Economic evaluations in Dentistry have been increasing in recent years. They are a relevant contribution if an economic issue exists. Knowing if a new intervention is an efficient way of allocating available (and scarce) resources (the concept of opportunity costs), a well-designed economic evaluation may be helpful. One option is to conduct a trial-based economic analysis, which extracts a considerable board of information from a trial. This approach produces a more controlled result since many sources of variations might be reduced. On the other hand, some aspects could not be predicted directly from the trial or even extrapolated. Thus, combining model-based analysis may be an idea. In this paper, we intended to discuss important aspects to be considered by researchers in further economic evaluations. This paper will be systematically divided into sessions related to the study design as time horizon and perspective, health effects, costs, and data analysis. In the end, we expect the reader could be able to plan a trial-based economic evaluation, which should be a careful, meticulous, quite laborious and especially transparent process.

Background Few studies have addressed the clinical parameters' predictive power related to caries lesion associated with their progression. This study assessed the predictive validity and proposed simplified models to predict short-term caries progression using clinical parameters related to caries lesion activity status. Methods The occlusal surfaces of primary molars, presenting no frank cavitation, were examined according to the following clinical predictors: colour, luster, cavitation, texture, and clinical depth. After one year, children were re-evaluated using the International Caries Detection and Assessment System to assess caries lesion progression. Progression was set as the outcome to be predicted. Univariate multilevel Poisson models were fitted to test each of the independent variables (clinical features) as predictors of short-term caries progression. The multimodel inference was made based on the Akaike Information Criteria and C statistic. Afterwards, plausible interactions among some of the variables were tested in the models to evaluate the benefit of combining these variables when assessing caries lesions. Results 205 children (750 surfaces) presented no frank cavitations at the baseline. After one year, 147 children were reassessed (70%). Finally, 128 children (733 surfaces) presented complete baseline data and had included primary teeth to be reassessed. Approximately 9% of the reassessed surfaces showed caries progression. Among the univariate models created with each one of these variables, the model containing the surface integrity as a predictor had the lowest AIC (364.5). Univariate predictive models tended to present better goodness-of-fit (AICs < 388) and discrimination (C:0.959–0.966) than those combining parameters (AIC:365–393, C:0.958–0.961). When only non-cavitated surfaces were considered, roughness compounded the model that better predicted the lesions' progression (AIC = 217.7, C:0.91). Conclusions Univariate model fitted considering the presence of cavitation show the best predictive goodness-of-fit and discrimination. For non-cavitated lesions, the simplest way to predict those lesions that tend to progress is by assessing enamel roughness. In general, the evaluation of other conjoint parameters seems unnecessary for all non-frankly cavitated lesions.

Few studies have addressed the predictive power of the clinical parameters used in assessing caries lesion activity. This study assessed the predictive validity of evaluating clinical parameters that are related to caries lesion activity status, individually and combined, in a long-term analysis. The occlusal surfaces of primary molars (1361 surfaces) were examined in 205 children according to the following clinical features: potential for plaque stagnation, colour, luster, cavitation, texture, and clinical depth. Cavities with frankly exposed dentine were excluded from this sample. After 1 year, 148 children (828 surfaces) were re-evaluated using the International Caries Detection and Assessment System to assess caries lesion progression. Progression was set as an outcome to verify the predictive power of the initially assessed clinical parameters. Different combinations of two or more parameters were also tested to check for any association with caries progression. Multilevel Poisson regression analyses were performed and the relative risk for each parameter/combination tested was calculated by considering a confidence interval of 95%. Forty percent of the reassessed surfaces presented caries progression after 1 year. Despite their surface integrity, dentine caries lesions were approximately 10-fold more likely and enamel lesions were approximately three-fold more likely to progress than sound surfaces. Similarly, cavitated lesions showed the highest risk of progression compared to sound/non-cavitated lesions. When only non-cavitated surfaces were considered, roughness proved to be a risk factor for caries progression. In conclusion, the lesions presenting clinical involvement of the dentine and even those cavitations clinically involving only the enamel had a higher risk of progression compared to sound or non-cavitated surfaces. For these lesions, the evaluation of other conjoint parameters seems unnecessary. Nevertheless, surface roughness can be a useful feature in predicting the risk of non-cavitated caries lesion progression.

Este estudo avaliou a retenção de conhecimento, em médio prazo, de graduandos expostos a uma atividade educativa de detecção de cárie. Esta é uma parte do estudo multicêntrico IuSTC. Alunos dos últimos anos foram convidados a participar e passaram pela atividade. Foram avaliados quanto à retenção do conhecimento após 1,5 ano. Avaliações teóricas e práticas (pontuadas de 0 a 10) foram preparadas para avaliar conhecimento, habilidades e atitudes. Os escores foram definidos como desfechos.  Análises de regressão multinível testaram a associação entre a performance dos alunos e sua percepção sobre a importância da atividade dentro do seu currículo.  Particularidades relacionadas à performance em tópicos específicos e diferentes tipos de avaliação também foram explorados. 302 alunos participaram das avaliações. Em média, os alunos tiveram medias (desvio-padrão (DP), de 6,68 (1,88) teórica e 5,5 (2,27) prática. A percepção dos alunos esteve associada com sua performance. Na avaliação teórica, os alunos tiveram pior performance ao relacionar a condição clínica com a histológica (21% de acertos) ou em justificar a conduta frente a lesões inativas (36% de acertos). Na avaliação prática, 70-90% dos alunos demonstraram habilidade de detectar, avaliar atividade e tomar decisões clínicas frente a lesões iniciais e severas, enquanto 50% avaliaram adequadamente as lesões moderadas e apenas 32% demonstrou atitude correta do manejo. Em conclusão, a retenção do conhecimento dos alunos está dentro do esperado em uma análise de médio prazo. Para alguns tópicos (por exemplo, relacionados a prática e justificativa de atitudes), a performance dos alunos tende a ser pior.