Page 88 - IJB-9-2

International Journal of Bioprinting Steam-sterilized and degradable FFF-printed PLA/PHA surgical guides

A Table 1. The means and standard deviations (SD) of the
measured variables.
Guide material MED610 PLA/PHA
Non‑sterile Sterile Non‑sterile Sterile
N = 5 N = 5 N = 5 N = 5
Angular deviation, 0.72 (0.55) 1.10 (0.77) 0.38 (0.53) 2.88 (0.75)
B mean (SD)
3D deviation at 0.38 (0.09) 0.36 (0.17) 0.49 (0.21) 0.94 (0.23)
implant base,
mean (SD)
3D deviation at 0.42 (0.13) 0.42 (0.23) 0.50 (0.23) 1.04 (0.19)
implant apex,
mean (SD)
C Highest values were seen in sterile PLA/PHA guides for angular
deviation, as well as 3D deviation at implant base and apex. PLA/PHA:
Polylactide/polyhydroxyalkanoate

Inaccuracy in implant position may occur because of
asymmetric bone structure, limited experience of the
[22]
D dentist, and limited mouth opening . Computer-
assisted implant surgery enables pre-surgical planning
of the future implant position along with the protection
of relevant anatomical structures and allows for a highly
precise surgery. There are different ways of performing
guided implant surgery: While dynamic guiding may be
impractical for most dental practices due to high cost and
Figure 4. Workflow of the deviation measurement. (A) Four-point the complexity of the procedure, static surgical guidance is
matching of planning model (blue) and model generated out of the post- a commonly used method in daily practices.
operative dataset (red). First step of fine tuning is done by a matching
algorithm by the software manufacturer. (B) Fine tuning of the matching A variety of methods for creating such 3D-printed
with coronar, sagital, and axial view and 3D overview for control (blue: surgical guides have evolved over time. FFF uses a melted
planning model and yellow: matched post-operative model); (C) Since thermoplastic extruded by the printer head, which is
the position of the placed implant cannot be recognized from the software
automatically, manual adjustment was carried out to superimpose the continuously layered on a platform, while in the material
red outlined model of the implant on the implant from the cone beam jetting process, a carriage jets photopolymers onto a
computed tomography scan. (D) Calculation of the deviations based on surface, which are then cured with ultraviolet light .
[21]
the surgical plan (blue-colored implant) and the post-operative situation
(red-colored implant) was done. The dimensional accuracy of such 3D models has been
found to be affected by several factors, such as quality of
MED610 showed significant differences (P = 0.01, P < 0.01 diagnostic radiographic imaging and radiographic template,
and P < 0.01). The same measurements for unsterilized accuracy of digital cast produced by scanning, accuracy of
guides, regardless of the material used, revealed no surgical template and its stable fit on the supporting tissue,
differences (Table 2). and surgeon’s execution of the planned surgery, and also
by process-specific factors, such as manufacturing process
4. Discussion itself, build orientation, number of objects being printed,
The aim of this study was to compare the structural stability types of sleeve inserts, and post-processing methods [21,22] .
and accuracy of PLA/PHA, a biodegradable 3D printing Several studies have been performed to analyze the effect
material, and MED610, a material jetting material for of disinfection and sterilization procedures on dimensional
medical applications, as surgical guides for short implants changes of 3D-printed guides. These characteristics are
with and without steam sterilization. The target variable generally assessed using various software tools to compare
was quantified by the deviation at the implant base and the STL datasets. The assessment of the postoperative implant
angle deviation. position is another method to quantify the accuracy of the
To achieve the best possible functional and esthetic surgical guide; here either a CBCT scan or an intraoral
outcome, optimal dental implant placement is crucial. scan is needed .
[21]

Volume 9 Issue 2 (2023) 80 https://doi.org/10.18063/ijb.v9i2.655