BACKGROUND Contamination of dentin with hemostatic agents might exert a deleterious effect on adhesive procedures on dentin. The present study was undertaken to investigate the effect of aluminum chloride hemostatic agent on marginal gaps in Cl V giomer restorations. MATERIAL AND METHODS Fifty sound bovine permanent incisors were selected for the purpose of this in vitro study and Cl V caviti...

This study examined the effect of four margin designs on marginal adaptation of Captek crowns during selected processing steps. Twenty-four Captek crowns were fabricated, six each of four margin designs: shoulder (Group A), chamfer (Group B), chamfer with bevel (Group C), and shoulder with bevel (Group D). Marginal discrepancies between crowns and matching dies were measured at selected points ...

Standard methods for survival analysis, such as the time-dependent Cox model, may produce biased effect estimates when there exist time-dependent confounders that are themselves affected by previous treatment or exposure. Marginal structural models are a new class of causal models the parameters of which are estimated through inverse-probability-of-treatment weighting; these models allow for ap...

This study examines the relationship between train traffic and the accident risk for road users at level crossings. The marginal effect of train traffic on the accident risk can be used to derive the marginal cost per train passage that is due to level crossing accidents. Based on Swedish data from 2000 to 2012 on level crossing accidents, train volume and crossing characteristics, the marginal...

For decades, economists have used the hedonic model to estimate demands for the implicit characteristics of differentiated commodities. The traditional cross-sectional approach can recover marginal willingness to pay for characteristics, but has faltered over a difficult endogeneity problem for non-marginal welfare measures. I show that when marginal prices can be reliably estimated, and when p...

In multi-unit auctions, such as auctions of commodities and securities, and financial exchanges, it is necessary to specify rationing rules to break ties between multiple marginal bids. The standard approach in the literature and in pratice is to ration marginal bids proportionally. This paper shows how bidding can be made more competitive if the rationing rule instead gives increasing priority...

In this paper, I develop a duopoly location model of differentiated products in which consumers’ product preferences vary positively with product prices. The level of preference price-dependence (“PPD”) is allowed to vary across consumers. I find that equilibrium prices increase with the PPD level of the marginal, or “just indifferent,” consumer, but are not influenced by the PPD levels of othe...

This paper estimates marginal returns to college for individuals induced to enroll in college by different marginal policy changes. The recent instrumental variables literature seeks to estimate this parameter, but in general it does so only under strong assumptions that are tested and found wanting. We show how to utilize economic theory and local instrumental variables estimators to estimate ...