Accuracy at radiography and probing for the diagnosis of proximal caries

In 63 teenagers the proximal surfaces of premolars to be extracted for orthodontic reasons and the adjacent surfaces of neighboring teeth, 598 surfaces in all, were examined radiographically and by probing. Direct inspection after extraction revealed that 51% of the surfaces had incipient carious lesions and 5% lesions with cavities. Of the surfaces with cavities 82.1% were correctly diagnosed radiographically if any radiolucency, regardless of its extent, was used as a diagnostic criterion. However, this yielded a false positive rate of 19.6%. If only radioluccncies extending at least into the inner third of the enamel were called positive the true positive rate was 36.7% and the associated false positive rate 1.6%. At a 5% cavity frequency the predictive positive values were 17% and 53%, respectively. Probing yielded a true positive rate of about 29% and a false positive rate of 1.1% with a predictive positive value of 50-57%. All radiolucencies extending into the dentin were associated with cavities. When the most liberal radiographic criterion was used 37.5% of all carious lesions, whether associated with a cavity or not, were detected and 3.8% of sound surfaces were falsely called carious. The corresponding predictive positive value at the actual rate of incipient lesions and lesions with cavities was 92.6%.     

A conceptual framework for modeling aggregate and cumulative exposures to chemicals

Computer simulation programs have been identified as useful tools for characterizing uncertainty and variability in longitudinal exposures to multiple sources by multiple routes of exposures. This paper provides a conceptual framework for such programs that separates and appropriately models the processes that determine uncertainty, inter- and intraindividual variability, as well as the processes that determine the relationships between the individuals and sources of exposure. The framework is based on a series of four nested loops. These are: the exposure event loop that models the route-specific doses to a person from one or more sources at one point in time; the time step loop that moves a person through time updating the sources and the person's characteristics, the interindividual variation loop that determines the initial characteristics of each person modeled, and finally the uncertainty loop that characterizes the uncertainty from model and parameter uncertainties. This framework provides a flexible and internally consistent approach for the design of simulation software.     

Determinants of response to a parent questionnaire about development and behaviour in 3 year olds: European multicentre study of congenital toxoplasmosis

Background  

We aimed to determine how response to a parent-completed postal questionnaire measuring development, behaviour, impairment, and parental concerns and anxiety, varies in different European centres.