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Cunico

Figure 8. Flexural strength of the proposed method and typical dental prosthesis [3,17,28-37] .

no layer marks, as the sintering process merged powder
grain and created object superficial tension which inhibits
the occurrence of mold layer marks. In addition, it is also
known that after the fabrication of the dental prosthesis,
the typical dental applications (CAD/CAM, slip casting,
etc.) are coupled with several stages of finishing and
making-up that improve the esthetic appearance of the
prosthesis so that they mimic the original human dent .
[38]
Therefore, the geometrical characteristics, mechanical
properties, and biocompatibility are the most important
aspects to be considered in this type of application.
Despite the preliminary results on the feasibility of the
proposed method, further studies are still needed to
improve mechanical strength, diversify the glass-ceramic
Figure 9. ZrSiO4-glass composite-based prosthetic crowns materials, applications, and biocompatibility.
fabricated by indirect fused deposition modeling collapsible tool.
The crown on the left side is of high grain densification with no 4. Conclusions
finishing and the crown on the right side is of low grain densification
with no finishing. Collectively, this study assessed the feasibility of the
glass-ceramic fabrication based on collapsible AM mold
that are comparable to the typical dental applications. of ZrSiO . The working proof generates new perspectives
4
Therefore, further studies might increase the flexural to AM in dentistry, ceramics, and medical applications,
strength up to the level of slip casting strength. It is whereas collapsible AM molds, such as we method used
also important to note that the volumetric shrinkage for in this study, can support fabrication up to 2300°C.
This study also identified that the holding
typical CAD/CAM dental application varies from 5 to temperature is the factor that mostly influences the
30% [3,4,17,27] . Therefore, the range of values found in this feasibility, strength, and shrinkage, followed by holding
work (13 – 25%) is compatible with the current state of time which directly affects the material densification
art, indicating potential application in the field. and grain growth. Besides, long time periods and high
This concept has been shown to work and open temperatures increase the densification and soften the
a new possibility to fabricate glass-ceramic materials material, leading to distorted geometry, and making the
by AM technologies using collapsible ceramic mold, method unfeasible. On the other hand, flexural strength
as presented in Figure 9. In this figure, two prosthetic fluctuates between 25 and 82 MPa and can be highly
crowns with no finishing were presented. The left-side affected by heating rate and cooling rate. Further studies
crown presents high grain densification while the right- are required to investigate the role of heating treatments
side crown with low grain densification. Both crowns have and increase mechanical and geometrical properties, as

International Journal of Bioprinting (2021)–Volume 7, Issue 1 97