Gross anatomic, histologic and ultrastructural studies were made on 32 floppy aortic valves (FAVs) resected at the time of aortic valvular replacement for aortic regurgitation. Patients with the FAVs had relatively long clinical courses and had severe aortic regurgitation with mild symptoms of heart failure. The sizes of the mechanical valves implanted in the patients with FAVs were not large, ...

Aging and the related changes in mechanical behavior of hard tissues of the human body are becoming increasingly important. In this study the influence of aging on the mechanical behavior of human enamel was evaluated using 3rd molars from young (18 < or = age < or = 30 years) and old (55 < or = age) patients. The hardness and elastic modulus were quantified using nanoindentation as a function ...

OBJECTIVES To compare re-treatment choices for MOD amalgam or resin composite restorations with or without cusp fracture among dentists in Kuwait. METHODS A random sample of 158 dentists completed a questionnaire designed to obtain socio-demographic, educational and work-related information and their choices for re-treatment of four scenarios of failed restorations on lower first molars: 1. M...

We have formulated the first constitutive model to describe the complete measured planar biaxial stress-strain relationship of the native and glutaraldehyde-treated aortic valve cusp using a structurally guided approach. When applied to native, zero-pressure fixed, and low-pressure fixed cusps, only three parameters were needed to simulate fully the highly anisotropic, and nonlinear in-plane bi...

OBJECTIVES Direct composite restorations are increasingly popular and a flowable bulk-fill base material (SDR, Dentsply) claims to minimise stress through a more flexible polymerisation process. This retrospective audit of restorations placed in general practice compares SDR based restorations with conventional composite restorations. METHODS Restorations were all placed by one operator using...

Quantitative studies of incremental markings retained within human enamel have reconstructed the duration and rate (crown and cusp formation times, initiation and completion, daily enamel secretion rates) of permanent tooth development. This approach has provided one way of estimating human age-at-death, and facilitated comparative dental studies of primate evolution. Similar applications from ...