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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Toothwhit"eu"ning

Bengtsson, Fredrik, Svanberg, Martin January 2016 (has links)
SyfteAtt utvärdera effekterna och bieffekterna av tandblekningsprodukter innehållande eller utsöndrande av väteperoxid på permanenta tänder hos personer under 18 år. Studien gjordes med tanke på barn som drabbats av missfärgade tänder med ett objektivt och subjektivt behandlingsbehov. Detta i syfte att insamla all nuvarande forskning på området samt ställa detta mot EU-direktiven utfärdade 2012. SökstrategierEn systematisk sökning av litteraturen gjordes i databaserna Medline, Cochrane, Embase och Scopus. Inkluderade artiklar skulle vara på antingen Engelska, Svenska, Danska eller Norska. SelektionskriterierStudierna skulle vara gjorda på personer under 18 år med produkter som innehöll eller utsöndrande väteperoxid. Enbart studier på permanenta tänder inkluderades. Studierna var tvungna att utvärdera positiva och/eller negativa effekter av behandlingen. Blekningen skulle utföras in vivo. Fallrapporter inkluderades enbart i syfte att finna eventuella allvarliga bieffekter. ResultatTotalt identifierades 214 artiklar varav 13 stycken uppfyllde inkluderings- och exkluderings-kriterierna. Fyra studier bedömdes ha låg risk av bias, åtta av medelhög samt en som hög risk av bias. Syftet och studiedesignen varierade mellan de inkluderade studierna. De flesta studierna var utförda på mildare missfärgningar samtidigt som de saknade erforderliga uppföljningstider. SlutsatsDet finns inte tillräckligt med studier gjorda på personer under 18 år som utvärderar effekterna av bleking med väteperoxid på fall med mer omfattande missfärgningar. Ett begränsat antal studier med medelhög risk av bias ger ett visst stöd för blekning med väteperoxid på mildare fall av missfärgningar. Samtidigt rapporterades ett stort antal milda, övergående bieffekter. Tills motsatsen bevisats finns ett etiskt stöd för EU-direktiven etablerade 2012. / AimTo investigate the effects and adverse events of tooth whitening performed on children with permanent teeth by the use of products containing or releasing hydrogen peroxide. This was made considering children affected by objectively and subjectively observed tooth discolorations in purpose to consolidate existing research and compare it to the EU directives established 2012.Search strategiesA systematic search of the literature was conducted using the databases Medline, Cochrane, Embase and Scopus. Only studies published in English, Swedish, Danish and Norwegian were included. Selection criteriaThe selection criteria aimed to include studies performed on patients under the age of 18, using whitening products containing or releasing hydrogen peroxide. The bleaching process had to be performed in vivo on permanent teeth. Case reports were included only to be separately reviewed looking for severe side effects and adverse events.ResultsA total of 214 articles were identified and 13 met the inclusion criteria. Four papers were judged to have a low risk of bias, eight a moderate risk and one a high risk of bias. Most studies were performed on mild discolorations while they lacked in necessary follow-up times.ConclusionThere are not enough studies evaluating the effect of using hydrogen peroxide to bleach more severe discolorations on individuals under 18 years old. A limited number of studies showed some support for bleaching with hydrogen peroxide on mild tooth discolorations. Parallel to this, the included studies demonstrated a high number of mild and transient adverse events. Until proven otherwise, the lack of studies gives some ethical support to the EU-directives established 2012.
12

Amperometric biosensor systems prepared on poly(aniline-ferrocenium hexafluorophosphate) composites doped with poly(vinyl sulfonic acid sodium salt).

Ndangili, Peter Munyao. January 2008 (has links)
<p>The main hypothesis in this study is the development of a nanocomposite mediated amperometric biosensor for detection of hydrogen peroxide. The aim is to combine the electrochemical properties of both polyaniline and ferrocenium hexafluorophosphate into highly conductive nano composites capable of exhibiting electrochemistry in non acidic media / shuttling electrons between HRP and GCE for biosensor applications.</p>
13

Amperometric biosensor systems prepared on poly(aniline-ferrocenium hexafluorophosphate) composites doped with poly(vinyl sulfonic acid sodium salt).

Ndangili, Peter Munyao. January 2008 (has links)
<p>The main hypothesis in this study is the development of a nanocomposite mediated amperometric biosensor for detection of hydrogen peroxide. The aim is to combine the electrochemical properties of both polyaniline and ferrocenium hexafluorophosphate into highly conductive nano composites capable of exhibiting electrochemistry in non acidic media / shuttling electrons between HRP and GCE for biosensor applications.</p>
14

Effects Of Hydrogen Peroxide Bleaching On Human Dentin And Enamel Microstructure And Function

Gokduman, Kurtulus 01 June 2005 (has links) (PDF)
In recent years bleaching of vital teeth has become popular among both dentist and patients. Different bleaching agents were used for this purpose. They are either applied professionally at high dose (office bleaching) or by patient at lower dose (home bleaching). In the present work we studied the effects of a high concentration bleaching agent (35% hydrogen peroxide), and a low concentration bleaching agent (17% carbamide peroxide) on human enamel and dentin using Fourier Transform Infrared (FTIR) Spectroscopic Technique. The OH stretching band of hydroxyapatite at 3567 cm-1 appeared in the spectra of enamel tissue which was absent in dentin. Carbamide peroxide and hydrogen peroxide treatment induced some differences in enamel and dentin spectra according to control group spectra. While the treatment of hydrogen peroxide leaded to significant decrease in mineral to matrix ratio, carbamide peroxide treatment did not cause decrease in this level. In addition, organic components of the teeth were changed after the treatment of bleaching agents. The frequency of the Amide A and Amide I bands were significantly changed for enamel tissue after the treatment of high concentration bleaching agent. However, it is observed that these changes result from two different bleaching methods are negligible in dentin tissue. In conclusion it can be stated that hydrogen peroxide treatment caused dramatic changes in enamel structure according to carbamide peroxide treatment, but two methods did not cause significant changes in dentin tissue.
15

Efeitos de regimes de sobreclareamento associados a produtos clareadores caseiros sobre o conteúdo mineral e a rugosidade do esmalte dentário humano / Overbleaching effects on mineral content and roughness of human enamel

Marianna Sorozini Ferreira de Miranda 09 December 2013 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O clareamento dental se tornou um dos tratamentos estéticos mais realizados nos consultórios odontológicos, devido à simplicidade técnica e popularização através da mídia. Consiste na utilização de géis à base de peróxido de carbamida, peróxido de hidrogénio e, em uma menor escala, de perborato de sódio, com intuito de oxidar moléculas responsáveis pela pigmentação da estrutura dentária. Apesar da grande quantidade de estudos sobre o tema, não se sabe os efeitos do uso excessivo desses agentes sobre a estrutura dentária. O objetivo deste estudo foi avaliar os efeitos sobre a rugosidade superficial e conteúdo mineral do esmalte dental humano submetido a regimes de sobreclareamento associados ao uso de géis clareadores caseiros: peróxido de carbamida 10% (Opalescence PF Regular 10%, Ultradent do Brasil Produtos Odontológicos Ltda., Indaiatuba, São Paulo), peróxido de hidrogênio 9,5% (DayWhite 9,5%, Discus, LLC Culver City, EUA), bem como tiras clareadoras (Oral-B WhiteStrips, Anderson Packaging, Rockford, Estados Unidos). Quatro fragmentos de esmalte obtidos a partir de cinco dentes foram submetidos a um diferente tratamento: Grupo I - armazenamento em saliva artificial por oito semanas; Grupo 2 oito semanas de tratamento com gel de peróxido de carbamida 10% por 6 horas diárias; Grupo 3 oito semanas de tratamento com gel de peróxido de hidrogênio 9,5% com duas aplicações diárias de 30 minutos; Grupo 4 oito semanas de tratamento com tiras clareadoras duas aplicações diárias de 30 minutos. A alteração no conteúdo mineral foi avaliada semanalmente em seis pontos de cada fragmento devidamente identificados através de um sistema de coordenadas (X, Y e Z) utilizando-se a técnica de fluorescência de raios X (Artax 200). Alterações na rugosidade superficial das amostras também foram avaliadas através de um rugosímetro 3D (FormTalysurf 60, Taylor Leicester, Reino Unido). Apenas o grupo 3 apresentou diferenças estatísticas significativas com relação aos níveis de rugosidade (p<0,05), porém não consideradas como clinicamente significativos. Para os demais tratamentos e intervalos propostos, não foram encontradas diferenças estatisticamente significativas (p>0,05). Desse modo, não houve alterações compatíveis com um processo de desmineralização ou aumento real da rugosidade da superfície. Nas condições desse estudo in vitro os géis clareadores caseiros foram considerados seguros. São necessários novos estudos in situ e in vitro que analisem os efeitos de regimes de sobreclareamento quando em condições de somatório de desafios intra-orais. / Tooth bleaching has become one of the most performed cosmetic treatments in dental offices because of the technical simplicity and popularization through media. It is based in the use of gels containing carbamide peroxide, hydrogen peroxide, and sodium perborate to oxidize molecules responsible for pigmentation of the tooth structure. Despite the large amount of studies of the topic, the effects of overuse of these agents on tooth structure are not established. The aim of this study was to evaluate the effects on the surface roughness and mineral content of the enamel submitted to overbleaching protocols associated with the use of home bleaching gels: 10 % carbamide peroxide (Opalescence PF 10 % Regular, Ultradent Dental Products of Brazil Ltd., Indaiatuba, São Paulo), hydrogen peroxide 9.5% (DayWhite 9.5%, Discus, LLC Culver City, EUA), as well as bleaching strips (Oral- B Whitestrips, Anderson Packaging, Rockford, USA). Four enamel fragments obtained from five teeth were subjected to different treatments: Group I - storage in artificial saliva for eight weeks; Group 2 eight-week exposure to 10% carbamide peroxide gel for 6 hours daily; Group 3 eight-week exposure to 9,5% hydrogen peroxide gel - two 30-minute application, Group 4 eight-week exposure to bleaching strips - twice daily for 30 minutes. The change in mineral content was assessed weekly with the analysis of six points in each fragment properly identified by a coordinate system (X, Y and Z) using the technique of X-ray fluorescence (Artax 200). Changes in surface roughness of the samples were also evaluated using a 3D perfilometer (FormTalysurf 60, Taylor Leicester, UK). Only group 3 showed statistically significant differences for roughness (p <0.05), but this is not considered as clinically important. For other proposed treatments and intervals, there were no statistically significant differences for any of the treatments tested in any of the proposed ranges (p > 0,05). There was no sign of demineralization process. Under these in vitro conditions, home bleaching gels were considered safe. Further in situ and in vivo studies are necessary to examine the effects of overbleaching protocols with all other intra-oral challenges.
16

Efeitos de regimes de sobreclareamento associados a produtos clareadores caseiros sobre o conteúdo mineral e a rugosidade do esmalte dentário humano / Overbleaching effects on mineral content and roughness of human enamel

Marianna Sorozini Ferreira de Miranda 09 December 2013 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O clareamento dental se tornou um dos tratamentos estéticos mais realizados nos consultórios odontológicos, devido à simplicidade técnica e popularização através da mídia. Consiste na utilização de géis à base de peróxido de carbamida, peróxido de hidrogénio e, em uma menor escala, de perborato de sódio, com intuito de oxidar moléculas responsáveis pela pigmentação da estrutura dentária. Apesar da grande quantidade de estudos sobre o tema, não se sabe os efeitos do uso excessivo desses agentes sobre a estrutura dentária. O objetivo deste estudo foi avaliar os efeitos sobre a rugosidade superficial e conteúdo mineral do esmalte dental humano submetido a regimes de sobreclareamento associados ao uso de géis clareadores caseiros: peróxido de carbamida 10% (Opalescence PF Regular 10%, Ultradent do Brasil Produtos Odontológicos Ltda., Indaiatuba, São Paulo), peróxido de hidrogênio 9,5% (DayWhite 9,5%, Discus, LLC Culver City, EUA), bem como tiras clareadoras (Oral-B WhiteStrips, Anderson Packaging, Rockford, Estados Unidos). Quatro fragmentos de esmalte obtidos a partir de cinco dentes foram submetidos a um diferente tratamento: Grupo I - armazenamento em saliva artificial por oito semanas; Grupo 2 oito semanas de tratamento com gel de peróxido de carbamida 10% por 6 horas diárias; Grupo 3 oito semanas de tratamento com gel de peróxido de hidrogênio 9,5% com duas aplicações diárias de 30 minutos; Grupo 4 oito semanas de tratamento com tiras clareadoras duas aplicações diárias de 30 minutos. A alteração no conteúdo mineral foi avaliada semanalmente em seis pontos de cada fragmento devidamente identificados através de um sistema de coordenadas (X, Y e Z) utilizando-se a técnica de fluorescência de raios X (Artax 200). Alterações na rugosidade superficial das amostras também foram avaliadas através de um rugosímetro 3D (FormTalysurf 60, Taylor Leicester, Reino Unido). Apenas o grupo 3 apresentou diferenças estatísticas significativas com relação aos níveis de rugosidade (p<0,05), porém não consideradas como clinicamente significativos. Para os demais tratamentos e intervalos propostos, não foram encontradas diferenças estatisticamente significativas (p>0,05). Desse modo, não houve alterações compatíveis com um processo de desmineralização ou aumento real da rugosidade da superfície. Nas condições desse estudo in vitro os géis clareadores caseiros foram considerados seguros. São necessários novos estudos in situ e in vitro que analisem os efeitos de regimes de sobreclareamento quando em condições de somatório de desafios intra-orais. / Tooth bleaching has become one of the most performed cosmetic treatments in dental offices because of the technical simplicity and popularization through media. It is based in the use of gels containing carbamide peroxide, hydrogen peroxide, and sodium perborate to oxidize molecules responsible for pigmentation of the tooth structure. Despite the large amount of studies of the topic, the effects of overuse of these agents on tooth structure are not established. The aim of this study was to evaluate the effects on the surface roughness and mineral content of the enamel submitted to overbleaching protocols associated with the use of home bleaching gels: 10 % carbamide peroxide (Opalescence PF 10 % Regular, Ultradent Dental Products of Brazil Ltd., Indaiatuba, São Paulo), hydrogen peroxide 9.5% (DayWhite 9.5%, Discus, LLC Culver City, EUA), as well as bleaching strips (Oral- B Whitestrips, Anderson Packaging, Rockford, USA). Four enamel fragments obtained from five teeth were subjected to different treatments: Group I - storage in artificial saliva for eight weeks; Group 2 eight-week exposure to 10% carbamide peroxide gel for 6 hours daily; Group 3 eight-week exposure to 9,5% hydrogen peroxide gel - two 30-minute application, Group 4 eight-week exposure to bleaching strips - twice daily for 30 minutes. The change in mineral content was assessed weekly with the analysis of six points in each fragment properly identified by a coordinate system (X, Y and Z) using the technique of X-ray fluorescence (Artax 200). Changes in surface roughness of the samples were also evaluated using a 3D perfilometer (FormTalysurf 60, Taylor Leicester, UK). Only group 3 showed statistically significant differences for roughness (p <0.05), but this is not considered as clinically important. For other proposed treatments and intervals, there were no statistically significant differences for any of the treatments tested in any of the proposed ranges (p > 0,05). There was no sign of demineralization process. Under these in vitro conditions, home bleaching gels were considered safe. Further in situ and in vivo studies are necessary to examine the effects of overbleaching protocols with all other intra-oral challenges.
17

Evaluación del pH y concentración de peróxido de hidrógeno en diferentes productos blanqueadores de venta libre. Estudio in vitro

Nuñez Linares, Juan Heriberto January 2024 (has links)
En odontología la demanda de tratamientos para aclarar los dientes ha aumentado, es así como han surgido los agentes blanqueadores de venta libre, que no requieren una supervisión profesional, es indispensable conocer las concentraciones de pH y peróxido de hidrogeno presentes en su composición. Objetivo: Comparar el pH y la concentración de peróxido de hidrógeno en diferentes productos blanqueadores de venta libre. Materiales y métodos: En esta investigación con diseño experimental in vitro, se analizaron 24 muestras entre colutorios y pastas dentales de 4 diferentes marcas para obtener el grado de pH con un medidor impermeable pHep®5 de Hanna y la concentración de peróxido de hidrogeno con un proceso químico denominado titulación. Resultados: La concentración de pH de los productos blanqueadores de venta libre osciló entre 3.1 a 7.48 y la concentración de peróxido de hidrogeno entre 1.60% y 4.93%. Conclusión: El agente blanqueador Colgate Optic White tuvo la concentración de pH màs baja, y la más alta para peróxido e hidrogeno. / In dentistry, the demand for treatments to lighten teeth has increased. This is how over-the- counter whitening agents have emerged, which do not require professional supervision. It is essential to know the pH and hydrogen peroxide concentrations present in their composition. Objective: Compare the pH and concentration of hydrogen peroxide in different over-the- counter whitening products. Materials and methods: In this research with an-in vitro experimental design, 24 samples of mouthwashes and toothpastes from 4 different brands were analyzed to obtain the pH level with a waterproof meter pHep®5 from Hanna and the concentration of hydrogen peroxide with a chemical process called titration. Results: The pH concentration of over-the-counter whitening products ranged from 3.1 to 7.48 and the hydrogen peroxide concentration ranged from 1.60% to 4.93%. Conclusion: Colgate Optic White whitening agent had the lowest pH concentration, and the highest for peroxide and hydrogen.
18

Efficacy and safety of various tooth-whitening products, with special reference to the three dimensional colour space (L*a*b*) measurements and the microhardness tests

Majeed, Abdul January 2011 (has links)
Tooth-whitening or tooth-bleaching has become an integral part of modern dental practice. Today, a large number of whitening products are available on the market which are commonly categorized into dentist-supervised home bleaching, in-office bleaching and over-the-counter bleaching products according to their mode of application. This thesis looks into safety and efficacy of various tooth-whitening products and methods.
19

Efficacy and safety of various tooth-whitening products, with special reference to the three dimensional colour space (L*a*b*) measurements and the microhardness tests

Majeed, Abdul January 2011 (has links)
Tooth-whitening or tooth-bleaching has become an integral part of modern dental practice. Today, a large number of whitening products are available on the market which are commonly categorized into dentist-supervised home bleaching, in-office bleaching and over-the-counter bleaching products according to their mode of application. This thesis looks into safety and efficacy of various tooth-whitening products and methods.
20

Efficacy and safety of various tooth-whitening products, with special reference to the three dimensional colour space (L*a*b*) measurements and the microhardness tests

Majeed, Abdul January 2011 (has links)
Philosophiae Doctor - PhD / Tooth-whitening or tooth-bleaching has become an integral part of modern dental practice. Today, a large number of whitening products are available on the market which are commonly categorized into dentist-supervised home bleaching, in-office bleaching and over-the-counter bleaching products according to their mode of application. This thesis looks into safety and efficacy of various tooth-whitening products and methods. / South Africa

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