The purpose of this study was to investigate how water aging of the resin cement influences the stress distribution in all-ceramic crowns and if there is an increase in the propensity for crown failure. The failure of all-ceramic crowns attributed to cement degradation was explored using a combination of experimental and numerical methods. Sectioned all-ceramic crown specimens were fabricated o...

AIM The aim of this clinical study was to compare the fracture resistance, marginal adaptation, and rate of recurrent caries of bonded and nonbonded amalgam restorations in endodontically treated premolar teeth. METHODS AND MATERIALS A total of 36 patients with endodontically treated maxillary first or second premolars were selected and divided into three groups. The treatments in all groups ...

BACKGROUND The anatomic shape of maxillary premolars show a tendency towards separation of their cusps during mastication after endodontic treatment. Preservation of the marginal ridge of endodontically treated and restored premolars can act as a strengthening factor and improve the fracture resistance. OBJECTIVES To evaluate the effect of varying thickness of marginal ridge on the fracture r...

OBJECTIVE In all ceramic fixed partial dentures the connector area is a common fracture location. The survival time of three-unit fixed partial dentures may be improved by altering the connector design in regions of maximum tension. The purpose of this study was to determine the effect of buccolingual increase of the connector width on the stress distribution in posterior fixed partial dentures...

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...