A randomized, parallel, examiner-blind clinical trial was conducted to compare two professionally dispensed vital bleaching systems. A total of 20 subjects were randomized to either the Crest Professional Whitestrips system or the Nite White Excel 2 tray system, balancing for baseline tooth color. During the 2-week treatment period, subjects were instructed to use the strip system for one-half ...

BACKGROUND Dakosaurus and Plesiosuchus are characteristic genera of aquatic, large-bodied, macrophagous metriorhynchid crocodylomorphs. Recent studies show that these genera were apex predators in marine ecosystems during the latter part of the Late Jurassic, with robust skulls and strong bite forces optimized for feeding on large prey. METHODOLOGY/PRINCIPAL FINDINGS Here we present comprehen...

This paper provides an insight into the efficiency and accuracy of a multibody approach to model gear transmission error. The is based on augmented Lagrangian contact formulation considering surface-to-surface detection. case spur helical gears transmitting power between parallel shafts considered. static error computed without any assumptions about lines positions orientations. Tooth wheel bod...

We establish a robust algorithm to analyze the influence of system uncertainties on transmission error spur gear pair under 2D simplification. The provides way generating smooth cutter profiles with machining and measuring thermal deformation through in material properties. Then, it produces realizations tooth based analytical method for accuracy computational efficiency. Numerical investigatio...

OBJECTIVE To determine the prevalence of tooth size discrepancies (TSDs) in an Irish orthodontic population among different malocclusion groups. MATERIALS AND METHODS From 850 pretreatment sets of orthodontic models at a university clinic, 240 were selected with 30 female and 30 male sets for each malocclusion (Class I, Class II division 1, Class II division 2, and Class III). Digital models ...

PURPOSE Articulation paper mark size is widely accepted as an indicator of forceful tooth contacts. However, mark size is indicative of contact location and surface area only, and does not quantify occlusal force. The purpose of this study is to determine if a relationship exists between the size of paper marks and the percentage of force applied to the same tooth. MATERIALS AND METHODS Thirt...

This article describes the use of three devices that replace the wax rims in the registration of the intermaxillary position and of the vertical dimension of occlusion in completely edentulous patients who have been treated with Brånemark implants. The devices consist of a mechanical "tooth" that can be adjusted in all three dimensions of space and of two plates that support the registration ma...

Damage to tooth root surfaces may occur during ultrasonic cleaning with both piezoelectric and magnetostrictive ultrasonic scalers. It is unclear which mechanism causes more damage or how their mechanism of action leads to such damage. Our null hypothesis is that tooth-surface defect dimensions, resulting from instrumentation with ultrasonic scalers, are independent of whether the scaler probe ...