International Journal of Oral and Maxillofacial Surgery
Technical Note
Facial RehabilitationRapid development of auricular prosthesis using CAD and rapid prototyping technologies
Facial Rehabilitation
Section snippets
Background information
Reverse engineering or 3D digitizing14 can be used to capture the morphology of deficient and normal ears3, as well as casts made by impression[1], [10]. Some blind spots (undercuts) result in missing data patches and need to be manually ‘stitched’, but the latest CT/MRI systems combined with medical modelling software can yield correct anatomical details15, and have been successfully used for the ear region[5], [8]. CT-scan data is also useful for prosthesis positioning18, CNC machining11 and
Computer-aided prosthesis development
The procedure involves five steps: (i) CT-image data acquisition for deficient and contralateral ears, (ii) reconstruction of the corresponding 3D models using medical modelling software, (iii) design of the missing ear using a haptic CAD system, (iv) fabrication of prosthesis master using RP system and (v) fabrication of the final prosthesis using a mould made from the master (Fig. 2). The steps are described for the case of a patient (male, 19 years) with congenital absence of the right ear (
Discussion
This work demonstrated how high accuracy in morphology and positioning can be achieved by finer CT scanning (0.63 mm slice thickness) coupled with the reverse stacking approach (to mirror the contralateral normal ear), if there is reasonable facial symmetry presented by the patient, as in this case. The haptic CAD system eased the design (to match the morphology of the deficient side), and smoothing of the final auricular prosthesis model. The use of RP technology enabled accurate reproduction
Acknowledgements
We acknowledge the assistance of Dr. K. Balabsubramanian and Mr. Nirmal Panda of Non Ferrous materials Technology Development Centre, Hyderabad in 3D model reconstruction from CT scan data. We would like to thank Ms. Mona Sharma, IIT Bombay, for assisting in FreeForm modelling. We would like to thank Dr. K.P. Karunakaran, Indian Institute of Technology, Bombay, for allowing the use of the FDM RP system, and Dr. P.B. Joshi, Maharashtra Institute of Technology, Pune, for allowing the use of the
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