Piezoelectric Teeth Aligners for Accelerated Orthodontics

In this paper, a new prototype is proposed for accelerated orthodontic tooth treatment. In contrast to conventional methods, where heavy vibration generators are used, the proposed design is light and small and may remain into patient’s mouth without obstructing his daily activities. To do that, a PVDF Piezoelectric actuator layer is incorporated into a bio-compatible flexible structure which is to be excited by an external electric source. Generally, application of cyclic loading (vibration) reverses bone loss, stimulates bone mass, induces cranial growth, and accelerates tooth movement. This reduce the pain experience and discomfort associated with the treatment and also enhances the patient compliance with the treatment. Vibration has the advantage of minimal side effects in comparison to medicinal treatments. This configuration enables the operator to adjust the vibration frequency as well as the orthodontic force exerted on the tooth.

Performance of a short piezoelectric fiber–reinforced composite actuator in vibration control of functionally graded circular cylindrical shell

For improved flexibility and conformability of piezoelectric fiber–reinforced composite actuator, it is reconstructed in a recent study by the use of short piezoelectric fibers (short piezoelectric fiber–reinforced composite) instead of continuous fibers (continuous piezoelectric fiber–reinforced composite). This modification facilitates its application in short piezoelectric fiber–reinforced composite layer form instead of continuous piezoelectric fiber–reinforced composite patch form particularly in case of host structures with highly curved boundary surfaces. But the corresponding change in actuation capability is a major issue for potential application of short piezoelectric fiber–reinforced composite that is studied in this work through the control of vibration of a functionally graded circular cylindrical shell under thermal environment. First, an arrangement of continuous piezoelectric fiber–reinforced composite actuator patches over the host shell surface is presented with an objective of controlling all modes of vibration. Next, the use of short piezoelectric fiber–reinforced composite actuator layer for similar control activity is demonstrated through an arrangement of electrode patches over its surfaces. Subsequently, an electric potential function is assumed for the consideration of electrode patches and a geometrically nonlinear coupled thermo-electro-mechanical incremental finite element model of the harmonically excited overall functionally graded shell is developed. The numerical results reveal actuation capability of short piezoelectric fiber–reinforced composite actuator layer with reference to that of the existing continuous piezoelectric fiber–reinforced composite/monolithic piezoelectric actuator patches. The effects of temperature, size of electrode patches, properties of piezoelectric fiber–reinforced composite, and functionally graded properties on the control activity of short piezoelectric fiber–reinforced composite/continuous piezoelectric fiber–reinforced composite actuator are also presented.

Design and Fabrication of Changeable Cell Culture Mold

Although the fabrication of engineered organs as replacements for damaged organs has been widely studied over the past decade, practical fabrication is very difficult because the engineered organ usually has a very complex structure and cannot be fabricated simply by using a fixed scaffold. Special attention has therefore been paid to methods of making engineered organs by assembling composite parts. Since structures of these individual parts are very different, fabrication using fixed scaffolds requires a lot of effort and time. The concept of a changeable scaffold offered by “changeable cell culture (C3) mold” is proposed in this paper as a means to simplify the fabrication of these parts. Using a thin PDMS membrane as an actuator layer enables various scaffold structures to be formed and altered, in turn enabling the fabrication of many different tissue structures.C3mold consists of a 3 × 3 microactuator array with a diameter of 500 µm and spacing of 650 µm. Plant oil is used as the working fluid enabling deformation of the actuator layer. Various micropatterned gel sheets are fabricated, in order to demonstrate the possibility of usingC3molds in future tissue fabrication.