3D-printed polycaprolactone scaffolds coated with beta tricalcium phosphate for bone regeneration.

BACKGROUND/PURPOSE: 3D-printing technology is an important tool for the bone tissue engineering (BTE). The aim of this study was to investigate the interaction of polycaprolactone (PCL) scaffolds and modified mesh PCL coated with beta TCP (PCL/ß-TCP) scaffolds with MG-63. METHODS: This study used the fused deposition modeling (FDM) technique with the 3D printing technique to fabricate the thermoplastic polymer and composite scaffolds. Scaffold structure and coating quality were observed under a scanning electron microscope (SEM). MG-63 cells were injected and attached to the mesh-manufactured PCL scaffolds. The biocompatibility of mesh structured PCL and PCL/ß-TCP scaffolds could be examined by measuring the viability of MG-63 cells of MTT assay. Bone cell differentiation was evaluated ALP activity by mineralization assay. RESULTS: The results showed that both mesh PCL scaffolds and PCL/ß-TCP scaffolds were non-toxic to the cells. The ALP activities of cells in PCL/ß-TCP scaffolds groups were significant differences and better than PCL groups in all groups at all experimental dates. The mineralization process was time-dependent, and significantly higher mineralization of osteosarcoma cells was observed on PCL/ß-TCP scaffolds at experimental dates. CONCLUSION: We concluded that both meshes structured PCL and PCL/ß-TCP scaffolds could promote the MG-63 cell growth, and PCL/ß-TCP was better than the PCL scaffolds for the outcome of MG63 cell differentiation and mineralization.

Efficacy of polyacrylate silver salt/polyvinylpyrrolidone-based liquid oral gel in management of concurrence chemoradiotherapy-induced oral mucositis.

BACKGROUND/PURPOSE: Acute oral mucositis (OM) is a painful complication of concurrent chemoradiotherapy (CCRT). This severe adverse symptom may impact on patient's quality of life, lead to malnutrition. Thus, finding more effective methods in OM management is very important. The purpose of this study is to evaluate the efficacy of polyacrylate silver salt/Polyvinylpyrrolidone-based liquid oral gel (named as polyacrylate silver salt oral gel) in improving the symptomatic relief of CCRT-induced oral mucositis and oral dysfunction in neck and head cancer patients. METHODS: In this study, 24 oral cancer patients underwent CCRT and having OM grade 2 or higher were randomly assigned into the test group and the control group. Both groups followed Multinational Association of Supportive Care in Cancer and International Society of Oral Oncology (MASCC/ISOO) clinical practice guidelines for the management of mucositis, but adding rinsing with 15 g oral gel right after oral hygiene treaded the test group. Clinical OM and oral function were assessed weekly for 4 consecutive weeks till 5-10 days after the completion of radiotherapy. For evaluation, Common Terminology Criteria for Adverse Events (CTCAE) v3.0 was used for collecting the data of OM grade. RESULTS: The results showed that polyacrylate silver salt oral gel had better effect for relieving the oral mucositis. There were statistically significant differences in OM grades (1.59 vs. 2.8, p < 0.0001) between the test group and the control group. CONCLUSION: Our clinical studies demonstrated that polyacrylate silver salt oral gel is an effective interventional option in terms of rapid mucositis healing.

Challenge Tooth Regeneration in Adult Dogs with Dental Pulp Stem Cells on 3D-Printed Hydroxyapatite/Polylactic Acid Scaffolds.

Tooth regeneration is an important issue. The purpose of this study was to explore the feasibility of using adult dental pulp stem cells on polylactic acid scaffolds for tooth regeneration. Three teeth were extracted from each side of the lower jaws of two adult dogs. In the experimental group, dental pulp stem cells were isolated and seeded in the 3D-printed hydroxyapatite/polylactic acid (HA/PLA) scaffolds for transplantation into left lower jaw of each dog. The right-side jaw of each dog was transplanted with cell-free scaffolds as the control group. Polychrome sequentially labeling was performed for observation of mineralization. Dental cone beam computed tomography (CBCT) irradiation was used for assessment. Nine months after surgery, dogs were euthanized, and the lower jaws of dogs were sectioned and fixed for histological observation with hematoxylin and eosin staining. The results showed that the degree of mineralization in the experimental group with cells seeded in the scaffolds was significantly higher than that of the control group transplanted with cell-free scaffolds. However, the HA/PLA scaffolds were not completely absorbed in both groups. It is concluded that dental pulp stem cells are important for the mineralization of tooth regeneration. A more rapid absorbable material was required for scaffold design for tooth regeneration.

Biphenyl liquid crystalline epoxy resin as a low-shrinkage resin-based dental restorative nanocomposite.

Low-shrinkage resin-based photocurable liquid crystalline epoxy nanocomposite has been investigated with regard to its application as a dental restoration material. The nanocomposite consists of an organic matrix and an inorganic reinforcing filler. The organic matrix is made of liquid crystalline biphenyl epoxy resin (BP), an epoxy resin consisting of cyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (ECH), the photoinitiator 4-octylphenyl phenyliodonium hexafluoroantimonate and the photosensitizer champhorquinone. The inorganic filler is silica nanoparticles (∼70-100 nm). The nanoparticles were modified by an epoxy silane of γ-glycidoxypropyltrimethoxysilane to be compatible with the organic matrix and to chemically bond with the organic matrix after photo curing. By incorporating the BP liquid crystalline (LC) epoxy resin into conventional ECH epoxy resin, the nanocomposite has improved hardness, flexural modulus, water absorption and coefficient of thermal expansion. Although the incorporation of silica filler may dilute the reinforcing effect of crystalline BP, a high silica filler content (∼42 vol.%) was found to increase the physical and chemical properties of the nanocomposite due to the formation of unique microstructures. The microstructure of nanoparticle embedded layers was observed in the nanocomposite using scanning and transmission electron microscopy. This unique microstructure indicates that the crystalline BP and nanoparticles support each other and result in outstanding mechanical properties. The crystalline BP in the LC epoxy resin-based nanocomposite was partially melted during exothermic photopolymerization, and the resin expanded via an order-to-disorder transition. Thus, the post-gelation shrinkage of the LC epoxy resin-based nanocomposite is greatly reduced, ∼50.6% less than in commercialized methacrylate resin-based composites. This LC epoxy nanocomposite demonstrates good physical and chemical properties and good biocompatibility, comparable to commercialized composites. The results indicate that this novel LC nanocomposite is worthy of development and has potential for further applications in clinical dentistry.

Regeneration of dentin-pulp complex with cementum and periodontal ligament formation using dental bud cells in gelatin-chondroitin-hyaluronan tri-copolymer scaffold in swine.

The purpose of this study is to use a tissue engineering approach for tooth regeneration. The swine dental bud cells (DBCs) were isolated from the developing mandibular teeth, expanded in vitro, and cultured onto cylinder scaffold gelatin-chrondroitin-hyaluronan-tri-copolymer (GCHT). After culturing in vitro, the DBCs/GCHT scaffold was autografted back into the original alveolar socket. Hematoxylin and eosin (H&E) staining combined with immunohistochemical staining were applied for identification of regenerated tooth structure. After 36-week post-transplantation, tooth-like structures, including well-organized dentin-pulp complex, cementum, and periodontal ligament, were evident in situ in two of six experimental animals. The size of the tooth structure (1 x 0.5 x 0.5 cm(3) and 0.5 x 0.5 x 0.5 cm(3) size) appeared to be dictated by the size of the GCHT scaffold (1 x 1 x 1.5 cm(3)). The third swine was demonstrated with irregular dentin-bony like calcified tissue about 1 cm in diameter without organized tooth or periodontal ligament formation. The other three swine in the experimental group showed normal bone formation and no tooth regeneration in the transplantation sites. The successful rate of tooth regeneration from DBCs/GCHT scaffolds' was about 33.3%. In the control group, three swine's molar teeth buds were removed without DBCs/GCHT implantation, the other three swine received GCHT scaffold implants without DBCs. After evaluation, no regenerated tooth was found in the transplantation site of the control group. The current results using DBSs/GCHT scaffold autotransplantation suggest a technical breakthrough for tooth regeneration.