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Tooth whitening has become a mainstream treatment, especially in the US, and is overall regarded as safe. However, there are still several side-effects associated to it; the most commonly reported being hypersensitivity (and resulting pain). The sensitivity related to tooth whitening is generally mild and transient, occurs early in the treatment, and usually decreases as treatment continues with cessationshortly after the treatment ends. This document is a literature review on the subject of tooth whitening induced sensitivity and presents the major hypotheses for the etiologies of this side-effect, and provides an overview of the possible solutions .

Tooth whitening using hydrogen peroxide gel formulation is a complexprocess which involves both chemistry and physics, and there is still some controversy about the efficiency of whitening processes, particularly with respect to the roles of temperature and irradiation with light. In this work we avoid the complications of the physics bystudying the basic interactions between whitening agents and stainmolecules in simple solutions. We demonstrate that blue light irradiation has a clear and large impact on the whitening process, and that IR irradiation serves only to increase the temperature. While raising the temperature can give a slight improvement to stain removal,it can easily lead to inefficiency through the acceleration of exothermic decomposition reactions.

Source-gated transistors (SGTs) have potentially very high output impedance and low saturation voltages, which make them ideal as building blocks for high performance analog circuits fabricated in thin-film technologies. The quality of the saturation is greatly influenced by the design of the field-relief structure incorporated into the source electrode. Starting from measurements on self-aligned polysilicon structures, we show through numerical simulations how the field plate design can be improved. A simple source field plate around 1μm long situated several tens of nm above the semiconductor can increase the low-voltage intrinsic gain by more than two orders of magnitude and offers adequate tolerance to process variations in a moderately scaled thin-film SGT.

Integrated, flat-panel lighting systems require high efficiency linear drivers which are stable under electrical stress and candeliver uniform performance across a large area. Owing to their lowsaturation voltage and flat saturation characteristic, source-gatedtransistors (SGTs) are ideally suited to act as power-efficient driving transistors in active matrix backplanes for lighting, low-powersignage and display screens. It is shown that SGTs are also very stable during electrical stress. The technology is compatible with standard TFT fabrication allowing FET and SGT devices to be integratedin the same design and fabrication run.

We report a split gate concept to enhance the performance of TrenchSuper Junction Thin Film Transistors (Trench SJ-HVTFT) fabricated inLow temperature Poly-silicon (LTPS) technology. Biasing the controland trench gates independently, breakdown voltages can be enhancedby 25 % while reducing the area specific on-state resistance by 13%.This technology enables incorporation of high voltage power conversion circuitry as well low voltage devices for embedded power management in displays and Lab on Chip applications.