ABSTRACT
Composites have been proven to have a cytotoxic effect on a variety of tissues and cells. Aim: The aim of this study was to analyse the degree of conversion of resins and its correlation with the cell viability in primary gingival fibroblasts. Methods: Resin-based silorane (Filtek P90) and conventional methacrylate resins (Filtek Z100, Filtek Z250 and Filtek Z350XT) were used to evaluate cell viability and the degree of conversion. The resins were light-cured by a LED for 20 and 40 seconds. The degree of conversion was analysed by Fourier transform infrared spectroscopy. Cellular metabolism was evaluated after 24 hours by the MTT assay (n = 6) using the storage solution of composite resin for either 24 hours or 12 days. Variance analysis (ANOVA) with a Bonferroni correction (p < 0.05) was performed to compare the groups. Results: The composite Filtek P90 showed a higher degree of conversion when polymerised for 40 or 20 seconds, while the composites Filtek Z100, Filtek Z250 and Filtek Z350XT showed similar degree of conversion. Only the Filtek Z100 resin was cytotoxic. Conclusion: We found no statistically significant correlation between cell viability and the degree of conversion
Subject(s)
Composite Resins , Cytotoxins , FibroblastsABSTRACT
ABSTRACT Introduction: The heat treatment of stainless steel wires is a routine clinical procedure adopted by many dentists in order to relieve the stress caused after performing bends in the archwire. Objective: This study aimed to evaluate the influence of heat treatment of stainless steel archwires with a rectangular section of 0.016 x 0.022'-in. Methods: For analysis of the dimensional stability, the anterior and posterior dimensions of forty 0.016 x 0.022-in stainless steel orthodontic archwires without heat treatment and 30 days after heat treatment were evaluated. For analysis of the mechanical properties, 12 stainless steel wire segments with the same rectangular section without heat treatment and 30 days after heat treatment were tested through tensile strength and strain tests. To evaluate if there were differences between the anterior and posterior dimensions, the results were analyzed by the Student's t-test. To compare the tensile strength and strain between the groups, the ANOVA test was used. The level of significance adopted was 95% (p< 0.05). Results: The heat treatment did not stop the expansion of archwires 30 days after their preparation, and there was no statistical difference in the tensile strength and strain tests with and without heat treatment. Conclusion: From the findings of this study, it can be conclude that the mechanical behavior of heat-treated stainless steel archwires is similar to that of archwires not subjected to heat treatment.
RESUMO Introdução: o tratamento térmico de fios de aço inoxidável é um procedimento clínico rotineiro adotado por muitos cirurgiões-dentistas para aliviar o estresse causado após a confecção de dobras no fio. O presente estudo avaliou a influência do tratamento térmico em fios de aço inoxidável com secção retangular de 0,016'' x 0,022''. Métodos: para análise da estabilidade dimensional, foram avaliadas as dimensões anteriores e posteriores de 40 arcos ortodônticos de aço inoxidável de 0,016'' x 0,022'' sem tratamento térmico e 30 dias após o tratamento térmico. Para análise das propriedades mecânicas, 12 segmentos de fio de aço inoxidável com a mesma secção retangular sem tratamento térmico e 30 dias após o tratamento térmico foram analisadas por testes de resistência à tração e tensão. Para verificar se houve diferenças entre as dimensões anteriores e posteriores, os resultados foram analisados pelo teste t de Student. Para comparar a resistência à tração e tensão entre os grupos, foi utilizado o teste ANOVA. O nível de significância adotado foi 95% (p< 0,05). Resultados: o tratamento térmico não interrompeu a expansão dos fios 30 dias após seu preparo, e não houve diferença estatística nos testes de resistência à tração e tensão com e sem o tratamento térmico. Conclusão: pelos achados desse estudo, conclui-se que o comportamento mecânico de fios submetidos a tratamento térmico é semelhante ao de fios de aço não submetidos ao tratamento térmico.
Subject(s)
Orthodontic Wires , Orthodontic Brackets , Stainless Steel , Surface Properties , Tensile Strength , Materials Testing , Dental Alloys , Hot TemperatureABSTRACT
Estratégias amplamente utilizadas para potencializar os efeitos citotóxicos de moléculas antitumorais com o objetivo de reduzir a dose aplicada e os efeitos colaterais são a inclusão molecular e a associação da quimioterapia com a hipertermia. No presente trabalho foram estudadas estas duas estratégias, sendo a primeira a inclusão molecular que é muito utilizada para aumentar a solubilidade, a absorção e a disponibilidade de moléculas; e a segunda, a hipertermia que é uma proposta de tratamento do câncer no qual as células do tumor são afetadas pela elevação da temperatura local, podendo ser associada com a quimioterapia para potencializar os efeitos dessa técnica. Para a inclusão molecular usou-se a hidroxipropil-¿-ciclodextrina (HP-¿-CD) a fim de aumentar a solubilidade, a absorção e a disponibilidade do erlotinibe (ERL), caracterizou-se fisico-quimicamente, e avaliou-se a citotoxicidade e a apoptosein vitro, e a angiogênese inflamatória in vivo em camundongos Swiss. Para avaliar o efeito citotóxico da hipertermia (aquecimento a 42°C ou 43°C por 1h) associada à cisplatina utilizou-se linhagens de câncer de mama triplo-negativos (MDA-MB-231, MDA-MB-436, MDA-MB-468 e HCC-1937), linhagens de câncer de colo do útero (ME-180 e SiHa) e linhagens de câncer de pulmão (A549 e H460). A caracterização físico-química mostrou a formação do complexo de inclusão em estado sólido e aquoso, e com uma razão molar entre o ERL e HP-¿-CD preferencialmente de 1:1. O estudo de solubilidade de fases mostrou um diagrama do tipo AL e a calorimetria de titulação isotérmica e a espectrometria de ressonância magnética nuclear, efeito Overhauser nuclear suportam essa formação...
Strategies widely used to potentiate the cytotoxic effects of antitumor molecules with the aim of reduce the applied dose and side effects are molecular inclusion and the combination of chemotherapy with hyperthermia. In this thesis, these two strategies were studied, the first molecular inclusion that is widely used to enhance solubility, absorption and availability molecules; and the second, hyperthermia which is a proposal for treatment of cancer where the tumor cells are affected by local temperature elevation and can be associated with chemotherapy to enhance the effects of this technique. For molecular inclusion used to hydroxypropyl--cyclodextrin (HP--CD) to enhance solubility, absorption and availability of erlotinib (ERL), was characterized physico chemically and evaluated the in vitro cytotoxicity and apoptosis, and in vivo inflammatory angiogenesis in Swiss mice. To evaluate the cytotoxic of hyperthermia (heating to 42°C or 43°C for 1h) associated with cisplatin was used triple-negative breast cancer cell lines (MDA-MB-231, MDA-MB-436, MDA-MB-468 and HCC-1937), cervical cancer cell lines (ME-180 and SiHa) and lung cancer cell lines (A549 and H460). The physico-chemical characterization showed the formation of the inclusion complex in solid and aqueous state and with a molar ratio between the ERL and HP--CD preferably 1:1. Phase-solubility ...
Subject(s)
Animals , Mice , Cyclodextrins , Hyperthermia, Induced , Neoplasms/therapy , Drug Therapy , Hot Temperature/therapeutic use , Apoptosis , Cytotoxins , Drug-Related Side Effects and Adverse Reactions , Solubility/radiation effects , Tumor Cells, Cultured , In Vitro TechniquesABSTRACT
Background: Aloe vera L., member of the Liliaceae family, has been shown to stimulate cell proliferation and contribute to healing and angiogenesis, has anti-bacterial, anti-fungal and anti-inflammatory activity. In addition, Aloe vera can be used as a support for drug transport. Our objective is to evaluate antimicrobial activity and cytotoxicity of sponges of Aloe vera L. for use as a carrying support of drugs. Results: In this work, sponge of free Aloe vera (AV) loaded with amoxicillin (AMX) or nystatin (NYS) at 1% w/w, were prepared and physico-chemically characterized via X-ray diffraction, Fourier Transform Infrared Spectroscopy and thermal analysis. Antimicrobial potency of AV sponge alone, loaded with AMX or NYS, against strains of Streptococcus mutans, Staphylococcus aureus, Aggregatibacter actinomycetemcomitans, Enterococcus faecalis and Candida albicans was determined. Osteoblasts and human gingival fibroblasts were cultivated on AV, Aloe vera loaded with amoxicillin (AV/AMX) and Aloe vera loaded with nystatin (AV/NYS) and cellular viability was assessed. The physico-chemical characterization performed suggested that the loaded drugs were dispersed in the sponge and those interactions between the AV sponge and the loaded drugs were weak. Furthermore, AV loaded with AMX or NYS demonstrated antimicrobial potency and osteoblasts and fibroblasts were viable after 24 hrs on free AV, and AV loaded with AMX or NYS. Conclusions: Our results indicate that sponges of free AV, loaded with AMX or NYS, are biocompatible and exhibit antimicrobial activity.