Functionally graded membrane deposited with PDLLA nanofibers encapsulating doxycycline and enamel matrix derivatives-loaded chitosan nanospheres for alveolar ridge regeneration.

Functionally graded membranes (FGM) with regenerative signals and nanofibrous topography mimicking the native extracellular matrix have been shown to improve the outcome of alveolar ridge regeneration (ARR). This study developed a novel FGM with doxycycline-enamel matrix derivative (EMD) nanofibrous composites deposition to coordinate anti-inflammation and differentiation signals, thus facilitating ARR. Doxycycline-loaded PDLLA nanofibers (PD), EMD-loaded chitosan nanospheres (CE), and CE-embedded PD (CE-PD) were fabricated by electrospinning, deposited on the surfaces of barrier membrane to develop a FGM, and the efficacy was validated by delivering the FGM to regenerate experimental alveolar ridge defects in rats. Results revealed that PD had potent antibacterial capability, and CE-PD allowed sustained release of EMD to promote osteogenesis in vitro. In the alveolar ridge defects, FGM with PD on the outer surface downregulated MMP-8, and wound dehiscence was further reduced with Cbfa1 upregulation in those treated by FGM with CE-PD on the inner surface at 1 week. FGM with CE-PD revealed significantly greater new bone formation and defect fill at 4 weeks. In conclusion, FGM with PD reduced early tissue breakdown and with CE-PD nanofibrous composites accelerated wound healing and facilitated osteogenesis, and thus could be an advantageous strategy for ARR.

Characterization of the stemness and osteogenic potential of oral and sinus mucosal cells.

BACKGROUND/PURPOSE: Covering the wounds from guided bone regeneration and sinus floor elevation with oral and sinus mucosa is a fundamental criterion for success. This study aimed to verify the regeneration capability of the mucosal connective tissue stromal cells by characterizing their stemness and osteogenic potentials. METHODS: Bone marrow stromal cells (BMSCs), alveolar mucosa cells (AMCs), keratinized gingival cells (KGCs), and sinus mucosal cells (SMCs), were isolated from four Sprague-Dawley rats. The morphology and viability of the cells were investigated under a confocal microscope and by Alamar Blue. Stem cell surface markers were evaluated by flow cytometry. Expressions of pluripotent factors after initial seeding and an early osteogenic gene following 24 h of osteoinduction were evaluated by realtime PCR. Trilineage differentiation capability in long-term inductive cell culture was assessed by Alizarin Red, Alcian Blue, and Oil Red O staining. RESULTS: BMSCs and AMCs were larger cells with smaller aspect ratios relative to KGCs and SMCs, and BMSCs revealed the greatest initial viability but the slowest proliferation. More than 94% of BMSCs, AMCs, and KGCs were double-positive for CD73 and CD90. Compared with BMSCs, AMCs expressed significantly higher Oct4 but reduced Cbfa1 after initial seeding, and AMCs and SMCs expressed significantly higher Cbfa1 following 24 h of osteoinduction. In long-term inductive cell culture, osteogenesis was observed in BMSCs, AMCs, and SMCs, chondrogenesis was observed in BMSCs, AMCs, and KGCs, and adipogenesis was evident in only BMSCs. CONCLUSION: AMCs contain a high percentage of stem/progenitor cells and show differentiation capability toward osteogenic lineage.

The treatment response of barrier membrane with amoxicillin-loaded nanofibers in experimental periodontitis.

BACKGROUND: Infection control is a major determinant of guided tissue regeneration (GTR). This study aims to develop an antibiotic-loaded membrane to assist periodontal repair. METHODS: Poly(D,L-lactic acid) (PDLLA) nanofibers encapsulating amoxicillin (PDLLA-AMX) were fabricated using the electrospinning technique, and their structures, drug encapsulation efficiency, and release characteristics were assessed. The viability and behaviors of periodontal ligament (PDL) cells on nanofibers, and antibacterial capabilities of nanofibers were evaluated in vitro. Early therapeutic efficiency of the antibiotic-loaded membranes was investigated in rats with ligature-induced experimental periodontitis, and the outcomes were evaluated by gene expression, microcomputed tomography imaging, and histology within 7 days of membrane placement. RESULTS: AMX was successfully encapsulated in the PDLLA nanofibers and released in a sustained manner. After initial attachment was achieved, cells stretched out along with the directions of nanofibers. The viability and expression of migration-associated gene of PDL cells were significantly improved, and the growth of Streptococcus sanguinis and Porphyromonas gingivalis was significantly reduced in the PDLLA-AMX group compared with the controls. On PDLLA-AMX-treated sites, wound dehiscence and sulcular inflammation were reduced. Collagen fiber matrix deposition was accelerated with upregulated type I collagen and interleukin-1ß, and downregulated matrix metalloproteinase-8, whereas periodontal bone level and the expressions of vascular endothelial growth factor and core-binding factor subunit alpha-1 were equivalent to conventional membrane treatment. CONCLUSIONS: PDLLA-AMX nanofibers inhibited bacterial growth and promoted the viability and mobility of PDL cells after initial cell attachment. Membranes with PDLLA-AMX nanofibers reduced inflammation and accelerated periodontal repair at an early stage, providing good prospects for the further development of GTR membranes.

Preclinical evaluation of a 3D-printed hydroxyapatite/poly(lactic-co-glycolic acid) scaffold for ridge augmentation.

BACKGROUND/PURPOSE: Supracrestal ridge augmentation (SRA) is a major challenge for clinicians. This study investigated the efficacy of a 3D-printed (3DP) hydroxyapatite/poly(lactic-co-glycolic acid) (HA/PLGA) scaffold as a potential biologic for SRA. METHODS: Scaffolds that were 5 mm in diameter and 2.5-mm thick with a 1.2-mm diameter through-and-through central hole composed of 90% HA and 10% PLGA were printed using an extrusion-based bioprinter. The HA/PLGA scaffold was fixed with a 1.2-mm titanium mini-implant on the buccal surface of rat mandible (Ti-HPS), and the outcome of SRA were compared with sites treated with a titanium mini-implant alone (control) and a titanium mini-implant covered with deproteinized bovine bone-derived matrix (Ti-DBBM) at 4 and 8 weeks by microcomputed tomography (micro-CT), back-scattered SEM, and histology assessments. RESULTS: The HA/PLGA scaffolds were 2.486 ± 0.082 mm thick with an outer diameter of 4.543 ± 0.057 mm and an inner diameter of 1.089 ± 0.045 mm, and the pore dimensions were 0.48-0.52 mm. There was significantly more mineralized tissue in the Ti-DBBM and Ti-HPS groups than in the control group at both time points. Newly formed bone (NB) was well-integrated with the DBBM and HA/PLGA scaffolds. The framework of the 3DP-HA/PLGA scaffold remained in place, and NB-implant contact (NBIC) was advanced to the middle level in the Ti-HPS group until 8 weeks, whereas dispersion of DBBM with a lower level NBIC was noted in the Ti-DBBM group at both time points. CONCLUSION: The 3DP HA/PLGA scaffold maintains supracrestal space and demonstrates osteoconductivity to facilitate SRA.

Regeneration of critical-sized mandibular defect using a 3D-printed hydroxyapatite-based scaffold: An exploratory study.

BACKGROUND: Three-dimensional (3D) printing has become an available technology to fabricate customized tissue engineering scaffolds with delicate architecture. This exploratory study aimed to evaluate the potential of a 3D-printed hydroxyapatite-based scaffold as a biomaterial for obtaining guided bone regeneration (GBR) in vivo. METHODS: Scaffolds composed of 90% hydroxyapatite and 10% poly(lactic-co-glycolic acid) were printed using a microextrusion process to fit 4 mm diameter and 0.5 mm thick through-and-through osseous defects on the mandibular ramus of rats, with unfilled defects serving as controls. Specimens were analyzed for regeneration-associated gene expression on day 7, and micro-computed tomography (micro-CT) and histology assessments were carried out on day 28. RESULTS: The scaffolds were 3.56 ± 0.43 mm (x-axis) and 4.02 ± 0.44 mm (y-axis) in diameter and 0.542 ± 0.035 mm thick (z-axis), with a mean pore size of 0.420 ± 0.028 × 0.328 ± 0.005 mm2 . Most scaffolds fit the defects well. Type I collagen, VEGF, and Cbfa1 were upregulated in the scaffold-treated defects by day 7. By day 28, de novo osteogenesis and scaffold-tissue integration were evident in the scaffold-treated defects, and entire mineralized tissue, as well as newly formed bone, was significantly promoted, as seen in the micro-CT and histologic analyses. CONCLUSION: The 3D-printed hydroxyapatite-based scaffold showed acceptable dimensional stability and demonstrated favorable osteoregenerative capability that fulfilled the need for GBR.