancerous diseases. The precise PDT treatment protocol definition must consider the performance difference between in vitroand in vivoapplications. This also occurs in other biological studies, and to partially overcome this difficulty, the simulated body fluids are generally applied as a prior understanding of the particularities of the different systems. However, in PDT these studies are scarce. In this work, we investigated the photoactivation of Erythrosine, a photosensitizer widely used in PDT, in different simulated body fluids. Differences in the photodegradation kinetics, triplet lifetime, and singlet oxygen generation were observed. The results can help to explain and to define PDT application protocols.

Biophysical characterization dataset of native nicotinic acetylcholine receptor in lipid-like detergent complexes.

For a long time, traditional purification and extraction methods for the native Torpedo californica nicotinic acetylcholine receptor in lipid-like detergent complex (nAChR-DC) have compromised its purity, functionality and X-ray structural studies possibility. The dataset presented in this article provide a characterization of the Torpedo californica nAChR-DC purified using a sequential purification processes developed in our laboratory [1]. This purification takes in consideration all of the physicochemical and functional requirements stablished by several researchers for the past three decades for the nAChR. These requirements were addressed in order to preserve the stability and functionality of nAChR-DC while ensuring the highest degree of protein purity. We focused on the effect of cholesteryl hemisuccinate (CHS) supplementation on nAChR conformational changes during the purification process. Data from the size exclusion chromatography of the nAChR-DC supplemented with CHS in concentrations ranging from 0.01 mM, 0.1 mM, 0.2 mM and 0.5 mM consistently demonstrated that 0.5 mM CHS affects receptor stability via disassemble of the pentameric oligomer. However, 0.2 mM CHS produced negligible nAChR-DC subunit disruption. The purified nAChR-DC has been characterized by circular dichroism (CD) and fluorescence recovery after photobleaching (FRAP), in order to assess its stability. The CD data was recorded in the wavelength range of 190-250 nm, showed that CHS induce a ⍺-helix to ß-sheet transition of the nAChR-DC. The nAChR-LFC-16 delipidation with Methyl-ß-Cyclodextrin decreased the percentage of α-helix and increased the ß-sheet antiparallel secondary structure and levels the percentage of turns to that of the nAChR-DC without CHS treatment. Additionally, the stability of the nAChR-DC supplemented with CHS and incorporated into lipid cubic phase (LCP) was monitored for a period of 30 days by means of FRAP. The LCP-FRAP data allowed to establish possible optimal crystallization conditions for the development of crystals from purified nAChR-conjugated to α-Bungarotoxin, Alexa Fluor ™ 488 (α-BTX) in order to obtain a high-resolution atomic structure by X-ray diffraction.

Off the wall: The rhyme and reason of Neurospora crassa hyphal morphogenesis.

The fungal cell wall building processes are the ultimate determinants of hyphal shape. In Neurospora crassa the main cell wall components, ß-1,3-glucan and chitin, are synthesized by enzymes conveyed by specialized vesicles to the hyphal tip. These vesicles follow different secretory routes, which are delicately coordinated by cargo-specific Rab GTPases until their accumulation at the Spitzenkörper. From there, the exocyst mediates the docking of secretory vesicles to the plasma membrane, where they ultimately get fused. Although significant progress has been done on the cellular mechanisms that carry cell wall synthesizing enzymes from the endoplasmic reticulum to hyphal tips, a lot of information is still missing. Here, the current knowledge on N. crassa cell wall composition and biosynthesis is presented with an emphasis on the underlying molecular and cellular secretory processes.

Spectroscopic, photochromic and kinetic behavior of photo conversion of Aberchrome 540™ in an ionic liquid media.

The photo-bleaching reaction of the chemical actinometer, Aberchrome 540™, is reported for the first time in a series of ionic liquids (ILs). This fulgide in its C-form undergoes an opening reaction to yield its E-form, when it is irradiated with UV light at wavelengths >400 nm. The magnitude of bleaching was monitored spectrophotometrically and their kinetics evaluated, obtaining first-order rate constants (kobs). The results obtained in different ILs suggest that changes in the rate constants (kobs) of the opening reaction of Aberchrome 540™ are mainly governed by weaker interactions such as coulombic (π* parameter) and Van der Waals interactions (δH2, parameter). In addition, the photochemical fatigue resistance was also studied in ILs media and compared with conventional solvents (benzene, toluene, etc.). In particular, we found that three different tendencies dependent on the ILs used exist. The first group of ILs where the reversibility of the fulgide is favored (for example, [Bmim][BF4], [Bmim][PF6] and [Bmim][OTf]), behaviour similar to conventional solvents. The second group corresponds to ILs where photo reversibility is partial; and finally, other group of ILs that prevented photo reversibility. It is proposed that depending on the ILs used, the stabilization of different forms of the fulgide can be controlled, thus resulting important in terms of choosing the appropriate ILs for a specific photochemical reaction.

Aligned ovine diaphragmatic myoblasts overexpressing human connexin-43 seeded on poly (L-lactic acid) scaffolds for potential use in cardiac regeneration.

Diaphragmatic myoblasts (DMs) are precursors of type-1 muscle cells displaying high exhaustion threshold on account that they contract and relax 20 times/min over a lifespan, making them potentially useful in cardiac regeneration strategies. Besides, it has been shown that biomaterials for stem cell delivery improve cell retention and viability in the target organ. In the present study, we aimed at developing a novel approach based on the use of poly (L-lactic acid) (PLLA) scaffolds seeded with DMs overexpressing connexin-43 (cx43), a gap junction protein that promotes inter-cell connectivity. DMs isolated from ovine diaphragm biopsies were characterized by immunohistochemistry and ability to differentiate into myotubes (MTs) and transduced with a lentiviral vector encoding cx43. After confirming cx43 expression (RT-qPCR and Western blot) and its effect on inter-cell connectivity (fluorescence recovery after photobleaching), DMs were grown on fiber-aligned or random PLLA scaffolds. DMs were successfully isolated and characterized. Cx43 mRNA and protein were overexpressed and favored inter-cell connectivity. Alignment of the scaffold fibers not only aligned but also elongated the cells, increasing the contact surface between them. This novel approach is feasible and combines the advantages of bioresorbable scaffolds as delivery method and a cell type that on account of its features may be suitable for cardiac regeneration. Future studies on animal models of myocardial infarction are needed to establish its usefulness on scar reduction and cardiac function.

Alterações morfológicas e químicas do esmalte humano após o clareamento dental: avaliação in situ / Morphological and chemical changes of human enamel after tooth bleaching: in situ evaluation

Introdução: A alteração de cor dos dentes apresenta-se como um dos fatores que mais concorrem para o desequilíbrio do sorriso, sendo o clareamento dental amplamente difundido e solicitado pelos pacientes. Objetivo: Este estudo in situ teve como objetivo avaliar as mudanças morfológicas e químicas do esmalte quando submetido a três agentes clareadores à base de peróxido de hidrogênio ativados com fonte de luz híbrida e um agente placebo (gel sem peróxido de hidrogênio), por meio do uso da espectrometria de energia dispersiva de raios-X (EDS). Metodologia: Fragmentos de terceiros molares humanos foram divididos em quatro grupos (n=12), para a realização de uma sessão de clareamento com cinco aplicações de oito minutos dos géis clareadores: Placebo (Plac); Lase Peroxide Flex 35% e 15% (DMC) (LPF35LH e LPF15LH); Gel experimental a 10% (DMC) (EXP10LHV), e foram fotocatalizados com luz híbrida: LED azul/laser de diodo (LH) (Whitening Lase II, DMC) ou LED violeta/laser de diodo (LHV) (luz experimental, DMC). Após o clareamento, os espécimes foram fixados a dispositivos intraorais usados pelos participantes durante 15 dias. A composição inorgânica e topografia da superfície de esmalte foram analisadas antes e após o clareamento, e depois de 3, 7 e 15 dias de exposição à saliva. Os valores elementares da composição foram analisados por ANOVA a um critério de medidas repetidas e teste de Tukey. Para a topografia os escores foram determinados por três examinadores previamente calibrados pelo teste Kappa e foi aplicado o teste estatístico de Friedman e Kruskal-Wallis, e as comparações individuais foram realizadas pelo teste de Dunn ( = 0,05). Resultados: De maneira geral, não houve alterações significativas na porcentagem elementar do esmalte nos diferentes períodos estudados. Ao analisar os dois principais elementos, o grupo LPF35HL obteve o menor valor de cálcio (Ca), possuindo diferença estatisticamente significante quando comparado com o grupo EXP10LHV, enquanto os valores de fosfato (P) permaneceram constantes. Morfologicamente somente o grupo EXP10LHV demostrou maior planificação da superfície quando comparado o período de 7 dias com 15 dias. Conclusão: Os diferentes protocolos clareadores empregados, demonstraram alterações pontuais na variação dos elementos químicos e na morfologia do esmalte dental ao longo do período de avaliação.(AU)

Introduction: The tooth color change is one of the factors that contributes most to the smile imbalance, and dental bleaching is widely diffused and requested by the patients. Objective: The aimed of this in situ study is to evaluate the morphological and chemical changes of the enamel when submitted to three activated hydrogen peroxide bleaching agents with hybrid light source and a placebo agent (gel without hydrogen peroxide), using energy-dispersive X-ray spectroscopy (EDS). Methodology: Fragments of human third molars were divided into four groups (n = 12) to perform a bleaching session with five eight minute applications of bleaching gels: Placebo (Plac); Lase Peroxide Flex 35% and 15% (DMC) (LPF35LH and LPF15LH); 10% experimental gel (DMC) (EXP10LHV), and photocatalyzed with hybrid light: blue LED / diode laser (LH) (Whitening Lase II, DMC) or violet LED / diode laser (LHV). After bleaching, the specimens were fixed to intraoral devices used by participants for 15 days. The inorganic composition and topography of the enamel surface were analyzed before and after bleaching, and after 3, 7 and 15 days of exposure to saliva. The elementary values of the composition were analyzed by one-way ANOVA at a repeated measures and Tukey's test. For the topography the scores were determined by three examiners previously calibrated by the Kappa test and the Friedman and Kruskal-Wallis statistical test were applied, and the individual comparisons were performed by the Dunn test ( = 0.05). Results: In general, there were no significant changes in the elemental percentage of enamel in the different periods studied. When analyzing the two main elements, the LPF35HL group had the lowest calcium (Ca) value, which had a statistically significant difference when compared to the EXP10LHV group, while the phosphate (P) values remained constant. Morphologically, only the EXP10LHV group showed greater surface planning when compared to the period of 7 days with 15 days. Conclusion: The different bleaching protocols employed showed specific alterations in the variation of the chemical elements and the morphology of the dental enamel during the evaluation period.(AU)

The photobleaching of the free and encapsulated metallic phthalocyanine and its effect on the photooxidation of simple molecules.

The photobleaching of an unsubstituted phthalocyanine (gallium(III) phthalocyanine chloride (GaPc)) and a substituted phthalocyanine (1,4-(tetrakis[4-(benzyloxy)phenoxy]phthalocyaninato) indium(III) chloride (InTBPPc)) was monitored for the free photosensitizers and for the phthalocyanines encapsulated into nanoparticles of PEGylated poly(D,L-lactide-co-glycolide) (PLGA-PEG). Phosphate-buffered solutions (PBS) and organic solutions of the free GaPc or the free InTBPPc, and suspensions of each encapsulated photosensitizer (2-15µmol/L) were irradiated using a laser diode of 665nm with a power of 1-104mW and a light dose of 7.5J/cm2. The relative absorbance (RA) of the free GaPc dissolved in 1-methyl-2-pyrrolidone (MP) decreased 8.4 times when the laser power increased from 1mW to 104mW. However, the free or encapsulated GaPc did not suffer the photobleaching in PBS solution. The RA values decreased 2.4 times and 22.2 times for the free InTBPPc dissolved in PBS solution and in dimethylformamide (DMF), respectively, but the encapsulated InTBPPc was only photobleached when the laser power was 104mW at 8µmol/L. The increase of the free GaPc concentration favored the photobleaching in MP until 8µmol/L while the increase from 2µmol/L to 5µmol/L reduced the photodegradation in PBS solution. However, the photobleaching of the free InTBPPc in DMF or in PBS solution, and of each encapsulated photosensitizer was not influenced by increasing the concentration. The influence of the photobleaching on the capability of the free and encapsulated GaPc and InTBPPc to photooxidate the simple molecules was investigated monitoring the fluorescence of dimethylanthracene (DMA) and the tryptophan (Trp). Free InTBPPc was 2.0 and 1.8 times faster to photooxidate the DMA and Trp than it was the free GaPc, but the encapsulated GaPc was 3.4 times more efficient to photooxidize the Trp than it was the encapsulated InTBPPc due to the photodegradation suffered by the encapsulated InTBPPc. The participation of the singlet oxygen was confirmed with the sodium azide in the photobleaching of all free and encapsulated photosensitizer, and in the photooxidation of the DMA and Trp. The asymmetry of InTBPPc increased the solubility of the free compound, decreasing the aggregation state of the photosensitizer and favoring the photobleaching process. The encapsulation shows capability in decreasing the photobleaching of both photosensitizers but the confocal micrographs showed that the increase of the solubility favored the InTBPPc photobleaching during the acquisition of optical cross section.

Assessment of the functionality and stability of detergent purified nAChR from Torpedo using lipidic matrixes and macroscopic electrophysiology.

In our previous study we examined the functionality and stability of nicotinic acetylcholine receptor (nAChR)-detergent complexes (nAChR-DCs) from affinity-purified Torpedo californica (Tc) using fluorescence recovery after photobleaching (FRAP) in Lipidic Cubic Phase (LCP) and planar lipid bilayer (PLB) recordings for phospholipid and cholesterol like detergents. In the present study we enhanced the functional characterization of nAChR-DCs by recording macroscopic ion channel currents in Xenopus oocytes using the two electrode voltage clamp (TEVC). The use of TEVC allows for the recording of macroscopic currents elicited by agonist activation of nAChR-DCs that assemble in the oocyte plasma membrane. Furthermore, we examined the stability of nAChR-DCs, which is obligatory for the nAChR crystallization, using a 30 day FRAP assay in LCP for each detergent. The present results indicate a marked difference in the fractional fluorescence recovery (ΔFFR) within the same detergent family during the 30 day period assayed. Within the cholesterol analog family, sodium cholate and CHAPSO displayed a minimum ΔFFR and a mobile fraction (MF) over 80%. In contrast, CHAPS and BigCHAP showed a marked decay in both the mobile fraction and diffusion coefficient. nAChR-DCs containing phospholipid analog detergents with an alkylphosphocholine (FC) and lysofoscholine (LFC) of 16 carbon chains (FC-16, LFC-16) were more effective in maintaining a mobile fraction of over 80% compared to their counterparts with shorter acyl chain (C12, C14). The significant differences in macroscopic current amplitudes, activation and desensitization rates among the different nAChR-DCs evaluated in the present study allow to dissect which detergent preserves both, agonist activation and ion channel function. Functionality assays using TEVC demonstrated that LFC16, LFC14, and cholate were the most effective detergents in preserving macroscopic ion channel function, however, the nAChR-cholate complex display a significant delay in the ACh-induce channel activation. In summary, these results suggest that the physical properties of the lipid analog detergents (headgroup and acyl chain length) are the most effective in maintaining both the stability and functionality of the nAChR in the detergent solubilized complex.

Avaliação in vivo da efetividade e do pH de géis clareadores no clareamento em consultório em 12 meses de acompanhamento / In vivo evaluation of the effectiveness and pH of bleaching gels for in office whitening- 12 months follow-up

O objetivo deste estudo in vivo, internacional, randomizado e duplo cedo foiavaliar comparativamente a efetividade e o pH de diferentes géis clareadores natécnica de clareamento em consultório, com e sem o emprego de fonte de luzhíbrida em função do grau de alteração de cor, sensibilidade e manutenção dotratamento ao longo de 12 meses de acompanhamento. Foram selecionados 48voluntários de acordo com os critérios de inclusão e exclusão. Os pacientes foramdivididos, de forma randomizada, em 4 grupos de 12 participantes cada, onde:Grupo EXP10 –5 aplicações do gel de peróxido de hidrogênio a 10% (GelExperimental – DMC Equipamentos) e ativação de luz híbrida de LED (violeta)/Laser(Experimental – DMC Equipamentos) com 7’ e 30” por aplicação, com tempo total de37’30; Grupo LP15 – 5 aplicações do gel de peróxido de hidrogênio 15% (LasePeroxide Lite – DMC Equipamentos) seguindo mesmo protocolo do grupo EXP10;Grupo TB35LH – 3 aplicações do gel de peróxido de hidrogênio a 35% (Total BlancOffice - DFL) e ativação de luz híbrida de LED (azul)/Laser (Whitening Lase II – DMCEquipamentos) de 7’ e 30” por aplicação, com tempo total de 22’30”; Grupo TB35 – 3aplicações do gel de peróxido de hidrogênio a 35% (Total Blanc Office - DFL) semativação com fonte de luz, totalizando 45”. A determinação dos valores de pH foirealizada com o peagômetro digital (Sentron Model 1001, Sentron) nos temposinicial e após o término do protocolo clareador. A aferição da cor foi feita comespectofotômetro VITA Easyshade antes do clareamento, após 24 horas, 1 semana,1, 6 e 12 meses. A sensibilidade dentária e grau de satisfação dos pacientes foramavaliados por meio do questionário VAS e IPS antes, imediatamente após oclareamento, 24 horas e uma semana após. Os resultados da alteração do pHreceberam tratamento estatístico pela ANOVA e teste de Bonferroni a 0,05%...

The aim of the present in vivo study, international, randomized and doubleearly was to comparatively evaluate the effectiveness and pH of different bleachingagents for in office bleaching techniques, with and without the use of a hybrid lightsource depending on the degree of color change, sensitivity and maintenancetreatment over a 12-month follow-up. Selected were 48 volunteers according to theinclusion and exclusion criteria. The patients were randomly divided into 4 groups of12 participants each, where: EXP Group10- 5 applications of 10% hydrogen peroxidegel (Experimental Gel - Equipment DMC) and activation of hybrid LED light (violet) /Laser (Experimental - Equipment DMC) with 7 "and 30" per application, with a totaltime of 37'30; LP15 Group- 5 applications of 15% hydrogen peroxide gel (LasePeroxide Lite - Equipment DMC) following the same protocol of the EXP10 Group;TB35LH Group- 3 applications of 35% hydrogen peroxide gel (of Blanc Office - DFL)and activation of hybrid LED light (blue) / Laser (Whitening Lase II - DMC Equipment)7 "and 30" per application, with a total time of 22'30; TB35 Group - 3 applications of35% hydrogen peroxide gel (of Blanc Office - DFL) without light activation, totaling45 ". The determination of pH was carried out with a digital pH meter (Sentron Model1001, Sentron) in the initial times and after the bleaching protocol. The colormeasurement was made with a VITA Easyshade spectrophotometer before thetreatment, after 24 hours, 1 week, 1, 6 and 12 months. Tooth sensitivity and degreeof patient satisfaction were assessed by the VAS IPS questionnaire before,immediately after bleaching, 24 hours and one week after. The pH change resultswere statistically processed by the ANOVA and Bonferroni tests at 0.05%...

Avaliação in vivo da efetividade e do pH de géis clareadores no clareamento em consultório em 12 meses de acompanhamento / In vivo evaluation of the effectiveness and pH of bleaching gels for in office whitening- 12 months follow-up

O objetivo deste estudo in vivo, internacional, randomizado e duplo cedo foiavaliar comparativamente a efetividade e o pH de diferentes géis clareadores natécnica de clareamento em consultório, com e sem o emprego de fonte de luzhíbrida em função do grau de alteração de cor, sensibilidade e manutenção dotratamento ao longo de 12 meses de acompanhamento. Foram selecionados 48voluntários de acordo com os critérios de inclusão e exclusão. Os pacientes foramdivididos, de forma randomizada, em 4 grupos de 12 participantes cada, onde:Grupo EXP10 –5 aplicações do gel de peróxido de hidrogênio a 10% (GelExperimental – DMC Equipamentos) e ativação de luz híbrida de LED (violeta)/Laser(Experimental – DMC Equipamentos) com 7’ e 30” por aplicação, com tempo total de37’30; Grupo LP15 – 5 aplicações do gel de peróxido de hidrogênio 15% (LasePeroxide Lite – DMC Equipamentos) seguindo mesmo protocolo do grupo EXP10;Grupo TB35LH – 3 aplicações do gel de peróxido de hidrogênio a 35% (Total BlancOffice - DFL) e ativação de luz híbrida de LED (azul)/Laser (Whitening Lase II – DMCEquipamentos) de 7’ e 30” por aplicação, com tempo total de 22’30”; Grupo TB35 – 3aplicações do gel de peróxido de hidrogênio a 35% (Total Blanc Office - DFL) semativação com fonte de luz, totalizando 45”. A determinação dos valores de pH foirealizada com o peagômetro digital (Sentron Model 1001, Sentron) nos temposinicial e após o término do protocolo clareador. A aferição da cor foi feita comespectofotômetro VITA Easyshade antes do clareamento, após 24 horas, 1 semana,1, 6 e 12 meses. A sensibilidade dentária e grau de satisfação dos pacientes foramavaliados por meio do questionário VAS e IPS antes, imediatamente após oclareamento, 24 horas e uma semana após. Os resultados da alteração do pHreceberam tratamento estatístico pela ANOVA e teste de Bonferroni a 0,05%...

The aim of the present in vivo study, international, randomized and doubleearly was to comparatively evaluate the effectiveness and pH of different bleachingagents for in office bleaching techniques, with and without the use of a hybrid lightsource depending on the degree of color change, sensitivity and maintenancetreatment over a 12-month follow-up. Selected were 48 volunteers according to theinclusion and exclusion criteria. The patients were randomly divided into 4 groups of12 participants each, where: EXP Group10- 5 applications of 10% hydrogen peroxidegel (Experimental Gel - Equipment DMC) and activation of hybrid LED light (violet) /Laser (Experimental - Equipment DMC) with 7 "and 30" per application, with a totaltime of 37'30; LP15 Group- 5 applications of 15% hydrogen peroxide gel (LasePeroxide Lite - Equipment DMC) following the same protocol of the EXP10 Group;TB35LH Group- 3 applications of 35% hydrogen peroxide gel (of Blanc Office - DFL)and activation of hybrid LED light (blue) / Laser (Whitening Lase II - DMC Equipment)7 "and 30" per application, with a total time of 22'30; TB35 Group - 3 applications of35% hydrogen peroxide gel (of Blanc Office - DFL) without light activation, totaling45 ". The determination of pH was carried out with a digital pH meter (Sentron Model1001, Sentron) in the initial times and after the bleaching protocol. The colormeasurement was made with a VITA Easyshade spectrophotometer before thetreatment, after 24 hours, 1 week, 1, 6 and 12 months. Tooth sensitivity and degreeof patient satisfaction were assessed by the VAS IPS questionnaire before,immediately after bleaching, 24 hours and one week after. The pH change resultswere statistically processed by the ANOVA and Bonferroni tests at 0.05%...

Alterações biomecânicas da córnea porcina com riboflavina fotossensibilizada por luz não-ultravioleta / Biomechanical changes on porcine corneas after riboflavin induced crosslink technique with non-UV light

OBJETIVO: Demonstrar a possibilidade de alterar a plasticidade do estroma corneano através da utilização do agente fotossensível riboflavina associado ao uso de iluminação não-ultravioleta. MÉTODOS: Experimento prospectivo duplo cego. Vinte e cinco olhos de porcos enucleados até 24 horas antes do experimento, foram divididos nos seguintes grupos: Grupo RB01+L-Riboflavina 0,1 por cento com irradiação de luz azul; Grupo RB01-Riboflavina 0,1 por cento sem irradiação de luz azul; Grupo RB05+L-Riboflavina 0,5 por cento com irradiação de luz azul; Grupo RB05-Riboflavina 0,5 por cento sem irradiação; Grupo L-Solução salina balanceada e irradiação de luz azul. RESULTADOS: Após o tratamento das informações dos grupos estudados, obtivemos diferenças estatisticamente significantes no grupos RB01+L e RB05+L(p<0,05). Os grupos sem irradiação de luz azul e o grupo somente com irradiação da luz azul sem riboflavina, não apresentaram diferenças estatisticamente significantes. CONCLUSÃO: A utilização de riboflavina para efetuar o processo de aumento de ligações covalentes entre as fibrilas colágenas pode ser uma das chaves para o controle de doenças da córnea como o ceratocone. Nas concentrações estudadas e doses de irradiância concebidas, o processo de aumento das características biomecânicas da córnea foram obtidas com sucesso.

PURPOSE: Demonstrate the possibility of changing the biomechanical behaviour of cornea stroma by usage of riboflavin associated with non-ultraviolet light. METHODS: Double blind prospective study. Twenty five porcine eyes enucleated 24 hours before the experiment, have been divided on the following groups : Riboflavin 0,1 percent with irradiation of blue light, Riboflavin 0,1 percent without irradiation of light , Riboflavin 0,5 percent with irradiation of blue light, Riboflavin 0,5 percent without irradiation of light and BSS with irradiation of light. RESULTS: Differences where noticed in groups 1 and 3 (p<0,05). The groups without irradiation and the group with only irradiation, had no significant difference on their results. CONCLUSION: The usage of riboflavin appears to increase the crosslink connections among collagen fibrills. On the studied concentrations studied and radiant parameters the increase of biomechanical characteristics of cornea have been obtained successfully.