Estudio del efecto citotóxico e irritativo de jabones para la limpieza cutánea / Study of the cytotoxic and irritant effects of skin cleansing soaps

Resumen Introducción: El jabón para el aseo cutáneo es de empleo común entre la población, sin embargo, es posible que cause daño a las células de la piel y modifique la barrera cutánea. Objetivo: Determinar el efecto citotóxico de los jabones en queratinocitos cultivados in vitro y correlacionarlo con la irritación clínica. Método: Se realizó una encuesta para conocer los jabones comerciales más utilizados y su cantidad; posteriormente, se evaluó su citotoxicidad en cultivos de queratinocitos humanos mediante el método de resazurina. Los jabones con mayor y menor citotoxicidad se aplicaron en piel de voluntarios sanos para evaluar su efecto en la barrera cutánea mediante ensayos de colorimetría y pérdida transepidérmica de agua. Resultados: De los jabones analizados, 37 % demostró ser tóxico para los queratinocitos in vitro. El jabón con mayor toxicidad indujo el mayor índice de eritema y pérdida transepidérmica de agua, en comparación con el jabón menos tóxico y el vehículo empleado como solución control. Conclusión: Los jabones comercializados para el aseo cutáneo pueden incluir ingredientes químicos que dañan los queratinocitos humanos y causan irritación subclínica de la barrera cutánea. Su utilización puede agravar dermatosis preexistentes, generar dermatitis xerósica o de contacto irritativa y causar atrofia y dermatoporosis.

Abstract Introduction: The use of soap for skin cleansing is common among the population. However, it is possible that it causes damage to skin cells and disrupts the skin barrier. Objective: To determine the cytotoxic effect of soaps on in vitro-cultured keratinocytes and to correlate it with clinical irritation. Method: A survey was conducted to find out the most widely used commercial soaps and their number. Subsequently, their cytotoxicity was evaluated in human keratinocyte cultures using the resazurin assay. The soaps with the highest and lowest cytotoxicity were applied to the skin of healthy volunteers to assess their effect on the skin barrier using colorimetry and transepidermal water loss (TEWL) assays. Results: Of the analyzed soaps, 37 % were shown to be toxic to keratinocytes in vitro. The soap with the highest toxicity induced the highest rate of erythema and TEWL, in comparison with the least toxic soap and the vehicle used as the control solution. Conclusion: Soaps marketed for skin cleansing can contain chemical ingredients that damage human keratinocytes and cause skin barrier subclinical irritation. Their use can worsen preexisting dermatoses, generate xerotic or irritant contact dermatitis, and cause atrophy and dermatoporosis.

The pH of the main Brazilian commercial moisturizers and liquid soaps: considerations on the repair of the skin barrier

Abstract: The pH of the skin is slightly acidic (4.6 to 5.8) which is important for appropriate antibacterial, antifungal, constitution of barrier function, as well as structuring and maturation of the stratum corneum. This study aimed to evaluate the pH of the main commercial moisturizers and liquid soaps in Brazil. Thus, pH of the products was quantified by pH meter in three measurements. A total of 38 moisturizers and six commercial liquid soaps were evaluated. Mean pH of 63% and 50% of the moisturizing and liquid soaps presented results above 5.5, disfavoring repair, function, and synthesis of dermal barrier.

Critical assessment of the pH of children's soap / Avaliação crítica do pH dos sabonetes infantis

Abstract Objective: To evaluate the pH value of children's antibacterial soaps and syndets used in children's baths and verify whether there is information regarding pH on the product label. Methods: Quantitative, cross-sectional, analytical observational study that included ninety soap samples, both in bar and liquid presentations, as follows: 67 children's soap (group 1), 17 antibacterial soaps (group 2), and 6 syndets (group 3). Each sample had its pH measured after 1% dilution. In addition to descriptive statistics, the Pearson-Yates chi-squared test and Student's t-tests were applied, considering the minimal significance level of 5%. The Wilcoxon-Mann-Whitney test, Fisher's exact test, and the Kruskal-Wallis test were used for inferential statistics. Results: The pH levels varied considerably between liquid and bar presentations, with lower levels (4.4-7.9) found for the liquids (p < 0.05). Syndets showed pH levels close to the ideal (slightly acid) and the antibacterial soaps showed the highest pH levels (up to 11.34) (p < 0.05). Only two of the soaps included in the study had information about their pH levels on the product packaging. Conclusions: Knowledge of the pH of children's soap by doctors and users is important, considering the great pH variability found in this study. Moreover, liquid soaps, and especially syndets, are the most recommended for the sensitive skin of neonates and infants, in order to guarantee skin barrier efficacy.

Resumo Objetivos: Avaliar o pH dos sabonetes infantis, antibacterianos e sindets (syntetic detergents) habitualmente usados em crianças, bem como verificar se há no rótulo desses produtos informação sobre seu pH. Métodos: Estudo observacional, analítico, transversal e quantitativo, que incluiu 90 sabonetes nas apresentações em barra e líquida, 67 infantis (grupo 1), 17 antibacterianos (grupo 2) e 6 sindets (grupo 3). Procedeu-se à mensuração do pH das amostras após diluição a 1%. Além da estatística descritiva, foram usados os testes de qui-quadrado Persons/Yates e t de Student, com nível de significância mínimo de 5%. Para a estatística inferencial, foram usados os testes de Wilcoxon-Mann-Whitney, exato de Fisher e Kruskal-Wallis. Resultados: O pH variou consideravelmente entre as formas líquida e em barra, com pHs menores (de 4,4 a 7,9) nos líquidos (p < 0,05). Os sindets mostraram pHs próximos ao ideal (levemente ácidos) e os antibacterianos apresentaram os maiores pHs (até 11,34) (p < 0.05). Apenas dois dos sabonetes analisados apresentavam no rótulo a indicação do pH. Conclusões: A observação do pH dos sabonetes infantis pelos médicos e usuários é importante, haja vista a grande variabilidade de valores de pH encontrados. Além disso, os sabonetes líquidos, e especialmente os sindets, são os mais recomendados para uso em recém-nascidos e lactentes com pele sensível, de forma a garantir a eficácia da barreira cutânea.

Effect of different disinfecting procedures on the hardness and color stability of two maxillofacial elastomers over time

Objective Disinfection procedures often cause deterioration in a maxillofacial prosthesis. Color and hardness alterations could lead to a replacement of the prosthesis. Material and Methods An experimental chlorinated polyethylene (CPE) and a commercial polydimethyl siloxane (PDMS) sample were treated with four different disinfection procedures for a period which simulates 1 year of clinical service. The applied disinfection procedures included microwave exposure and immersion in three solutions, sodium hypochlorite, neutral soap and a commercial disinfecting soap. Shore A hardness (∆H) and color differences (∆E) were determined before and after each procedure. All data were analyzed by Two Way Analysis of Variance (ANOVA) and Tukey's post hoc tests at a level of α=0.05. Results The samples presented significant alterations in color and hardness after the different disinfection treatments. The color differences (∆E) were at least eye detectable in all cases and clinically unacceptable in most of the cases, with values ranging from 1.51 to 4.15 and from 1.54 to 5.92 for the PDMS and CPE material, respectively. Hardness was decreased after all the disinfection procedures in the PDMS, while for the CPE, a decrement was observed after disinfection with sodium hypochlorite and neutral soap and an increment after microwave exposure and the disinfection with a commercial antimicrobial agent. The PDMS samples presented greater alterations in color and hardness after disinfection with sodium hypochlorite solution, while the microwave exposure caused negligible effects. The CPE samples were affected most after disinfection when treated with neutral soap, and more slightly when disinfected with sodium hypochlorite solution. Conclusions The disinfection procedures caused alterations in color and hardness of the examined materials. The most suitable disinfection procedure for ...

Effect of five brands of latex gloves on the setting time of polyvinyl siloxane putty impression materials.

Addition silicone impression materials have been used as impression material for more than 20 years. Although they are among the most expensive impression materials, they became popular during the past decade as they have excellent physical properties. Prevention of infection is an important aspect in dental treatment since dental professionals are routinely exposed to the wide variety of microorganisms present in saliva. Gloves are the most common protective measure used during dental treatment. The gloves are mostly made of latex. In this study, we examine how the setting time of three types polyvinyl putty materials were affected by the use of five different brands of latex gloves and one brand of vinyl gloves. Each material was first mixed without wearing gloves according to the manufacturer's instructions. After the stipulated mixing time, the setting time was measured using the Vicat needle. The setting time is measured from the time of mixing till the time that the needle does not produce any indentation on the surface of the material. The putty material was then mixed with gloved hands (using the five different brands of latex gloves in turn) and the setting time was measured. Then the material was mixed with washed gloved hands, and the setting time was measured again. Finally, the material was mixed with vinyl gloved hands and the setting time was measured. The following conclusions were drawn from the study: Reprosil™ and Express™ showed significant variation in the setting time with the latex gloved hands. There was no significant variation in the setting time when material was mixed with unwashed vs washed gloved hands. Vinyl gloves did not significantly affect the setting time of any of the putty impression materials.

Estudio del efecto irritativo de los jabones para piel delicada / Study of the irritative effect of soaps on sensitive skin

La elección de un jabón sobre otro depende principalmente de preferencias individuales, sin embargo, el tipo de piel que tiene cada paciente influye en esta elección. En este estudio investigamos el efecto irritativo de los jabones utilizados para la piel delicada. Se expusieron 15 sujetos de piel sensible (con prueba del parche positiva para lauril sulfato de sodio al 0.13 por ciento) a emulsiones de jabón al 8 por ciento durante cinco días seguidos y se registró la aparición de eritema, descamación y fisuración. De esta manera se evaluaron 22 jabones y sustitutos de jabón. Además se estudiaron las características de cada producto, su pH, contenido de detergentes, perfume y exceso de grasa. Los resultados indicaron que la mayor parte de los jabones y sustitutos de jabón poseen un pH demasiado alcalino, y que una gran cantidad de ellos no reúnen las característicasadecuadas para rotularse como jabones neutros y mucho menos útiles para piel sensible. Sin embargo, cinco de ellos prácticamente no produjeron irritación. Podemos concluir que en nuestri país contamos con productos adecuados para el aseo cotidiano en personas con piel sensible