Background: Facial impression methods have been used to fabricate auricular prostheses; however, deformation due to the weight of the impression material remains. This study aimed to investigate the accuracy of auricular three-dimensional (3D) data obtained using a 3D optical extraoral scanner and an intraoral scanner compared with that of a conventional facial impression method. Methods: Six auricles were digitized using an extraoral scanner with and without a reference board around the auricle and an intraoral scanner. Auricle casts fabricated using auricle impressions were scanned using a laboratory scanner. All obtained data were superimposed, and the 3D deformations of the different methods were evaluated using measurement mapping and root mean square (RMS) values. The length, width, and height of the auricular casts and scanned data were measured and compared with the sizes of the original auricles measured using a caliper. Results: Large displacements of the back and margins of the ears were observed, and the RMS values ranged from 0.5–2.4 mm. Larger widths and smaller heights of the scanned and impression data were observed compared to the anthropometric ear data. Conclusions: The study concluded that the fabrication of auricular prostheses using optical scanning is clinically acceptable. All examined scanning techniques demonstrated discrepancies within acceptable limits when compared to the conventional facial impression method.

Unreasonable medical fees can cause problems such as increased medical costs, greater medical disparities, decreased medical standards, and physician shortages. To prevent such problems, it is important to set appropriate medical fees, ensure their proper use, and improve the efficiency of medical care. The treatment of patients with maxillofacial defects is generally more expensive compared with general prosthodontic treatment because it involves more materials and requires more frequently follow-ups for longer period. However, the actual time required for maxillofacial prosthetic treatment is unclear. Therefore, in this study, we aimed to clarify the amount of time spent treating maxillofacial prosthetic patients. We analyzed clinical data from patients undergoing routine maxillofacial prosthetic treatment, irrespective of difficulty level, at 8 university hospitals and 2 dental clinics. We also collected data from maxillofacial prosthodontists on the treatment time required for various Japanese health insurance items, including the fabrication of maxillofacial prostheses. The results revealed that some aspects of maxillofacial prosthetic treatment may take longer to perform and are more costly to perform than previously thought, suggesting the need for some adjustments to the health insurance reimbursement system. Maintaining an appropriate balance between expenditures and fees will greatly benefit patients and physicians, ensuring positive health outcomes and a healthy society.

Air entrapment during silicone mixing and processing can result in porosities in maxillofacial prostheses, compromising esthetics, mechanical properties, and hygiene. However, the combined effects of mixing method, thixotropic agent (TA), and polymerization pressure on the presence of porosities have not been fully clarified. The purpose of the present study was to evaluate the effects of polymerization pressure, mixing method, and TA amount on the pore formation of a facial silicone material. Cylindrical silicone specimens (N=96) were fabricated using 2 mixing methods (manual or mechanical), 4 TA levels (0, 1, 2, 3 drops), and 2 polymerization conditions (with or without pressure). Porosity, pore number, and maximum pore diameter were measured by using microcomputed tomography. Data were analyzed with 3-way analysis of variance (α=.05). Pressurization markedly reduced the porosity and pore number, regardless of the mixing method or TA amount (P<.001). Without pressure, mechanical mixing produced significantly fewer pores than manual mixing (P<.001). In manual mixing without pressure, adding TA decreased the pore number but increased the maximum pore diameter. No significant effect of TA was observed with mechanical mixing (P=.102). Polymerization under pressure was the most effective method of minimizing porosities. In situations where pressure cannot be applied, mechanical or manual mixing with limited TA can reduce pore incorporation in silicone prostheses.