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How to Sterilize 3D Printed Objects for Surgical Use? An Evaluation of the Volumetric Deformation of 3D-Printed Genioplasty Guide in PLA and PETG after Sterilization by Low-Temperature Hydrogen Peroxide Gas Plasma

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Introduction In the present time, there is rapid development in the application of 3D printing technology in surgery. One of the challenges encountered by the surgeon is the sterilization of these 3D-printed objects for use in the operating room. Materials and Methods Forty-two identical cutting guides used for genioplasty were 3D-printed: twenty-one in Polylactic acid (PLA) and twenty-one in Polyethylene terephthalate glycol (PETG). The guides were CT scanned after printing. They were then sterilized with the low-temperature hydrogen peroxide gas plasma technique (Sterrad®). A CT scan of the guides was also performed at T1 (after printing) and T2 (after sterilization). A software (Cloudcompare ®) was then used to accurately compare the volume of each guide at T0 (the initial computer-aided designed guide) vs T1 and T1 vs T2. Statistical analysis was then performed. Results Although there are differences that are statistically significant for each series between T0 and T2 and T1 and T2 for both PLA and PETG, this had no impact on the clinical use of sterilized objects using hydrogen peroxide sterilization technique because these morphological differences were minimal at less than 0.2mm. Conclusion Morphological deformations induced by the hydrogen peroxide sterilization are sub-millimeter and acceptable for surgical use. The hydrogen peroxide sterilization is, therefore, an alternative to avoid the deformation of 3D-printed objects made from PLA and PETG during conventional steam sterilization (autoclave). To the best of our knowledge, this is the first study regarding the morphologic deformation of 3D-printed objects in PLA and PETG after sterilization for medical use.
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DOI: 10.2174/1874210601913010410, 2019, 13, 410-417
The Open Dentistry Journal
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RESEARCH ARTICLE
How to Sterilize 3D Printed Objects for Surgical Use? An Evaluation of the
Volumetric Deformation of 3D-Printed Genioplasty Guide in PLA and PETG
after Sterilization by Low-Temperature Hydrogen Peroxide Gas Plasma
Olivier Oth1,*, César Dauchot1, Maria Orellana1 and Régine Glineur1
1Department of Oral and Maxillofacial Surgery, Hôpital Erasme, Université Libre de Bruxelles, Route de Lennik 808, 1070, Brussels, Belgium
Abstract:
Introduction:
In the present time, there is rapid development in the application of 3D printing technology in surgery. One of the challenges encountered by the
surgeon is the sterilization of these 3D-printed objects for use in the operating room.
Materials and Methods:
Forty-two identical cutting guides used for genioplasty were 3D-printed: twenty-one in Polylactic acid (PLA) and twenty-one in Polyethylene
terephthalate glycol (PETG). The guides were CT scanned after printing. They were then sterilized with the low-temperature hydrogen peroxide
gas plasma technique (Sterrad®). A CT scan of the guides was also performed at T1 (after printing) and T2 (after sterilization). A software
(Cloudcompare ®) was then used to accurately compare the volume of each guide at T0 (the initial computer-aided designed guide) vs T1 and T1
vs T2. Statistical analysis was then performed.
Results:
Although there are differences that are statistically significant for each series between T0 and T2 and T1 and T2 for both PLA and PETG, this had
no impact on the clinical use of sterilized objects using hydrogen peroxide sterilization technique because these morphological differences were
minimal at less than 0.2mm.
Conclusion:
Morphological deformations induced by the hydrogen peroxide sterilization are sub-millimeter and acceptable for surgical use. The hydrogen
peroxide sterilization is, therefore, an alternative to avoid the deformation of 3D-printed objects made from PLA and PETG during conventional
steam sterilization (autoclave). To the best of our knowledge, this is the first study regarding the morphologic deformation of 3D-printed objects in
PLA and PETG after sterilization for medical use.
Keywords: 3D printing, CADCAM, Additive manufacturing, Fused deposition modelling, Maxillofacial surgery, Orthognathic surgery,
Genioplasty, Polylactic acid, PLA, PETG, Polyethylene terephthalate glycol, Sterilization, Hydrogen peroxide gas plasma, Sterrad sterilization
system.
Article History Received: June 11, 2019 Revised: August 26, 2019 Accepted: October 20, 2019
1. INTRODUCTION
In the present time, there is a surge in the use of 3D
printing technology in surgery, especially in the area of cranio-
maxillofacial surgery. 3D printing, also known as rapid
prototyping and/or additive manufacturing, is becoming a
significant tool in maxillo facial surgery [1].
* Address correspondence to this author at the Department of Oral and
Maxillofacial Surgery, Hôpital Erasme, Université Libre de Bruxelles, Route de
Lennik 808, 1070, Brussels, Belgium: Tel: +32/2.555.31.11;
E-mail: oth.olivier@gmail.com
Examples of applications of 3D printing in cranio-maxillo-
facial surgery are: anatomical models for teaching purposes,
intraoperative visualization of the anatomical structures, anato-
mical models using the mirroring technique for pre-bending of
osteosynthesis material, and surgical guides used intra opera-
tively in implantology, orthognathic surgery, oncologic, and
reconstructive maxillofacial surgery.
There are two possibilities for a surgeon to use 3D printing
technologies in practice: Either to call upon outside firms to
deal with design and 3D printing, or to understand the design
How to Sterilize 3D Printed Objects for Surgical Use? The Open Dentistry Journal, 2019, Volume 13 411
and 3D printing within its hospital institution, aka “in-house
printing”, or “point of care manufacturing”. In both cases, the
surgeon is faced with the problem of sterilization of 3D-printed
objects, which is mandatory for their use in the operating room.
Sterilization can be performed by 2 types of recognized
methods [2]: 1) Thermal sterilization by dry heat or steam, aka
moist heat sterilization or autoclave; 2) Low-temperature
sterilization: chemical (with ethylene oxide or hydrogen
peroxide for example), or with radiation (ionizing or UV).
Our in-house 3D-printing medical department used a Fused
Deposition Modeling (FDM) 3D-printer. Thermoplastic
polymers are the most ideal printing materials for additive
manufacturing processes, such as FDM due to their low
melting temperature [3]. The problem with plastic bio-
materials such as Polylactic Acid (PLA) and Polyethylene
Terephthalate Glycol (PETG) is that they are sensitive to
conventional thermal steam sterilization techniques, including
the temperature of 121 degree Celsius and above with high
rates of humidity). These materials are deformed with this type
of sterilization.
Thermal sterilization by dry heat is no longer authorized in
the European Union. Ultraviolet light sterilization is a method
of sterilization based on the sensitivity of microorganisms to
get exposed to low wavelengths of ultraviolet light. This
method is used in research laboratories to prepare sterile
worktops, for the preservation of food, or the purification of air
or water. Ionizing radiation is used by medical equipment
companies and food decontamination [4]. The materials are
packaged and stored in a shipping container that is gamma
irradiated. Therefore, this method is not suitable for a 3D
printing laboratory in a healthcare institute.
Ethylene oxide leads to changes in the polymer structures,
provokes molecular weight loss and creates a toxic deposit on
the surface of the object. Ethylene oxide sterilization is thus not
recommended for PLA or PETG [5].
For all these reasons, the study was focused on hydrogen
peroxide low-temperature sterilization. This sterilization tech-
nique exploits the synergism between peroxide and low temp-
erature gas plasma to rapidly destroy microorganisms [6]. At
the completion of this sterilization process, no toxic residues
remain on the sterilized items. The technology is known to be
particularly suited to the sterilization of heat and moisture
sensitive instruments since process temperatures do not exceed
about 50°C and sterilization occurs in a low moisture environ-
ment. The efficacy of the process has been demonstrated
against a broad spectrum of microorganisms. This method has
advantages over ethylene oxide including sterilization of
safety, ease of maintenance and no requirement for aeration
time [7].
Many articles can be found related to the applications of
3D-printed devices in medicine, yet very few of them fully
describe the technique of disinfection/sterilization. Only two
articles were found focusing on the sterilization of 3D printed
objects [8, 9].
The referenced object chosen for this study is a cutting
guide used in orthognathic surgery to perform genioplasty.
Genioplasty is a widely used surgical technique to correct chin
deformity. It consists of an osteotomy of the inferior border of
the mandible allowing movement of the chin in three dimen-
sions and positioning it in its new desired position [10]. This
guide can aid the surgeon in not touching the surrounding
noble anatomical structures (dental roots, inferior alveolar
nerve) and guide his surgical gesture as he performs this
osteotomy.
The aim of this study was to investigate the morphological
effect of the hydrogen peroxide low-temperature sterilization
on surgical objects that are 3D-printed in PLA and PETG. The
reference object chosen for this study is a cutting-edge guide
used in orthognathic surgery to perform genioplasty. Genio-
plasty is a widely used surgical technique to correct chin
deformity.
2. METHODS
To investigate the effect of hydrogen peroxide, low-
temperature sterilization on surgical objects 3D-printed in PLA
and PETG, the following study was designed.
2.1. 3D Printing Process
The surgical guides are designed in the maxillofacial
department, with a protocol developed and optimized for
several years. Two series of 21 identical guides were printed:
one series was printed in PLA (makerbot® PLA filament 1.75
mm), and the other in PETG (taulman® 3D guidel!ne® filament
1.75 mm).
The 3D printer model is a Replicator+® (Makerbot Indus-
tries®, New York, USA) operating on the principle of additive
technology, Fused Deposit Modelling. Table 1 shows the
parameters of the 3D-printer used for each material. Table 2
shows the physical properties of the solidified form of PLA and
PETG.
Table 1. Range of process parameters of the 3D printer for PLA and PETG.
Parameters Range for PLA Parameters Range for PETG
Layer thickness (mm) 0.1 mm Layer thickness (mm) 0.3 mm
Nozzle diameter (mm) 0,5 mm Nozzle diameter (mm) 0,5 mm
Part Bed temperature (°C) not heated room temperature (15-25) Part Bed temperature (°C) not heated room temperature (15-25)
Extruder head speed 150 mm/sec Extruder head speed 150 mm/sec
Temperature of extruder (°C) 215 Temperature of extruder (°C) 215
412 The Open Dentistry Journal, 2019, Volume 13 Oth et al.
Table 2. Physical properties of solidified PLA and PETG.
Parameters Value of solidified PLA Parameters Value of solidified PETG
Grade 4043D Grade not available
Density (g/cm3) 1.24 Density (g/cm3) 1.27
Glass Transition Temperature (°C) 60 Glass Transition Temperature (°C) 77
Melting point (°C) 160 Melting point (°C) 100
2.2. Sterilization Process
STERRAD® 100S (Johnson & Johnson® company), a low-
temperature hydrogen peroxide sterilizer, with one short cycle
of 50 minutes with temperature always lower than 55 °C was
used to sterilize the guides.
2.3. Comparison and Validation Process: Morphological
Analysis
The morphology of the guide was compared 3 times: T0 =
the guide computer-designed in 3D before 3D printing (STL
file); T1 = the guide after 3D printing and before sterilization;
T2 = the guide after 3D printing and after low-temperature
hydrogen peroxide sterilization.
Before sterilization (T1), each series of guides in PLA and
PETG were scanned with a CT-scanner using a high-resolution
protocol with the following acquisition settings; system:
SOMATOM Emotion 16, tube current: 130 mAs, gray-scale:
16 bits, potential: 130 kV, scan time 35 s, voxel size: 0.01 mm3
(0.24 mm x 0.24 mm x 0.20 mm).
After sterilization (T2), each series was again scanned with
the same CT-scanner and with the same acquisition settings.
The DICOM images were exported and 3D Slicer®
software was used to segment the guide and create STL files
(the file extension used in 3D printing). Blender® software was
then used to isolate each guide of both series.
To compare the morphology of the guides, Cloud
Compare® program was used. The principle of this software is
to decompose an object, into a number (n) of points (voxel
points) and then compare the deviation of the points of the
reference guide with respect to the compared guide. 3D
designed reference guide (T0) was compared with the sterilized
guide (T2) and the printed non-sterilized guide (T1) with the
sterilized guide (T2) (Figs. 1-4).
2.4. Statistical Analysis
Once the data was collected, Student t-paired tests were
used to evaluate the differences in mean distances of the
reference 3D-designed guide (t0), and the post sterilization
guide (t2) and printed guide (t1) and sterilized guide (t2).
Random factor ANOVAs were used to test the differences in
morphometric means between 21 PLA guides and 21 PETG
guides. A p-value of less than 5% was considered significant.
Statistical analyses were performed with the R software
(version 3.5.1).
Fig. (1). (from left to right): Genioplasty guide designed in 3D (T0) –
3D-printed guide non-sterilized (T1) – Guide after sterilization (T2).
Fig. (2). Process of alignment of two scanned guide with the software Cloudcompare®.
How to Sterilize 3D Printed Objects for Surgical Use? The Open Dentistry Journal, 2019, Volume 13 413
Fig. (3). Comparison of 2 guides via the C2M function and extraction of the comparative data.
3. RESULTS
3.1. PLA T0 - T2 (Reference 3D-Designed Guide
Sterilized Guide)
18 out of the 21 guides have a significant average
difference after the effect of printing and sterilization. In this
series, the largest difference in average is 0.147 mm between
the points of the guide. The ANOVA shows a significant
average difference between the guides (Table 3).
3.2. PLA T1 - T2 (Printed Guide – Sterilized Guide)
19 out of the 21 guides have a significant average
difference after the effect of sterilization. In this series, the
largest difference in average is 0.1887 mm between the points
of the guide. The ANOVA shows a significant average
difference between the guides (Table 4).
3.3. PETG T0-T2 (Reference 3D-Designed Guide – Sterilized
Guide)
Only 1 out of the 21 guides do not have a significant
average difference after the effect of printing and sterilization.
In this series, the largest difference in average is 0.1887 mm
between the points of the guide. The ANOVA shows a
significant average difference between the guides (Table 5).
3.4. PETG T1-T2 (Printed Guide – Sterilized Guide)
21 guides have a significant average difference after the
effect of printing. The largest difference in average is 0.0976
mm (Table 6).
Fig. (4). Example of histogram and Gauss curve of the deviation of the points of one guide at T2 compared to the referenced object (guide at T0)
obtained with CloudCompare®.
Gauss: mean = 0.024261 / std.dev. = 0.150409 [66 classes]
240
200
160
120
80
40
0
-0.3 -0.15 0 0.15 0.3 0.45 0.6
Temp. approx. distances
Count
414 The Open Dentistry Journal, 2019, Volume 13 Oth et al.
Table 3. PLA T0 - T2 (reference 3D-designed guide – sterilized guide).
Guide
ID nMean difference
t0-t2 SD P-value* Lower 95% CI Upper 95%
CI P-value**
1 4001 0,113 0,338 <0.001 0,1035 0,1243
<0.001
2 4033 0,147 0,218 <0.001 0,1402 0,1536
3 4350 0,094 0,369 <0.001 0,0845 0,1063
4 4097 0,126 0,298 <0.001 0,1184 0,1366
5 4178 0,096 0,379 <0.001 0,0870 0,1099
6 4240 0,058 0,440 <0.001 0,0472 0,0736
7 4186 0,123 0,338 <0.001 0,1156 0,1360
8 4177 0,068 0,424 <0.001 0,0574 0,0830
9 4122 0,115 0,327 <0.001 0,1062 0,1261
10 4307 0,111 0,359 <0.001 0,1015 0,1229
11 4501 0,118 0,374 <0.001 0,1081 0,1299
12 4203 0,101 0,346 <0.001 0,0934 0,1142
13 4617 0,041 0,480 <0.001 0,0282 0,0558
14 4323 0,077 0,421 <0.001 0,0652 0,0902
15 4452 -0,015 0,475 0,088 -0,0260 0,0018
16 4360 -0,007 0,484 0,435 -0,0200 0,0086
17 4386 -0,009 0,489 0,342 -0,0214 0,0074
18 4134 0,127 0,330 <0.001 0,1188 0,1388
19 4252 0,099 0,400 <0.001 0,0887 0,1127
20 4187 0,132 0,330 <0.001 0,1250 0,1449
21 4107 0,135 0,310 <0.001 0,1263 0,1452
*Paired t-test; **One way fixed factor ANOVA
Table 4. PLA T0 - T2 (reference 3D-designed guide – sterilized guide).
Guide
ID NMean difference
t1-t2 SD P-value* Lower 95% CI Upper 95% CI P-value**
1 4001 0,1887 0,1546 <0.001 0,184 0,194
<0.001
2 4033 0,0047 0,1360 0,026 0,001 0,009
3 4350 0,0255 0,1416 <0.001 0,022 0,030
4 4097 0,0014 0,1335 0,366 -0,002 0,006
5 4178 0,0341 0,1411 <0.001 0,031 0,039
6 4240 0,0242 0,1505 <0.001 0,020 0,029
7 4186 0,0221 0,1451 <0.001 0,019 0,028
8 4177 0,0307 0,1515 <0.001 0,027 0,036
9 4122 0,0296 0,1408 <0.001 0,026 0,035
10 4307 0,0161 0,1441 <0.001 0,012 0,021
11 4501 0,0147 0,1387 <0.001 0,011 0,019
12 4203 0,0051 0,1326 0,003 0,002 0,010
13 4617 0,0476 0,1581 <0.001 0,043 0,053
14 4323 0,0021 0,1410 0,2463 -0,002 0,007
15 4452 -0,0052 0,1472 0,045 -0,0001 -0,009
16 4360 0,0220 0,1379 <0.001 0,018 0,026
17 4386 0,0250 0,1422 <0.001 0,021 0,030
18 4134 0,0140 0,1427 <0.001 0,010 0,019
19 4252 0,0153 0,1516 <0.001 0,011 0,020
20 4187 0,0349 0,1417 <0.001 0,032 0,040
21 4107 0,0039 0,1426 0,047 0,0001 0,0087
*Paired t-test; **One way fixed factor ANOVA
How to Sterilize 3D Printed Objects for Surgical Use? The Open Dentistry Journal, 2019, Volume 13 415
Table 5. PETG T0-T2 (reference 3D-designed guide – sterilized guide).
Guide
ID NMean difference
t0-t2 DS Lower 95% CI Upper 95% CI P-value* P-value**
1 4130 0,1980 0,2660 0,1911 0,2073 <0.001
<0.001
2 4156 0,0039 0,4283 -0,0070 0,0189 0,3693
3 4277 0,1449 0,2787 0,1373 0,1539 <0.001
4 5208 0,1971 0,2566 0,1887 0,2026 <0.001
5 4130 0,1837 0,2570 0,1771 0,1927 <0.001
6 4092 0,1781 0,2659 0,1709 0,1871 <0.001
7 4114 0,1752 0,2488 0,1688 0,1839 <0.001
8 4336 0,1125 0,3221 0,1040 0,1231 <0.001
9 4197 0,1576 0,3322 0,1499 0,1699 <0.001
10 4132 0,1863 0,2194 0,1806 0,1939 <0.001
11 4165 0,1774 0,2715 0,1709 0,1874 <0.001
12 4196 0,1648 0,2873 0,1582 0,1755 <0.001
13 4512 0,1890 0,1724 0,1845 0,1945 <0.001
14 4372 0,1782 0,2151 0,1726 0,1853 <0.001
15 4216 0,1615 0,3124 0,1535 0,1723 <0.001
16 4102 0,1890 0,2225 0,1831 0,1966 <0.001
17 4193 0,1681 0,3056 0,1611 0,1796 <0.001
18 4081 0,1722 0,2564 0,1649 0,1806 <0.001
19 4133 0,1448 0,3218 0,1365 0,1560 <0.001
20 4115 0,1684 0,2730 0,1614 0,1780 <0.001
21 4113 0,1717 0,2667 0,1650 0,1812 <0.001
*Paired t-test; **One way fixed factor ANOVA
Table 6. PETG T0-T2 (reference 3D-designed guide – sterilized guide).
Guide
ID NMean difference
t1-t2 DS Lower 95% CI Upper 95% CI P-value* P-value**
1 4130 0,1055 0,1299 0,103 0,111 <0.001
<0.001
2 4156 -0,0116 0,1485 -0,015 -0,006 <0.001
3 4277 0,0352 0,1427 0,031 0,040 <0.001
4 5208 0,0846 0,1306 0,080 0,087 <0.001
5 4130 0,0727 0,1367 0,069 0,078 <0.001
6 4092 0,0576 0,1329 0,054 0,062 <0.001
7 4114 0,0651 0,1381 0,062 0,070 <0.001
8 4336 0,0088 0,1297 0,005 0,013 <0.001
9 4197 0,0672 0,1348 0,064 0,072 <0.001
10 4132 0,0798 0,1235 0,077 0,084 <0.001
11 4165 0,0500 0,1411 0,047 0,055 <0.001
12 4196 0,0541 0,1414 0,051 0,059 <0.001
13 4512 0,0868 0,1192 0,084 0,091 <0.001
14 4372 0,0582 0,1251 0,055 0,062 <0.001
15 4216 0,0827 0,1399 0,079 0,088 <0.001
16 4102 0,0906 0,1333 0,087 0,095 <0.001
17 4193 0,0976 0,1420 0,094 0,103 <0.001
18 4081 0,0743 0,1240 0,071 0,078 <0.001
19 4133 0,0808 0,1371 0,077 0,086 <0.001
20 4115 0,0776 0,1417 0,074 0,083 <0.001
21 4113 0,0767 0,1376 0,073 0,082 <0.001
*Paired t-test; **One way fixed factor ANOVA
416 The Open Dentistry Journal, 2019, Volume 13 Oth et al.
4. DISCUSSION
Very few papers have studied the sterilization of 3D-
printed objects. Kozakiewicz has studied the effect of sterili-
zation on paper-based 3D-printed solids [9]. Shaheen has
studied the effect of sterilization of objects printed with the
PolyJet technology (Stratasys, Eden Prairie, MN USA). Limit
to disinfection of the 3D-printed objects should be avoided in
all cases [8].
According to Bathia and Ramadurai [11], the material
released from an FDM 3D-printer is sterile since it leaves the
extruder at 220°C (well above the 121°C recommended for
steam sterilization). But contamination of the printing plate is
always possible and a totally sterile manipulation of the object
from 3D printing to the operating room cannot be guaranteed.
The use of a conventional sterilization technique and the
preservation of the sterilized object in a package provided for
this purpose are therefore necessary.
PLA and PETG are very common bio-materials in 3D-
desktop FDM-printer. Those materials do not bear high
temperature. This guide in PLA and PETG melted under a
short cycle of 5 minutes under 121°C with thermal steam
sterilization, making the use of autoclave impossible. This is
the reason why this technique of sterilization is not recomm-
ended. But this finding is inconsistent with the study of
Boursier et al. [12] who concluded that PLA printed-objects
with FDM 3D printer can be sterilized with an autoclave.
Boursier et al. scanned a cat’s femur after dissection, printed it,
sterilized it and compared its deformation with handly measu-
rements. This inconsistency could be explained by the fact that
Boursier et al. use a different 3D printer and a PLA from
another brand. PLA is a polymer composed of L-lactide and D-
lactide chains. The thermal and mechanical properties of PLA
depend on the ratio and distribution of L- and D-LA in the
polymer chains. The melting temperatures and the transition
glass temperature could thus vary from one brand to another.
Because the temperature of hydrogen peroxide sterilization
always stays lower than 55°C, this technique can be applied to
all subtypes of PLA.
No study about sterilization of PETG was found in the
literature. The use of PETG (taulman® 3D guidel!ne® filament
1.75 mm) for additive manufacturing in medical use should be
preferred because of its proven biocompatibility in accordance
with the industrial standard, its European ISO10993 certifi-
cation and its American FDA-approval [13].
The other sterilization techniques have significant
disadvantages. Thermal sterilization by dry heat is currently
prohibited in the hospitals of the European Union (because of
inactivity on prions). Radiation sterilization is used in the food
and medical device industry and its use is not suitable for
hospitals. Ethylene oxide should be avoided because it leads to
changes in the polymer structures, provokes molecular weight
loss and creates a toxic deposit on the surface of the object. In
comparison, with the hydrogen peroxide low-temperature
sterilization, no toxic residues remain on the sterilized items.
This technique is effective, safe and does not require aeration
time compared to ethylene oxide [7].
Regarding the results in morphology variations, although
there are differences that are statistically significant for each
series between T0 and T2 and T1 and T2 for both PLA and
PETG, this has no impact on the clinical use of sterilized
objects using hydrogen peroxide sterilization technology.
Indeed, these morphological differences are minimal and less
than 0.2 mm. Furthermore, these differences could also be
simply related to 3D reconstruction from scanners since their
degree of accuracy is equal to 0.4 mm or to the layer thickness
of the 3D printing or both. Considering these parameters, an
accuracy of 0.2 mm seems reasonable from a surgical stand-
point.
Therefore, the use of the hydrogen peroxide low-
temperature sterilization for sterilization of 3D printed objects
in PLA and PETG is strongly recommended.
Finally, in this study, a genioplasty guide was used as a
reference object but this sterilization technique can be
extrapolated to any other 3D printed object for medical
purposes. This technique has successfully been tested for the
sterilization of other medical objects (e.g.: the anatomical
model of mandible), and no deformation of the 3D-printed
object was observed after 3D printing and after sterilization.
CONCLUSION
Steam sterilization is not suitable for the PLA and PETG
3D-printing material, because other sterilization methods were
excluded for different reasons. And because sterilization is
mandatory for the use of 3D-printing medical objects in the
operating room, a study was conducted to evaluate the morpho-
logical effect of hydrogen peroxide sterilization on a surgical
genioplasty guide 3D-printed with PLA and PETG.
This one concludes that the morphological deformations
induced by the hydrogen peroxide sterilization are sub milli-
meter and compatible with surgical use. The hydrogen per-
oxide sterilization is, therefore, an alternative avoiding the
deformation of 3D-printed objects from PLA and PETG during
their sterilization with steam sterilization (autoclave).
To the best of our knowledge, this is the first study about
the morphologic deformation of 3D-printed objects in PLA and
PETG for medical use after sterilization.
LIST OF ABBREVIATIONS
FDM = Fused-Deposition-Modeling
PLA = Polylactic Acid
PETG = Polyethylene Perephthalate Glycol
L-LA = L-Lactide
D-LA = D-Lactide
ETHICS APPROVAL AND CONSENT TO
PARTICIPATE
This study received the approval of the Ethics Committee
of Erasme Hospital, Université Libre de Bruxelles, Brussels,
Belgium under the reference: SRB_201808_171.
How to Sterilize 3D Printed Objects for Surgical Use? The Open Dentistry Journal, 2019, Volume 13 417
HUMAN AND ANIMAL RIGHTS
No animals/humans were used in the study that are the
basis of this research.
CONSENT FOR PUBLICATION
Not applicable.
AVAILABILITY OF DATA AND MATERIAL
The data that support the findings of this study are
available from corresponding author ( O. Oth) upon reasonable
request.
FUNDING
Dr. Olivier Oth received a financial grant of the direction
Board of Erasme Hospital to conduct this study (Grant No.
2018/06).
CONFLICT OF INTEREST
The authors declare no conflict of interest, financial or
otherwise.
ACKNOWLEDGEMENTS
We sincerely thank Charline Maertens de Noordhout for
her help in producing statistical data. We also sincerely thank
Prof. Stéphane Louryan for his help in producing radiological
data.
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... The raft is used for printers that struggle with adhesion as they do not have a heated bed, which can be seen in Fig. 5, with small layers being placed for easy adhesion of print materials. Standard settings included using a 0.2 mm layer thickness, extruding at 215 C on a heated bed of 50 C, which is standard for such renders [Oth et al. (2019)]. Several 3D printers were used to create these visor frames, where the number produced depends on the capabilities of the machine. ...
... The speci¯c properties relating to PLA, such as thermal and mechanical, depend on the distribution ratio of these chains. Thus, the melting temperatures could vary from one brand to another, especially when factoring in Super PLA [Oth et al. (2019)]. It is interesting to note that thermal sterilization across the European Union is prohibited in hospitals at the time of writing. ...
... Although other forms of sterilization such as radiation and ethylene oxide are used in other areas such as food, these could not be used in this instance as they can potentially create toxicity on the surface of these objects. As a result, a safer technique is low-temperature sterilization with hydrogen peroxide as residues are not formed [Oth et al. (2019)]. ...
Health systems were severely strained at the start of the COVID-19 pandemic, where the demand for personal protection equipment (PPE) could not be met. The challenge faced by many countries was how to innovate quickly to create PPE and other needed solutions. The subsequent research gap identified was a lack of practical insights on how to support such novel technology adoption, particularly those that stem from Industry 4.0 (I4.0) within a developing world context. To address this previous literature on I4.0 technology, the role of innovation environments and theoretical principles of technology adoption was reviewed. A practical case from an academic makerspace based in a South African university was then assessed. It was selected due to its direct role in rapid solutions development of PPE using additive manufacturing (AM) until such a time that manufacturers could set up production on a larger scale. It was found that AM and other novel technologies have facilitated innovative solutions to address the significant impacts of the pandemic. Key to which were practices identified of an innovation environment that supported early-stage adoption of AM to achieve this even in a developing country context. The findings imply that innovation environments offer an agile platform to leverage innovation by streamlining certain critical success factors of I4.0 technology adoption, which is presented in a model. However, individual skills developed by such environments to enhance innovation capabilities within this paradigm require further research.
... Based on mentioned research [18], hydrogen peroxide sterilization is the best alternative to avoid the deformation of PLA and PETG AM objects. It is also preferable to steam sterilization for PLA and PETG, as it causes only submillimeter morphological distortions, instead of dynamically damaging the materials in consequence of high temperature (121 °C for 5 min) [19]. ...
... Electron beam and gamma radiation are also a practice in the mentioned above field and are safely used for PLA and PETG. However, ethylene oxide cannot be implemented for PLA and PETG, as it inflicts the polymeric structures, causing weight loss and creating a risk of inducing toxic deposits on the surface of the element [19]. On the other hand, UV and gamma radiation does not impact the alignment of the fibers, therefore are suitable for PLA sterilization [20]. ...
... Usage of the PETG in FFF technology seems to be a good alternative in some solutions where much more expensive AM technologies are unnecessary. This statement results from our previous research, connected with other material also dedicated for medical solutions-316L steel obtained during selective laser melting (SLM) process [17][18][19][20][21]. ...
Article
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In this paper, the influence of disinfection on structural and mechanical properties of additive manufactured (AM) parts was analyzed. All AM parts used for a fight against COVID19 were disinfected using available methods-including usage of alcohols, high temperature, ozonation, etc.-which influence on AM parts properties has not been sufficiently analyzed. During this research , three types of materials dedicated for were tested in four different disinfection times and two disinfection liquid concentrations. It has been registered that disinfection liquid penetrated void into material's volume, which caused an almost 20% decrease in tensile properties in parts manufactured using a glycol-modified version of polyethylene terephthalate (PETG).
... None of the morphological assays used in this study for the detection of deformation and changes in geometry showed a notable difference between the analysis of the samples before and after low-temperature (54 • C) sterilization. Similarly to our results, another group reported the better quality of surgical guides 3D-printed with PLA and PETG when sterilized in HPP [13]. They concluded that following low-temperature sterilization, the discrepancies in noted deformations were submillimeter in size and had no clinical significance for such medical applications. ...
Article
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Three-dimensionally-printed aortic templates are increasingly being used to aid in the modification of stent grafts in the treatment of urgent, complex aortic disorders, often of an emergency nature. The direct contact between the aortic template and the stent graft implies the necessity of complete sterility. Currently, the efficacy of sterilizing aortic templates and the effect of sterilization on the geometry of tubular aortic models are unknown. A complex case of aortic arch dissection was selected to prepare a 3D-printed aortic arch template, which was then manufactured in six popular printing materials: polylactic acid (PLA), nylon, polypropylene (PP), polyethylene terephthalate glycol (PETG), and a rigid and flexible photopolymer resin using fused deposition modeling (FDM) and stereolithography (SLA). The 3D models were contaminated with Geobacillus stearothermophilus broth and Bacillus atrophaeus. The sterilization was performed using three different methods: heat (105 °C and 121 °C), hydrogen peroxide plasma, and ethylene oxide gas. Before and after sterilization, the aortic templates were scanned using computed tomography to detect any changes in their morphology by comparing the dimensions. All sterilization methods were effective in the elimination of microorganisms. Steam sterilization in an autoclave at 121 °C caused significant deformation of the aortic templates made of PLA, PETG, and PP. The other materials had stable geometries, and changes during mesh comparisons were found to be submillimeter. Similarly, plasma, gas, and heat at 105 °C did not change the shapes of aortic templates observed macroscopically and using mesh analysis. All mean geometry differences were smaller than 0.5 mm. All sterilization protocols tested in our study were equally effective in destroying microorganisms; however, differences occurred in the ability to induce 3D object deformation. Sterilization at high temperatures deformed aortic templates composed of PLA, PETG, and PP. This method was suitable for nylon, flexible, and rigid resin-based models. Importantly, plasma and gas sterilization were appropriate for all tested printing materials, including PLA, PETG, PP, nylon, flexible and rigid resins. Moreover, sterilization of all the printed models using our novel protocol for steam autoclaving at 105 °C was also 100% effective, which could represent a significant advantage for health centers, which can therefore use one of the most popular and cheap methods of medical equipment disinfection for the sterilization of 3D models as well.
... In recent years, research on the reliability of the navigation template after sterilisation has gradually increased. The divergence of the research is whether the navigation template is reliable after high-pressure steam sterilisation [18][19][20][21][22] , but safety of chemical-based sterilisation is unanimously recognised. Different from previous studies, we found that chemical-based sterilisation also had a risk of deformation, and the deformation was related to the parameters of the module. ...
Article
Full-text available
3D printed navigational templates have facilitated the accurate treatment of orthopaedic patients. However, during practical operation, it is found that the location hole occasionally deviates from the ideal channel. As such, there will be a security risk in clinical applications. The purpose of this study was to evaluate the influence of chemical-based sterilisation methods on the dimensional accuracy of different materials and the influence of module parameters on the degree of deformation. We found that polylactic (PLA) modules sterilised with ethylene oxide (EO) would undergo micro-deformation, and these micro-deformation characteristics depend on the building direction, i.e., the module stretches in the Z direction and shrinks in the X and Y directions. Heat-resisting polylactide (HR-PLA) has the same melting temperature ( T m ) as PLA, but its glass transition temperature ( T g ) is greater than the EO sterilisation temperature, so there is no obvious deformation after EO sterilisation. The layer height of the module were inversely proportional to the degree of deformation in the same sterilisation method. The deformation time of the module is concentrated within 2 h after heating. The micro-deformation of the 3D printing module depends on its T g , sterilisation temperature, and duration of the sterilisation cycle.
... En este contexto, el ABS es más susceptible a sufrir contracción durante el enfriamiento. El PETG, es un termoplástico con gran resistencia al impacto, rígido, transparente, lavable y esterilizable, lo cual que lo hace un material preferido para ser utilizado en barreras faciales; posee mayor resistencia a la temperatura que el PLA, lo cual puede favorecer los procesos de esterilización, pero no es biodegradable (Oth et al., 2020). La elección de materiales para futuras producciones de barreras faciales en el contexto de la pandemia COVID 19, requiere de una toma de decisiones en torno a costos, biodegradabilidad, facilidad para el diseño de geometrías, incorporación de nanomateriales para otorgar propiedades elevadas en términos de resistencia a empañarse, resistencia bacterial (González-Henríquez et al., 2019), entre otras. ...
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The work developed by an interdisciplinary team of professionals from the Biobío region of Chile, in the context of a global health emergency caused by the SARS-CoV-2 virus is presented. The objective was to design, manufacture and distribute a facial barrier in response to the lack of Personal Protective Equipment (PPE) in the health sector. The periods of confinement resulted in difficulties in accessing essential PPE, due to transport logistics alterations and increased demand. To deliver solutions, the coordinated action of professionals, technological capabilities and available materials was essential. The methodology addresses stages of identification of needs for psychological and physical comfort of health personnel, based on their experience of using facial barriers; identification of national regulations for PPE; identification of the material and technological resources available in the region for the design and manufacture of facial barriers; ideation process in the Design Research Laboratory of the Universidad del Bío-Bío; validation with users; laboratory validation; disinfection and distribution. The results show aspects of user perception with respect to two prototypes. Results of laboratory tests in accordance with current regulations contribute to know the protection benefits of the final proposal. The discussion refers to the interdisciplinary contribution, the integration of the user in the design process and a prospective approach. The conclusions present a reflection on the experience developed to deliver effective responses in complex times.
... PLA is very easy to work with in 3D printing, which is attractive for environmental reasons [13]. Hydrogen peroxide sterilization is an alternative to avoid the deformation of 3D-printed objects made from PLA during conventional steam sterilization (autoclave) [14]. On the other hand, research on the comparison of environmental impacts has also been carried out [15]. ...
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Full-text available
The exponential growth of additive manufacturing techniques and their applications to accessory manufacturing for personal protective equipment (PPE) is becoming a reality. In the forthcoming years it will be able to supply local demands with more efficient and easier to use devices for medical protection. In this article we propose a method of customizing the design and manufacture of PPE accessories such as the Ear-Saver and Anti Contact Key. The proposal considers not only innovative aspects of the product design and rapid manufacturing issues, but also defines a framework considering the product lifecycle and outlines important indicators from economic, social and sustainable perspectives. A set of experimental case studies that are included to enrich the proposed framework and its metrics allows better assessment of the different activities and the environmental impact of the product.
... The 3D-printed parts of the system can be sterilised with hydrogen peroxide, meaning the device can be reused between patients without deformation [12]. However, given the system excluding the servo is reasonably inexpensive, it is recommended the valve is not used across multiple patients, if used in a clinical setting to avoid cross-contamination risk. ...
Article
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A 3D-printed three/two-way valve compatible with respiratory circuits is presented. It is actuated by a servo motor (HXT12K), which is able to be controlled by any PWM-capable micro controller. The valve sufficiently isolates respiratory circuits to deliver fully customisable mechanical ventilation breathing cycles, with differences in driving and end-expiratory pressures of up to 30cmH2O successfully demonstrated. It is suitable for multiplexing ventilators for in-series breathing, or providing separate ventilation to each individual lung in a single patient. Each switching valve costs approximately $16USD, $10 of which is the servo motor which can be reused, allowing subsequent devices for only $6USD of 3D printing and common engineering components. The valve has proven reliable for at least 50,000 state changes over at least one month.
... The sterilization methods adequate for different 3D printing materials have been tested in terms of infection rate and dimensional stability, or, on the contrary, geometrical deformation [11,[23][24][25][26]. Low-temperature VHP has been used for sterilization of printouts produced by FDP in ABS. ...
Article
Full-text available
Background Material extrusion is used to 3D print anatomic models and guides. Sterilization is required if a 3D printed part touches the patient during an intervention. Vaporized Hydrogen Peroxide (VHP) is one method of sterilization. There are four factors to consider when sterilizing an anatomic model or guide: sterility, biocompatibility, mechanical properties, and geometric fidelity. This project focuses on geometric fidelity for material extrusion of one polymer acrylonitrile butadiene styrene (ABS) using VHP. Methods De-identified computed tomography (CT) image data from 16 patients was segmented using Mimics Innovation Suite (Materialise NV, Leuven, Belgium). Eight patients had maxillary and mandibular defects depicted with the anatomic models, and eight had mandibular defects for the anatomic guides. Anatomic models and guides designed from the surfaces of CT scan reconstruction and segementation were 3D printed in medical-grade acrylonitrile butadiene styrene (ABS) material extrusion. The 16 parts underwent low-temperature sterilization with VHP. The dimensional error was estimated after sterilization by comparing scanned images of the 3D printed parts. Results The average of the estimated mean differences between the printed pieces before and after sterilization were − 0,011 ± 0,252 mm (95%CI − 0,011; − 0,010) for the models and 0,003 ± 0,057 mm (95%CI 0,002; 0,003) for the guides. Regarding the dimensional error of the sterilized parts compared to the original design, the estimated mean differences were − 0,082 ± 0,626 mm (95%CI − 0,083; − 0,081) for the models and 0,126 ± 0,205 mm (95%CI 0,126, 0,127) for the guides. Conclusion This project tested and verified dimensional stability, one of the four prerequisites for introducing vaporized hydrogen peroxide into 3D printing of anatomic models and guides; the 3D printed parts maintained dimensional stability after sterilization.
... The 3D-printed parts of the system can be sterilised with hydrogen peroxide, meaning the device can be reused between patients or subjects, if required. There should be minimal deformation to the Venturi [6]. It is also feasible to print multiple single-use Venturis, as each only uses approximately 15 g of filament and some hosing, thereby ensuring low costs. ...
Article
Full-text available
A low-cost but reliable flow and pressure sensor is an impediment to development of medical equipment, and studies of human respiratory function, which is characterised by relatively low pressures and flows. A Venturi tube (D1=15mm,D2=10mm) connected to a differential pressure sensor (SDP816-125Pa) allows accurate measurement of flow between 5-75L·min-1, with Pearson Correlation over 4min at 50Hz ⩾0.97, and distance correlation ⩾0.96. The pressure measurement was similarly accurate using a MPVZ4006GW7U. Both sensors provide an analogue output from a 5.0V supply, aiding compatibility and customisation. Each populated PCB costs approximately $50USD, and each Venturi sensor costs approximately $1USD. Multiple configurations exist, allowing flow rates up to 250L·min-1, increased resolution for specific ranges, and different physical characteristics.
... 25 Other sources have shown sterilisation by low-temperature hydrogen peroxide gas plasma, though this may not be a viable option for many settings. 26 Some elements of the PAPR may not be sufficiently cleaned with a wipe, like the utility belt made with poly web material. For thorough cleaning, the belt should be removed from the power box and submerged in a basin filled with either ethanol or isopropyl alcohol. ...
Article
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Objectives: To design a low-cost 3D printable powered air-purifying respirator (PAPR) that meets National Institute for Occupational Safety and Health (NIOSH) standard for flow rate and Occupational Safety and Health Administration (OSHA) standard for particle filtration for loose-fitting PAPRs and that can be made with a 3D printer and widely available materials. Design: Detailed description of components, assembly instructions and testing of a novel PAPR design in an academic laboratory following respective protocols. The assembled PAPR must meet NIOSH standards of flow rate, 170 L/min; OSHA fit factor for particle filtration, ≥250 and maintain positive pressure during regular and deep breathing. Main outcome measures: The PAPR design was run through a series of tests: air flow (L/min), particle filtration (quantitative and qualitative) and positive pressure measured inside the helmet (mm Hg). Results: Flow rate was 443.32 L/min (NIOSH standard: minimum 170 L/min) and overall fit factor for particle filtration was 1362 (OSHA pass level: ≥500), n=1. The device passed qualitative particle filtration, n=2, and measured peak pressure of 6mm Hg (>0 mm Hg indicates positive pressure) in the helmet, n=1. Conclusions: The Hygieia PAPR is a low-cost, easily accessible, just-in-time 3D printable PAPR design that meets minimum NIOSH and OSHA standards for flow-rate and particle filtration for loose-fitting PAPR devices to be made and used when industry-made designs are unavailable.
Article
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Objective: Our study aimed to determine the possibility of using models created with a low-cost, paper based 3D printer in an operating room. Therefore influence of different methods of sterilization on models was tested and cytotoxicity of generated models was determined. Material and methods: 30 cuboids divided into three groups were used for verification of shape stability after sterilization. Each group was sterilized either with: Ethylene oxide in temperature 55˚C, Hydrogen peroxide gas plasma in temperature 60˚C or Gamma irradiation at 21˚C, 25kGy. Each cuboid was measured using calliper three times before and three times after sterilization. Results were analysed statistically in Statgraphics Plus. Statistical significance was determined as p< 0.05. Sixty cylinders divided into six groups were used for cytotoxicity tests. Three of those groups were covered before sterilization with 2-octyl-cyanoacrylate. Each group was sterilized with one of the previously described methods. Cytotoxicity was tested by Nanostructural and Molecular Biophysics Laboratory in Technopark Lodz using normal adult human dermal fibroblasts. Survival of cells was tested using spectrophotometry with XTT and was defined as ratio of absorbency of tested probe to absorbency of control probe. Calcein/Ethidium dyeing test was performed according to LIVE/DEAD Viability/Cytotoxicity Kit protocol. Observation was done under Olympus GX71 fluorescence microscope. Results: There was no statistically significant difference for established statistical significance p=0.05 in cuboids dimensions before and after sterilization regardless of sterilization method. In XTT analysis all samples showed higher cytotoxicity against normal, human, adult dermal fibroblast culture when compared to positive control. ANOVA statistical analysis confirmed that 2-octyl cyanoacrylate coating of paper model improved biological behaviour of the material. It decreased cytotoxicity of the model independently of sterilization method. In calcein/ethidium dyeing test due to the high fluorescence of the background caused by cylinders of analysed substance it was impossible to perform the exact analysis of the number of marked cells. Conclusions: Acquired results allow to conclude that Mcor Technology Matrix 300 3D paper-based models can be used in operating room only if covered with cyanoacrylate tissue adhesive. Nemesis relevance: We found no statistically significant difference in cuboids dimensions before and after sterilization regardless of sterilization method. Three-dimensional paper-based models present with high cytotoxicity without coating.
Article
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The standard sterilization method for most medical devices over the past 40 years involves gamma irradiation. During sterilization, gamma rays efficiently eliminate microorganisms from the medical devices and tissue allografts, but also significantly change molecular structure of irradiated products, particularly fragile biologics such as cytokines, chemokines and growth factors. Accordingly, gamma radiation significantly alters biomechanical properties of bone, tendon, tracheal, skin, amnion tissue grafts and micronized amniotic membrane injectable products. Similarly, when polymer medical devices are sterilized by gamma radiation, their physico-chemical characteristics undergo modification significantly affecting their clinical use. Several animal studies demonstrated that consummation of irradiated food provoked genome instability raising serious concerns regarding oncogenic potential of irradiated consumables. These findings strongly suggest that new, long-term, prospective clinical studies should be conducted in near future to investigate whether irradiated food is safe for human consumption. In this review, we summarized current knowledge regarding molecular mechanisms responsible for deleterious effects of gamma radiation with focusing on its significance for food safety and biomechanical characteristics of medical devices, and tissue allografts, especially injectable biologics.
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Objectives To assess the effect of two of the most commonly used sterilization techniques on 3D printed clinical objects. Materials & Methods The two sterilization methods used in our hospital and investigated in this paper are: Steam heat and Gas plasma. Three objects were printed and tested in this study: a tooth replica, an orthognathic final splint, a surgical cutting guide for the purpose of mandible reconstruction. For each of the 3 objects, 4 copies were made: one original STL object, one copy of the object pre-sterilization, one copy of post-steam heat sterilization, and one copy of post-gas plasma sterilization. Each printed object was scanned using a high resolution CBCT protocol and the compared (morphologically and volumetrically). Results At the level of volumetric changes, no difference was found between pre and post-sterilization for both methods evaluated. As for the morphological changes, only differences were noticed with the orthognathic splint object indicating deformation of the printed splints after sterilization. Larger differences were observed with heat sterilization, making it less reliable. Conclusion Sterilization of dental objects to be used in a clinical setting may lead to deformation of the printed model, especially for heat sterilization. Further investigations are needed to confirm these findings.
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Introduction: The purpose of the present report was to describe our indications, results and complications of computer-aided design and computer-aided modeling CAD/CAM surgical splints, cutting guides and custom-made implants in orthognathic surgery. Patients and methods: We analyzed the clinical and radiological data of ten consecutive patients with dentofacial deformities treated using a CAD/CAM technique. Four patients had surgical splints and cutting guides for correction of maxillomandibular asymmetries, three had surgical cutting guides and customized internal distractors for correction of severe maxillary deficiencies and three had custom-made implants for additional chin contouring and/or mandibular defects following bimaxillary osteotomies and sliding genioplasty. We recorded age, gender, dentofacial deformity, surgical procedure and intra- and postoperative complications. Results: All of the patients had stable cosmetic results with a high rate of patient satisfaction at the 1-year follow-up examination. No intra- and/or postoperative complications were encountered during any of the different steps of the procedure. Discussion: This study demonstrated that the application of CAD/CAM patient-specific surgical splints, cutting guides and custom-made implants in orthognathic surgery allows for a successful outcome in the ten patients presented in this series.
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3D Printing promises to produce complex biomedical devices according to computer design using patient-specific anatomical data. Since its initial use as pre-surgical visualization models and tooling molds, 3D Printing has slowly evolved to create one-of-a-kind devices, implants, scaffolds for tissue engineering, diagnostic platforms, and drug delivery systems. Fueled by the recent explosion in public interest and access to affordable printers, there is renewed interest to combine stem cells with custom 3D scaffolds for personalized regenerative medicine. Before 3D Printing can be used routinely for the regeneration of complex tissues (e.g. bone, cartilage, muscles, vessels, nerves in the craniomaxillofacial complex), and complex organs with intricate 3D microarchitecture (e.g. liver, lymphoid organs), several technological limitations must be addressed. In this review, the major materials and technology advances within the last five years for each of the common 3D Printing technologies (Three Dimensional Printing, Fused Deposition Modeling, Selective Laser Sintering, Stereolithography, and 3D Plotting/Direct-Write/Bioprinting) are described. Examples are highlighted to illustrate progress of each technology in tissue engineering, and key limitations are identified to motivate future research and advance this fascinating field of advanced manufacturing.
Article
Objectives The main purpose of this study was to determine the reproducibility and accuracy of a three-dimensional (3D) bone model printed on a desktop 3D-printer based on fused deposition modelling (FDM) technology with polylactic acid (PLA) and the effect of autoclave sterilization on the printed models. Methods Computed tomographic images of the tibia were obtained from 10 feline cadavers, used to create a bone surface-rendering file and sent to the 3D printing software. Right and left tibias were each printed five times with the FDM desktop 3D printer using PLA plastic material. Plastic models and cadaveric bones were measured with a profile projector device at six predetermined landmarks. Plastic bones were then sterilized using an autoclave before being re-measured applying the same method. Analyses of printed model size reliability were conducted using intra-class correlation coefficients (ICC) and Bland–Altman plots. Results The ICC always showed an almost perfect agreement when comparing 3D-printed models issued from the same cadaveric bone. The ICC showed moderate agreement for one measurement and strong/perfect agreement for others when comparing a cadaveric bone with the corresponding 3D model. Concerning the comparison of the same 3D-printed model, before and after sterilization, ICC showed either strong or perfect agreement. Clinical Significance Rapid-prototyping with our FDM desktop 3D-printer using PLA was an accurate, a reproducible and a sterilization-compliant way to obtain 3D plastic models.
Article
A review of regulatory clearances for selected new sterilization and disinfection products for the period January 2012-June 2015 indicates continued leverage of established technologies for steam and low-temperature sterilization, and high-level disinfection. New products in these areas were typically modified and improved versions of existing products, with the exception of a new combination hydrogen peroxide/ozone sterilizer. Development of new low-temperature sterilization technologies to address continued evolution of complex medical devices is expected to continue.
Chapter
One of the areas where algorithmic or parametric programming has made its biggest contribution is in Computer Aided Design. The traditional CAD/CAM programs simply offer a STATIC visual aid to users for the documentation of a preconceived part or assembly. No provision exists to determine the effects of desired changes on performance.
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The Sterrad Sterilization System by Advanced Sterilization Products (ASP) exploits the synergism between peroxide and low temperature gas plasma (an excited or ionized gas) to rapidly destroy microorganisms (Figure 1). At the completion of the sterilization process based on this technology, no toxic residues remain on the sterilized items. The technology is particularly suited to the sterilization of heat and moisture sensitive instruments since process temperatures do not exceeded about 50 degrees C (140 degrees F) and sterilization occurs in a low moisture environment. Total process time is about one hour. The efficacy of the process has been demonstrated against a broad spectrum or microorganisms and on a large number of substrates used in medical instruments.
Article
The STERRAD 100 sterilization system (Johnson & Johnson Medical Ltd) uses low temperature hydrogen peroxide gas plasma for sterilization of heat labile equipment. The efficacy of the machine was tested by contaminating a standard set of instruments with different organisms and using a filtration method to assess recovery of organisms from the wash fluids of instruments post-sterilization. Experiments were performed under clean (the organism only) and dirty (organism mixed with egg protein) conditions. A parallel study conducted using a 3M STERIVAC ethylene oxide sterilizer could not be completed owing to closure of the ethylene oxide plant. For sterilization of instruments with long and narrow lumens, hydrogen peroxide adaptors are necessary. The STERRAD 100 sterilizer can achieve effective sterilization of heat labile instruments with a reduction of 6 log10 cfu/mL of organisms tested. This method has the advantages over ethylene oxide sterilization of safety, ease of maintenance and no requirement for aeration time.