150
different models produced with different layer thickness: FDM (Makerbot Industries,
Brooklyn, USA – 100 μm), Polyjet printing (Stratasys, Eden Prairie, USA – 16 μm)
and STL (3D Systems, Rock Hill, USA – 50 μm), resulting in statistically significant differences between the plaster and three 3D printed models. The model manufactured by FDM was the closest replica to the plaster model, despite the greater
thickness of the layer (Rebong et al. 2018). Jeong et al. (2018) compared 3D printed
and milled PMMA models, and highlighted the superior accuracy of the 3D printing
method compared to materials produced by the milling method. However, both
methods have limits, which need to be improved to be applied as working models.
7.3.2 3D Printed Polymers for Bone Regeneration, Dental
Implants, and Maxillofacial, Oral
and Orthognathic Surgeries
Recent advances in the field of 3D imaging by cone-beam computed tomography
(CBCT) in dentistry have allowed more accurate treatment planning. 3D printed
polymeric models for surgical planning based on CT data were first obtained, almost
30 years ago, using STL technology. Since then, RP polymers have been widely
used to obtain surgical templates for the insertion of dental implants, models for
surgical planning, osteotomy/cutting guides, repositioning guides, spacers for
orthognathic surgery, among others (Lin et al. 2018).
The position of the prosthetically driven implant is of great importance in order
to achieve an esthetic and functional implant-supported restoration. Guided implant
surgery based on CBCT analysis and planning has been shown to be successful,
thus increasing the predictability of dental implants therapy. Upon planning, surgical templates can be manufactured from polymers and pre-polymerized blocks by
3D printing or milling. However, the former is more accurate than the latter
(Tahmaseb et al. 2014; Cristache and Gurbanescu 2017). In this context, Chen et al.
(2019) investigated the accuracy, reproducibility, and one-month stability of surgical templates fabricated using three different CAD-CAM additive techniques: direct
metal printing, PolyJet and STL. The last two with photopolymerized polymers and
the first with Co-Cr metal alloy. The highest precision and reproducibility were
obtained with the PolyJet technique even after 1 month (Chen et al. 2019).
Printing polymers models based on data acquired from CBCT allows adequate
pre-planning of complex cases and the fabrication of grafting parts before the procedure, thus shortening the surgical time and increasing the procedure predictability
(Barazanchi et al. 2017). Wang et al. (2018) proposed a technique for trimming
porous high-density poly(ethylene) (HDPE) as a long-lasting biomaterial for the
reconstruction of bone defects, to be used for the remodeling of the mandibular
contour, before surgery, with the help of a 3D printed surgical template.
Simulated models of the final treatment could be manufactured at a reduced cost,
helping patients understand the surgical strategy and visualize the result of the
C. M. Cristache and E. E. Totu
different models produced with different layer thickness: FDM (Makerbot Industries,
Brooklyn, USA – 100 μm), Polyjet printing (Stratasys, Eden Prairie, USA – 16 μm)
and STL (3D Systems, Rock Hill, USA – 50 μm), resulting in statistically significant differences between the plaster and three 3D printed models. The model manufactured by FDM was the closest replica to the plaster model, despite the greater
thickness of the layer (Rebong et al. 2018). Jeong et al. (2018) compared 3D printed
and milled PMMA models, and highlighted the superior accuracy of the 3D printing
method compared to materials produced by the milling method. However, both
methods have limits, which need to be improved to be applied as working models.
7.3.2 3D Printed Polymers for Bone Regeneration, Dental
Implants, and Maxillofacial, Oral
and Orthognathic Surgeries
Recent advances in the field of 3D imaging by cone-beam computed tomography
(CBCT) in dentistry have allowed more accurate treatment planning. 3D printed
polymeric models for surgical planning based on CT data were first obtained, almost
30 years ago, using STL technology. Since then, RP polymers have been widely
used to obtain surgical templates for the insertion of dental implants, models for
surgical planning, osteotomy/cutting guides, repositioning guides, spacers for
orthognathic surgery, among others (Lin et al. 2018).
The position of the prosthetically driven implant is of great importance in order
to achieve an esthetic and functional implant-supported restoration. Guided implant
surgery based on CBCT analysis and planning has been shown to be successful,
thus increasing the predictability of dental implants therapy. Upon planning, surgical templates can be manufactured from polymers and pre-polymerized blocks by
3D printing or milling. However, the former is more accurate than the latter
(Tahmaseb et al. 2014; Cristache and Gurbanescu 2017). In this context, Chen et al.
(2019) investigated the accuracy, reproducibility, and one-month stability of surgical templates fabricated using three different CAD-CAM additive techniques: direct
metal printing, PolyJet and STL. The last two with photopolymerized polymers and
the first with Co-Cr metal alloy. The highest precision and reproducibility were
obtained with the PolyJet technique even after 1 month (Chen et al. 2019).
Printing polymers models based on data acquired from CBCT allows adequate
pre-planning of complex cases and the fabrication of grafting parts before the procedure, thus shortening the surgical time and increasing the procedure predictability
(Barazanchi et al. 2017). Wang et al. (2018) proposed a technique for trimming
porous high-density poly(ethylene) (HDPE) as a long-lasting biomaterial for the
reconstruction of bone defects, to be used for the remodeling of the mandibular
contour, before surgery, with the help of a 3D printed surgical template.
Simulated models of the final treatment could be manufactured at a reduced cost,
helping patients understand the surgical strategy and visualize the result of the
C. M. Cristache and E. E. Totu