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

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.

Perturbation Measurements on the Degree of Naturalness of Synthesized Vowels.

OBJECTIVE: To determine the impact of jitter and shimmer on the degree of naturalness perception of synthesized vowels produced by acoustical simulation with glottal pulses (GP) and with solid model of the vocal tract (SMVT). STUDY DESIGN: Prospective study. METHODS: Synthesized vowels were produced in three steps: 1. Eighty GP were developed (20 with jitter, 20 with shimmer, 20 with jitter+shimmer, 20 without perturbation); 2. A SMVT was produced based on magnetic resonance imaging (MRI) from a woman during phonation-/ε/ and using rapid prototyping technology; 3. Acoustic simulations were performed to obtain eighty synthesized vowels-/ε /. Two experiments were performed. First Experiment: three judges rated 120 vowels (20 humans+80 synthesized+20% repetition) as "human" or "synthesized". Second Experiment: twenty PowerPoint slide sequences were created. Each slide had 4 synthesized vowels produced with the four perturbation condition. Evaluators were asked to rate the vowels from the most natural to the most artificial. RESULTS: First Experiment: all the human vowels were classified as human; 27 out of eighty synthesized vowels were rated as human, 15 of those were produced with jitter+shimmer, 10 with jitter, 2 without perturbation and none with shimmer. Second Experiment: Vowels produced with jitter+shimmer were considered as the most natural. Vowels with shimmer and without perturbation were considered as the most artificial. CONCLUSIONS: The association of jitter and shimmer increased the degree of naturalness of synthesized vowels. Acoustic simulations performed with GP and using SMVT demonstrated a possible method to test the effect of the perturbation measurements on synthesized voices.

Analysis of Mandibular Test Specimens Used to Assess a Bone Fixation System.

The aim of this study was to assess through biomechanical testing if different synthetic materials used to fabricate test specimens have a different biomechanical behavior in comparison with other materials when simulating in vitro load resistance of a fixation method established for sagittal split ramus osteotomy (SSRO). Thirty synthetic and standardized human hemimandible replicas with SSRO were divided into three groups of 10 samples each. Group A-ABS plastic; Group B-polyamide; and Group C-polyurethane. These were fixated with three bicortical position screws (16 mm in length, 2.0-mm system) in an inverted l pattern using perforation guide and 5-mm advancement. Each sample was submitted to linear vertical load, and load strength values were recorded at 1, 3, 5, 7, and 10 mm of displacement. The means and standard deviation were compared using the analysis of variance (p < 0.05) and the Tukey test. A tendency for lower values was observed in Group B in comparison with Groups A and C. At 3 and 5 mm of displacement, a difference between Groups A and C was found in comparison with Group B (p < 0.05). At 7 and 10 mm of displacement, a difference was found among the three groups, in which Group C showed the highest values and Group B the lowest (p < 0.05). Taking into consideration the results obtained and the behavior of each material used as a substrate, significant differences occurred among the materials when compared among them.

Dimensional error in selective laser sintering and 3D-printing of models for craniomaxillary anatomy reconstruction.

BACKGROUND: Selective laser sintering (SLS) and three-dimensional printing (3DPtrade mark) are rapid prototyping (RP) techniques to fabricate prototypes from biomedical images. To be used in maxillofacial surgery, these models must accurately reproduce the craniofacial skeleton. PURPOSE: To analyze the capacity of SLS and 3DPtrade mark models to reproduce craniomaxillary anatomy and their dimensional error. MATERIAL: Dry skull, helical computed-tomography images, SLS and 3DPtrade mark prototypes, and electronic calliper. METHODS: Tomographic images of a dry skull were manipulated with the InVesalius biomedical software. Prototypes were fabricated using SLS and 3DPtrade mark techniques. Ten linear measurements were made on the models and compared with corresponding dry skull measurements (criterion standard) carried out with an electronic calliper. RESULTS: We observed a dimensional error of 2.10 and 2.67% for SLS and 3DPtrade mark models, respectively. The models satisfactorily reproduced anatomic details, except for thin bones, small foramina and acute bone projections. The SLS prototypes showed greater dimensional precision and reproduced craniomaxillary anatomy more accurately than the 3DPtrade mark models. CONCLUSION: Both SLS and 3DPtrade mark models provided acceptable precision and may be useful aids in most maxillofacial surgeries.