296
Silicone could be considered as one of those reduced options for materials. Plastics
and metal structures with complex features could be fabricated by 3D manufacturing by extrusion process. The thermoplastic polymers could also be manufactured
by initial hot melt extrusion, followed by cooling, and final solidification process,
thus leading to target shape of the structure (Roh et al. 2017).
3D printing of elastomeric polymers such as PDMS compared to thermoplastic
materials is more difficult since the precursors of elastomeric polymers are liquid.
In addition, silicone printing is technically complex since it needs to be heated or a
special curing process must be applied. Moreover, post-curing may require UV curing agents (Roh et al. 2017; Jindal et al. 2018; Unkovskiy et al. 2018).
The conventional fabrication process of a maxillofacial prosthesis is challenging
and requires complex laboratory procedures and the final step depends on the
prosthodontist’s artistic abilities (Cevik and Yildirim-Bicer 2017). The first step in
the manufacturing process is to make the conventional impression of the defect site,
then hand sculpt with dental wax, thus creating molds, and the final step is silicone
curing and intrinsic and extrinsic coloration (Jindal et al. 2016).
Recently, new technologies are used to capture digital images of the non-defect
site and the duplication of this site that leads to design a prosthesis digitally without
the use of conventional printing technique. In this regard, optical surface laser scanners or computerize tomography (CT) images are commercially available to obtain
a digital impression of the defect site (Karayazgan-Saracoglu et al. 2009; Watson
and Hatamleh 2014). In this regard, 3D surface data could be design by computeraided design (CAD) software and the data can be printed on metal, plastic, resin or
other hard materials which are not suitable for direct fabrication of a maxillofacial
prosthesis (Jindal et al. 2018). In addition, the coloration of the maxillofacial prosthesis is the most difficult problem to obtain acceptable aesthetic results. With this
in mind, an intrinsic coloring kit has been used to obtain the basic color of the prosthesis (Hu et al. 2014). Then, the extrinsic coloration has been adjusted to obtain the
final color of the silicone. On the negative side, intrinsic coloring agents can jeopardize the mechanical strength of the silicone rubber, while the extrinsic color is more
likely to change in response to moisture, heat or UV radiation (Hu et al. 2014).
Therefore, the coloring process is one of the most challenging processes in the manufacture of a maxillofacial prosthesis.
Anatomic molds, such as negative and the positive molds, can be manufactured
by 3D printing to be used as a mold for additional silicone prostheses (Jindal et al.
2016, 2018). In the current digital workflow of a maxillofacial prosthesis it consists
of digital printing of the healthy site and obtaining the image reflected for the defect
site and the manufacturing of the molds. Other processes consist of the conventional
manufacturing of the silicone prosthesis. The most challenging problem is the manufacture of direct printing of maxillofacial silicone prostheses. Therefore, the recent
research relies on the direct silicone printing by eliminating the conventional laboratory processes (Jindal et al. 2016, 2018; Roh et al. 2017; Unkovskiy et al. 2018).
Unkovskiy et al. (2018) reported an early application of a directly printed a silicone nasal prosthesis. The authors showed that the marginal integrity of the printed
silicone prosthesis was lacking in some areas because of the scantiness in the
P. Cevik
Silicone could be considered as one of those reduced options for materials. Plastics
and metal structures with complex features could be fabricated by 3D manufacturing by extrusion process. The thermoplastic polymers could also be manufactured
by initial hot melt extrusion, followed by cooling, and final solidification process,
thus leading to target shape of the structure (Roh et al. 2017).
3D printing of elastomeric polymers such as PDMS compared to thermoplastic
materials is more difficult since the precursors of elastomeric polymers are liquid.
In addition, silicone printing is technically complex since it needs to be heated or a
special curing process must be applied. Moreover, post-curing may require UV curing agents (Roh et al. 2017; Jindal et al. 2018; Unkovskiy et al. 2018).
The conventional fabrication process of a maxillofacial prosthesis is challenging
and requires complex laboratory procedures and the final step depends on the
prosthodontist’s artistic abilities (Cevik and Yildirim-Bicer 2017). The first step in
the manufacturing process is to make the conventional impression of the defect site,
then hand sculpt with dental wax, thus creating molds, and the final step is silicone
curing and intrinsic and extrinsic coloration (Jindal et al. 2016).
Recently, new technologies are used to capture digital images of the non-defect
site and the duplication of this site that leads to design a prosthesis digitally without
the use of conventional printing technique. In this regard, optical surface laser scanners or computerize tomography (CT) images are commercially available to obtain
a digital impression of the defect site (Karayazgan-Saracoglu et al. 2009; Watson
and Hatamleh 2014). In this regard, 3D surface data could be design by computeraided design (CAD) software and the data can be printed on metal, plastic, resin or
other hard materials which are not suitable for direct fabrication of a maxillofacial
prosthesis (Jindal et al. 2018). In addition, the coloration of the maxillofacial prosthesis is the most difficult problem to obtain acceptable aesthetic results. With this
in mind, an intrinsic coloring kit has been used to obtain the basic color of the prosthesis (Hu et al. 2014). Then, the extrinsic coloration has been adjusted to obtain the
final color of the silicone. On the negative side, intrinsic coloring agents can jeopardize the mechanical strength of the silicone rubber, while the extrinsic color is more
likely to change in response to moisture, heat or UV radiation (Hu et al. 2014).
Therefore, the coloring process is one of the most challenging processes in the manufacture of a maxillofacial prosthesis.
Anatomic molds, such as negative and the positive molds, can be manufactured
by 3D printing to be used as a mold for additional silicone prostheses (Jindal et al.
2016, 2018). In the current digital workflow of a maxillofacial prosthesis it consists
of digital printing of the healthy site and obtaining the image reflected for the defect
site and the manufacturing of the molds. Other processes consist of the conventional
manufacturing of the silicone prosthesis. The most challenging problem is the manufacture of direct printing of maxillofacial silicone prostheses. Therefore, the recent
research relies on the direct silicone printing by eliminating the conventional laboratory processes (Jindal et al. 2016, 2018; Roh et al. 2017; Unkovskiy et al. 2018).
Unkovskiy et al. (2018) reported an early application of a directly printed a silicone nasal prosthesis. The authors showed that the marginal integrity of the printed
silicone prosthesis was lacking in some areas because of the scantiness in the
P. Cevik