Changes Can be Studied When the Measurement Instrument is Different at Different Time Points

Microleakage of Bulk-Fill Composites at Two Different Time Points

Objectives: Microleakage is the main concern in composite restorations. This study aimed to compare the microleakage of two bulk-fill and one conventional composite at two different time points. Methods: Class II cavities were prepared in 60 premolar teeth and divided into six groups of 20. Groups 1 and 4 were incrementally filled with Grandio composite. Groups 2 and 5 were filled with X-tra...

Comparing the Productivities of Two Units at Two Different Points in Time

microleakage of bulk-fill composites at two different time points

objectives: microleakage is the main concern in composite restorations. this study aimed to compare the microleakage of two bulk-fill and one conventional composite at two different time points. methods: class ii cavities were prepared in 60 premolar teeth and divided into six groups of 20. groups 1 and 4 were incrementally filled with grandio composite. groups 2 and 5 were filled with x-tra fi...

How Different Can Two Intersecting Families Be?

To measure the difference between two intersecting families F ,G ⊆ 2[n] we introduce the quantity D(F ,G) = |{(F,G) : F ∈ F , G ∈ G, F ∩ G = ∅}|. We prove that if F is k-uniform and G is l-uniform, then for large enough n and for any i 6= j Fi = {F ⊆ [n] : i ∈ F, |F | = k} and Fj = {F ⊆ [n] : j ∈ F, |F | = l} form an optimal pair of families (that is D(F ,G) ≤ D(Fi,Fj) for all uniform and inter...

An inquiry into the different perspectives that can be used when eliciting preferences in health.

There are a number of perspectives that an individual could be asked to adopt in studies designed to elicit preferences for use in informing resource allocation decisions in health care. This paper develops a conceptual framework that clearly distinguishes between six different perspectives. It is argued that the appropriate perspective to use depends on normative considerations and the particu...