ABSTRACT Objective: To determine the prevalence of malocclusion and associated factors in children and the level of knowledge of mothers participating in the child care group of a basic health unit. Material and Methods: This is a cross-sectional study conducted in children between 18 and 72 months of a childcare group in Pelotas. Children whose parents or legal guardians signed the informed consent term participated in the study. Data were collected through a questionnaire previously tested and applied to the mothers, and a clinical examination of children's occlusion were performed by examiners after training and calibration. Statistical analysis was descriptive and analytic. In the bivariate analyses, it was used the Pearson, Fisher or Linear Trend Qui-Square tests and, in the multivariate analysis, the Poisson regression. Prevalence ratios and 95% confidence intervals were obtained, and a p-value <0.05 was used. Results: Forty-seven children were included and 41.3% presented malocclusion. The prevalence of malocclusion was associated with a higher number of children in the family (p<0.005) and breastfeeding for more than 12 months (p<0.05). The highest prevalence of open bite was associated with the use of a pacifier and working mothers (p<0.05). Conclusion: Most mothers reported having knowledge about the time and use of pacifiers in childhood. In this group, the prevalence of malocclusion in children was high and associated with behavioral and social factors.

Resumo O objetivo deste estudo foi avaliar in vitro e in situ os efeitos de dois tratamentos clareadores sobre a microdureza do esmalte dental humano. Sessenta blocos de esmalte obtidos de trinta molares recentemente extraídos foram utilizados. Os espécimes foram polidos com lixas sob refrigeração com água. As amostras de esmalte foram divididas aleatoriamente em quatro grupos e tratadas com 10% de peróxido de hidrogênio (HP) ou fitas de clareamento (WS) contendo 10% de peróxido de hidrogênio, testadas em duas condições experimentais: in vitro ou in situ. Para o ensaio in situ, seis voluntários foram selecionados e usaram um aparelho intra-oral contendo blocos de esmalte, enquanto que para a condição in vitro, os espécimes foram mantidos em água deionizada após os protocolos de clareamento. Os tratamentos clareadores foram aplicadas durante uma hora/dia durante 14 dias. Quantidades semelhantes de agentes de clareamento foram usadas nas duas condições. Antes e após os tratamentos de clareamento, a análise da microdureza foi realizada. A análise estatística (ANOVA e teste de Tukey) mostrou que, na condição in situ não houve redução estatisticamente significante na microdureza do esmalte clareado (p>0,05). Diminuição significativa na dureza foi observada nos blocos de esmalte clareados, em ambos os tratamentos, na condição in vitro (p <0,05). Em relação aos agentes de clareamento, os resultados in situ não mostraram nenhuma diferença entre a HP e WS, enquanto que in vitro, WS produziu o menor valor de dureza. Conclui-se que não houve nenhum efeito deletério na dureza do esmalte, em nenhum dos protocolos de clareamento ao usar um modelo in situ. A diminuição da dureza foi observada somente na condição in vitro.

Abstract The aim of this study was to evaluate in vitro and in situ the effects of two bleaching treatments on human enamel surface microhardness. Sixty enamel slabs from recently extracted thirty molars were used. The specimens were polished with sandpapers under water-cooling. The enamel samples were randomly divided in four groups, treated with 10% hydrogen peroxide (HP) or Whitening Strips (WS) containing 10% hydrogen peroxide and using two conditions: in vitro or in situ model. For in situ condition, six volunteers wore an intra-oral appliance containing enamel slabs, while for in vitro condition the specimens were kept in deionized water after the bleaching protocols. The bleaching treatments were applied one-hour daily for 14 days. Similar amounts of bleaching agents were used in both conditions. Before and after bleaching treatments, microhardness was measured. Statistical analysis (ANOVA and Tukey test) showed that in the in situ condition there was no statistically significant microhardness reduction in the bleached enamel (p>0.05). Significant decrease in hardness was observed for enamel slabs bleached with both treatments in the in vitro condition (p<0.05). Regarding the bleaching agents, in situ results showed no difference between HP and WS, while in vitro WS produced the lowest hardness value. It could be concluded that there was no deleterious effect on enamel produced by any of the bleaching protocols used in the in situ model. The reduction of hardness was only observed in vitro.

AIM: To identify a possible association between the occurrence of dental caries and tooth erosion and to correlate the dietary factor with an increased risk of dental caries. METHODS: A cross-sectional study in a multistage random sample of 1,211, 8 to 12-years-old Brazilian schoolchildren in private and public schools was conducted in Pelotas, Brazil. The prevalence of dental caries and tooth erosion was assessed. Dietary habits data were collected by a structured questionnaire. Data were analyzed using Poisson regression model taking into account the cluster sample (Prevalence ratio - PR; 95% Confidence Interval - CI). RESULTS: The prevalence of dental caries and tooth erosion was 32.4% (95% CI: 30.0; 35.2) and 25.0% (95% CI: 23.4; 29.0), respectively. Most children had high consumption of sweets (65%). Consumption of fruits, such as oranges (31%), strawberries (23.6%), pineapple (12%), and natural fruit juices (oranges, lemon) was low. Soft drinks consumption, 3 or more times a week was observed in 40% of the children. CONCLUSIONS: Dental caries was not statistically associated with tooth erosion. The consumption of acidic fruits/drinks was not associated with dental caries. Dental caries and dental erosion were not associated with each other and with acidic fruits or drinks consumption.

AIM: To determine the prevalence and the hygiene methods used by 6-16-year-old private school children and adolescents to clean removable orthodontic appliances (ROA) in the city of Pelotas, RS, Brazil. METHODS: A cross-sectional study was conducted in private schools located in the urban area after the school tutors signed an informed consent form. Questionnaires were applied to children using removable orthodontic appliances. Data regarding hygiene methods of orthodontic appliances were collected. Descriptive analysis was performed. Pearson's chi-square test and Linear Trend with a confidence level of 95% were used for analytical analysis. RESULTS: Children using ROA in private schools were 7.6%. The most frequent hygiene method used was mechanical cleansing with toothbrush and toothpaste (85.6%). Daily cleansing was the frequency most reported by children (51.6%). CONCLUSIONS: Use of ROA in students from private schools was low and the most used hygiene method was brushing with toothpaste.