Sample size calculation is part of the early stages of conducting an epidemiological, clinical or lab study. In preparing a scientific paper, there are ethical and methodological indications for its use. Two investigations conducted with the same methodology and achieving equivalent results, but different only in terms of sample size, may point the researcher in different directions when it comes to making clinical decisions. Therefore, ideally, samples should not be small and, contrary to what one might think, should not be excessive. The aim of this paper is to discuss in clinical language the main implications of the sample size when interpreting a study.

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Serious difficulties in reporting results were encountered when using ICDAS II and PUFA separately in an epidemiological survey in a child population in Brazil. That necessitated the development of a comprehensive but pragmatic caries assessment index. This publication describes the rationale, development and content of a novel caries assessment index. Strengths and weaknesses of ICDAS II, PUFA and other indices were analysed. The novel caries index developed for use in epidemiological surveys is termed 'Caries Assessment Spectrum and Treatment' (CAST). 'Spectrum' indicates what is considered the main strength of the new index - its usefulness in describing the complete range of stages of carious lesion progression: from no carious lesion, through caries protection (sealant) and caries cure (restoration) to lesions in enamel and dentine, and the advanced stages of carious lesion progression in pulpal and tooth-surrounding tissue. CAST combines elements of the ICDAS II and PUFA indices, and the M- and F-components of the DMF index. A DMF score can easily be calculated from the CAST score, thereby enabling retention of the use of existing DMF scores. The CAST index for use in epidemiological surveys is very promising. It should be validated and its reliability and usefulness be tested in different age groups in different countries and cultures.

A new non-invasive method to consistently obtain high-quality images of the palatal masticatory mucosa is described. Measurements of this mucosa could be obtained at different locations on the palate.

The purpose of this retrospective study was to determine the prevalence of hypodontia and associated dental anomalies in patients undergoing orthodontic treatment in Brasília, Brazil, over a 2 year period (1998-2000). The records of 1049 orthodontic patients between 10 and 15.7 years of age (507 males and 542 females) from 16 orthodontic clinics were analysed. Descriptive statistics were performed for the study variables. A chi-square test was used to determine the difference in the prevalence of hypodontia between genders. The prevalence of hypodontia was 6.3 per cent (39.4 per cent males and 60.6 per cent females) with no statistically significant difference between the genders. One case of oligodontia was observed. The maxillary lateral incisor was the most frequently missing tooth, followed by the mandibular second premolar. All cases of hypodontia, except one, were associated with at least one other dental anomaly. These associated dental anomalies were retained primary teeth (30.3 per cent), ectopic canine eruption (25.8 per cent), taurodontism (21.2 per cent), and peg-shaped maxillary lateral incisors (16.7 per cent).