tooth fracture is a common dental problem. by extension of cavity dimensions, the remaining tooth structure weakens and occlusal forces may cause tooth fracture. the aim of this study was to evaluate and compare the fracture resistance of teeth restored with direct and indirect composite restorations.sixty-five sound maxillary premolar teeth were chosen and randomly divided into five groups eac...

Enamel prism-packing patterns reflect the past history of ameloblasts, providing information about growth patterns in tooth development. Here, the area and density of enamel prisms on the cuspal surface of molar teeth were measured to examine if the onset and rate of enamel apposition differ according to stage of development and/or cusp type. Scanning electron-microscopic images were taken from...

Abstract. In many applications of practical interest, for example, in control theory, economics, electronics and neural networks, the dynamics of the system under consideration can be modelled by an endomorphism, which is a discrete smooth map that does not have a uniquely defined inverse; one also speaks simply of a noninvertible map. In contrast to the better known case of a dynamical system ...

The Hamiltonian Hopf bifurcation is described by part of a swallowtail surface. In this short note it is shown that this swallowtail is actually a non-transversally unfolded cusp singularity, and that the swallowtail surface is obtained by folding a cusp along a fold line that is tangent to the cusp and moving along the cusp.

OBJECTIVES To determine the frequency, variability, sexual dimorphism and bilateral symmetry of fourteen dental crown traits in the deciduous and permanent dentition of 60 dental models (35 women and 25 men) obtained from a native, indigenous group of Nasa school children of the Musse Ukue group in the municipality of Morales, Department of Cauca, Colombia. METHODS This is a quantitative, des...

Left coronary cusp perforation is an extremely rare consequence of blunt chest trauma. A 22-year-old male presented after a motor vehicle accident with dyspnea. Transthoracic echocardiogram (TTE) and transesophageal echocardiogram (TEE) showed moderate to severe aortic regurgitation with prolapsing right coronary cusp. In the operating room he was found to have a left coronary cusp tear near th...

OBJECTIVE Patients with supracoronary ascending aortic aneurysms can have aortic insufficiency (AI) due to dilatation of the sinotubular junction and/or associated cusp pathology. The incidence and types of cusp lesions as well as the effect of AI severity and cusp repair techniques on outcome in this patient population is not well defined. METHODS Since 1996, 55 patients (mean age: 65 ± 13 y...