Color translation from monoscopic photogrammetry +ID Methodology into a Polyjet final 3D printed facial prosthesis

Abstract

Background: The artistic techniques necessary to fabricate facial prostheses mainly depend on individual skill and are not a resource easily reproduced. Digital technology has contributed to improved outcomes, often combining analog and new digital techniques in the same workflow. Methods: This article aims to present an innovative workflow to produce a final colored 3D printed and facial prosthesis by UV-map color translation into colored resin 3D printing. A modified +ID Methodology was used to obtain 3D models with the calibrated 3D printable patient's skin color. No hands-on physical molding, manual sculpture, or intrinsic silicone coloration was used. Results: The outcome resulted in acceptable aesthetics, adaptation, and an approximate color match after extrinsic coloration. The patient reported good comfort and acceptance. Conclusions: A direct resin 3D printed prosthesis may be a viable alternative, especially for rapid delivery as an immediate prosthesis or an option when there is no experienced anaplastogist to manufacture a conventional prosthesis.

Keywords: 3D printing; color; head and neck neoplasms; maxillofacial prosthesis; prosthesis design.

Figure 1.. Clinical delineation of the limits of the process is determined before 3D photogrammetry capture.

(Written informed consent for publication of the patient’s details and publication of the identifiable image in Figure 1 was obtained from the patient).

Figure 2.. Ideal coverage of the face of the patient in each capture is approximately 80% of total image without cutting off the ears; and, in Anterior-Posterior perspective, no nose tip cutting ensuring full facial data capture.

Appropriate focus is important to optimize data registration and to avoid blurry zones that may compromise the result. (Written informed consent for publication of the patient’s details and publication of the identifiable image in Figure 2 was obtained from the patient).

Figure 3.. Graphic of the suggested 39 photo captures suitable for photogrammetry, according to PlusID Methodology, for an extensive orbit case like the one presented in this article.

The angle between photo 1 and 13 has an angle of approximately 120 degrees with the point of interest to ensure accuracy beyond the frontal region of the face.

Figure 4.. 3D Model (OBJ+UVmap) of the face of our subject, obtained by the monoscopic photogrammetry feature from OrtogOnBlender after the alignment, scaling and after erasing external areas out of interest.

Notice that the delimitations of the prosthesis, decided and drawn clinically before the photo captures, were appropriately reproduced and will be helpful to transport the clinical needs of the 3D modeling tools. (Written informed consent for publication of the patient’s details and publication of the identifiable image in Figure 4 was obtained from the patient).

Figure 5.. The UV-Map resultant of the photogrammetry process.

This UV map wraps the 3D model (OBJ), aligned with the MTL in order to obtain full color aligned to the 3D geometry. (Written informed consent for publication of the patient’s details and publication of the identifiable image in Figure 5 was obtained from the patient).

Figure 6.. Mirroring of the healthy side of the face, sculpting tools, Boolean operations, and application of multiresolution and displacement modifiers resources were used to ensure the fit, adaptation and realistic skin detail reproduction.

The prosthesis looks gray because the UV-Map was hidden, allowing the mesh to be shown. (Written informed consent for publication of the patient’s details and publication of the identifiable image in Figure 6 was obtained from the patient).

Figure 7.. Visualization of the VRML file into GrabCad Print® software of Stratasys® suitable to communicate with the CMYKW color printing resources and with the approximation of color according to the loaded resins.

(Written informed consent for publication of the patient’s details and publication of the identifiable image in Figure 7 was obtained from the patient).

Figure 8.. (a) Perspective of the clean 3D full colored printed facial orbital prosthesis before arrangement on the patient.

Radika light cured translucent resin was applied on the eyeball structures to enhance the glaze effect. (b) Perspective of the clean 3D full color printed facial orbital prosthesis before arrangement on the patient. Radika light cured translucent resin was applied on the eyeball structure to enhance the glaze effect. (Written informed consent for publication of the patient’s details and publication of the identifiable image in Figure 8 was obtained from the patient).

Figure 9.. Visualization of the installed prosthesis on the patient, adhered by medical-grade prosthetic adhesive.

(Written informed consent for publication of the patient’s details and publication of the identifiable image in Figure 9 was obtained from the patient).