Shape optimization for additive manufacturing of removable partial dentures - A new paradigm for prosthetic CAD/CAM

• Main Authors: Ahmad, R. (Author), Chen, J. (Author), Li, Q. (Author), Li, W. (Author), Sasaki, K. (Author), Suenaga, H. (Author), Swain, M. (Author)
• Format: Article
• Language: English
• Published: Public Library of Science 2015
• Subjects: adaptation; additive manufacturing; adult; algorithm; Article; bi directional evolutionary structural optimization; computer aided design; computer aided manufacturing; computer assisted tomography; Computer-Aided Design; contact pressure; controlled study; cost effectiveness analysis; denture design; Denture Design; denture modification; Denture, Partial, Removable; digital imaging; female; finite element analysis; human; Humans; hydrostatic pressure; in vitro study; in vivo study; integration; machine learning; mandible; Mandible; materials testing; Materials Testing; mathematical model; middle aged; minimal residual disease; Models, Molecular; molecular model; nanofabrication; outcome assessment; pain assessment; pathology; pressure; Pressure; pressure pain threshold; process design; process optimization; quantitative analysis; removable partial denture; residual ridge resorption; sensitivity analysis; shape optimization; simulation; soft tissue; tooth disease; tooth prosthesis
• Online Access: View Fulltext in Publisher; View in Scopus

 With ever-growing aging population and demand for denture treatments, pressure-induced mucosa lesion and residual ridge resorption remain main sources of clinical complications. Conventional denture design and fabrication are challenged for its labor and experience intensity, urgently necessitating an automatic procedure. This study aims to develop a fully automatic procedure enabling shape optimization and additive manufacturing of removable partial dentures (RPD), tomaximize the uniformity of contact pressure distribution on the mucosa, thereby reducing associated clinical complications. A 3D heterogeneous finite element (FE) model was constructed from CT scan, and the critical tissue of mucosa was modeled as a hyperelastic material from in vivo clinical data. A contact shape optimization algorithm was developed based on the bi-directional evolutionary structural optimization (BESO) technique. Both initial and optimized dentures were prototyped by 3D printing technology and evaluated with in vitro tests. Through the optimization, the peak contact pressure was reduced by 70%, and the uniformity was improved by 63%. In vitro tests verified the effectiveness of this procedure, and the hydrostatic pressure induced in the mucosa is well below clinical pressure-pain thresholds (PPT), potentially lessening risk of residual ridge resorption. This proposed computational optimization and additive fabrication procedure provides a novel method for fast denture design and adjustment at low cost, with quantitative guidelines and computer aided design and manufacturing (CAD/CAM) for a specific patient. The integration of digitalizedmodeling, computational optimization, and free-form fabrication enablesmore efficient clinical adaptation. The customized optimal denture design is expected to minimize pain/discomfort and potentially reduce long-term residual ridge resorption. Copyright: © 2015 Chen et al.