3D BIOPRINTING IN ORAL AND PERIODONTAL TISSUES
MATERIALS FOR 3D PRINTING OF SCAFFOLDS AND CRANIOFACIAL TISSUES
POLYMERS AND HYDROGELS
Polymer hydrogels are an ideal choice for the improvement of printable materials for tissue building. Hydrogels exhibit remarkable capacity of rheological, mechanical, substance, and organic properties; high biocompatibility; and comparability to local ECM (Annabi et al. 2014). Engineered polymers are probably material of choice most usually utilized for 3D imprinting in biomedical applications (Woodruff and Hutmacher 2010). High temperature leads to a reduction in cell viability and bioactivity and due to this direct incorporation is avoided. (Hutmacher et al. 2004) . Hydrogels are fundamentally utilized for tissue designing 3D printed artistic platforms, cells have a tendency to rapidly populate the framework surface, subsequently building up a closed cell to cell cooperations and differentiation. Ceramics are much-lowered rates of degradation when compared to hydrogels which helps in structural and tissue remodeling. The main disadvantage of ceramic scaffolds is too brittle.
Fused deposition of ceramics(FDC) generally consists of extruding mixture of inorganic particles. It includes three steps,
1. Mixture stage, bioceramic particles are mixed with a solvent with organic surfactant(binder)to obtain good flow. which includes the arrangement of the slurry. The bioceramic particles are blended in a dissolvable (fluid or nonaqueous) with a low convergence of natural polymers/surfactants, called the fastener, to acquire satisfactory flowability.
2. Green ceramic and binder burnout stage involves deposition of filament mixture in the predetermined structure before drying and burnout. including the statement of fibers of slurry following a foreordained example preceding drying and introduction to a high temperature to wear out the natural segment of the blend.
3. Sintering stage involves exposure of green form to high temperature(greater than 1000 C)for migration of atom to form "necks."
By adjusting the viscosity of mixture vapourization of the solvent, shape retention of the strut can be controlled in 3D rapid prototyped bioceramics. (Morissette and Lewis 2000).
THREE-DIMENSIONAL PRINTING APPLIED TO CRANIOFACIAL REGENERATION
BONE
FDM scaffolds are usually suited for high load bearing areas. Polycaprolactone FDM plugs were used for alveolar preservation with reasonable success. Cylindrical scaffolds of polycaprolactone incorporating 20%of tricalcium phosphate synthesized by FDM. These filaments are 300 mm in diameter with 0° to 90° separated by 1200 mm thus maintaining 70% porosity with 22.2Mpa of elastic modulus. Goh et al. (2015), When these scaffolds were added with RH-BMP 7 and implanted in bone defects in a sheep model results were encouraging and bone formation was superior compared to autologous bone graft (Reichert et al. 2012)
PERIODONTAL COMPLEX
The multiphasic construct is capable of capitulating various compartments of the periodontal complex. In this one approach, involves biphasic scaffolds consisting of FDM compartment to promote bone formation and solution electrospun membrane. These scaffolds were modified by adding a layer of calcium phosphate onto the FDM bone compartment favoring neovascularization of the periodontal complex. These modifications significantly increase bone formation and allowed the attachment of functionally oriented periodontal ligament fibers. .Further advancement involving in the customization of biphasic construct obtained by CAD-CAM technology.These construct with aligned microchannels along the surface of periodontal complex results in good periodontal fiber angulation. (Lee et al.2014).developed a triphasic scaffold using 3D printing by adjusting pore size, shape, the porosity of different compartments that leads to the growth of cementum-like tissues, periodontal fibers, and bone.
WHOLE TOOTH REGENERATION
An early prototype of 3D printed structures replicating anatomy of the tooth using composite ink of polycaprolactone and hydroxyapatite have bee tested (Kim et al. 2010). Cell aggregates mimicking the epithelial-mesenchymal interface is the fundamental step in the whole tooth regeneration. (Nakao et al. 2007; Ikeda et al. 2009; Zhang et al. 2010).Size and positioning of the cell aggregates is the important factor in the development of tooth germ as well as the growth of cusp in the tooth. Along these lines, the mission for the controlled on-request arrangement of designed teeth may extraordinarily profit by 3D printing
CONCLUSION
Though,3D printing shows promising results it has to go long way for the regeneration for periodontal complex and tooth.
REFERENCES
Annabi N, Tamayol A, Uquillas JA, Akbari M, Bertassoni LE, Cha C, Camci-Unal G, Dokmeci MR, Peppas NA, Khademhosseini A. 2014. 25th Anniversary article: rational design and applications of hydrogels in regenerative medicine. Adv Mater. 26(1):85–123.
Bajaj P, Schweller RM, Khademhosseini A, West JL, Bashir R. 2014. 3D biofabrication strategies for tissue engineering and regenerative medicine. Annu Rev Biomed Eng. 16:247–276
Bakarich SE, Gorkin R III, in het Panhuis M, Spinks GM. 2014. Three-dimensional printing fiber reinforced hydrogel composites. ACS Appl Mater Interfaces. 6(18):15998–16006.
Barron JA, Wu P, Ladouceur HD, Ringeisen BR. 2004. Biological laser printing: a novel technique for creating heterogeneous 3-dimensional cell patterns. Biomed Microdevices. 6(2):139–147.
Bertassoni LE. 2015. Bioprinting of human organs. Australasian Science. April:34–35. Bertassoni LE, Cardoso JC, Manoharan V, Cristino AL, Bhise NS, Araujo WA, Zorlutuna P, Vrana NE, Ghaemmaghami AM, Dokmeci MR, et al. 2014. Direct-write bioprinting of cell-laden methacrylated gelatin hydrogels. Biofabrication. 6(2):024105.
