Jin Sun, Yaoyang Xiong, Xiaobo Chen and Juntong Xi
The purpose of this paper is to propose an imperfect symmetry transform framework for orbital prosthesis modelling.
Abstract
Purpose
The purpose of this paper is to propose an imperfect symmetry transform framework for orbital prosthesis modelling.
Design/methodology/approach
Current models of patients with orbital defects have imperfect symmetries. Commonly used methods, such as principal component analysis (PCA) or iterative closest points algorithm (ICP), do not detect perfect symmetries and therefore produce poor results. The authors propose an improved ICP algorithm based on the M‐estimator, which can remove outliers from the optimization and detect incorrect symmetry. Using this algorithm, the mid‐facial plane of a patient's facial model can be precisely obtained despite perturbation of the facial shape due to the defect.
Findings
The results showed that the orbital prosthesis fitted well to the patient's appearance. Clinical applications confirmed that this framework is attractive and has the potential for use in creating desired orbital prostheses or other bilateral maxillofacial prostheses in daily clinical practice.
Practical implications
The method described in this report will improve the fabrication accuracy of orbital prostheses or other bilateral maxillofacial prostheses.
Originality/value
This imperfect symmetry transform framework has great potential for use in clinical applications because of its advantages over other existing methods in terms of accuracy.
Details
Keywords
Jin Sun, Juntong Xi, Xiaobo Chen and Yaoyang Xiong
The purpose of this paper is to describe a computer‐aided design/manufacturing (CAD/CAM) system for fabricating facial prostheses.
Abstract
Purpose
The purpose of this paper is to describe a computer‐aided design/manufacturing (CAD/CAM) system for fabricating facial prostheses.
Design/methodology/approach
The CAD/CAM system can be used for fabricating custom‐made facial prostheses with symmetrical or asymmetrical features. This system integrates non‐contact structured light scanning, reverse engineering and rapid prototyping manufacturing technology. Fringe projection based on the combination of the phase‐shift and grey‐code methods is used for data collection. A robust approach is proposed to calculate the mid‐plane of the human face without any knowledge of the centroid position or the principal axis in data processing.
Findings
Results show that the proposed method increases the fabrication accuracy and reduces the operating time. Patients were satisfied with the rehabilitation results as the custom‐made facial prostheses fitted them well.
Practical implications
This study improves the fabrication accuracy of facial prostheses. Three‐dimensional data of the facial surface of a patient needing a facial prosthesis were obtained with almost no harm to his body; after a series of robust processes, a precise and suitable aesthetic facial prosthesis was fabricated.
Originality/value
This system has bright prospects for clinical application because of its advantages over other methods in terms of speed, accuracy, safety, cost, etc.