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. 2020 Mar 19;9(3):832.
doi: 10.3390/jcm9030832.

Accuracy Assessment of Molded, Patient-Specific Polymethylmethacrylate Craniofacial Implants Compared to Their 3D Printed Originals

Affiliations

Accuracy Assessment of Molded, Patient-Specific Polymethylmethacrylate Craniofacial Implants Compared to Their 3D Printed Originals

Dave Chamo et al. J Clin Med. .

Abstract

The use of patient-specific implants (PSIs) in craniofacial surgery is often limited due to a lack of expertise and/or production costs. Therefore, a simple and cost-efficient template-based fabrication workflow has been developed to overcome these disadvantages. The aim of this study is to assess the accuracy of PSIs made from their original templates. For a representative cranial defect (CRD) and a temporo-orbital defect (TOD), ten PSIs were made from polymethylmethacrylate (PMMA) using computer-aided design (CAD) and three-dimensional (3D) printing technology. These customized implants were measured and compared with their original 3D printed templates. The implants for the CRD revealed a root mean square (RMS) value ranging from 1.128 to 0.469 mm with a median RMS (Q1 to Q3) of 0.574 (0.528 to 0.701) mm. Those for the TOD revealed an RMS value ranging from 1.079 to 0.630 mm with a median RMS (Q1 to Q3) of 0.843 (0.635 to 0.943) mm. This study demonstrates that a highly precise duplication of PSIs can be achieved using this template-molding workflow. Thus, virtually planned implants can be accurately transferred into haptic PSIs. This workflow appears to offer a sophisticated solution for craniofacial reconstruction and continues to prove itself in daily clinical practice.

Keywords: 3D printing; PMMA; accuracy; additive manufacturing; craniofacial reconstruction; cranioplasty; molding; patient-specific implant.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
3D printed skull models with the defect area shown. (a) cranial defect (CRD); (b) temporo-orbital defect (TOD).
Figure 2
Figure 2
Comparison of the 3D printed templates (a,b, beige) with the patient-specific implants according to the n-point registration with five manually placed control points (c,d, purple), and the superimposition (e,f). Left: cranial template and PSI; right: temporo-orbital template and PSI.
Figure 2
Figure 2
Comparison of the 3D printed templates (a,b, beige) with the patient-specific implants according to the n-point registration with five manually placed control points (c,d, purple), and the superimposition (e,f). Left: cranial template and PSI; right: temporo-orbital template and PSI.
Figure 3
Figure 3
Descriptive data distribution illustrating the difference between the CRD-PSIs (models 1 to 10) and the CRD 3D printed template. (a) Mean difference ± SD (mm); (b) Median difference (Q1 to Q3) (mm).
Figure 4
Figure 4
Descriptive data distribution illustrating the difference between the TOD-PSIs (models 1 to 10) and the TOD 3D printed template. (a) Mean difference ± SD (mm); (b) Median difference (Q1 to Q3) (mm).
Figure 5
Figure 5
Box plot illustrating the accuracy comparison with respect to the root mean square (RMS) values (mm) between the polymethylmethacrylate (PMMA) CRD-PSI and TOD-PSI test groups (● describes the statistical outlier, CRD-PSI 01).
Figure 6
Figure 6
Color-coded deviation maps within each test group after applying the best-fit method and generating a 3D comparison to evaluate the accuracy. CRD-PSI: (a) squamous (outer) surface; (c) cerebral (inner) surface; TOD-PSI: (b) squamous (outer) surface; (d) cerebral (inner) surface.

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