Simulation of tissue-prosthesis margin interface by using surface scanning and digital design for auricular prostheses. L McHutchion, D Aalto.

Date: April 2020 (Online).
Source: The Journal of Prosthetic Dentistry. Presented at seventh Biennial Congress of the Advanced Digital Technology in Head and Neck Reconstruction Foundation in Tokyo, Japan (June 22, 2019).
Statement of problem: One of the most challenging aspects of auricular prosthesis design and fabrication is ensuring that the prosthesis fits the patient through a range of head and facial movements. Techniques used in conventional prosthetic treatment pathways account for issues of prosthesis fit, but this challenge has not been fully addressed in emerging treatment pathways that use digital technology.
Objective: The purpose of this clinical study was to develop and evaluate a digital workflow by using surface scan data and incorporating the simulation of tissue movement into the design of auricular prostheses that fit the participant through a range of facial movements. An iterative design process was used to develop a design workflow through a sequential case series of participants with auricular prostheses.
Materials and Methods: Scan data were acquired from a case series of 5 participants with existing implant-retained auricular prostheses. An iterative design process was used to digitally design auricular prostheses that fit the participants through a range of jaw and facial movements. The fit, shape, and retention of the digitally designed and conventionally made prostheses were assessed and compared. Design considerations were identified and documented through the iterative design process.
Results: A final design workflow was iteratively developed based on the 5 participants. The shapes of the digitally designed prostheses were well matched to nontreatment anatomy overall. Prosthesis fit was variable: Some digitally designed prostheses fit the participant intimately through a range of movements, and others experienced significant gaps between the margins and the tissues.
Conclusions: An iterative design process provided a method of working toward quality improvement. Although the final design workflow provides a generally successful method of manipulating scan data in the design of auricular prostheses, the prosthesis fit at the anterior margin during facial movements remains variable and requires further development to achieve a consistently acceptable solution.

Article: Simulation of tissue-prosthesis margin interface by using surface scanning and digital design for auricular prostheses.
Authors: Lindsay McHutchion BSc, MS, Daniel Aalto PhD. Institute for Reconstructive Sciences in Medicine, Edmonton, Canada