Page 478 - IJB-10-5

International Journal of Bioprinting 3D-printed post-otoplasty ear retainer

Figure 4. Results from mechanical tests performed at 37°. (A) Stress-strain curve from uniaxial tensile (UT; blue), equal biaxial tensile (BT; red), and
plane tensile (PT; green) tests, (B) stress-relaxation test at 5% (green) and 20% (red) strain, and (C) volumetric compression test of the resin sample.

Table 2. Stress, strain, and deformation of auricular skin soft tissue and the soft gel retainer.

Parameter Skin soft tissue Retainer
Contact stress (kPa) 291 394
Von Mises stress (kPa) 93 97
Minimum principal stress (kPa) 94 110
Von Mises strain 0.052 0.042
Displacement (mm) 0.31 (Compression deformation of the surrounding skin upon contact is 0.10~0.16)

(n = 19; 95%), followed by “adjustability” (n = 18; 80%), The discomfort from the retainer may be due to the
“weight” (n = 15; 75%), and “dimensions” (n = 17; 85%). Only over-fitness of the 3D-printing retainer, suggesting further
several participants were not satisfied with the retainer, mostly personalized optimization for each individual in future
attributed to “comfort” (n = 4; 20%). Two participants failed to designs. On the sixth day of evaluation, a patient expressed
finish the one-week experiment due to the retainer’s “weight” minor concerns about compliance, possibly due to the
and “discomfort,” respectively. These two patients cannot be varying sensitivity levels of different patients to the retainer.
evaluated for durability and effectiveness because they did None of the patients experienced pruritus after wearing
not consistently wear the retainer. These two patients did not the 3D-printed retainer, indicating that the material used
comment (denoted as N/A) on the retainer’s “durability” and has hypoallergenic properties after light-curing and post-
“effectiveness.” The two most reported answers were comfort processing and suggesting that the retainer is suitable for
(n = 4; 20%), simplicity of use (n = 3; 15%). long-term wearing.

Volume 10 Issue 5 (2024) 470 doi: 10.36922/ijb.3986