Table 2.

Comparison of different techniques (listed in alphabetical order) for the fabrication of bioceramic scaffolds (non-composite) on the basis of their advantages and disadvantages.

Technique	Advantages	Disadvantages	Reference
Foaming methods (general)	Allows manufacturing of both closed and open-cell foams; good versatility of final part shapes, as the solution can be cast in molds without additional machining	Difficulty in achieving high interconnectivity; non-porous external surface	Jones and Hench (2003) and Colombo (2006)
H2O2 foaming	Simple	Low porosity control laminar pore structure with poor 3-D interconnection	Li et al. (2002) and Navarro et al. (2004)
Sol–gel foaming	Hierarchical structure can be obtained (macroporous scaffold combined with ordered mesoporous texture)	Need for a high degree of control of the foam	Akkus et al. (2002) and Jones and Hench (2004)
In situ polymerization of organic monomer (gel-cast foaming)	Highly porous ceramic; high-strength properties due to the less flawed structure and dense struts and walls produced	Low pore interconnectivity	Sepulveda and Binner (1999), Ortega et al. (2002), Ramay and Zhang (2003), and Wu et al. (2011b)
Organic phase burning-out/space holder	High mechanical strength	Difficult to obtain a homogeneous distribution of pores; poor interconnectivity	Baino et al. (2009) and Wu et al. (2009)
Solid freeform fabrication (SFF) (general)	Customized objects; reproducible	Costly; resolution needs to be improved to the micro-scale	Hollister (2005)
SLA	Complex internal features can be obtained	Only applicable using ceramic/photopolymer blends	Levy et al. (1997), Tesavibul et al. (2012), Scalera et al. (2014), and Sabree et al. (2015)
SLS	High accuracy; good mechanical strength; a broad range of materials can be processed	High temperatures during process; trapped powder is difficult to remove	Hutmacher et al. (2004)
3-D printing	Fast processing; no toxic components; water used as a binder; tunable mechanical properties	Trapped powder issue	Yun et al. (2007), Fu et al. (2011a,b), Garcia et al. (2011), Wu et al. (2011a), Bose et al. (2013), and Liu et al. (2013)
Sponge replication	Reticulated open-cell material; applicable to any ceramic material that can be dispersed into a suspension; no toxic chemicals needed	Mechanical properties might be poor	Chen et al. (2006), Zhu et al. (2008), Vitale-Brovarone et al. (2009), Zhu and Kaskel (2009), Wu et al. (2010), Baino et al. (2013), and Baino and Vitale-Brovarone (2014)
Starch consolidation	Environment-friendly; low-cost	Pores might be poorly interconnected	Lyckfeldt and Ferreira (1998) and Vitale-Brovarone et al. (2004, 2005)
Thermal bonding of short glass fibers	Simple; no need for any additional material except fibers and mold; glassy scaffolds can be obtained	Mechanical properties might be poor	Pirhonen et al. (2003), Moimas et al. (2006), Gu et al. (2013), and Tirkkonen et al. (2013)