Biomedical subjects

Chi-Mun Cheah

Publications and source records attributed to Chi-Mun Cheah.

3 recordsLinked to original sources

PubMedDate not supplied

Automatic algorithm for generating complex polyhedral scaffold structures for tissue engineering.

In this article, an approach for tissue-engineering (TE) scaffold fabrication by way of integrating computer-based medical imaging, computer graphics, data manipulation techniques, computer-aided design (CAD), and rapid prototyping (RP) technologies is introduced. The aim is to provide a generic solution for the production of scaffolds that can potentially meet the diverse requirements of TE applications. In the work presented, a novel parametric library of open polyhedral unit cells is developed to assist the user in designing the microarchitecture of the scaffold according to the requirements of its final TE application. Once an open polyhedral unit cell design is selected and sized, a specially developed algorithm is employed to assemble the microarchitecture of the scaffold while adhering to the external geometry of the patient's anatomy generated from medical imaging data. RP fabrication techniques are then employed to build the scaffolds according to the CAD-generated designs. The combined application of such technologies promises unprecedented scaffold qualities with spatially and anatomically accurate three-dimensional forms as well as highly consistent and reproducible microarchitectures. The integrated system also has great potential in providing new cost-effective and rapid solutions to customized made-to-order TE scaffold production.

Algorithms↗

PubMedDate not supplied

Integration of laser surface digitizing with CAD/CAM techniques for developing facial prostheses. Part 1: Design and fabrication of prosthesis replicas.

PURPOSE: This article presents a novel manufacturing approach that integrates laser surface digitizing/scanning and computer-aided design (CAD) and manufacturing (CAM) to achieve automated fabrication of spatially and anatomically accurate extraoral facial prostheses. MATERIALS AND METHODS: Topologic data of the patient's face, including the site of deformity and the anatomy of a healthy "donor" organ, were acquired using laser surface digitizing. Two different CAD data manipulation techniques were developed to alleviate problems encountered in laser-digitized data sets. To reduce patient involvement, fitting of the prosthesis was conducted using a computer model of the patient's face. Once finalized, rapid prototyping techniques were employed to fabricate a master pattern to cast the final prosthesis. RESULTS: Three case studies involving different facial prostheses were conducted to evaluate the integrated manufacturing system. The results demonstrated the many advantages of the system for facial prosthesis production. CONCLUSION: With the new manufacturing approach, reduced patient discomfort, minimal dependence on the artistic skills of the prosthetist, and short turnaround times for prosthesis production can be expected.

Computer Simulation↗

PubMedDate not supplied

Integration of laser surface digitizing with CAD/CAM techniques for developing facial prostheses. Part 2: Development of molding techniques for casting prosthetic parts.

PURPOSE: This article presents a novel manufacturing approach that integrates laser surface digitizing/scanning and computer-aided design and manufacturing (CAD/CAM) to achieve automated fabrication of spatially and anatomically accurate extraoral facial prostheses. MATERIALS AND METHODS: Contrary to the approach in part 1 for fabricating positive replicas of prostheses, the approaches presented here are focused on designing and producing negative molds of the final prostheses using CAD, rapid prototyping, and rapid tooling techniques. The molds were applied directly to cast the final prostheses, thereby eliminating conventional flasking and investing procedures. RESULTS: Three different facial prostheses were produced to evaluate the proposed approach for prosthesis production. The advantages of this alternative manufacturing approach over the approach presented in part 1 and conventional techniques are discussed. The limitations encountered with the integrated manufacturing system are highlighted. CONCLUSION: With the new techniques, reduced patient discomfort, minimal dependence on the artistic skills of the prosthetist, and short turnaround times for prosthesis production can be expected.

Biocompatible Materials↗