In this study, enamel micro-cracks produced around composite restorations were observed on surfaces and vertical sections, using a stereomicroscope and a scanning electron microscope (SEM). The effects of various clinical factors, i.e. the curing system, the marginal form and the polishing period after filling, on the incidence of marginal enamel micro-cracks were examined. Enamel micro-cracks ...

statement of problem: chemo-mechanical caries removal is an effective alternative to the traditional rotary drilling method. one of the factors that can influence micro-leakage is the method of caries removal. objectives: to compare the micro-leakage of resin composite in primary dentition using self-etch and all-in one adhesives following conventional and chemo-mechanical caries removal. mater...

X-ray micro-analysis was used to determine the elemental composition of the tooth, amalgam, and base material of ten aged, amalgam-restored, posterior teeth after they had been fractured across the amalgam-tooth interface. Subsequently, replicas were used to remove marginal seal material from each interface for examination by x-ray micro-analysis. The results show that P and Sn were present in ...

Marginal and internal adaptation is critical for the success of indirect restorations. New imaging systems make it possible to evaluate these parameters with precision and non-destructively. This study evaluated the marginal and internal adaptation of zirconia copings fabricated with two different systems using both silicone replica and microcomputed tomography (micro-CT) assessment methods. A ...

Resource misallocation can lower aggregate total factor productivity (TFP). We use micro data on manufacturing establishments to try to quantify the extent of this misallocation in China and India in recent years. Viewing the data through the prism of the Melitz model of monopolistically competitive firms, we estimate sizable gaps in marginal products of labor and capital across plants within n...

This paper uses individual tax returns micro data from 1960 to 1997 to analyze whether taxpayers bunch at the kink points of the U.S. income tax schedule generated by jumps in marginal tax rates. Clear evidence of bunching is found only at the threshold of the first tax bracket where tax liability starts. Evidence for other kink points is weak or null. The large jumps in marginal tax rates crea...

PURPOSE The purpose of this study was to verify the clinical-feasibility of additive manufacturing by comparing the accuracy of four different manufacturing methods for metal coping: the conventional lost wax technique (CLWT); subtractive methods with wax blank milling (WBM); and two additive methods, multi jet modeling (MJM), and micro-stereolithography (Micro-SLA). MATERIALS AND METHODS Thi...

The objective of the study was to measure the marginal and internal fit of zirconia-based all-ceramic three-unit fixed partial dentures (FPDs) (Y-TZP - LAVA, 3M-ESPE), using a novel methodology based on micro-computed tomography (micro-CT) technology. Stainless steel models of prepared abutments were fabricated to design FPDs. Ten frameworks were produced with 9 mm2 connector cross-sections usi...