Orientador: Carlos Rocha Gomes Torres / Coorientadora: Lívia Maria Andaló Tenuta / Banca: Natália Cortez Gutierrez / Banca: Maria Filomena Rocha Lima Huhtala / Resumo: O estudo avaliou se os efeitos deletérios do clareamento no esmalte dental podem ser minimizados pela adição de sais de cálcio e/ou fósforo em variadas concentrações, na formulação do agente clareador, tornando-o progressivamente mais saturado em relação ao conteúdo mineral do esmalte.Inicialmente foi determinada a concentração dos elementos cálcio (Ca) e fósforo (P)no agente clareador,provenientes da dissolução do esmalte dental pelo tratamento até atingir seu ponto de saturação. Para tal amostras de esmalte foram trituradas e expostas ao peróxido de hidrogênio (PH) à 35% em pH7, até que um equilíbrio mineral fosse obtido. A concentração mineral na solução foi determinada através dos métodos de ICP-AES. A seguir o coeficiente de solubilidade de diversos sais de cálcio e fósforo em PH à 35%foi determinado. Aquele mais solúvel para cada elemento foi utilizado para a formulação dos agentes clareadores.Foram preparados 120 espécimes a partir da face vestibular de dentes incisivos bovinos, em formato circular com 4 mm de diâmetro, padronizando-se a espessura de esmalte e dentina em 1mm cada, embutidos em resina branca. Os espécimes foram enumerados e imersos em saliva artificial por 15 dias. Após esse período, foram realizadas leituras iniciais da microdureza Knoop do esmalte empregando um microdurômetro (FM-700, Future-Tech, Tóquio, Japão), da rugosidade superficial em um perfilômetro de contato (MarSurf GD 25, Mahr, Goettingen, Alemanha) e da cor das amostras utilizando espectr... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract : The study evaluated whether the deleterious effects of bleaching on tooth enamel can be minimized by adding calcium and / or phosphorus salts at varying concentrations in the bleaching agent formulation, making it progressively more saturated relative to the enamel mineral content. Initially, the concentration of calcium (Ca) and phosphorus (P) elements in the bleaching agent were determined, resulting from the dissolution of dental enamel by the treatment until reaching its saturation point. For such enamel samples were crushed and exposed to hydrogen peroxide (PH) at 35% at pH7, until a mineral balance was obtained. The mineral concentration in the solution was determined by ICP-AES methods. Then the solubility coefficient of several calcium and phosphorus salts in PH at 35% was determined. The most soluble for each element was used for the bleaching agent formulation. 120 specimens were prepared from the vestibular face of bovine incisor teeth, in circular format with 4 mm diameter, and the thickness of enamel and dentin was standardized in 1 mm each, embedded in white resin. The specimens were enumerated and immersed in artificial saliva for 15 days. After that, initial Knoop enamel microhardness measurements were performed using a microdurometer (FM700, Future-Tech, Tokyo, Japan), of surface roughness in a contact profilometer (MarSurf GD 25, Mahr, Goettingen, Germany) and of the samples using a colorimetric reflectance spectrophotometer (CM 2600d - Konica Minolta, Osaka, Japan). All experimental groups were cleared with pH solutions at 35% (w / w) adjusted for pH 7. The specimens were divided into 6 groups according to the amount of calcium and phosphorus added in each bleaching solution, based on saturation at relation to HA, they are: CN (negative control) - the specimens were treated with ultra pure water; CP (positive control) - the specimens were ...(Complete abstract click electronic access below) / Mestre

Objetivo: Avaliar clinicamente o efeito do peróxido de hidrogênio em concentrações de 20%, 30% e 38% no grau de clareamento, assim como a sensibilidade dental antes, após o clareamento e depois de 7, 14 e 30 dias. Material e Método: Foi utilizado um modelo de meia-arcada para comparação dos produtos em um mesmo paciente. Sessenta e nove voluntários foram selecionados e receberam orientações sobre o tratamento a ser realizado. Os voluntários foram divididos aleatóriamente em três grupos, cada grupo contendo 23 pacientes, sendo Grupo 1: Peróxido de hidrogênio 20% versus Peróxido de hidrogênio 30%; Grupo 2: Peróxido de Hidrogênio 20% versus Peróxido de hidrogênio 38%; Grupo 3: Peróxido de hidrogênio 30% versus Peróxido de hidrogênio 38%. Os voluntários receberam duas sessões de clareamento de consultório, com intervalo de 7 dias. A cor dental de incisivos e caninos superiores foi avaliada com uso do espectrofotômetro digital Easyshade antes, após o clareamento e depois de 7, 14 e 30 dias. Para a avaliação da sensibilidade dental, os pacientes responderam a um questionário, com uso de uma escala visual analógica (VAS) antes, durante o clareamento, imediatamente após, após 1 e 24 horas e depois de 7, 14 e 30 dias. Resultados: A análise de variância (ANOVA) mostrou haver diferença estatísticamente significante entre os peróxidos de hidrogênio nas concentrações de 20%, 30% e 38%, entre os dentes caninos e incisivos e entre os períodos, dentro de cada um dos grupos avaliados. O peróxido de hidrogênio 30% apresentou maior alteração de cor dental em comparação às concentrações de peróxido de hidrogênio 20% e 30%. Os dentes caninos apresentaram maiores valores de alteração de cor quando comparados aos incisivos. Em relação à sensibilidade dental, não houve diferença significante entre as concentrações do peróxido de hidrogênio avaliadas (p=0,15), excessão no período durante o clareamento, em que o peróxido de hidrogênio 20% apresentou menor grau de sensibilidade se comparado aos géis de 30% e 38%. Após 24 horas da aplicação dos diferentes peróxidos de hidrogênio, não houve relato de sensibilidade dental. Conclusão: O peróxido de hidrogênio 30% provocou maior alteração de cor dental se comparado aos peróxidos de hidrogênio 20% e 38%. Após 7 dias do tratamento clareador, houve uma estabilização da cor dental em todos os grupos avaliados. / Objective: To clinically evaluate the effect on shade change of hydrogen peroxide in concentrations of 20%, 30% and 38% as well as dental sensitivity, assessed immediately before the whitening treatment and 7,14 and 30 days after. Material and Method: The split arch model was used to compare different products in the same patient. Sixty nine volunteers were selected and instructed on the procedures. The volunteers were randomly divided into 3 groups of 23 patients each. Group 1: hydrogen peroxide 20% versus hydrogen peroxide 30%; Group 2: hydrogen peroxide 20% versus hydrogen peroxide 38%; Group 3: hydrogen peroxide 30% versus hydrogen peroxide 38%. Each patient was submitted to two in office whitening session with a 7 days interval between them. The shade of superior incisives and canines was assesses with a digital Easyshade spectrophotometer immediately before and after the whitening treatment as well as 7,14 and 30 days after treatment. For the dental sensitivity evaluation, patients filled out a questionary, with the aid of a analogical visual scale (VAS) before, during the treatment, after, 1 hour, 24 hours, 7, 14 and 30 days post treatment, Results: ANOVA test showed a statistically significant difference between the different concentration of hydrogen peroxide, and also a statistically significant difference amongst canines and incisive teeth, within each experimental group. Hydrogen peroxide 30% showed greater shade change when compared to hydrogen peroxide 20% and 38%. The canine teeth showed higher shade change when compared to incisive teeth. Regarding dental sensitivity, no statistically significant difference was observed for the different concentrations evaluated (p=0.15). 24 hours after whitening treatment there were no reports of dental sensitivity. Conclusion: Hydrogen peroxide at 30% showed greater shade change when compared to hydrogen peroxide at 20% and 38%. 7 days post whitening treatment all groups evaluated showed shade stability.

Os pacientes, cada vez mais, têm sido atraídos pela estética. Muitas vezes, a alteração de cor dos dentes compromete a harmonia do sorriso. As alterações de cor podem estar presentes nos dentes vitalizados, podendo ser fisiológicas ou relacionadas ao uso incorreto de medicamentos. Podem, também, estar presentes nos dentes tratados endodonticamente, neste caso, o escurecimento pode relacionar-se aos produtos de degeneração pulpar ou ao uso inadequado dos materiais. Para tentar resolver estes problemas existem as técnicas de clareamento dental, que têm por objetivo devolver a harmonia estética do sorriso, tendo como grande vantagem a conservação da estrutura dental, além de ser um procedimento mais simples e barato do que os procedimentos que envolvem trabalhos protéticos. As técnicas de clareamento são diferentes para o tratamento de dentes vitalizados e não vitalizados. O objetivo deste trabalho foi avaliar a efetividade de quatro técnicas para clarear dentes não vitais. Foram utilizados 40 dentes bovinos, manchados artificialmente com sangue. Após o manchamento, os dentes foram divididos em 4 grupos de 10 dentes e cada grupo recebeu um tratamento diferente. As técnicas utilizadas foram as seguintes: Hi-Lite ativado por luz halógena, peróxido de hidrogênio ativado por laser de argônio, peróxido de hidrogênio ativado por espátula aquecida e "walking bleach". Os resultados mostraram que as quatro técnicas foram eficientes, capazes de promover o efeito clareador de maneira satisfatória. Porém, existiram diferenças estatisticamente significantes em relação à tonalidade de cor. Os grupos tratados com peróxido de hidrogênio ativado pelo laser de argônio e pela técnica "walking bleach" apresentaram resultados estéticos superiores em relação aos grupos tratados com Hi-Lite ativado por luz halógena e peróxido de hidrogênio ativado por espátula aquecida. / The patients more and more have been attracted by aesthetics. Many times the discoloration that occurs in the teeth compromises the smile harmony. These shade alterations should happen in vital teeth and could be physiological or related to some medicine and should happen in nonvital teeth too. In this case the darkness should be due to products of pulpal decomposition or due to the incorrect use of medicaments. Trying to solve this problem there are bleaching techniques to be used on the discolored tooth. Bleaching procedure provides an alternative more conservative and cheap modality for treating discolored teeth compared to prosthesis preserving dental structure and turning back the smile aesthetics and harmony. Bleaching systems are different for treating vital and nonvital teeth. The purpose of this research is the evaluation of the effectiveness of four techniques to lighten nonvital teeth. Forty bovine teeth were used, artificially stained with blood. The four techniques used were the following : Hi-Lite activated by halogen light hydrogen peroxide activated by argon laser, hydrogen peroxide activated by heated instrument and walking bleach. The teeth were stained and divided into four groups of ten teeth and each group received a different treatment. The results showed that the four techniques were effective and able to promote satisfactory bleaching. However, some statistically significant differences related to the shades were noted. The two groups: hydrogen peroxide activated by argon laser and walking bleach, showed better aesthetics results in comparison to the other two groups: Hi-Lite activated by halogen light and hydrogen peroxide activated by heated instrument.

O objetivo deste estudo in vitro foi avaliar a força de adesão de sistemas adesivos sobre superfícies de esmalte bovino submetidas previamente, ou não, a tratamento clareador com gel a base de peróxido de carbamida (Opalescence PF), em diferentes concentrações (10%, 15% e 20%), através de ensaio mecânico de microcisalhamento. As superfícies de esmalte vestibular de 56 incisivos bovinos íntegros foram aplainadas e divididas em 14 grupos. G. 01: foram confeccionados cilindros com sistema adesivo Single Bond (SB) e resina composta (RC) Z-250 (controle); G. 02: foram confeccionados cilindros com sistema adesivo Clearfil SE Bond (CF) e RC Z-250 (controle); G. 03: clareamento com Opalescence PF (Op) 10% e cilindros confeccionados com SB e RC, 12 horas após o término do tratamento clareador; G. 04: clareamento com Op 15% e cilindros confeccionados conforme descrito para 03; G. 05: clareamento com Op 20% e cilindros confeccionados conforme descrito para 03; G. 06: clareamento com Op 10% e cilindros confeccionados com CF e RC, 12 horas após o término do tratamento clareador; G. 07: clareamento com Op 15% e cilindros confeccionados conforme descrito para 06; G. 08: clareamento com Op 20% e cilindros confeccionados conforme descrito para 06; G. 09: clareamento com Op 10% e cilindros confeccionados com sistema adesivo SB e RC, 01 semana após o término do tratamento clareador; G. 10: clareamento com Op 15% e cilindros confeccionados conforme descrito para 09; G. 11: clareamento com Op 20% e cilindros confeccionados conforme descrito para 09; G. 12: clareamento com Op 10% e cilindros confeccionados com CF e RC, 01 semana após o término do tratamento clareador; G. 13: clareamento com Op 15% e cilindros confeccionados conforme descrito para 12; G. 14: clareamento com Op 20% e cilindros confeccionados conforme descrito para 12. As amostras dos grupos 03 a 14 foram clareadas durante 02 semanas (08 horas/dia). Os resultados obtidos mostraram que as médias de adesão dos grupos 03, 04, 05 e 06, 07, 08 foram estatisticamente menores (p<0,05) que as médias obtidas para seus respectivos grupos controle (01 ou 02). Para o sistema adesivo monocomponente, as médias de adesão dos cilindros confeccionados 01 semana após o término do tratamento clareador, independente da concentração do peróxido de carbamida, foram estatisticamente semelhantes (p>0,05) às do respectivo grupo controle e tenderam a ser maiores que os valores de adesão obtidos nos cilindros confeccionados 12 horas após o término do clareamento, porém, em valores absolutos, a recuperação dos valores de adesão não foi completa (p<0,05). Para o sistema autocondicionante, as médias de adesão dos cilindros confeccionados 01 semana após o término do tratamento clareador foram estatisticamente semelhantes às do respectivo grupo controle (p>0,05), independente da concentração do agente clareador, havendo recuperação dos baixos valores de adesão obtidos quando os cilindros foram confeccionados 12 horas após o término do tratamento clareador. / The aim of this in vitro study was to evaluate the microshear bond strength of adhesive systems to bovine enamel surfaces previously submitted, or not, to bleach treatment with carbamide peroxide gel (Opalescence PF), in different concentrations (10%, 15% and 20%). The flat enamel surfaces of 56 bovine incisors were randomly divided in 14 groups. G. 01: cylinders made with Single Bond adhesive system (SB) and Z-250 composite (C) (control); G. 02: cylinders made with Clearfil SE Bond (CF) adhesive system and Z-250 (C) (control); G. 03: bleaching treatment with Opalescence PF (Op) 10% and cylinders made with SB and C, 12 hours after finishing the bleach regimen; G. 04: bleaching treatment with Op 15% and cylinders made according to 03; G. 05: bleaching treatment with Op 20% and cylinders made according to 03; G. 06: bleaching treatment with Op 10% and cylinders made with CF and C, 12 hours after finishing the bleach regimen; G. 07: bleaching treatment with Op 15% and cylinders made according to 06; G. 08: bleaching treatment with Op 20% and cylinders made according to 06; G. 09: bleaching treatment with Op 10% and cylinders made with SB and C, 01 week after finishing the bleach regimen; G. 10: bleaching treatment with Op 15% and cylinders made according to 09; G. 11: bleaching treatment with Op 20% and cylinders made according to 09; G. 12: bleaching treatment with Op 10% and cylinders made with CF and C, 01 week after finishing the bleach regimen; G. 13: bleaching treatment with Op 15% and cylinders made according to 12; G. 14: bleaching treatment with Op 20% and cylinders made according to 12. The specimens from groups 03 to 14 were bleached during 02 weeks, 08 hours/day, placed in individualized trays. During the remaining daily 16 hours, teeth were immersed in artificial saliva. Before microshear tests, the samples were stored in distilled water at 37 o C, for 24 hours. The results showed that bond strengths of groups 03, 04, 05 and 06, 07, 08 were statistically lower (p<0,05) when compared with their respective control group (01 or 02). For the all-etch adhesive system, the bond strength of the cylinders placed 01 week after the end of bleaching regimen, independent of the carbamide peroxide gel concentration, showed no significant differences (p>0,05) when compared with their respective control group and tended to be higher when compared with groups where adhesion were made 12 hours after the end of the bleaching treatment, with the same adhesive system. However, in absolute terms, the recuperation of the bond strength were incomplete (p<0,05). For the self-etch adhesive system, the bond strength of the cylinders placed 01 week after the end of bleaching regimen, independent of the carbamide peroxide gel concentration, showed no significant differences (p>0,05) when compared with their respective control group, recovering the bond strength values obtained when cylinders were made 12 hours after the end of the bleach regimen.

Orientador: Alessandra Bühler Borges / Coorientadora: Rayssa Ferreira Zanatta / Banca: Cesar Rogério Pucci / Banca: Daniele Mara da Silva Ávila Nogueira / Resumo: O objetivo deste estudo foi avaliar a degradação do peróxido de hidrogênio em altas concentrações (35-40%), durante uma simulação de sessão de clareamento de consultório, utilizando produtos comercialmente disponíveis com dois protocolos de aplicação. Foram medidas também a eficácia clareadora dos géis, a alteração de pH dos mesmos, bem como o potencial de alteração da microdureza e rugosidade superficial do esmalte. Para tal, espécimes de dentes bovinos em forma de disco com 4 mm de diâmetro e 2 mm de espessura (1 mm de esmalte e 1 mm de dentina) foram preparados para tal 105 espécimes, embutidos em resina acrílica, polidos e divididos nos seguintes grupos, de acordo com o tipo de gel clareador: Pola Office Plus (POP - SDI PH-37,5%), Opalescence Boost (OPB - Ultradent PH-40%) e Whiteness HP (WHP - FGM PH-35%). Cada grupo foi dividido em dois subgrupos conforme o protocolo de aplicação (n = 15): com e sem troca do gel clareador durante a sessão de clareamento. A alteração de cor das amostras foi medida por espectrofotometria de acordo com o sistema CIE L*a*b*, antes e após a sessão de clareamento. A superfície do esmalte foi analisada com microdurômetro e perfilômetro, para mensuração da microdureza Knoop (KHN) e rugosidade superficial (Ra). Outros 30 espécimes adicionais em dentes bovinos foram confeccionados para mensuração da concentração do peróxido de hidrogênio e pH. A concentração e pH dos géis foram medidos por meio da titulação com permanganato de potássio (KMnO4) e ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The aim of this study was to evaluate the degradation of hydrogen peroxide at high concentrations (35-40%) during a clinic whitening session simulation using commercially available products with two application protocols. The bleaching efficiency of the gels, pH change, as well as the alteration potential of the enamel microhardness and surface roughness (Ra) were measured. For this, disc-shaped bovine tooth specimens of 4 mm diameter and 2 mm thickness (1 mm enamel and 1 mm dentin) were prepared 105 specimens, embedded in acrylic resin, polished, and divided into the following groups according to the type of bleaching gel: Pola Office Plus (POP - SDI PH-37,5%), Opalescence Boost (OPB - Ultradent PH-40%), and Whiteness HP (WHP - FGM PH-35%). Each group was divided into two subgroups, according to the application protocol (n = 15): with and without exchange of the gel during the whitening session. The specimens' color change was measured by spectrophotometry according to the CIE system L*a*b*, before and after the bleaching session. The enamel surface was analyzed with a microhardner and profilometer, to measure the Knoop microhardness and surface roughness (Ra). Another 30 specimens in bovine teeth were made to measure the hydrogen peroxide concentration and pH. The concentration and pH of the gels were measured by titration with potassium permanganate (KMnO4) and by a pH meter and specific electrode, respectively, before and after said application times thereof. The degradation of the gels was calculated as a function of the initial concentration. The results were submitted to the ANOVA test and Tukey's multiple comparison test (5%). All gels presented similar bleaching efficacy (ΔE and ΔE00) comparing SA and MA. There were no significant differences between KHN and Ra means comparing SA and MA for the same gel. Although peroxide degradation significantly increased with time, the final gels concen.. / Mestre

No description available.

<p>Aim and Objectives: To assess the effect of bleaching on the marginal integrity of Class V composite resin restorations. To determine the effect of a 6% hydrogen peroxide over the counter and a 38% hydrogen peroxide in-office vital bleaching treatment products on the microleakage of Class V composite restorations.</p>

No description available.

This thesis addresses the mechanisms involved in cellulosedegradation in general and Totally Chlorine Free (TCF) bleachingof pulp in particular. The thesis shows that the cellulosedegradation during high consistency ozone bleaching is explainedby free radical chain reactions. By simulation, it has been shown that the number, weight andviscosity average of liner polymer chain length can be used tocalculate the number of random scissions in a linear polymer ofany molecular weight distribution, provided that there is acalibrated Mark-Houwink equation. A model describing partialdegradation of molecular weight distributions of linear polymersmeasured with viscometry was developed and verifiedexperimentally. The model predicts viscometric measurement ofchemical cellulose degradation by a rapidly reacting reagent tobe strongly dependent on cellulose accessibility. The role of free radical reactions in cellulose degradationwas studied by varying the amount of ferrous ions and ozone addedto the cotton linters. The result was compared to the resultsobtained from cellulose of lower crystallinity (cellulose beads)by measuring average chain length. When a ferryl ion reacted withcotton linters in the presence of ozone, the very formation ofone glycosidic radical was more significant to degradation thanthe final step of forming one oxidised glycoside. The inefficientdegradation observed of the oxidation step is explainable by theamount of accessible glycosides being too small to influenceviscometry. The efficient degradation observed in associationwith the glycosidic radical formation is explained by initiationof free radical chain reactions that are propagated as long asthere is ozone in the system. As none of these phenomena werefound in the less crystalline cellulose, cellulose structureappears to be important for how free radical mediated cellulosedegradation develops. The theory of free radical chain reactions coupled withdiffusion suggests a concentric expansion of the chain reactionsoutwards from the initial site of radical formation duringozonation of carbohydrates. This was confirmed by demonstratingfree radical chain reactions spreading from a spot of initiationoutwards during ozonation of a filter paper, using a pH-indicatorto monitor acid formation. Furthermore, the interior and exteriorof cellulose fibres doped with initiator were shown to bepermeated by small holes after ozonation. Ethylene glycol was shown to improve the selectivity duringozone bleaching of oxygen bleached kraft pulp at pH 3. Optimalconditions were obtained at pH 3 for 25 wt% ethylene glycol. Theinfluence of ethylene glycol on selectivity is explained by aproportion of the free radical chain reactions being carried bythe ethylene glycol instead of the cellulose during ozonebleaching. The observations were summarised in the form of amodel where the observed degradations for pulp, bleached pulp andcotton fibres during both ozone bleaching and ethylene glycolassisted ozone bleaching were shown to agree with each other. From g-irradiation of ozonised aqueous solutions of alcohol,the rate constant of superoxide formation from the peroxylradical of methanol was estimated to be 10 s-1. Rate constants of the reactions between ozone andalkylperoxyl radicals were determined to be around 104M-1s-1. The possibility of the reaction betweenalkylperoxyl radicals and ozone contributing significantly tofree radical chain reactions during ozonation of carbohydratesand alcohols could therefore be ruled out. Cellulose, degradation, free radical, ozone, selectivity,ethylene glycol, alcohol, bleaching, kraft pulp, cotton linters,delignification, fibre, fibril, crystallinity, ferryl ion, freeradical chain reactions, TCF, viscometry, molecular weightdistributions, random scissions.

Light skin color sits within a space of privilege. While this has global significance and relevance, it is particularly true in Jamaica, a former British colony. The majority of the population is of African descent, yet there is an elevation of Eurocentric values and a denigration of Afrocentric values in many facets of life, specifically in the promotion of light skin as an indicator of beauty and social status. The purpose of this study was to examine the psychological and socio-cultural factors that influence the practice of skin bleaching in the postcolonial society of Jamaica. Additionally, the study outlined the nation's efforts to combat the skin-bleaching phenomenon. The naturalistic paradigm of inquiry was used to frame the study and to collect and analyze data. The sample consisted of fifteen participants—twelve participants (six males and six females) with a history of skin bleaching; a retailer of skin lightening products; a local dermatologist who has written and published in local newspapers on the practice; and a representative from the Ministry of Health who was integrally involved in the national educational efforts to ban the practice. Data came from three sources: in-depth interviews with respondents; observation of participant's skin-bleaching practices; and a review of local cultural artifacts from popular culture and the media. Data from the audio recorded and transcribed interviews were analyzed using a thematic analysis. Some of the findings reveal that there are multiple and inconsistent definitions of bleaching; skin bleaching enjoys mixed reviews—much attributed to economic and social class distinctions; bleachers demonstrate and boast of their expertise in managing the bleaching process suggesting, that because of this expertise, they are immune to any negative side-effects of the practice; the bleaching practice was found to be intermittent, time consuming and laborious, costly and addictive; there are several motivations for the skin-bleaching practice, and these are primarily connected to issues of fashion, beauty, popularity, self-image and acceptability; there is a certain level of defiance towards the government‘s efforts to ban bleaching yet an expressed sense of responsibility among bleachers. The overall findings show that there is a bias in Jamaica for light skin over dark skin and these values are taught in non-formal and informal ways from very early in life. The practice of skin bleaching is of social and public health concern, and this study has implications for national policy, practice and theory.