Page 128 - MSAM-4-2

Materials Science in Additive Manufacturing Mouthguards: Disinfection versus properties changes

A

B

C

D

Figure 2. Multi-material parts after 3D printing, using high-impact polystyrene and thermoplastic polyurethane (TPU)—(A) bi-layered and (B) tri-layered
configurations; and poly(methyl methacrylate) and TPU—(C) bi-layered and (D) tri-layered configurations. Scale bars: 10 mm

Figure 3. Schematic representation of the disinfection methodology applied to the 3D-printed surfaces

Table 3. Printing parameters of the 3D‑printed specimens and incubated at 37℃ for 1 h. They were then subjected to
one of the two disinfection methods. After disinfection, the
Configuration Arrangement Tbed Filament Tprinting specimens were incubated at 37℃ for an additional 24 h
(℃) (℃)
Tri-layered PMMA-TPU-PMMA 90 TPU 230 to promote bacterial colony growth. CFUs were counted
at the end of this incubation period. Non-disinfected
configuration PMMA 240 specimens served as controls. The disinfection effectiveness
HIPS-TPU-HIPS 90 TPU 230 was determined by comparing the CFU counts between
HIPS 240 disinfected and control groups.
Bi-layered TPU-PMMA 40 TPU 230
configuration PMMA 240 2.5. Post-processing characterization
2.5.1. Mechanical characterization
TPU-HIPS 40 TPU 230
HIPS 240 To evaluate the flexural mechanical properties of the
Notes: Tbed: Bed temperature; Tprinting: Printing temperature. multi-material specimens (60 × 10 × 2 mm³), a three-
Abbreviations: HIPS: High-impact polystyrene; PMMA: Poly (methyl point bending test was conducted using a Shimadzu
methacrylate); TPU: Thermoplastic polyurethane. Autograph AGS-X Universal Testing Machine (Shimadzu,
Japan) equipped with a 5 kN load cell, operating at a test
immersion for 5 min) or physical (irradiated with UVC speed of 2 mm/min. Flexural strength (σ ) and flexural
light for 45 min) disinfection. modulus (E) were determined for each configuration and
f
f
To simulate mouthguard contamination during use, treatment condition following the ASTM D790 standard
8
specimens were first inoculated with S. aureus (~10 cells/mL) recommendations. 34

Volume 4 Issue 2 (2025) 5 doi: 10.36922/MSAM025130018