Background The mandible is a functional bio-organ that supports facial structures and helps mastication and speaking. Large mandible defects, generally greater than 6-cm segment loss, may require composite tissue reconstruction such as osteocutaneous-vascularized free flap which has a limitation of additional surgery and a functional morbidity at the donor site. A 3D bio-printing technology is recently developed to overcome the limitation in the composite reconstruction of the mandible using osteocutaneous-vascularized free flap. Review Scaffold, cells, and bioactive molecules are essential for a 3D bio-printing. For mandibular reconstruction, materials in a 3D bio-printing require mechanical strength, resilience, and biocompatibility. Recently, an integrated tissue and organ printing system with multiple cartridges are designed and it is capable of printing polymers to reinforce the printed structure, such as hydrogel. Conclusion For successful composite tissue reconstruction of the mandible, biologic considerations and components should be presented with a comprehensive on-demand online platform model of customized approaches.

Background Magnesium alloys have been receiving much attention for use in biodegradable metal implants because of their excellent mechanical properties and biocompatibility. However, their rapid breakdown and low bioactivity can cause the implant to lose mechanical integrity before the bone is completely healed. Moreover, hydrogen gas released during degradation can significantly delay the tissue regeneration process. To solve the instability of magnesium alloys, Zn and Ca can be added to improve the mechanical properties and biocompatibility. One other way to improve the mechanical properties of Mg is plasma electrolytic oxidation (PEO), which provides a dense, thick ceramic-like coating on the Mg surface. In this study, high-purity Mg was selected as the control, and Mg-1wt%Zn-0.1wt%Ca alloy and PEO-treated Mg-1wt%Zn-0.1wt%Ca alloy were selected as the test materials; the results of radiographic and histological analyses of their biocompatibility are reported herein. Materials and method Nineteen New Zealand white rabbits were used in the study. Rod-bars (Ø2.7 × 13.6 mm) were placed on both paravertebral muscles, and cannulated screws (Ø2.7x10mm) were placed on both femur condyle notches. Each animal was implanted in all four sites. X-rays were taken at 0, 2, 4, 8, and 12 weeks, micro-CT, and live-CT were taken at 4, 8, and 12 weeks. At weeks 4, 8, and 12, individuals representing each group were selected and sacrificed to prepare specimens for histopathological examination. Result The results confirm that in vivo, Mg-1wt%Zn-0.1wt%Ca alloy had higher corrosion resistance than high-purity Mg and safely degraded over time without causing possible side effects (foreign body or inflammatory reactions, etc.). In addition, PEO treatment of Mg-1wt%Zn-0.1wt%Ca alloy had a positive effect on fracture recovery by increasing the bonding area with bone. Conclusion Our results suggest that PEO treatment of Mg-1wt%Zn-0.1wt%Ca alloy can be a promising biomaterials in the field of various clinical situations such as orthopedic and maxillofacial surgerys.

Background: There are many different techniques to achieve intermaxillary fixation (IMF) for open reduction of mandible fractures. The arch bar has long been used as the gold standard of IMF to assist open reduction. However, owing to its long operating time, risk of needle stick injury, and gingival trauma, surgeons looked into different treatment options for IMF, such as the skeletal anchorage system (SAS). Therefore, this study aimed to compare the stability between IMF with arch bar and IMF with SAS based on computed tomography image. Materials and Methods: In this retrospective study, postoperative computed tomography and panoramic radiographs were taken 1 week and 6 months after surgery, respectively. The treatment of mandibular fractures using IMF with arch bar and SAS were compared by evaluating changes in the dental midlines and condyle positions. Thirty patients with mandibular fractures were enrolled into 2 groups-IMF with arch bar and IMF with SAS. Results: The arch bar showed slightly more deviation in dental midline. In SAS, the condyle moved more medially compared with the arch bar. Conclusions: Skeletal anchorage system could be used for IMF with reliable stability in mandible fracture. There were no significant differences in the treatment outcome between the 2 groups.